Index: third_party/zlib/zlib.h |
=================================================================== |
--- third_party/zlib/zlib.h (revision 113739) |
+++ third_party/zlib/zlib.h (working copy) |
@@ -1,7 +1,7 @@ |
/* zlib.h -- interface of the 'zlib' general purpose compression library |
- version 1.2.3, July 18th, 2005 |
+ version 1.2.5, April 19th, 2010 |
- Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler |
+ Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler |
This software is provided 'as-is', without any express or implied |
warranty. In no event will the authors be held liable for any damages |
@@ -37,41 +37,44 @@ |
extern "C" { |
#endif |
-#define ZLIB_VERSION "1.2.3" |
-#define ZLIB_VERNUM 0x1230 |
+#define ZLIB_VERSION "1.2.5" |
+#define ZLIB_VERNUM 0x1250 |
+#define ZLIB_VER_MAJOR 1 |
+#define ZLIB_VER_MINOR 2 |
+#define ZLIB_VER_REVISION 5 |
+#define ZLIB_VER_SUBREVISION 0 |
/* |
- The 'zlib' compression library provides in-memory compression and |
- decompression functions, including integrity checks of the uncompressed |
- data. This version of the library supports only one compression method |
- (deflation) but other algorithms will be added later and will have the same |
- stream interface. |
+ The 'zlib' compression library provides in-memory compression and |
+ decompression functions, including integrity checks of the uncompressed data. |
+ This version of the library supports only one compression method (deflation) |
+ but other algorithms will be added later and will have the same stream |
+ interface. |
- Compression can be done in a single step if the buffers are large |
- enough (for example if an input file is mmap'ed), or can be done by |
- repeated calls of the compression function. In the latter case, the |
- application must provide more input and/or consume the output |
+ Compression can be done in a single step if the buffers are large enough, |
+ or can be done by repeated calls of the compression function. In the latter |
+ case, the application must provide more input and/or consume the output |
(providing more output space) before each call. |
- The compressed data format used by default by the in-memory functions is |
+ The compressed data format used by default by the in-memory functions is |
the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped |
around a deflate stream, which is itself documented in RFC 1951. |
- The library also supports reading and writing files in gzip (.gz) format |
+ The library also supports reading and writing files in gzip (.gz) format |
with an interface similar to that of stdio using the functions that start |
with "gz". The gzip format is different from the zlib format. gzip is a |
gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. |
- This library can optionally read and write gzip streams in memory as well. |
+ This library can optionally read and write gzip streams in memory as well. |
- The zlib format was designed to be compact and fast for use in memory |
+ The zlib format was designed to be compact and fast for use in memory |
and on communications channels. The gzip format was designed for single- |
file compression on file systems, has a larger header than zlib to maintain |
directory information, and uses a different, slower check method than zlib. |
- The library does not install any signal handler. The decoder checks |
- the consistency of the compressed data, so the library should never |
- crash even in case of corrupted input. |
+ The library does not install any signal handler. The decoder checks |
+ the consistency of the compressed data, so the library should never crash |
+ even in case of corrupted input. |
*/ |
typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); |
@@ -126,45 +129,45 @@ |
typedef gz_header FAR *gz_headerp; |
/* |
- The application must update next_in and avail_in when avail_in has |
- dropped to zero. It must update next_out and avail_out when avail_out |
- has dropped to zero. The application must initialize zalloc, zfree and |
- opaque before calling the init function. All other fields are set by the |
- compression library and must not be updated by the application. |
+ The application must update next_in and avail_in when avail_in has dropped |
+ to zero. It must update next_out and avail_out when avail_out has dropped |
+ to zero. The application must initialize zalloc, zfree and opaque before |
+ calling the init function. All other fields are set by the compression |
+ library and must not be updated by the application. |
- The opaque value provided by the application will be passed as the first |
- parameter for calls of zalloc and zfree. This can be useful for custom |
- memory management. The compression library attaches no meaning to the |
+ The opaque value provided by the application will be passed as the first |
+ parameter for calls of zalloc and zfree. This can be useful for custom |
+ memory management. The compression library attaches no meaning to the |
opaque value. |
- zalloc must return Z_NULL if there is not enough memory for the object. |
+ zalloc must return Z_NULL if there is not enough memory for the object. |
If zlib is used in a multi-threaded application, zalloc and zfree must be |
thread safe. |
- On 16-bit systems, the functions zalloc and zfree must be able to allocate |
- exactly 65536 bytes, but will not be required to allocate more than this |
- if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, |
- pointers returned by zalloc for objects of exactly 65536 bytes *must* |
- have their offset normalized to zero. The default allocation function |
- provided by this library ensures this (see zutil.c). To reduce memory |
- requirements and avoid any allocation of 64K objects, at the expense of |
- compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). |
+ On 16-bit systems, the functions zalloc and zfree must be able to allocate |
+ exactly 65536 bytes, but will not be required to allocate more than this if |
+ the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers |
+ returned by zalloc for objects of exactly 65536 bytes *must* have their |
+ offset normalized to zero. The default allocation function provided by this |
+ library ensures this (see zutil.c). To reduce memory requirements and avoid |
+ any allocation of 64K objects, at the expense of compression ratio, compile |
+ the library with -DMAX_WBITS=14 (see zconf.h). |
- The fields total_in and total_out can be used for statistics or |
- progress reports. After compression, total_in holds the total size of |
- the uncompressed data and may be saved for use in the decompressor |
- (particularly if the decompressor wants to decompress everything in |
- a single step). |
+ The fields total_in and total_out can be used for statistics or progress |
+ reports. After compression, total_in holds the total size of the |
+ uncompressed data and may be saved for use in the decompressor (particularly |
+ if the decompressor wants to decompress everything in a single step). |
*/ |
/* constants */ |
#define Z_NO_FLUSH 0 |
-#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ |
+#define Z_PARTIAL_FLUSH 1 |
#define Z_SYNC_FLUSH 2 |
#define Z_FULL_FLUSH 3 |
#define Z_FINISH 4 |
#define Z_BLOCK 5 |
+#define Z_TREES 6 |
/* Allowed flush values; see deflate() and inflate() below for details */ |
#define Z_OK 0 |
@@ -176,8 +179,8 @@ |
#define Z_MEM_ERROR (-4) |
#define Z_BUF_ERROR (-5) |
#define Z_VERSION_ERROR (-6) |
-/* Return codes for the compression/decompression functions. Negative |
- * values are errors, positive values are used for special but normal events. |
+/* Return codes for the compression/decompression functions. Negative values |
+ * are errors, positive values are used for special but normal events. |
*/ |
#define Z_NO_COMPRESSION 0 |
@@ -207,119 +210,140 @@ |
#define zlib_version zlibVersion() |
/* for compatibility with versions < 1.0.2 */ |
+ |
/* basic functions */ |
ZEXTERN const char * ZEXPORT zlibVersion OF((void)); |
/* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
- If the first character differs, the library code actually used is |
- not compatible with the zlib.h header file used by the application. |
- This check is automatically made by deflateInit and inflateInit. |
+ If the first character differs, the library code actually used is not |
+ compatible with the zlib.h header file used by the application. This check |
+ is automatically made by deflateInit and inflateInit. |
*/ |
/* |
ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); |
- Initializes the internal stream state for compression. The fields |
- zalloc, zfree and opaque must be initialized before by the caller. |
- If zalloc and zfree are set to Z_NULL, deflateInit updates them to |
- use default allocation functions. |
+ Initializes the internal stream state for compression. The fields |
+ zalloc, zfree and opaque must be initialized before by the caller. If |
+ zalloc and zfree are set to Z_NULL, deflateInit updates them to use default |
+ allocation functions. |
The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: |
- 1 gives best speed, 9 gives best compression, 0 gives no compression at |
- all (the input data is simply copied a block at a time). |
- Z_DEFAULT_COMPRESSION requests a default compromise between speed and |
- compression (currently equivalent to level 6). |
+ 1 gives best speed, 9 gives best compression, 0 gives no compression at all |
+ (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION |
+ requests a default compromise between speed and compression (currently |
+ equivalent to level 6). |
- deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not |
- enough memory, Z_STREAM_ERROR if level is not a valid compression level, |
+ deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
+ memory, Z_STREAM_ERROR if level is not a valid compression level, or |
Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible |
- with the version assumed by the caller (ZLIB_VERSION). |
- msg is set to null if there is no error message. deflateInit does not |
- perform any compression: this will be done by deflate(). |
+ with the version assumed by the caller (ZLIB_VERSION). msg is set to null |
+ if there is no error message. deflateInit does not perform any compression: |
+ this will be done by deflate(). |
*/ |
ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); |
/* |
deflate compresses as much data as possible, and stops when the input |
- buffer becomes empty or the output buffer becomes full. It may introduce some |
- output latency (reading input without producing any output) except when |
+ buffer becomes empty or the output buffer becomes full. It may introduce |
+ some output latency (reading input without producing any output) except when |
forced to flush. |
- The detailed semantics are as follows. deflate performs one or both of the |
+ The detailed semantics are as follows. deflate performs one or both of the |
following actions: |
- Compress more input starting at next_in and update next_in and avail_in |
- accordingly. If not all input can be processed (because there is not |
+ accordingly. If not all input can be processed (because there is not |
enough room in the output buffer), next_in and avail_in are updated and |
processing will resume at this point for the next call of deflate(). |
- Provide more output starting at next_out and update next_out and avail_out |
- accordingly. This action is forced if the parameter flush is non zero. |
+ accordingly. This action is forced if the parameter flush is non zero. |
Forcing flush frequently degrades the compression ratio, so this parameter |
- should be set only when necessary (in interactive applications). |
- Some output may be provided even if flush is not set. |
+ should be set only when necessary (in interactive applications). Some |
+ output may be provided even if flush is not set. |
- Before the call of deflate(), the application should ensure that at least |
- one of the actions is possible, by providing more input and/or consuming |
- more output, and updating avail_in or avail_out accordingly; avail_out |
- should never be zero before the call. The application can consume the |
- compressed output when it wants, for example when the output buffer is full |
- (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK |
- and with zero avail_out, it must be called again after making room in the |
- output buffer because there might be more output pending. |
+ Before the call of deflate(), the application should ensure that at least |
+ one of the actions is possible, by providing more input and/or consuming more |
+ output, and updating avail_in or avail_out accordingly; avail_out should |
+ never be zero before the call. The application can consume the compressed |
+ output when it wants, for example when the output buffer is full (avail_out |
+ == 0), or after each call of deflate(). If deflate returns Z_OK and with |
+ zero avail_out, it must be called again after making room in the output |
+ buffer because there might be more output pending. |
Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to |
- decide how much data to accumualte before producing output, in order to |
+ decide how much data to accumulate before producing output, in order to |
maximize compression. |
If the parameter flush is set to Z_SYNC_FLUSH, all pending output is |
flushed to the output buffer and the output is aligned on a byte boundary, so |
- that the decompressor can get all input data available so far. (In particular |
- avail_in is zero after the call if enough output space has been provided |
- before the call.) Flushing may degrade compression for some compression |
- algorithms and so it should be used only when necessary. |
+ that the decompressor can get all input data available so far. (In |
+ particular avail_in is zero after the call if enough output space has been |
+ provided before the call.) Flushing may degrade compression for some |
+ compression algorithms and so it should be used only when necessary. This |
+ completes the current deflate block and follows it with an empty stored block |
+ that is three bits plus filler bits to the next byte, followed by four bytes |
+ (00 00 ff ff). |
+ If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the |
+ output buffer, but the output is not aligned to a byte boundary. All of the |
+ input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. |
+ This completes the current deflate block and follows it with an empty fixed |
+ codes block that is 10 bits long. This assures that enough bytes are output |
+ in order for the decompressor to finish the block before the empty fixed code |
+ block. |
+ |
+ If flush is set to Z_BLOCK, a deflate block is completed and emitted, as |
+ for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to |
+ seven bits of the current block are held to be written as the next byte after |
+ the next deflate block is completed. In this case, the decompressor may not |
+ be provided enough bits at this point in order to complete decompression of |
+ the data provided so far to the compressor. It may need to wait for the next |
+ block to be emitted. This is for advanced applications that need to control |
+ the emission of deflate blocks. |
+ |
If flush is set to Z_FULL_FLUSH, all output is flushed as with |
Z_SYNC_FLUSH, and the compression state is reset so that decompression can |
restart from this point if previous compressed data has been damaged or if |
- random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
+ random access is desired. Using Z_FULL_FLUSH too often can seriously degrade |
compression. |
If deflate returns with avail_out == 0, this function must be called again |
with the same value of the flush parameter and more output space (updated |
avail_out), until the flush is complete (deflate returns with non-zero |
- avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
+ avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
avail_out is greater than six to avoid repeated flush markers due to |
avail_out == 0 on return. |
If the parameter flush is set to Z_FINISH, pending input is processed, |
- pending output is flushed and deflate returns with Z_STREAM_END if there |
- was enough output space; if deflate returns with Z_OK, this function must be |
+ pending output is flushed and deflate returns with Z_STREAM_END if there was |
+ enough output space; if deflate returns with Z_OK, this function must be |
called again with Z_FINISH and more output space (updated avail_out) but no |
- more input data, until it returns with Z_STREAM_END or an error. After |
- deflate has returned Z_STREAM_END, the only possible operations on the |
- stream are deflateReset or deflateEnd. |
+ more input data, until it returns with Z_STREAM_END or an error. After |
+ deflate has returned Z_STREAM_END, the only possible operations on the stream |
+ are deflateReset or deflateEnd. |
Z_FINISH can be used immediately after deflateInit if all the compression |
- is to be done in a single step. In this case, avail_out must be at least |
- the value returned by deflateBound (see below). If deflate does not return |
+ is to be done in a single step. In this case, avail_out must be at least the |
+ value returned by deflateBound (see below). If deflate does not return |
Z_STREAM_END, then it must be called again as described above. |
deflate() sets strm->adler to the adler32 checksum of all input read |
so far (that is, total_in bytes). |
deflate() may update strm->data_type if it can make a good guess about |
- the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered |
- binary. This field is only for information purposes and does not affect |
- the compression algorithm in any manner. |
+ the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered |
+ binary. This field is only for information purposes and does not affect the |
+ compression algorithm in any manner. |
deflate() returns Z_OK if some progress has been made (more input |
processed or more output produced), Z_STREAM_END if all input has been |
consumed and all output has been produced (only when flush is set to |
Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example |
- if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible |
- (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not |
+ if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible |
+ (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not |
fatal, and deflate() can be called again with more input and more output |
space to continue compressing. |
*/ |
@@ -328,13 +352,13 @@ |
ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); |
/* |
All dynamically allocated data structures for this stream are freed. |
- This function discards any unprocessed input and does not flush any |
- pending output. |
+ This function discards any unprocessed input and does not flush any pending |
+ output. |
deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the |
stream state was inconsistent, Z_DATA_ERROR if the stream was freed |
- prematurely (some input or output was discarded). In the error case, |
- msg may be set but then points to a static string (which must not be |
+ prematurely (some input or output was discarded). In the error case, msg |
+ may be set but then points to a static string (which must not be |
deallocated). |
*/ |
@@ -342,10 +366,10 @@ |
/* |
ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); |
- Initializes the internal stream state for decompression. The fields |
+ Initializes the internal stream state for decompression. The fields |
next_in, avail_in, zalloc, zfree and opaque must be initialized before by |
- the caller. If next_in is not Z_NULL and avail_in is large enough (the exact |
- value depends on the compression method), inflateInit determines the |
+ the caller. If next_in is not Z_NULL and avail_in is large enough (the |
+ exact value depends on the compression method), inflateInit determines the |
compression method from the zlib header and allocates all data structures |
accordingly; otherwise the allocation will be deferred to the first call of |
inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to |
@@ -353,95 +377,108 @@ |
inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough |
memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
- version assumed by the caller. msg is set to null if there is no error |
- message. inflateInit does not perform any decompression apart from reading |
- the zlib header if present: this will be done by inflate(). (So next_in and |
- avail_in may be modified, but next_out and avail_out are unchanged.) |
+ version assumed by the caller, or Z_STREAM_ERROR if the parameters are |
+ invalid, such as a null pointer to the structure. msg is set to null if |
+ there is no error message. inflateInit does not perform any decompression |
+ apart from possibly reading the zlib header if present: actual decompression |
+ will be done by inflate(). (So next_in and avail_in may be modified, but |
+ next_out and avail_out are unused and unchanged.) The current implementation |
+ of inflateInit() does not process any header information -- that is deferred |
+ until inflate() is called. |
*/ |
ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); |
/* |
inflate decompresses as much data as possible, and stops when the input |
- buffer becomes empty or the output buffer becomes full. It may introduce |
+ buffer becomes empty or the output buffer becomes full. It may introduce |
some output latency (reading input without producing any output) except when |
forced to flush. |
- The detailed semantics are as follows. inflate performs one or both of the |
+ The detailed semantics are as follows. inflate performs one or both of the |
following actions: |
- Decompress more input starting at next_in and update next_in and avail_in |
- accordingly. If not all input can be processed (because there is not |
- enough room in the output buffer), next_in is updated and processing |
- will resume at this point for the next call of inflate(). |
+ accordingly. If not all input can be processed (because there is not |
+ enough room in the output buffer), next_in is updated and processing will |
+ resume at this point for the next call of inflate(). |
- Provide more output starting at next_out and update next_out and avail_out |
- accordingly. inflate() provides as much output as possible, until there |
- is no more input data or no more space in the output buffer (see below |
- about the flush parameter). |
+ accordingly. inflate() provides as much output as possible, until there is |
+ no more input data or no more space in the output buffer (see below about |
+ the flush parameter). |
- Before the call of inflate(), the application should ensure that at least |
- one of the actions is possible, by providing more input and/or consuming |
- more output, and updating the next_* and avail_* values accordingly. |
- The application can consume the uncompressed output when it wants, for |
- example when the output buffer is full (avail_out == 0), or after each |
- call of inflate(). If inflate returns Z_OK and with zero avail_out, it |
- must be called again after making room in the output buffer because there |
- might be more output pending. |
+ Before the call of inflate(), the application should ensure that at least |
+ one of the actions is possible, by providing more input and/or consuming more |
+ output, and updating the next_* and avail_* values accordingly. The |
+ application can consume the uncompressed output when it wants, for example |
+ when the output buffer is full (avail_out == 0), or after each call of |
+ inflate(). If inflate returns Z_OK and with zero avail_out, it must be |
+ called again after making room in the output buffer because there might be |
+ more output pending. |
- The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, |
- Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much |
- output as possible to the output buffer. Z_BLOCK requests that inflate() stop |
- if and when it gets to the next deflate block boundary. When decoding the |
- zlib or gzip format, this will cause inflate() to return immediately after |
- the header and before the first block. When doing a raw inflate, inflate() |
- will go ahead and process the first block, and will return when it gets to |
- the end of that block, or when it runs out of data. |
+ The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, |
+ Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much |
+ output as possible to the output buffer. Z_BLOCK requests that inflate() |
+ stop if and when it gets to the next deflate block boundary. When decoding |
+ the zlib or gzip format, this will cause inflate() to return immediately |
+ after the header and before the first block. When doing a raw inflate, |
+ inflate() will go ahead and process the first block, and will return when it |
+ gets to the end of that block, or when it runs out of data. |
The Z_BLOCK option assists in appending to or combining deflate streams. |
Also to assist in this, on return inflate() will set strm->data_type to the |
- number of unused bits in the last byte taken from strm->next_in, plus 64 |
- if inflate() is currently decoding the last block in the deflate stream, |
- plus 128 if inflate() returned immediately after decoding an end-of-block |
- code or decoding the complete header up to just before the first byte of the |
- deflate stream. The end-of-block will not be indicated until all of the |
- uncompressed data from that block has been written to strm->next_out. The |
- number of unused bits may in general be greater than seven, except when |
- bit 7 of data_type is set, in which case the number of unused bits will be |
- less than eight. |
+ number of unused bits in the last byte taken from strm->next_in, plus 64 if |
+ inflate() is currently decoding the last block in the deflate stream, plus |
+ 128 if inflate() returned immediately after decoding an end-of-block code or |
+ decoding the complete header up to just before the first byte of the deflate |
+ stream. The end-of-block will not be indicated until all of the uncompressed |
+ data from that block has been written to strm->next_out. The number of |
+ unused bits may in general be greater than seven, except when bit 7 of |
+ data_type is set, in which case the number of unused bits will be less than |
+ eight. data_type is set as noted here every time inflate() returns for all |
+ flush options, and so can be used to determine the amount of currently |
+ consumed input in bits. |
+ The Z_TREES option behaves as Z_BLOCK does, but it also returns when the |
+ end of each deflate block header is reached, before any actual data in that |
+ block is decoded. This allows the caller to determine the length of the |
+ deflate block header for later use in random access within a deflate block. |
+ 256 is added to the value of strm->data_type when inflate() returns |
+ immediately after reaching the end of the deflate block header. |
+ |
inflate() should normally be called until it returns Z_STREAM_END or an |
- error. However if all decompression is to be performed in a single step |
- (a single call of inflate), the parameter flush should be set to |
- Z_FINISH. In this case all pending input is processed and all pending |
- output is flushed; avail_out must be large enough to hold all the |
- uncompressed data. (The size of the uncompressed data may have been saved |
- by the compressor for this purpose.) The next operation on this stream must |
- be inflateEnd to deallocate the decompression state. The use of Z_FINISH |
- is never required, but can be used to inform inflate that a faster approach |
- may be used for the single inflate() call. |
+ error. However if all decompression is to be performed in a single step (a |
+ single call of inflate), the parameter flush should be set to Z_FINISH. In |
+ this case all pending input is processed and all pending output is flushed; |
+ avail_out must be large enough to hold all the uncompressed data. (The size |
+ of the uncompressed data may have been saved by the compressor for this |
+ purpose.) The next operation on this stream must be inflateEnd to deallocate |
+ the decompression state. The use of Z_FINISH is never required, but can be |
+ used to inform inflate that a faster approach may be used for the single |
+ inflate() call. |
In this implementation, inflate() always flushes as much output as |
possible to the output buffer, and always uses the faster approach on the |
- first call. So the only effect of the flush parameter in this implementation |
+ first call. So the only effect of the flush parameter in this implementation |
is on the return value of inflate(), as noted below, or when it returns early |
- because Z_BLOCK is used. |
+ because Z_BLOCK or Z_TREES is used. |
If a preset dictionary is needed after this call (see inflateSetDictionary |
below), inflate sets strm->adler to the adler32 checksum of the dictionary |
chosen by the compressor and returns Z_NEED_DICT; otherwise it sets |
strm->adler to the adler32 checksum of all output produced so far (that is, |
total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described |
- below. At the end of the stream, inflate() checks that its computed adler32 |
+ below. At the end of the stream, inflate() checks that its computed adler32 |
checksum is equal to that saved by the compressor and returns Z_STREAM_END |
only if the checksum is correct. |
- inflate() will decompress and check either zlib-wrapped or gzip-wrapped |
- deflate data. The header type is detected automatically. Any information |
- contained in the gzip header is not retained, so applications that need that |
- information should instead use raw inflate, see inflateInit2() below, or |
- inflateBack() and perform their own processing of the gzip header and |
- trailer. |
+ inflate() can decompress and check either zlib-wrapped or gzip-wrapped |
+ deflate data. The header type is detected automatically, if requested when |
+ initializing with inflateInit2(). Any information contained in the gzip |
+ header is not retained, so applications that need that information should |
+ instead use raw inflate, see inflateInit2() below, or inflateBack() and |
+ perform their own processing of the gzip header and trailer. |
inflate() returns Z_OK if some progress has been made (more input processed |
or more output produced), Z_STREAM_END if the end of the compressed data has |
@@ -449,27 +486,28 @@ |
preset dictionary is needed at this point, Z_DATA_ERROR if the input data was |
corrupted (input stream not conforming to the zlib format or incorrect check |
value), Z_STREAM_ERROR if the stream structure was inconsistent (for example |
- if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, |
+ next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, |
Z_BUF_ERROR if no progress is possible or if there was not enough room in the |
- output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and |
+ output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and |
inflate() can be called again with more input and more output space to |
- continue decompressing. If Z_DATA_ERROR is returned, the application may then |
- call inflateSync() to look for a good compression block if a partial recovery |
- of the data is desired. |
+ continue decompressing. If Z_DATA_ERROR is returned, the application may |
+ then call inflateSync() to look for a good compression block if a partial |
+ recovery of the data is desired. |
*/ |
ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); |
/* |
All dynamically allocated data structures for this stream are freed. |
- This function discards any unprocessed input and does not flush any |
- pending output. |
+ This function discards any unprocessed input and does not flush any pending |
+ output. |
inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state |
- was inconsistent. In the error case, msg may be set but then points to a |
+ was inconsistent. In the error case, msg may be set but then points to a |
static string (which must not be deallocated). |
*/ |
+ |
/* Advanced functions */ |
/* |
@@ -484,55 +522,57 @@ |
int memLevel, |
int strategy)); |
- This is another version of deflateInit with more compression options. The |
- fields next_in, zalloc, zfree and opaque must be initialized before by |
- the caller. |
+ This is another version of deflateInit with more compression options. The |
+ fields next_in, zalloc, zfree and opaque must be initialized before by the |
+ caller. |
- The method parameter is the compression method. It must be Z_DEFLATED in |
+ The method parameter is the compression method. It must be Z_DEFLATED in |
this version of the library. |
The windowBits parameter is the base two logarithm of the window size |
- (the size of the history buffer). It should be in the range 8..15 for this |
- version of the library. Larger values of this parameter result in better |
- compression at the expense of memory usage. The default value is 15 if |
+ (the size of the history buffer). It should be in the range 8..15 for this |
+ version of the library. Larger values of this parameter result in better |
+ compression at the expense of memory usage. The default value is 15 if |
deflateInit is used instead. |
- windowBits can also be -8..-15 for raw deflate. In this case, -windowBits |
- determines the window size. deflate() will then generate raw deflate data |
+ windowBits can also be -8..-15 for raw deflate. In this case, -windowBits |
+ determines the window size. deflate() will then generate raw deflate data |
with no zlib header or trailer, and will not compute an adler32 check value. |
- windowBits can also be greater than 15 for optional gzip encoding. Add |
+ windowBits can also be greater than 15 for optional gzip encoding. Add |
16 to windowBits to write a simple gzip header and trailer around the |
- compressed data instead of a zlib wrapper. The gzip header will have no |
- file name, no extra data, no comment, no modification time (set to zero), |
- no header crc, and the operating system will be set to 255 (unknown). If a |
+ compressed data instead of a zlib wrapper. The gzip header will have no |
+ file name, no extra data, no comment, no modification time (set to zero), no |
+ header crc, and the operating system will be set to 255 (unknown). If a |
gzip stream is being written, strm->adler is a crc32 instead of an adler32. |
The memLevel parameter specifies how much memory should be allocated |
- for the internal compression state. memLevel=1 uses minimum memory but |
- is slow and reduces compression ratio; memLevel=9 uses maximum memory |
- for optimal speed. The default value is 8. See zconf.h for total memory |
- usage as a function of windowBits and memLevel. |
+ for the internal compression state. memLevel=1 uses minimum memory but is |
+ slow and reduces compression ratio; memLevel=9 uses maximum memory for |
+ optimal speed. The default value is 8. See zconf.h for total memory usage |
+ as a function of windowBits and memLevel. |
- The strategy parameter is used to tune the compression algorithm. Use the |
+ The strategy parameter is used to tune the compression algorithm. Use the |
value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a |
filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no |
string match), or Z_RLE to limit match distances to one (run-length |
- encoding). Filtered data consists mostly of small values with a somewhat |
- random distribution. In this case, the compression algorithm is tuned to |
- compress them better. The effect of Z_FILTERED is to force more Huffman |
+ encoding). Filtered data consists mostly of small values with a somewhat |
+ random distribution. In this case, the compression algorithm is tuned to |
+ compress them better. The effect of Z_FILTERED is to force more Huffman |
coding and less string matching; it is somewhat intermediate between |
- Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as |
- Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy |
- parameter only affects the compression ratio but not the correctness of the |
- compressed output even if it is not set appropriately. Z_FIXED prevents the |
- use of dynamic Huffman codes, allowing for a simpler decoder for special |
- applications. |
+ Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as |
+ fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The |
+ strategy parameter only affects the compression ratio but not the |
+ correctness of the compressed output even if it is not set appropriately. |
+ Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler |
+ decoder for special applications. |
- deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
- memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid |
- method). msg is set to null if there is no error message. deflateInit2 does |
- not perform any compression: this will be done by deflate(). |
+ deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
+ memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid |
+ method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is |
+ incompatible with the version assumed by the caller (ZLIB_VERSION). msg is |
+ set to null if there is no error message. deflateInit2 does not perform any |
+ compression: this will be done by deflate(). |
*/ |
ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, |
@@ -540,37 +580,37 @@ |
uInt dictLength)); |
/* |
Initializes the compression dictionary from the given byte sequence |
- without producing any compressed output. This function must be called |
- immediately after deflateInit, deflateInit2 or deflateReset, before any |
- call of deflate. The compressor and decompressor must use exactly the same |
+ without producing any compressed output. This function must be called |
+ immediately after deflateInit, deflateInit2 or deflateReset, before any call |
+ of deflate. The compressor and decompressor must use exactly the same |
dictionary (see inflateSetDictionary). |
The dictionary should consist of strings (byte sequences) that are likely |
to be encountered later in the data to be compressed, with the most commonly |
- used strings preferably put towards the end of the dictionary. Using a |
+ used strings preferably put towards the end of the dictionary. Using a |
dictionary is most useful when the data to be compressed is short and can be |
predicted with good accuracy; the data can then be compressed better than |
with the default empty dictionary. |
Depending on the size of the compression data structures selected by |
deflateInit or deflateInit2, a part of the dictionary may in effect be |
- discarded, for example if the dictionary is larger than the window size in |
- deflate or deflate2. Thus the strings most likely to be useful should be |
- put at the end of the dictionary, not at the front. In addition, the |
- current implementation of deflate will use at most the window size minus |
- 262 bytes of the provided dictionary. |
+ discarded, for example if the dictionary is larger than the window size |
+ provided in deflateInit or deflateInit2. Thus the strings most likely to be |
+ useful should be put at the end of the dictionary, not at the front. In |
+ addition, the current implementation of deflate will use at most the window |
+ size minus 262 bytes of the provided dictionary. |
Upon return of this function, strm->adler is set to the adler32 value |
of the dictionary; the decompressor may later use this value to determine |
- which dictionary has been used by the compressor. (The adler32 value |
+ which dictionary has been used by the compressor. (The adler32 value |
applies to the whole dictionary even if only a subset of the dictionary is |
actually used by the compressor.) If a raw deflate was requested, then the |
adler32 value is not computed and strm->adler is not set. |
deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a |
- parameter is invalid (such as NULL dictionary) or the stream state is |
+ parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
inconsistent (for example if deflate has already been called for this stream |
- or if the compression method is bsort). deflateSetDictionary does not |
+ or if the compression method is bsort). deflateSetDictionary does not |
perform any compression: this will be done by deflate(). |
*/ |
@@ -581,26 +621,26 @@ |
This function can be useful when several compression strategies will be |
tried, for example when there are several ways of pre-processing the input |
- data with a filter. The streams that will be discarded should then be freed |
+ data with a filter. The streams that will be discarded should then be freed |
by calling deflateEnd. Note that deflateCopy duplicates the internal |
- compression state which can be quite large, so this strategy is slow and |
- can consume lots of memory. |
+ compression state which can be quite large, so this strategy is slow and can |
+ consume lots of memory. |
deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
- (such as zalloc being NULL). msg is left unchanged in both source and |
+ (such as zalloc being Z_NULL). msg is left unchanged in both source and |
destination. |
*/ |
ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); |
/* |
This function is equivalent to deflateEnd followed by deflateInit, |
- but does not free and reallocate all the internal compression state. |
- The stream will keep the same compression level and any other attributes |
- that may have been set by deflateInit2. |
+ but does not free and reallocate all the internal compression state. The |
+ stream will keep the same compression level and any other attributes that |
+ may have been set by deflateInit2. |
- deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
- stream state was inconsistent (such as zalloc or state being NULL). |
+ deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
+ stream state was inconsistent (such as zalloc or state being Z_NULL). |
*/ |
ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, |
@@ -610,18 +650,18 @@ |
Dynamically update the compression level and compression strategy. The |
interpretation of level and strategy is as in deflateInit2. This can be |
used to switch between compression and straight copy of the input data, or |
- to switch to a different kind of input data requiring a different |
- strategy. If the compression level is changed, the input available so far |
- is compressed with the old level (and may be flushed); the new level will |
- take effect only at the next call of deflate(). |
+ to switch to a different kind of input data requiring a different strategy. |
+ If the compression level is changed, the input available so far is |
+ compressed with the old level (and may be flushed); the new level will take |
+ effect only at the next call of deflate(). |
Before the call of deflateParams, the stream state must be set as for |
- a call of deflate(), since the currently available input may have to |
- be compressed and flushed. In particular, strm->avail_out must be non-zero. |
+ a call of deflate(), since the currently available input may have to be |
+ compressed and flushed. In particular, strm->avail_out must be non-zero. |
deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source |
- stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR |
- if strm->avail_out was zero. |
+ stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if |
+ strm->avail_out was zero. |
*/ |
ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, |
@@ -645,9 +685,10 @@ |
uLong sourceLen)); |
/* |
deflateBound() returns an upper bound on the compressed size after |
- deflation of sourceLen bytes. It must be called after deflateInit() |
- or deflateInit2(). This would be used to allocate an output buffer |
- for deflation in a single pass, and so would be called before deflate(). |
+ deflation of sourceLen bytes. It must be called after deflateInit() or |
+ deflateInit2(), and after deflateSetHeader(), if used. This would be used |
+ to allocate an output buffer for deflation in a single pass, and so would be |
+ called before deflate(). |
*/ |
ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, |
@@ -655,21 +696,21 @@ |
int value)); |
/* |
deflatePrime() inserts bits in the deflate output stream. The intent |
- is that this function is used to start off the deflate output with the |
- bits leftover from a previous deflate stream when appending to it. As such, |
- this function can only be used for raw deflate, and must be used before the |
- first deflate() call after a deflateInit2() or deflateReset(). bits must be |
- less than or equal to 16, and that many of the least significant bits of |
- value will be inserted in the output. |
+ is that this function is used to start off the deflate output with the bits |
+ leftover from a previous deflate stream when appending to it. As such, this |
+ function can only be used for raw deflate, and must be used before the first |
+ deflate() call after a deflateInit2() or deflateReset(). bits must be less |
+ than or equal to 16, and that many of the least significant bits of value |
+ will be inserted in the output. |
- deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
+ deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
stream state was inconsistent. |
*/ |
ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, |
gz_headerp head)); |
/* |
- deflateSetHeader() provides gzip header information for when a gzip |
+ deflateSetHeader() provides gzip header information for when a gzip |
stream is requested by deflateInit2(). deflateSetHeader() may be called |
after deflateInit2() or deflateReset() and before the first call of |
deflate(). The text, time, os, extra field, name, and comment information |
@@ -682,11 +723,11 @@ |
1.3.x) do not support header crc's, and will report that it is a "multi-part |
gzip file" and give up. |
- If deflateSetHeader is not used, the default gzip header has text false, |
+ If deflateSetHeader is not used, the default gzip header has text false, |
the time set to zero, and os set to 255, with no extra, name, or comment |
fields. The gzip header is returned to the default state by deflateReset(). |
- deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
+ deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
stream state was inconsistent. |
*/ |
@@ -694,43 +735,50 @@ |
ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, |
int windowBits)); |
- This is another version of inflateInit with an extra parameter. The |
+ This is another version of inflateInit with an extra parameter. The |
fields next_in, avail_in, zalloc, zfree and opaque must be initialized |
before by the caller. |
The windowBits parameter is the base two logarithm of the maximum window |
size (the size of the history buffer). It should be in the range 8..15 for |
- this version of the library. The default value is 15 if inflateInit is used |
- instead. windowBits must be greater than or equal to the windowBits value |
+ this version of the library. The default value is 15 if inflateInit is used |
+ instead. windowBits must be greater than or equal to the windowBits value |
provided to deflateInit2() while compressing, or it must be equal to 15 if |
- deflateInit2() was not used. If a compressed stream with a larger window |
+ deflateInit2() was not used. If a compressed stream with a larger window |
size is given as input, inflate() will return with the error code |
Z_DATA_ERROR instead of trying to allocate a larger window. |
- windowBits can also be -8..-15 for raw inflate. In this case, -windowBits |
- determines the window size. inflate() will then process raw deflate data, |
+ windowBits can also be zero to request that inflate use the window size in |
+ the zlib header of the compressed stream. |
+ |
+ windowBits can also be -8..-15 for raw inflate. In this case, -windowBits |
+ determines the window size. inflate() will then process raw deflate data, |
not looking for a zlib or gzip header, not generating a check value, and not |
- looking for any check values for comparison at the end of the stream. This |
+ looking for any check values for comparison at the end of the stream. This |
is for use with other formats that use the deflate compressed data format |
- such as zip. Those formats provide their own check values. If a custom |
+ such as zip. Those formats provide their own check values. If a custom |
format is developed using the raw deflate format for compressed data, it is |
recommended that a check value such as an adler32 or a crc32 be applied to |
the uncompressed data as is done in the zlib, gzip, and zip formats. For |
- most applications, the zlib format should be used as is. Note that comments |
+ most applications, the zlib format should be used as is. Note that comments |
above on the use in deflateInit2() applies to the magnitude of windowBits. |
- windowBits can also be greater than 15 for optional gzip decoding. Add |
+ windowBits can also be greater than 15 for optional gzip decoding. Add |
32 to windowBits to enable zlib and gzip decoding with automatic header |
detection, or add 16 to decode only the gzip format (the zlib format will |
- return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is |
- a crc32 instead of an adler32. |
+ return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a |
+ crc32 instead of an adler32. |
inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
- memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg |
- is set to null if there is no error message. inflateInit2 does not perform |
- any decompression apart from reading the zlib header if present: this will |
- be done by inflate(). (So next_in and avail_in may be modified, but next_out |
- and avail_out are unchanged.) |
+ memory, Z_VERSION_ERROR if the zlib library version is incompatible with the |
+ version assumed by the caller, or Z_STREAM_ERROR if the parameters are |
+ invalid, such as a null pointer to the structure. msg is set to null if |
+ there is no error message. inflateInit2 does not perform any decompression |
+ apart from possibly reading the zlib header if present: actual decompression |
+ will be done by inflate(). (So next_in and avail_in may be modified, but |
+ next_out and avail_out are unused and unchanged.) The current implementation |
+ of inflateInit2() does not process any header information -- that is |
+ deferred until inflate() is called. |
*/ |
ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, |
@@ -738,8 +786,8 @@ |
uInt dictLength)); |
/* |
Initializes the decompression dictionary from the given uncompressed byte |
- sequence. This function must be called immediately after a call of inflate, |
- if that call returned Z_NEED_DICT. The dictionary chosen by the compressor |
+ sequence. This function must be called immediately after a call of inflate, |
+ if that call returned Z_NEED_DICT. The dictionary chosen by the compressor |
can be determined from the adler32 value returned by that call of inflate. |
The compressor and decompressor must use exactly the same dictionary (see |
deflateSetDictionary). For raw inflate, this function can be called |
@@ -748,26 +796,26 @@ |
dictionary that was used for compression is provided. |
inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a |
- parameter is invalid (such as NULL dictionary) or the stream state is |
+ parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is |
inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the |
- expected one (incorrect adler32 value). inflateSetDictionary does not |
+ expected one (incorrect adler32 value). inflateSetDictionary does not |
perform any decompression: this will be done by subsequent calls of |
inflate(). |
*/ |
ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); |
/* |
- Skips invalid compressed data until a full flush point (see above the |
- description of deflate with Z_FULL_FLUSH) can be found, or until all |
- available input is skipped. No output is provided. |
+ Skips invalid compressed data until a full flush point (see above the |
+ description of deflate with Z_FULL_FLUSH) can be found, or until all |
+ available input is skipped. No output is provided. |
- inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
- if no more input was provided, Z_DATA_ERROR if no flush point has been found, |
- or Z_STREAM_ERROR if the stream structure was inconsistent. In the success |
- case, the application may save the current current value of total_in which |
- indicates where valid compressed data was found. In the error case, the |
- application may repeatedly call inflateSync, providing more input each time, |
- until success or end of the input data. |
+ inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR |
+ if no more input was provided, Z_DATA_ERROR if no flush point has been |
+ found, or Z_STREAM_ERROR if the stream structure was inconsistent. In the |
+ success case, the application may save the current current value of total_in |
+ which indicates where valid compressed data was found. In the error case, |
+ the application may repeatedly call inflateSync, providing more input each |
+ time, until success or end of the input data. |
*/ |
ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, |
@@ -782,73 +830,118 @@ |
inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not |
enough memory, Z_STREAM_ERROR if the source stream state was inconsistent |
- (such as zalloc being NULL). msg is left unchanged in both source and |
+ (such as zalloc being Z_NULL). msg is left unchanged in both source and |
destination. |
*/ |
ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); |
/* |
This function is equivalent to inflateEnd followed by inflateInit, |
- but does not free and reallocate all the internal decompression state. |
- The stream will keep attributes that may have been set by inflateInit2. |
+ but does not free and reallocate all the internal decompression state. The |
+ stream will keep attributes that may have been set by inflateInit2. |
- inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
- stream state was inconsistent (such as zalloc or state being NULL). |
+ inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source |
+ stream state was inconsistent (such as zalloc or state being Z_NULL). |
*/ |
+ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, |
+ int windowBits)); |
+/* |
+ This function is the same as inflateReset, but it also permits changing |
+ the wrap and window size requests. The windowBits parameter is interpreted |
+ the same as it is for inflateInit2. |
+ |
+ inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source |
+ stream state was inconsistent (such as zalloc or state being Z_NULL), or if |
+ the windowBits parameter is invalid. |
+*/ |
+ |
ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, |
int bits, |
int value)); |
/* |
This function inserts bits in the inflate input stream. The intent is |
- that this function is used to start inflating at a bit position in the |
- middle of a byte. The provided bits will be used before any bytes are used |
- from next_in. This function should only be used with raw inflate, and |
- should be used before the first inflate() call after inflateInit2() or |
- inflateReset(). bits must be less than or equal to 16, and that many of the |
- least significant bits of value will be inserted in the input. |
+ that this function is used to start inflating at a bit position in the |
+ middle of a byte. The provided bits will be used before any bytes are used |
+ from next_in. This function should only be used with raw inflate, and |
+ should be used before the first inflate() call after inflateInit2() or |
+ inflateReset(). bits must be less than or equal to 16, and that many of the |
+ least significant bits of value will be inserted in the input. |
- inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
+ If bits is negative, then the input stream bit buffer is emptied. Then |
+ inflatePrime() can be called again to put bits in the buffer. This is used |
+ to clear out bits leftover after feeding inflate a block description prior |
+ to feeding inflate codes. |
+ |
+ inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source |
stream state was inconsistent. |
*/ |
+ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); |
+/* |
+ This function returns two values, one in the lower 16 bits of the return |
+ value, and the other in the remaining upper bits, obtained by shifting the |
+ return value down 16 bits. If the upper value is -1 and the lower value is |
+ zero, then inflate() is currently decoding information outside of a block. |
+ If the upper value is -1 and the lower value is non-zero, then inflate is in |
+ the middle of a stored block, with the lower value equaling the number of |
+ bytes from the input remaining to copy. If the upper value is not -1, then |
+ it is the number of bits back from the current bit position in the input of |
+ the code (literal or length/distance pair) currently being processed. In |
+ that case the lower value is the number of bytes already emitted for that |
+ code. |
+ |
+ A code is being processed if inflate is waiting for more input to complete |
+ decoding of the code, or if it has completed decoding but is waiting for |
+ more output space to write the literal or match data. |
+ |
+ inflateMark() is used to mark locations in the input data for random |
+ access, which may be at bit positions, and to note those cases where the |
+ output of a code may span boundaries of random access blocks. The current |
+ location in the input stream can be determined from avail_in and data_type |
+ as noted in the description for the Z_BLOCK flush parameter for inflate. |
+ |
+ inflateMark returns the value noted above or -1 << 16 if the provided |
+ source stream state was inconsistent. |
+*/ |
+ |
ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, |
gz_headerp head)); |
/* |
- inflateGetHeader() requests that gzip header information be stored in the |
+ inflateGetHeader() requests that gzip header information be stored in the |
provided gz_header structure. inflateGetHeader() may be called after |
inflateInit2() or inflateReset(), and before the first call of inflate(). |
As inflate() processes the gzip stream, head->done is zero until the header |
is completed, at which time head->done is set to one. If a zlib stream is |
being decoded, then head->done is set to -1 to indicate that there will be |
- no gzip header information forthcoming. Note that Z_BLOCK can be used to |
- force inflate() to return immediately after header processing is complete |
- and before any actual data is decompressed. |
+ no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be |
+ used to force inflate() to return immediately after header processing is |
+ complete and before any actual data is decompressed. |
- The text, time, xflags, and os fields are filled in with the gzip header |
+ The text, time, xflags, and os fields are filled in with the gzip header |
contents. hcrc is set to true if there is a header CRC. (The header CRC |
- was valid if done is set to one.) If extra is not Z_NULL, then extra_max |
+ was valid if done is set to one.) If extra is not Z_NULL, then extra_max |
contains the maximum number of bytes to write to extra. Once done is true, |
extra_len contains the actual extra field length, and extra contains the |
extra field, or that field truncated if extra_max is less than extra_len. |
If name is not Z_NULL, then up to name_max characters are written there, |
terminated with a zero unless the length is greater than name_max. If |
comment is not Z_NULL, then up to comm_max characters are written there, |
- terminated with a zero unless the length is greater than comm_max. When |
- any of extra, name, or comment are not Z_NULL and the respective field is |
- not present in the header, then that field is set to Z_NULL to signal its |
+ terminated with a zero unless the length is greater than comm_max. When any |
+ of extra, name, or comment are not Z_NULL and the respective field is not |
+ present in the header, then that field is set to Z_NULL to signal its |
absence. This allows the use of deflateSetHeader() with the returned |
structure to duplicate the header. However if those fields are set to |
allocated memory, then the application will need to save those pointers |
elsewhere so that they can be eventually freed. |
- If inflateGetHeader is not used, then the header information is simply |
+ If inflateGetHeader is not used, then the header information is simply |
discarded. The header is always checked for validity, including the header |
CRC if present. inflateReset() will reset the process to discard the header |
information. The application would need to call inflateGetHeader() again to |
retrieve the header from the next gzip stream. |
- inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
+ inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source |
stream state was inconsistent. |
*/ |
@@ -869,9 +962,9 @@ |
See inflateBack() for the usage of these routines. |
inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of |
- the paramaters are invalid, Z_MEM_ERROR if the internal state could not |
- be allocated, or Z_VERSION_ERROR if the version of the library does not |
- match the version of the header file. |
+ the paramaters are invalid, Z_MEM_ERROR if the internal state could not be |
+ allocated, or Z_VERSION_ERROR if the version of the library does not match |
+ the version of the header file. |
*/ |
typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); |
@@ -891,15 +984,15 @@ |
inflateBackInit() must be called first to allocate the internal state |
and to initialize the state with the user-provided window buffer. |
inflateBack() may then be used multiple times to inflate a complete, raw |
- deflate stream with each call. inflateBackEnd() is then called to free |
- the allocated state. |
+ deflate stream with each call. inflateBackEnd() is then called to free the |
+ allocated state. |
A raw deflate stream is one with no zlib or gzip header or trailer. |
This routine would normally be used in a utility that reads zip or gzip |
files and writes out uncompressed files. The utility would decode the |
- header and process the trailer on its own, hence this routine expects |
- only the raw deflate stream to decompress. This is different from the |
- normal behavior of inflate(), which expects either a zlib or gzip header and |
+ header and process the trailer on its own, hence this routine expects only |
+ the raw deflate stream to decompress. This is different from the normal |
+ behavior of inflate(), which expects either a zlib or gzip header and |
trailer around the deflate stream. |
inflateBack() uses two subroutines supplied by the caller that are then |
@@ -925,7 +1018,7 @@ |
calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called |
immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in |
must also be initialized, and then if strm->avail_in is not zero, input will |
- initially be taken from strm->next_in[0 .. strm->avail_in - 1]. |
+ initially be taken from strm->next_in[0 .. strm->avail_in - 1]. |
The in_desc and out_desc parameters of inflateBack() is passed as the |
first parameter of in() and out() respectively when they are called. These |
@@ -935,15 +1028,15 @@ |
On return, inflateBack() will set strm->next_in and strm->avail_in to |
pass back any unused input that was provided by the last in() call. The |
return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR |
- if in() or out() returned an error, Z_DATA_ERROR if there was a format |
- error in the deflate stream (in which case strm->msg is set to indicate the |
- nature of the error), or Z_STREAM_ERROR if the stream was not properly |
- initialized. In the case of Z_BUF_ERROR, an input or output error can be |
- distinguished using strm->next_in which will be Z_NULL only if in() returned |
- an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to |
- out() returning non-zero. (in() will always be called before out(), so |
- strm->next_in is assured to be defined if out() returns non-zero.) Note |
- that inflateBack() cannot return Z_OK. |
+ if in() or out() returned an error, Z_DATA_ERROR if there was a format error |
+ in the deflate stream (in which case strm->msg is set to indicate the nature |
+ of the error), or Z_STREAM_ERROR if the stream was not properly initialized. |
+ In the case of Z_BUF_ERROR, an input or output error can be distinguished |
+ using strm->next_in which will be Z_NULL only if in() returned an error. If |
+ strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning |
+ non-zero. (in() will always be called before out(), so strm->next_in is |
+ assured to be defined if out() returns non-zero.) Note that inflateBack() |
+ cannot return Z_OK. |
*/ |
ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); |
@@ -999,23 +1092,22 @@ |
/* utility functions */ |
/* |
- The following utility functions are implemented on top of the |
- basic stream-oriented functions. To simplify the interface, some |
- default options are assumed (compression level and memory usage, |
- standard memory allocation functions). The source code of these |
- utility functions can easily be modified if you need special options. |
+ The following utility functions are implemented on top of the basic |
+ stream-oriented functions. To simplify the interface, some default options |
+ are assumed (compression level and memory usage, standard memory allocation |
+ functions). The source code of these utility functions can be modified if |
+ you need special options. |
*/ |
ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, |
const Bytef *source, uLong sourceLen)); |
/* |
Compresses the source buffer into the destination buffer. sourceLen is |
- the byte length of the source buffer. Upon entry, destLen is the total |
- size of the destination buffer, which must be at least the value returned |
- by compressBound(sourceLen). Upon exit, destLen is the actual size of the |
+ the byte length of the source buffer. Upon entry, destLen is the total size |
+ of the destination buffer, which must be at least the value returned by |
+ compressBound(sourceLen). Upon exit, destLen is the actual size of the |
compressed buffer. |
- This function can be used to compress a whole file at once if the |
- input file is mmap'ed. |
+ |
compress returns Z_OK if success, Z_MEM_ERROR if there was not |
enough memory, Z_BUF_ERROR if there was not enough room in the output |
buffer. |
@@ -1025,11 +1117,11 @@ |
const Bytef *source, uLong sourceLen, |
int level)); |
/* |
- Compresses the source buffer into the destination buffer. The level |
+ Compresses the source buffer into the destination buffer. The level |
parameter has the same meaning as in deflateInit. sourceLen is the byte |
- length of the source buffer. Upon entry, destLen is the total size of the |
+ length of the source buffer. Upon entry, destLen is the total size of the |
destination buffer, which must be at least the value returned by |
- compressBound(sourceLen). Upon exit, destLen is the actual size of the |
+ compressBound(sourceLen). Upon exit, destLen is the actual size of the |
compressed buffer. |
compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough |
@@ -1040,22 +1132,20 @@ |
ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); |
/* |
compressBound() returns an upper bound on the compressed size after |
- compress() or compress2() on sourceLen bytes. It would be used before |
- a compress() or compress2() call to allocate the destination buffer. |
+ compress() or compress2() on sourceLen bytes. It would be used before a |
+ compress() or compress2() call to allocate the destination buffer. |
*/ |
ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, |
const Bytef *source, uLong sourceLen)); |
/* |
Decompresses the source buffer into the destination buffer. sourceLen is |
- the byte length of the source buffer. Upon entry, destLen is the total |
- size of the destination buffer, which must be large enough to hold the |
- entire uncompressed data. (The size of the uncompressed data must have |
- been saved previously by the compressor and transmitted to the decompressor |
- by some mechanism outside the scope of this compression library.) |
- Upon exit, destLen is the actual size of the compressed buffer. |
- This function can be used to decompress a whole file at once if the |
- input file is mmap'ed. |
+ the byte length of the source buffer. Upon entry, destLen is the total size |
+ of the destination buffer, which must be large enough to hold the entire |
+ uncompressed data. (The size of the uncompressed data must have been saved |
+ previously by the compressor and transmitted to the decompressor by some |
+ mechanism outside the scope of this compression library.) Upon exit, destLen |
+ is the actual size of the uncompressed buffer. |
uncompress returns Z_OK if success, Z_MEM_ERROR if there was not |
enough memory, Z_BUF_ERROR if there was not enough room in the output |
@@ -1063,136 +1153,199 @@ |
*/ |
-typedef voidp gzFile; |
+ /* gzip file access functions */ |
-ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); |
/* |
- Opens a gzip (.gz) file for reading or writing. The mode parameter |
- is as in fopen ("rb" or "wb") but can also include a compression level |
- ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for |
- Huffman only compression as in "wb1h", or 'R' for run-length encoding |
- as in "wb1R". (See the description of deflateInit2 for more information |
- about the strategy parameter.) |
+ This library supports reading and writing files in gzip (.gz) format with |
+ an interface similar to that of stdio, using the functions that start with |
+ "gz". The gzip format is different from the zlib format. gzip is a gzip |
+ wrapper, documented in RFC 1952, wrapped around a deflate stream. |
+*/ |
+typedef voidp gzFile; /* opaque gzip file descriptor */ |
+ |
+/* |
+ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); |
+ |
+ Opens a gzip (.gz) file for reading or writing. The mode parameter is as |
+ in fopen ("rb" or "wb") but can also include a compression level ("wb9") or |
+ a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only |
+ compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' |
+ for fixed code compression as in "wb9F". (See the description of |
+ deflateInit2 for more information about the strategy parameter.) Also "a" |
+ can be used instead of "w" to request that the gzip stream that will be |
+ written be appended to the file. "+" will result in an error, since reading |
+ and writing to the same gzip file is not supported. |
+ |
gzopen can be used to read a file which is not in gzip format; in this |
case gzread will directly read from the file without decompression. |
- gzopen returns NULL if the file could not be opened or if there was |
- insufficient memory to allocate the (de)compression state; errno |
- can be checked to distinguish the two cases (if errno is zero, the |
- zlib error is Z_MEM_ERROR). */ |
+ gzopen returns NULL if the file could not be opened, if there was |
+ insufficient memory to allocate the gzFile state, or if an invalid mode was |
+ specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). |
+ errno can be checked to determine if the reason gzopen failed was that the |
+ file could not be opened. |
+*/ |
-ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); |
+ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); |
/* |
- gzdopen() associates a gzFile with the file descriptor fd. File |
- descriptors are obtained from calls like open, dup, creat, pipe or |
- fileno (in the file has been previously opened with fopen). |
- The mode parameter is as in gzopen. |
- The next call of gzclose on the returned gzFile will also close the |
- file descriptor fd, just like fclose(fdopen(fd), mode) closes the file |
- descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). |
- gzdopen returns NULL if there was insufficient memory to allocate |
- the (de)compression state. |
+ gzdopen associates a gzFile with the file descriptor fd. File descriptors |
+ are obtained from calls like open, dup, creat, pipe or fileno (if the file |
+ has been previously opened with fopen). The mode parameter is as in gzopen. |
+ |
+ The next call of gzclose on the returned gzFile will also close the file |
+ descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor |
+ fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, |
+ mode);. The duplicated descriptor should be saved to avoid a leak, since |
+ gzdopen does not close fd if it fails. |
+ |
+ gzdopen returns NULL if there was insufficient memory to allocate the |
+ gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not |
+ provided, or '+' was provided), or if fd is -1. The file descriptor is not |
+ used until the next gz* read, write, seek, or close operation, so gzdopen |
+ will not detect if fd is invalid (unless fd is -1). |
*/ |
+ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); |
+/* |
+ Set the internal buffer size used by this library's functions. The |
+ default buffer size is 8192 bytes. This function must be called after |
+ gzopen() or gzdopen(), and before any other calls that read or write the |
+ file. The buffer memory allocation is always deferred to the first read or |
+ write. Two buffers are allocated, either both of the specified size when |
+ writing, or one of the specified size and the other twice that size when |
+ reading. A larger buffer size of, for example, 64K or 128K bytes will |
+ noticeably increase the speed of decompression (reading). |
+ |
+ The new buffer size also affects the maximum length for gzprintf(). |
+ |
+ gzbuffer() returns 0 on success, or -1 on failure, such as being called |
+ too late. |
+*/ |
+ |
ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); |
/* |
- Dynamically update the compression level or strategy. See the description |
+ Dynamically update the compression level or strategy. See the description |
of deflateInit2 for the meaning of these parameters. |
+ |
gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not |
opened for writing. |
*/ |
-ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); |
+ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); |
/* |
- Reads the given number of uncompressed bytes from the compressed file. |
- If the input file was not in gzip format, gzread copies the given number |
- of bytes into the buffer. |
- gzread returns the number of uncompressed bytes actually read (0 for |
- end of file, -1 for error). */ |
+ Reads the given number of uncompressed bytes from the compressed file. If |
+ the input file was not in gzip format, gzread copies the given number of |
+ bytes into the buffer. |
-ZEXTERN int ZEXPORT gzwrite OF((gzFile file, |
- voidpc buf, unsigned len)); |
+ After reaching the end of a gzip stream in the input, gzread will continue |
+ to read, looking for another gzip stream, or failing that, reading the rest |
+ of the input file directly without decompression. The entire input file |
+ will be read if gzread is called until it returns less than the requested |
+ len. |
+ |
+ gzread returns the number of uncompressed bytes actually read, less than |
+ len for end of file, or -1 for error. |
+*/ |
+ |
+ZEXTERN int ZEXPORT gzwrite OF((gzFile file, |
+ voidpc buf, unsigned len)); |
/* |
Writes the given number of uncompressed bytes into the compressed file. |
- gzwrite returns the number of uncompressed bytes actually written |
- (0 in case of error). |
+ gzwrite returns the number of uncompressed bytes written or 0 in case of |
+ error. |
*/ |
-ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); |
+ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); |
/* |
- Converts, formats, and writes the args to the compressed file under |
- control of the format string, as in fprintf. gzprintf returns the number of |
- uncompressed bytes actually written (0 in case of error). The number of |
- uncompressed bytes written is limited to 4095. The caller should assure that |
- this limit is not exceeded. If it is exceeded, then gzprintf() will return |
- return an error (0) with nothing written. In this case, there may also be a |
- buffer overflow with unpredictable consequences, which is possible only if |
- zlib was compiled with the insecure functions sprintf() or vsprintf() |
- because the secure snprintf() or vsnprintf() functions were not available. |
+ Converts, formats, and writes the arguments to the compressed file under |
+ control of the format string, as in fprintf. gzprintf returns the number of |
+ uncompressed bytes actually written, or 0 in case of error. The number of |
+ uncompressed bytes written is limited to 8191, or one less than the buffer |
+ size given to gzbuffer(). The caller should assure that this limit is not |
+ exceeded. If it is exceeded, then gzprintf() will return an error (0) with |
+ nothing written. In this case, there may also be a buffer overflow with |
+ unpredictable consequences, which is possible only if zlib was compiled with |
+ the insecure functions sprintf() or vsprintf() because the secure snprintf() |
+ or vsnprintf() functions were not available. This can be determined using |
+ zlibCompileFlags(). |
*/ |
ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); |
/* |
- Writes the given null-terminated string to the compressed file, excluding |
+ Writes the given null-terminated string to the compressed file, excluding |
the terminating null character. |
- gzputs returns the number of characters written, or -1 in case of error. |
+ |
+ gzputs returns the number of characters written, or -1 in case of error. |
*/ |
ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); |
/* |
- Reads bytes from the compressed file until len-1 characters are read, or |
- a newline character is read and transferred to buf, or an end-of-file |
- condition is encountered. The string is then terminated with a null |
- character. |
- gzgets returns buf, or Z_NULL in case of error. |
+ Reads bytes from the compressed file until len-1 characters are read, or a |
+ newline character is read and transferred to buf, or an end-of-file |
+ condition is encountered. If any characters are read or if len == 1, the |
+ string is terminated with a null character. If no characters are read due |
+ to an end-of-file or len < 1, then the buffer is left untouched. |
+ |
+ gzgets returns buf which is a null-terminated string, or it returns NULL |
+ for end-of-file or in case of error. If there was an error, the contents at |
+ buf are indeterminate. |
*/ |
-ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); |
+ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); |
/* |
- Writes c, converted to an unsigned char, into the compressed file. |
- gzputc returns the value that was written, or -1 in case of error. |
+ Writes c, converted to an unsigned char, into the compressed file. gzputc |
+ returns the value that was written, or -1 in case of error. |
*/ |
-ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); |
+ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); |
/* |
- Reads one byte from the compressed file. gzgetc returns this byte |
- or -1 in case of end of file or error. |
+ Reads one byte from the compressed file. gzgetc returns this byte or -1 |
+ in case of end of file or error. |
*/ |
-ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); |
+ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); |
/* |
- Push one character back onto the stream to be read again later. |
- Only one character of push-back is allowed. gzungetc() returns the |
- character pushed, or -1 on failure. gzungetc() will fail if a |
- character has been pushed but not read yet, or if c is -1. The pushed |
- character will be discarded if the stream is repositioned with gzseek() |
- or gzrewind(). |
+ Push one character back onto the stream to be read as the first character |
+ on the next read. At least one character of push-back is allowed. |
+ gzungetc() returns the character pushed, or -1 on failure. gzungetc() will |
+ fail if c is -1, and may fail if a character has been pushed but not read |
+ yet. If gzungetc is used immediately after gzopen or gzdopen, at least the |
+ output buffer size of pushed characters is allowed. (See gzbuffer above.) |
+ The pushed character will be discarded if the stream is repositioned with |
+ gzseek() or gzrewind(). |
*/ |
-ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); |
+ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); |
/* |
- Flushes all pending output into the compressed file. The parameter |
- flush is as in the deflate() function. The return value is the zlib |
- error number (see function gzerror below). gzflush returns Z_OK if |
- the flush parameter is Z_FINISH and all output could be flushed. |
- gzflush should be called only when strictly necessary because it can |
- degrade compression. |
+ Flushes all pending output into the compressed file. The parameter flush |
+ is as in the deflate() function. The return value is the zlib error number |
+ (see function gzerror below). gzflush is only permitted when writing. |
+ |
+ If the flush parameter is Z_FINISH, the remaining data is written and the |
+ gzip stream is completed in the output. If gzwrite() is called again, a new |
+ gzip stream will be started in the output. gzread() is able to read such |
+ concatented gzip streams. |
+ |
+ gzflush should be called only when strictly necessary because it will |
+ degrade compression if called too often. |
*/ |
-ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, |
- z_off_t offset, int whence)); |
/* |
- Sets the starting position for the next gzread or gzwrite on the |
- given compressed file. The offset represents a number of bytes in the |
- uncompressed data stream. The whence parameter is defined as in lseek(2); |
+ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, |
+ z_off_t offset, int whence)); |
+ |
+ Sets the starting position for the next gzread or gzwrite on the given |
+ compressed file. The offset represents a number of bytes in the |
+ uncompressed data stream. The whence parameter is defined as in lseek(2); |
the value SEEK_END is not supported. |
+ |
If the file is opened for reading, this function is emulated but can be |
- extremely slow. If the file is opened for writing, only forward seeks are |
+ extremely slow. If the file is opened for writing, only forward seeks are |
supported; gzseek then compresses a sequence of zeroes up to the new |
starting position. |
- gzseek returns the resulting offset location as measured in bytes from |
+ gzseek returns the resulting offset location as measured in bytes from |
the beginning of the uncompressed stream, or -1 in case of error, in |
particular if the file is opened for writing and the new starting position |
would be before the current position. |
@@ -1202,69 +1355,128 @@ |
/* |
Rewinds the given file. This function is supported only for reading. |
- gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
+ gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) |
*/ |
+/* |
ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); |
+ |
+ Returns the starting position for the next gzread or gzwrite on the given |
+ compressed file. This position represents a number of bytes in the |
+ uncompressed data stream, and is zero when starting, even if appending or |
+ reading a gzip stream from the middle of a file using gzdopen(). |
+ |
+ gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
+*/ |
+ |
/* |
- Returns the starting position for the next gzread or gzwrite on the |
- given compressed file. This position represents a number of bytes in the |
- uncompressed data stream. |
+ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); |
- gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) |
+ Returns the current offset in the file being read or written. This offset |
+ includes the count of bytes that precede the gzip stream, for example when |
+ appending or when using gzdopen() for reading. When reading, the offset |
+ does not include as yet unused buffered input. This information can be used |
+ for a progress indicator. On error, gzoffset() returns -1. |
*/ |
ZEXTERN int ZEXPORT gzeof OF((gzFile file)); |
/* |
- Returns 1 when EOF has previously been detected reading the given |
- input stream, otherwise zero. |
+ Returns true (1) if the end-of-file indicator has been set while reading, |
+ false (0) otherwise. Note that the end-of-file indicator is set only if the |
+ read tried to go past the end of the input, but came up short. Therefore, |
+ just like feof(), gzeof() may return false even if there is no more data to |
+ read, in the event that the last read request was for the exact number of |
+ bytes remaining in the input file. This will happen if the input file size |
+ is an exact multiple of the buffer size. |
+ |
+ If gzeof() returns true, then the read functions will return no more data, |
+ unless the end-of-file indicator is reset by gzclearerr() and the input file |
+ has grown since the previous end of file was detected. |
*/ |
ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); |
/* |
- Returns 1 if file is being read directly without decompression, otherwise |
- zero. |
+ Returns true (1) if file is being copied directly while reading, or false |
+ (0) if file is a gzip stream being decompressed. This state can change from |
+ false to true while reading the input file if the end of a gzip stream is |
+ reached, but is followed by data that is not another gzip stream. |
+ |
+ If the input file is empty, gzdirect() will return true, since the input |
+ does not contain a gzip stream. |
+ |
+ If gzdirect() is used immediately after gzopen() or gzdopen() it will |
+ cause buffers to be allocated to allow reading the file to determine if it |
+ is a gzip file. Therefore if gzbuffer() is used, it should be called before |
+ gzdirect(). |
*/ |
ZEXTERN int ZEXPORT gzclose OF((gzFile file)); |
/* |
- Flushes all pending output if necessary, closes the compressed file |
- and deallocates all the (de)compression state. The return value is the zlib |
- error number (see function gzerror below). |
+ Flushes all pending output if necessary, closes the compressed file and |
+ deallocates the (de)compression state. Note that once file is closed, you |
+ cannot call gzerror with file, since its structures have been deallocated. |
+ gzclose must not be called more than once on the same file, just as free |
+ must not be called more than once on the same allocation. |
+ |
+ gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a |
+ file operation error, or Z_OK on success. |
*/ |
+ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); |
+ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); |
+/* |
+ Same as gzclose(), but gzclose_r() is only for use when reading, and |
+ gzclose_w() is only for use when writing or appending. The advantage to |
+ using these instead of gzclose() is that they avoid linking in zlib |
+ compression or decompression code that is not used when only reading or only |
+ writing respectively. If gzclose() is used, then both compression and |
+ decompression code will be included the application when linking to a static |
+ zlib library. |
+*/ |
+ |
ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); |
/* |
- Returns the error message for the last error which occurred on the |
- given compressed file. errnum is set to zlib error number. If an |
- error occurred in the file system and not in the compression library, |
- errnum is set to Z_ERRNO and the application may consult errno |
- to get the exact error code. |
+ Returns the error message for the last error which occurred on the given |
+ compressed file. errnum is set to zlib error number. If an error occurred |
+ in the file system and not in the compression library, errnum is set to |
+ Z_ERRNO and the application may consult errno to get the exact error code. |
+ |
+ The application must not modify the returned string. Future calls to |
+ this function may invalidate the previously returned string. If file is |
+ closed, then the string previously returned by gzerror will no longer be |
+ available. |
+ |
+ gzerror() should be used to distinguish errors from end-of-file for those |
+ functions above that do not distinguish those cases in their return values. |
*/ |
ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); |
/* |
- Clears the error and end-of-file flags for file. This is analogous to the |
- clearerr() function in stdio. This is useful for continuing to read a gzip |
+ Clears the error and end-of-file flags for file. This is analogous to the |
+ clearerr() function in stdio. This is useful for continuing to read a gzip |
file that is being written concurrently. |
*/ |
+ |
/* checksum functions */ |
/* |
These functions are not related to compression but are exported |
- anyway because they might be useful in applications using the |
- compression library. |
+ anyway because they might be useful in applications using the compression |
+ library. |
*/ |
ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); |
/* |
Update a running Adler-32 checksum with the bytes buf[0..len-1] and |
- return the updated checksum. If buf is NULL, this function returns |
- the required initial value for the checksum. |
- An Adler-32 checksum is almost as reliable as a CRC32 but can be computed |
- much faster. Usage example: |
+ return the updated checksum. If buf is Z_NULL, this function returns the |
+ required initial value for the checksum. |
+ An Adler-32 checksum is almost as reliable as a CRC32 but can be computed |
+ much faster. |
+ |
+ Usage example: |
+ |
uLong adler = adler32(0L, Z_NULL, 0); |
while (read_buffer(buffer, length) != EOF) { |
@@ -1273,9 +1485,10 @@ |
if (adler != original_adler) error(); |
*/ |
+/* |
ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, |
z_off_t len2)); |
-/* |
+ |
Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 |
and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for |
each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of |
@@ -1285,9 +1498,11 @@ |
ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); |
/* |
Update a running CRC-32 with the bytes buf[0..len-1] and return the |
- updated CRC-32. If buf is NULL, this function returns the required initial |
- value for the for the crc. Pre- and post-conditioning (one's complement) is |
- performed within this function so it shouldn't be done by the application. |
+ updated CRC-32. If buf is Z_NULL, this function returns the required |
+ initial value for the for the crc. Pre- and post-conditioning (one's |
+ complement) is performed within this function so it shouldn't be done by the |
+ application. |
+ |
Usage example: |
uLong crc = crc32(0L, Z_NULL, 0); |
@@ -1298,9 +1513,9 @@ |
if (crc != original_crc) error(); |
*/ |
+/* |
ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); |
-/* |
Combine two CRC-32 check values into one. For two sequences of bytes, |
seq1 and seq2 with lengths len1 and len2, CRC-32 check values were |
calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 |
@@ -1339,16 +1554,57 @@ |
inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) |
#define inflateBackInit(strm, windowBits, window) \ |
inflateBackInit_((strm), (windowBits), (window), \ |
- ZLIB_VERSION, sizeof(z_stream)) |
+ ZLIB_VERSION, sizeof(z_stream)) |
+/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or |
+ * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if |
+ * both are true, the application gets the *64 functions, and the regular |
+ * functions are changed to 64 bits) -- in case these are set on systems |
+ * without large file support, _LFS64_LARGEFILE must also be true |
+ */ |
+#if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0 |
+ ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); |
+ ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); |
+ ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); |
+ ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); |
+ ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); |
+ ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); |
+#endif |
+#if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0 |
+# define gzopen gzopen64 |
+# define gzseek gzseek64 |
+# define gztell gztell64 |
+# define gzoffset gzoffset64 |
+# define adler32_combine adler32_combine64 |
+# define crc32_combine crc32_combine64 |
+# ifdef _LARGEFILE64_SOURCE |
+ ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); |
+ ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); |
+ ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); |
+ ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); |
+ ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); |
+ ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); |
+# endif |
+#else |
+ ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); |
+ ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); |
+ ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); |
+ ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); |
+ ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); |
+ ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); |
+#endif |
+ |
+/* hack for buggy compilers */ |
#if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) |
- struct internal_state {int dummy;}; /* hack for buggy compilers */ |
+ struct internal_state {int dummy;}; |
#endif |
+/* undocumented functions */ |
ZEXTERN const char * ZEXPORT zError OF((int)); |
-ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); |
+ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); |
ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); |
+ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); |
#ifdef __cplusplus |
} |