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author | Petr Mrázek <peterix@gmail.com> | 2013-09-26 02:58:09 +0200 |
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committer | Petr Mrázek <peterix@gmail.com> | 2013-09-26 02:59:56 +0200 |
commit | 2c8dc0b855c38c5204d398ad306fa9cf43be1ada (patch) | |
tree | 59429d658012a3df0e548e1a5f08100fb2930fc0 /depends/lzma/wrapper/lzma_header.c | |
parent | af234f35029de8c46aefecd8b9345b30ae1c51b0 (diff) | |
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Compression algo dependencies, still need hackery...
Diffstat (limited to 'depends/lzma/wrapper/lzma_header.c')
-rw-r--r-- | depends/lzma/wrapper/lzma_header.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/depends/lzma/wrapper/lzma_header.c b/depends/lzma/wrapper/lzma_header.c new file mode 100644 index 00000000..ab32549f --- /dev/null +++ b/depends/lzma/wrapper/lzma_header.c @@ -0,0 +1,134 @@ +/* + * Written in 2009 by Lloyd Hilaiel + * + * License + * + * All the cruft you find here is public domain. You don't have to credit + * anyone to use this code, but my personal request is that you mention + * Igor Pavlov for his hard, high quality work. + */ + +/* XXX: clean this up, it's mostly lifted from pavel */ + +#include "lzma_header.h" + +#include <string.h> +#include <assert.h> + +#define ELZMA_LZMA_HEADER_SIZE 13 +#define ELZMA_LZMA_PROPSBUF_SIZE 5 + +/**************** + Header parsing + ****************/ + +#ifndef UINT64_MAX +#define UINT64_MAX ((unsigned long long)-1) +#endif + +/* Parse the properties byte */ +static char lzmadec_header_properties(unsigned char *pb, unsigned char *lp, unsigned char *lc, + const unsigned char c) +{ + /* pb, lp and lc are encoded into a single byte. */ + if (c > (9 * 5 * 5)) + return -1; + *pb = c / (9 * 5); /* 0 <= pb <= 4 */ + *lp = (c % (9 * 5)) / 9; /* 0 <= lp <= 4 */ + *lc = c % 9; /* 0 <= lc <= 8 */ + + assert(*pb < 5 && *lp < 5 && *lc < 9); + return 0; +} + +/* Parse the dictionary size (4 bytes, little endian) */ +static char lzmadec_header_dictionary(unsigned int *size, const unsigned char *buffer) +{ + unsigned int i; + *size = 0; + for (i = 0; i < 4; i++) + *size += (unsigned int)(*buffer++) << (i * 8); + /* The dictionary size is limited to 256 MiB (checked from + * LZMA SDK 4.30) */ + if (*size > (1 << 28)) + return -1; + return 0; +} + +/* Parse the uncompressed size field (8 bytes, little endian) */ +static void lzmadec_header_uncompressed(unsigned long long *size, unsigned char *is_streamed, + const unsigned char *buffer) +{ + unsigned int i; + + /* Streamed files have all 64 bits set in the size field. + * We don't know the uncompressed size beforehand. */ + *is_streamed = 1; /* Assume streamed. */ + *size = 0; + for (i = 0; i < 8; i++) + { + *size += (unsigned long long)buffer[i] << (i * 8); + if (buffer[i] != 255) + *is_streamed = 0; + } + assert((*is_streamed == 1 && *size == UINT64_MAX) || + (*is_streamed == 0 && *size < UINT64_MAX)); +} + +static void initLzmaHeader(struct elzma_file_header *hdr) +{ + memset((void *)hdr, 0, sizeof(struct elzma_file_header)); +} + +static int parseLzmaHeader(const unsigned char *hdrBuf, struct elzma_file_header *hdr) +{ + if (lzmadec_header_properties(&(hdr->pb), &(hdr->lp), &(hdr->lc), *hdrBuf) || + lzmadec_header_dictionary(&(hdr->dictSize), hdrBuf + 1)) + { + return 1; + } + lzmadec_header_uncompressed(&(hdr->uncompressedSize), &(hdr->isStreamed), hdrBuf + 5); + + return 0; +} + +static int serializeLzmaHeader(unsigned char *hdrBuf, const struct elzma_file_header *hdr) +{ + unsigned int i; + + memset((void *)hdrBuf, 0, ELZMA_LZMA_HEADER_SIZE); + + /* encode lc, pb, and lp */ + *hdrBuf++ = hdr->lc + (hdr->pb * 45) + (hdr->lp * 45 * 9); + + /* encode dictionary size */ + for (i = 0; i < 4; i++) + { + *(hdrBuf++) = (unsigned char)(hdr->dictSize >> (i * 8)); + } + + /* encode uncompressed size */ + for (i = 0; i < 8; i++) + { + if (hdr->isStreamed) + { + *(hdrBuf++) = 0xff; + } + else + { + *(hdrBuf++) = (unsigned char)(hdr->uncompressedSize >> (i * 8)); + } + } + + return 0; +} + +void initializeLZMAFormatHandler(struct elzma_format_handler *hand) +{ + hand->header_size = ELZMA_LZMA_HEADER_SIZE; + hand->init_header = initLzmaHeader; + hand->parse_header = parseLzmaHeader; + hand->serialize_header = serializeLzmaHeader; + hand->footer_size = 0; + hand->serialize_footer = NULL; +} |