| Index: xz/src/liblzma/api/lzma/vli.h
|
| ===================================================================
|
| --- xz/src/liblzma/api/lzma/vli.h (revision 0)
|
| +++ xz/src/liblzma/api/lzma/vli.h (revision 0)
|
| @@ -0,0 +1,167 @@
|
| +/**
|
| + * \file lzma/vli.h
|
| + * \brief Variable-length integer handling
|
| + *
|
| + * In the .xz format, most integers are encoded in a variable-length
|
| + * representation, which is sometimes called little endian base-128 encoding.
|
| + * This saves space when smaller values are more likely than bigger values.
|
| + *
|
| + * The encoding scheme encodes seven bits to every byte, using minimum
|
| + * number of bytes required to represent the given value. Encodings that use
|
| + * non-minimum number of bytes are invalid, thus every integer has exactly
|
| + * one encoded representation. The maximum number of bits in a VLI is 63,
|
| + * thus the vli argument must be less than or equal to UINT64_MAX / 2. You
|
| + * should use LZMA_VLI_MAX for clarity.
|
| + */
|
| +
|
| +/*
|
| + * Author: Lasse Collin
|
| + *
|
| + * This file has been put into the public domain.
|
| + * You can do whatever you want with this file.
|
| + *
|
| + * See ../lzma.h for information about liblzma as a whole.
|
| + */
|
| +
|
| +#ifndef LZMA_H_INTERNAL
|
| +# error Never include this file directly. Use <lzma.h> instead.
|
| +#endif
|
| +
|
| +
|
| +/**
|
| + * \brief Maximum supported value of variable-length integer
|
| + */
|
| +#define LZMA_VLI_MAX (UINT64_MAX / 2)
|
| +
|
| +/**
|
| + * \brief VLI value to denote that the value is unknown
|
| + */
|
| +#define LZMA_VLI_UNKNOWN UINT64_MAX
|
| +
|
| +/**
|
| + * \brief Maximum supported length of variable length integers
|
| + */
|
| +#define LZMA_VLI_BYTES_MAX 9
|
| +
|
| +
|
| +/**
|
| + * \brief VLI constant suffix
|
| + */
|
| +#define LZMA_VLI_C(n) UINT64_C(n)
|
| +
|
| +
|
| +/**
|
| + * \brief Variable-length integer type
|
| + *
|
| + * This will always be unsigned integer. Valid VLI values are in the range
|
| + * [0, LZMA_VLI_MAX]. Unknown value is indicated with LZMA_VLI_UNKNOWN,
|
| + * which is the maximum value of the underlaying integer type.
|
| + *
|
| + * In future, even if lzma_vli is defined to be something other than uint64_t,
|
| + * it is guaranteed that 2 * LZMA_VLI_MAX will not overflow lzma_vli.
|
| + * This simplifies integer overflow detection.
|
| + */
|
| +typedef uint64_t lzma_vli;
|
| +
|
| +
|
| +/**
|
| + * \brief Simple macro to validate variable-length integer
|
| + *
|
| + * This is useful to test that application has given acceptable values
|
| + * for example in the uncompressed_size and compressed_size variables.
|
| + *
|
| + * \return True if the integer is representable as VLI or if it
|
| + * indicates unknown value.
|
| + */
|
| +#define lzma_vli_is_valid(vli) \
|
| + ((vli) <= LZMA_VLI_MAX || (vli) == LZMA_VLI_UNKNOWN)
|
| +
|
| +
|
| +/**
|
| + * \brief Encode a variable-length integer
|
| + *
|
| + * This function has two modes: single-call and multi-call. Single-call mode
|
| + * encodes the whole integer at once; it is an error if the output buffer is
|
| + * too small. Multi-call mode saves the position in *vli_pos, and thus it is
|
| + * possible to continue encoding if the buffer becomes full before the whole
|
| + * integer has been encoded.
|
| + *
|
| + * \param vli Integer to be encoded
|
| + * \param vli_pos How many VLI-encoded bytes have already been written
|
| + * out. When starting to encode a new integer, *vli_pos
|
| + * must be set to zero. To use single-call encoding,
|
| + * set vli_pos to NULL.
|
| + * \param out Beginning of the output buffer
|
| + * \param out_pos The next byte will be written to out[*out_pos].
|
| + * \param out_size Size of the out buffer; the first byte into
|
| + * which no data is written to is out[out_size].
|
| + *
|
| + * \return Slightly different return values are used in multi-call and
|
| + * single-call modes.
|
| + *
|
| + * Single-call (vli_pos == NULL):
|
| + * - LZMA_OK: Integer successfully encoded.
|
| + * - LZMA_PROG_ERROR: Arguments are not sane. This can be due
|
| + * to too little output space; single-call mode doesn't use
|
| + * LZMA_BUF_ERROR, since the application should have checked
|
| + * the encoded size with lzma_vli_size().
|
| + *
|
| + * Multi-call (vli_pos != NULL):
|
| + * - LZMA_OK: So far all OK, but the integer is not
|
| + * completely written out yet.
|
| + * - LZMA_STREAM_END: Integer successfully encoded.
|
| + * - LZMA_BUF_ERROR: No output space was provided.
|
| + * - LZMA_PROG_ERROR: Arguments are not sane.
|
| + */
|
| +extern LZMA_API(lzma_ret) lzma_vli_encode(lzma_vli vli, size_t *vli_pos,
|
| + uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow;
|
| +
|
| +
|
| +/**
|
| + * \brief Decode a variable-length integer
|
| + *
|
| + * Like lzma_vli_encode(), this function has single-call and multi-call modes.
|
| + *
|
| + * \param vli Pointer to decoded integer. The decoder will
|
| + * initialize it to zero when *vli_pos == 0, so
|
| + * application isn't required to initialize *vli.
|
| + * \param vli_pos How many bytes have already been decoded. When
|
| + * starting to decode a new integer, *vli_pos must
|
| + * be initialized to zero. To use single-call decoding,
|
| + * set this to NULL.
|
| + * \param in Beginning of the input buffer
|
| + * \param in_pos The next byte will be read from in[*in_pos].
|
| + * \param in_size Size of the input buffer; the first byte that
|
| + * won't be read is in[in_size].
|
| + *
|
| + * \return Slightly different return values are used in multi-call and
|
| + * single-call modes.
|
| + *
|
| + * Single-call (vli_pos == NULL):
|
| + * - LZMA_OK: Integer successfully decoded.
|
| + * - LZMA_DATA_ERROR: Integer is corrupt. This includes hitting
|
| + * the end of the input buffer before the whole integer was
|
| + * decoded; providing no input at all will use LZMA_DATA_ERROR.
|
| + * - LZMA_PROG_ERROR: Arguments are not sane.
|
| + *
|
| + * Multi-call (vli_pos != NULL):
|
| + * - LZMA_OK: So far all OK, but the integer is not
|
| + * completely decoded yet.
|
| + * - LZMA_STREAM_END: Integer successfully decoded.
|
| + * - LZMA_DATA_ERROR: Integer is corrupt.
|
| + * - LZMA_BUF_ERROR: No input was provided.
|
| + * - LZMA_PROG_ERROR: Arguments are not sane.
|
| + */
|
| +extern LZMA_API(lzma_ret) lzma_vli_decode(lzma_vli *vli, size_t *vli_pos,
|
| + const uint8_t *in, size_t *in_pos, size_t in_size)
|
| + lzma_nothrow;
|
| +
|
| +
|
| +/**
|
| + * \brief Get the number of bytes required to encode a VLI
|
| + *
|
| + * \return Number of bytes on success (1-9). If vli isn't valid,
|
| + * zero is returned.
|
| + */
|
| +extern LZMA_API(uint32_t) lzma_vli_size(lzma_vli vli)
|
| + lzma_nothrow lzma_attr_pure;
|
|
|
| Property changes on: xz/src/liblzma/api/lzma/vli.h
|
| ___________________________________________________________________
|
| Added: svn:eol-style
|
| + LF
|
|
|
|
|