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Update compressor and decompressor

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This commit is contained in:
Stella Lau 2017-07-06 16:47:08 -07:00
parent b96ad327a4
commit 3bbfa1249e
2 changed files with 33 additions and 11 deletions
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40
contrib/long_distance_matching/ldm.c
View File

@ -20,6 +20,8 @@
#define RUN_BITS (8-ML_BITS)
#define RUN_MASK ((1U<<RUN_BITS)-1)
//#define LDM_DEBUG
typedef uint8_t BYTE;
typedef uint16_t U16;
typedef uint32_t U32;
@ -173,6 +175,7 @@ size_t LDM_compress(void const *source, void *dest, size_t source_size,
while (ip < ilimit) {
const BYTE *match;
BYTE *token;
/* Find a match */
{
const BYTE *forwardIp = ip;
@ -196,8 +199,10 @@ size_t LDM_compress(void const *source, void *dest, size_t source_size,
unsigned const litLength = (unsigned)(ip - anchor);
token = op++;
#ifdef LDM_DEBUG
printf("Cur position: %zu\n", anchor - istart);
printf("LitLength %zu. (Match offset). %zu\n", litLength, ip - match);
#endif
/*
fwrite(match, 4, 1, stdout);
printf("\n");
@ -207,16 +212,17 @@ size_t LDM_compress(void const *source, void *dest, size_t source_size,
int len = (int)litLength - RUN_MASK;
*token = (RUN_MASK << ML_BITS);
for (; len >= 255; len -= 255) {
*op++ = (BYTE)len;
*op++ = 255;
}
*op++ = (BYTE)len;
} else {
*token = (BYTE)(litLength << ML_BITS);
}
#ifdef LDM_DEBUG
printf("Literals ");
fwrite(anchor, litLength, 1, stdout);
printf("\n");
#endif
LDM_wild_copy(op, anchor, op + litLength);
op += litLength;
}
@ -232,10 +238,11 @@ _next_match:
unsigned matchCode;
matchCode = LDM_count(ip + MINMATCH, match + MINMATCH,
matchlimit);
#ifdef LDM_DEBUG
printf("Match length %zu\n", matchCode + MINMATCH);
fwrite(ip, MINMATCH + matchCode, 1, stdout);
printf("\n");
#endif
ip += MINMATCH + matchCode;
if (matchCode >= ML_MASK) {
*token += ML_MASK;
@ -251,7 +258,9 @@ _next_match:
} else {
*token += (BYTE)(matchCode);
}
#ifdef LDM_DEBUG
printf("\n");
#endif
}
anchor = ip;
@ -308,24 +317,33 @@ size_t LDM_decompress(void const *source, void *dest, size_t compressed_size,
length += s;
} while (s == 255);
}
#ifdef LDM_DEBUG
printf("Literal length: %zu\n", length);
#endif
/* copy literals */
cpy = op + length;
#ifdef LDM_DEBUG
printf("Literals ");
fwrite(ip, length, 1, stdout);
printf("\n");
#endif
LDM_wild_copy(op, ip, cpy);
ip += length;
op = cpy;
/* get offset */
offset = LDM_readLE16(ip);
#ifdef LDM_DEBUG
printf("Offset: %zu\n", offset);
#endif
ip += 2;
match = op - offset;
// LDM_write32(op, (U32)offset);
/* get matchlength */
length = token & ML_MASK;
printf("Match length: %zu\n", length);
if (length == ML_MASK) {
unsigned s;
do {
@ -334,16 +352,20 @@ size_t LDM_decompress(void const *source, void *dest, size_t compressed_size,
} while (s == 255);
}
length += MINMATCH;
#ifdef LDM_DEBUG
printf("Match length: %zu\n", length);
#endif
/* copy match */
cpy = op + length;
// Inefficient for now
while (match < cpy - offset) {
*op++ = *match++;
}
}
// memcpy(dest, source, compressed_size);
return compressed_size;
return op - (BYTE *)dest;
}

4
contrib/long_distance_matching/main-ldm.c
View File

@ -229,7 +229,7 @@ static size_t decompress(const char *fname, const char *oname) {
}
/* go to the location corresponding to the last byte */
if (lseek(fdout, statbuf.st_size - 1, SEEK_SET) == -1) {
if (lseek(fdout, 2*statbuf.st_size - 1, SEEK_SET) == -1) {
perror("lseek error");
return 1;
}
@ -264,7 +264,7 @@ static size_t decompress(const char *fname, const char *oname) {
size_t size_out = LDM_decompress(src, dst, statbuf.st_size,
statbuf.st_size);
#endif
ftruncate(fdout, size_out);
//ftruncate(fdout, size_out);
close(fdin);
close(fdout);