Add an unpatched version of xz, XZ Utils, to /trunk/deps/third_party

xz/src/liblzma/api/lzma/vli.h

+/**
+ * \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;