Defines | |
#define | LZMA_VLI_MAX (UINT64_MAX / 2) |
Maximum supported value of variable-length integer. | |
#define | LZMA_VLI_UNKNOWN UINT64_MAX |
VLI value to denote that the value is unknown. | |
#define | LZMA_VLI_BYTES_MAX 9 |
Maximum supported length of variable length integers. | |
#define | LZMA_VLI_C(n) UINT64_C(n) |
VLI constant suffix. | |
#define | lzma_vli_is_valid(vli) ((vli) <= LZMA_VLI_MAX || (vli) == LZMA_VLI_UNKNOWN) |
Simple macro to validate variable-length integer. | |
Typedefs | |
typedef uint64_t | lzma_vli |
Variable-length integer type. | |
Functions | |
LZMA_API (lzma_ret) lzma_vli_encode(lzma_vli vli | |
Encodes variable-length integer. | |
LZMA_API (uint32_t) lzma_vli_size(lzma_vli vli) lzma_attr_pure | |
Get the number of bytes required to encode a VLI. | |
Variables | |
size_t *lzma_restrict | vli_pos |
size_t *lzma_restrict uint8_t *lzma_restrict | out |
size_t *lzma_restrict uint8_t *lzma_restrict size_t *lzma_restrict | out_pos |
size_t *lzma_restrict uint8_t *lzma_restrict size_t *lzma_restrict size_t | out_size |
size_t *lzma_restrict const uint8_t *lzma_restrict | in |
size_t *lzma_restrict const uint8_t *lzma_restrict size_t *lzma_restrict | in_pos |
size_t *lzma_restrict const uint8_t *lzma_restrict size_t *lzma_restrict size_t | in_size |
This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
#define LZMA_VLI_MAX (UINT64_MAX / 2) |
#define LZMA_VLI_UNKNOWN UINT64_MAX |
VLI value to denote that the value is unknown.
Referenced by LZMA_API(), lzma_decoder_init(), and message_filters().
#define LZMA_VLI_BYTES_MAX 9 |
#define LZMA_VLI_C | ( | n | ) | UINT64_C(n) |
#define lzma_vli_is_valid | ( | vli | ) | ((vli) <= LZMA_VLI_MAX || (vli) == LZMA_VLI_UNKNOWN) |
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.
Referenced by LZMA_API().
typedef uint64_t lzma_vli |
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 typdefined to something else than uint64_t, it is guaranteed that 2 * LZMA_VLI_MAX will not overflow lzma_vli. This simplifies integer overflow detection.
LZMA_API | ( | lzma_ret | ) |
Encodes variable-length integer.
Calculate Block Header Size.
Decodes variable-length integer.
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 at maximum of UINT64_MAX / 2. You should use LZMA_VLI_MAX for clarity.
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.
vli | Integer to be encoded | |
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. | |
out | Beginning of the output buffer | |
out_pos | The next byte will be written to out[*out_pos]. | |
out_size | Size of the out buffer; the first byte into which no data is written to is out[out_size]. |
Multi-call (vli_pos != NULL):
Like lzma_vli_encode(), this function has single-call and multi-call modes.
vli | Pointer to decoded integer. The decoder will initialize it to zero when *vli_pos == 0, so application isn't required to initialize *vli. | |
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. | |
in | Beginning of the input buffer | |
in_pos | The next byte will be read from in[*in_pos]. | |
in_size | Size of the input buffer; the first byte that won't be read is in[in_size]. |
Multi-call (vli_pos != NULL):
References LZMA_FILTERS_MAX, LZMA_OK, LZMA_PROG_ERROR, lzma_vli_is_valid, LZMA_VLI_UNKNOWN, and return_if_error.
LZMA_API | ( | uint32_t | ) |
Get the number of bytes required to encode a VLI.
liblzma version number as an integer
Calculate CRC32.
Although not all Check IDs have a check algorithm associated, the size of every Check is already frozen. This function returns the size (in bytes) of the Check field with the specified Check ID. The values are: { 0, 4, 4, 4, 8, 8, 8, 16, 16, 16, 32, 32, 32, 64, 64, 64 }
If the argument is not in the range [0, 15], UINT32_MAX is returned.
Calculates CRC32 using the polynomial from the IEEE 802.3 standard.
buf | Pointer to the input buffer | |
size | Size of the input buffer | |
crc | Previously returned CRC value. This is used to calculate the CRC of a big buffer in smaller chunks. Set to zero when there is no previous value. |
References lzma_crc32_table, LZMA_VLI_BYTES_MAX, and LZMA_VLI_MAX.