LCOM1920-T02G10

/**

 * \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 a 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 encoded 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

 *

 * 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.

 *

 * lzma_vli will be uint64_t for the foreseeable future. If a bigger size

 * is needed in the future, it is guaranteed that 2 * LZMA_VLI_MAX will

 * not overflow lzma_vli. This simplifies integer overflow detection.

 */

typedef uint64_t lzma_vli;

/**

 * \brief       Validate a 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 in

 *                        multi-call mode, *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 in multi-call

 *                        mode, *vli_pos must be initialized to zero. To

 *                        use single-call decoding, set vli_pos 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;