FastLZ: Update to upstream version 0.5.0

Upstream development restarted after 13 years. Changes:

2020-02-02: Version 0.5.0

    Minor speed improvement on the decompressor.
    Prevent memory violation when decompressing corrupted input.

2020-01-10: Version 0.4.0

    Only code & infrastructure clean-up, no new functionality.
This commit is contained in:
Rémi Verschelde 2020-04-30 14:24:03 +02:00
parent d29514acce
commit 5167c9186a
4 changed files with 500 additions and 462 deletions

View file

@ -260,7 +260,7 @@ License: BSD-3-clause
Files: ./thirdparty/misc/fastlz.c
./thirdparty/misc/fastlz.h
Comment: FastLZ
Copyright: 2005-2007, Ariya Hidayat
Copyright: 2005-2020, Ariya Hidayat
License: Expat
Files: ./thirdparty/misc/hq2x.cpp

View file

@ -371,7 +371,7 @@ Collection of single-file libraries used in Godot components.
* License: MIT
- `fastlz.{c,h}`
* Upstream: https://github.com/ariya/FastLZ
* Version: git (f121734, 2007)
* Version: 0.5.0 (4f20f54d46f5a6dd4fae4def134933369b7602d2, 2020)
* License: MIT
- `hq2x.{cpp,h}`
* Upstream: https://github.com/brunexgeek/hqx

View file

@ -1,9 +1,6 @@
/*
FastLZ - lightning-fast lossless compression library
Copyright (C) 2007 Ariya Hidayat (ariya@kde.org)
Copyright (C) 2006 Ariya Hidayat (ariya@kde.org)
Copyright (C) 2005 Ariya Hidayat (ariya@kde.org)
/*
FastLZ - Byte-aligned LZ77 compression library
Copyright (C) 2005-2020 Ariya Hidayat <ariya.hidayat@gmail.com>
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
@ -24,274 +21,148 @@
THE SOFTWARE.
*/
#if !defined(FASTLZ_COMPRESSOR) && !defined(FASTLZ_DECOMPRESSOR)
#include "fastlz.h"
#include <stdint.h>
/*
* Always check for bound when decompressing.
* Generally it is best to leave it defined.
*/
#define FASTLZ_SAFE
#if defined(FASTLZ_USE_SAFE_DECOMPRESSOR) && (FASTLZ_USE_SAFE_DECOMPRESSOR == 0)
#undef FASTLZ_SAFE
#endif
/*
* Give hints to the compiler for branch prediction optimization.
*/
#if defined(__GNUC__) && (__GNUC__ > 2)
#define FASTLZ_EXPECT_CONDITIONAL(c) (__builtin_expect((c), 1))
#define FASTLZ_UNEXPECT_CONDITIONAL(c) (__builtin_expect((c), 0))
#if defined(__clang__) || (defined(__GNUC__) && (__GNUC__ > 2))
#define FASTLZ_LIKELY(c) (__builtin_expect(!!(c), 1))
#define FASTLZ_UNLIKELY(c) (__builtin_expect(!!(c), 0))
#else
#define FASTLZ_EXPECT_CONDITIONAL(c) (c)
#define FASTLZ_UNEXPECT_CONDITIONAL(c) (c)
#define FASTLZ_LIKELY(c) (c)
#define FASTLZ_UNLIKELY(c) (c)
#endif
/*
* Use inlined functions for supported systems.
*/
#if defined(__GNUC__) || defined(__DMC__) || defined(__POCC__) || defined(__WATCOMC__) || defined(__SUNPRO_C)
#define FASTLZ_INLINE inline
#elif defined(__BORLANDC__) || defined(_MSC_VER) || defined(__LCC__)
#define FASTLZ_INLINE __inline
#else
#define FASTLZ_INLINE
#endif
/*
* Prevent accessing more than 8-bit at once, except on x86 architectures.
*/
#if !defined(FASTLZ_STRICT_ALIGN)
#define FASTLZ_STRICT_ALIGN
#if defined(__i386__) || defined(__386) /* GNU C, Sun Studio */
#undef FASTLZ_STRICT_ALIGN
#elif defined(__i486__) || defined(__i586__) || defined(__i686__) /* GNU C */
#undef FASTLZ_STRICT_ALIGN
#elif defined(_M_IX86) /* Intel, MSVC */
#undef FASTLZ_STRICT_ALIGN
#elif defined(__386)
#undef FASTLZ_STRICT_ALIGN
#elif defined(_X86_) /* MinGW */
#undef FASTLZ_STRICT_ALIGN
#elif defined(__I86__) /* Digital Mars */
#undef FASTLZ_STRICT_ALIGN
#endif
#endif
/*
* FIXME: use preprocessor magic to set this on different platforms!
*/
typedef unsigned char flzuint8;
typedef unsigned short flzuint16;
typedef unsigned int flzuint32;
/* prototypes */
int fastlz_compress(const void* input, int length, void* output);
int fastlz_compress_level(int level, const void* input, int length, void* output);
int fastlz_decompress(const void* input, int length, void* output, int maxout);
#define MAX_COPY 32
#define MAX_LEN 264 /* 256 + 8 */
#define MAX_DISTANCE 8192
#if !defined(FASTLZ_STRICT_ALIGN)
#define FASTLZ_READU16(p) *((const flzuint16*)(p))
#if defined(FASTLZ_SAFE)
#define FASTLZ_BOUND_CHECK(cond) \
if (FASTLZ_UNLIKELY(!(cond))) return 0;
#else
#define FASTLZ_READU16(p) ((p)[0] | (p)[1]<<8)
#define FASTLZ_BOUND_CHECK(cond) \
do { \
} while (0)
#endif
#define HASH_LOG 13
#define HASH_SIZE (1<< HASH_LOG)
#define HASH_MASK (HASH_SIZE-1)
#define HASH_FUNCTION(v,p) { v = FASTLZ_READU16(p); v ^= FASTLZ_READU16(p+1)^(v>>(16-HASH_LOG));v &= HASH_MASK; }
#define MAX_COPY 32
#define MAX_LEN 264 /* 256 + 8 */
#define MAX_L1_DISTANCE 8192
#define MAX_L2_DISTANCE 8191
#define MAX_FARDISTANCE (65535 + MAX_L2_DISTANCE - 1)
#undef FASTLZ_LEVEL
#define FASTLZ_LEVEL 1
#define FASTLZ_READU16(p) ((p)[0] | (p)[1] << 8)
#undef FASTLZ_COMPRESSOR
#undef FASTLZ_DECOMPRESSOR
#define FASTLZ_COMPRESSOR fastlz1_compress
#define FASTLZ_DECOMPRESSOR fastlz1_decompress
static FASTLZ_INLINE int FASTLZ_COMPRESSOR(const void* input, int length, void* output);
static FASTLZ_INLINE int FASTLZ_DECOMPRESSOR(const void* input, int length, void* output, int maxout);
#include "fastlz.c"
#define HASH_LOG 13
#define HASH_SIZE (1 << HASH_LOG)
#define HASH_MASK (HASH_SIZE - 1)
#define HASH_FUNCTION(v, p) \
{ \
v = FASTLZ_READU16(p); \
v ^= FASTLZ_READU16(p + 1) ^ (v >> (16 - HASH_LOG)); \
v &= HASH_MASK; \
}
#undef FASTLZ_LEVEL
#define FASTLZ_LEVEL 2
int fastlz1_compress(const void* input, int length, void* output) {
const uint8_t* ip = (const uint8_t*)input;
const uint8_t* ip_bound = ip + length - 2;
const uint8_t* ip_limit = ip + length - 12 - 1;
uint8_t* op = (uint8_t*)output;
#undef MAX_DISTANCE
#define MAX_DISTANCE 8191
#define MAX_FARDISTANCE (65535+MAX_DISTANCE-1)
const uint8_t* htab[HASH_SIZE];
uint32_t hval;
#undef FASTLZ_COMPRESSOR
#undef FASTLZ_DECOMPRESSOR
#define FASTLZ_COMPRESSOR fastlz2_compress
#define FASTLZ_DECOMPRESSOR fastlz2_decompress
static FASTLZ_INLINE int FASTLZ_COMPRESSOR(const void* input, int length, void* output);
static FASTLZ_INLINE int FASTLZ_DECOMPRESSOR(const void* input, int length, void* output, int maxout);
#include "fastlz.c"
int fastlz_compress(const void* input, int length, void* output)
{
/* for short block, choose fastlz1 */
if(length < 65536)
return fastlz1_compress(input, length, output);
/* else... */
return fastlz2_compress(input, length, output);
}
int fastlz_decompress(const void* input, int length, void* output, int maxout)
{
/* magic identifier for compression level */
int level = ((*(const flzuint8*)input) >> 5) + 1;
if(level == 1)
return fastlz1_decompress(input, length, output, maxout);
if(level == 2)
return fastlz2_decompress(input, length, output, maxout);
/* unknown level, trigger error */
return 0;
}
int fastlz_compress_level(int level, const void* input, int length, void* output)
{
if(level == 1)
return fastlz1_compress(input, length, output);
if(level == 2)
return fastlz2_compress(input, length, output);
return 0;
}
#else /* !defined(FASTLZ_COMPRESSOR) && !defined(FASTLZ_DECOMPRESSOR) */
static FASTLZ_INLINE int FASTLZ_COMPRESSOR(const void* input, int length, void* output)
{
const flzuint8* ip = (const flzuint8*) input;
const flzuint8* ip_bound = ip + length - 2;
const flzuint8* ip_limit = ip + length - 12;
flzuint8* op = (flzuint8*) output;
const flzuint8* htab[HASH_SIZE];
const flzuint8** hslot;
flzuint32 hval;
flzuint32 copy;
uint32_t copy;
/* sanity check */
if(FASTLZ_UNEXPECT_CONDITIONAL(length < 4))
{
if(length)
{
if (FASTLZ_UNLIKELY(length < 4)) {
if (length) {
/* create literal copy only */
*op++ = length-1;
*op++ = length - 1;
ip_bound++;
while(ip <= ip_bound)
*op++ = *ip++;
return length+1;
}
else
while (ip <= ip_bound) *op++ = *ip++;
return length + 1;
} else
return 0;
}
/* initializes hash table */
for (hslot = htab; hslot < htab + HASH_SIZE; hslot++)
*hslot = ip;
for (hval = 0; hval < HASH_SIZE; ++hval) htab[hval] = ip;
/* we start with literal copy */
copy = 2;
*op++ = MAX_COPY-1;
*op++ = MAX_COPY - 1;
*op++ = *ip++;
*op++ = *ip++;
/* main loop */
while(FASTLZ_EXPECT_CONDITIONAL(ip < ip_limit))
{
const flzuint8* ref;
flzuint32 distance;
while (FASTLZ_LIKELY(ip < ip_limit)) {
const uint8_t* ref;
uint32_t distance;
/* minimum match length */
flzuint32 len = 3;
uint32_t len = 3;
/* comparison starting-point */
const flzuint8* anchor = ip;
/* check for a run */
#if FASTLZ_LEVEL==2
if(ip[0] == ip[-1] && FASTLZ_READU16(ip-1)==FASTLZ_READU16(ip+1))
{
distance = 1;
ip += 3;
ref = anchor - 1 + 3;
goto match;
}
#endif
const uint8_t* anchor = ip;
/* find potential match */
HASH_FUNCTION(hval,ip);
hslot = htab + hval;
HASH_FUNCTION(hval, ip);
ref = htab[hval];
/* update hash table */
htab[hval] = anchor;
/* calculate distance to the match */
distance = anchor - ref;
/* update hash table */
*hslot = anchor;
/* is this a match? check the first 3 bytes */
if(distance==0 ||
#if FASTLZ_LEVEL==1
(distance >= MAX_DISTANCE) ||
#else
(distance >= MAX_FARDISTANCE) ||
#endif
*ref++ != *ip++ || *ref++!=*ip++ || *ref++!=*ip++)
if (distance == 0 || (distance >= MAX_L1_DISTANCE) || *ref++ != *ip++ ||
*ref++ != *ip++ || *ref++ != *ip++)
goto literal;
#if FASTLZ_LEVEL==2
/* far, needs at least 5-byte match */
if(distance >= MAX_DISTANCE)
{
if(*ip++ != *ref++ || *ip++!= *ref++)
goto literal;
len += 2;
}
match:
#endif
/* last matched byte */
ip = anchor + len;
/* distance is biased */
distance--;
if(!distance)
{
if (!distance) {
/* zero distance means a run */
flzuint8 x = ip[-1];
while(ip < ip_bound)
if(*ref++ != x) break; else ip++;
}
else
for(;;)
{
/* safe because the outer check against ip limit */
if(*ref++ != *ip++) break;
if(*ref++ != *ip++) break;
if(*ref++ != *ip++) break;
if(*ref++ != *ip++) break;
if(*ref++ != *ip++) break;
if(*ref++ != *ip++) break;
if(*ref++ != *ip++) break;
if(*ref++ != *ip++) break;
while(ip < ip_bound)
if(*ref++ != *ip++) break;
break;
}
uint8_t x = ip[-1];
while (ip < ip_bound)
if (*ref++ != x)
break;
else
ip++;
} else
for (;;) {
/* safe because the outer check against ip limit */
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
while (ip < ip_bound)
if (*ref++ != *ip++) break;
break;
}
/* if we have copied something, adjust the copy count */
if(copy)
/* copy is biased, '0' means 1 byte copy */
*(op-copy-1) = copy-1;
if (copy) /* copy is biased, '0' means 1 byte copy */
*(op - copy - 1) = copy - 1;
else
/* back, to overwrite the copy count */
op--;
@ -304,248 +175,417 @@ static FASTLZ_INLINE int FASTLZ_COMPRESSOR(const void* input, int length, void*
len = ip - anchor;
/* encode the match */
#if FASTLZ_LEVEL==2
if(distance < MAX_DISTANCE)
{
if(len < 7)
{
*op++ = (len << 5) + (distance >> 8);
*op++ = (distance & 255);
}
else
{
if (FASTLZ_UNLIKELY(len > MAX_LEN - 2))
while (len > MAX_LEN - 2) {
*op++ = (7 << 5) + (distance >> 8);
for(len-=7; len >= 255; len-= 255)
*op++ = 255;
*op++ = len;
*op++ = MAX_LEN - 2 - 7 - 2;
*op++ = (distance & 255);
}
}
else
{
/* far away, but not yet in the another galaxy... */
if(len < 7)
{
distance -= MAX_DISTANCE;
*op++ = (len << 5) + 31;
*op++ = 255;
*op++ = distance >> 8;
*op++ = distance & 255;
}
else
{
distance -= MAX_DISTANCE;
*op++ = (7 << 5) + 31;
for(len-=7; len >= 255; len-= 255)
*op++ = 255;
*op++ = len;
*op++ = 255;
*op++ = distance >> 8;
*op++ = distance & 255;
}
}
#else
if(FASTLZ_UNEXPECT_CONDITIONAL(len > MAX_LEN-2))
while(len > MAX_LEN-2)
{
*op++ = (7 << 5) + (distance >> 8);
*op++ = MAX_LEN - 2 - 7 -2;
*op++ = (distance & 255);
len -= MAX_LEN-2;
len -= MAX_LEN - 2;
}
if(len < 7)
{
if (len < 7) {
*op++ = (len << 5) + (distance >> 8);
*op++ = (distance & 255);
}
else
{
} else {
*op++ = (7 << 5) + (distance >> 8);
*op++ = len - 7;
*op++ = (distance & 255);
}
#endif
/* update the hash at match boundary */
HASH_FUNCTION(hval,ip);
HASH_FUNCTION(hval, ip);
htab[hval] = ip++;
HASH_FUNCTION(hval,ip);
HASH_FUNCTION(hval, ip);
htab[hval] = ip++;
/* assuming literal copy */
*op++ = MAX_COPY-1;
*op++ = MAX_COPY - 1;
continue;
literal:
*op++ = *anchor++;
ip = anchor;
copy++;
if(FASTLZ_UNEXPECT_CONDITIONAL(copy == MAX_COPY))
{
copy = 0;
*op++ = MAX_COPY-1;
}
literal:
*op++ = *anchor++;
ip = anchor;
copy++;
if (FASTLZ_UNLIKELY(copy == MAX_COPY)) {
copy = 0;
*op++ = MAX_COPY - 1;
}
}
/* left-over as literal copy */
ip_bound++;
while(ip <= ip_bound)
{
while (ip <= ip_bound) {
*op++ = *ip++;
copy++;
if(copy == MAX_COPY)
{
if (copy == MAX_COPY) {
copy = 0;
*op++ = MAX_COPY-1;
*op++ = MAX_COPY - 1;
}
}
/* if we have copied something, adjust the copy length */
if(copy)
*(op-copy-1) = copy-1;
if (copy)
*(op - copy - 1) = copy - 1;
else
op--;
#if FASTLZ_LEVEL==2
/* marker for fastlz2 */
*(flzuint8*)output |= (1 << 5);
#endif
return op - (flzuint8*)output;
return op - (uint8_t*)output;
}
static FASTLZ_INLINE int FASTLZ_DECOMPRESSOR(const void* input, int length, void* output, int maxout)
{
const flzuint8* ip = (const flzuint8*) input;
const flzuint8* ip_limit = ip + length;
flzuint8* op = (flzuint8*) output;
flzuint8* op_limit = op + maxout;
flzuint32 ctrl = (*ip++) & 31;
int loop = 1;
#if defined(FASTLZ_USE_MEMMOVE) && (FASTLZ_USE_MEMMOVE == 0)
do
{
const flzuint8* ref = op;
flzuint32 len = ctrl >> 5;
flzuint32 ofs = (ctrl & 31) << 8;
static void fastlz_memmove(uint8_t* dest, const uint8_t* src, uint32_t count) {
do {
*dest++ = *src++;
} while (--count);
}
static void fastlz_memcpy(uint8_t* dest, const uint8_t* src, uint32_t count) {
return fastlz_memmove(dest, src, count);
}
if(ctrl >= 32)
{
#if FASTLZ_LEVEL==2
flzuint8 code;
#endif
len--;
ref -= ofs;
if (len == 7-1)
#if FASTLZ_LEVEL==1
len += *ip++;
ref -= *ip++;
#else
do
{
code = *ip++;
len += code;
} while (code==255);
code = *ip++;
ref -= code;
/* match from 16-bit distance */
if(FASTLZ_UNEXPECT_CONDITIONAL(code==255))
if(FASTLZ_EXPECT_CONDITIONAL(ofs==(31 << 8)))
{
ofs = (*ip++) << 8;
ofs += *ip++;
ref = op - ofs - MAX_DISTANCE;
}
#endif
#ifdef FASTLZ_SAFE
if (FASTLZ_UNEXPECT_CONDITIONAL(op + len + 3 > op_limit))
return 0;
#include <string.h>
if (FASTLZ_UNEXPECT_CONDITIONAL(ref-1 < (flzuint8 *)output))
return 0;
#endif
if(FASTLZ_EXPECT_CONDITIONAL(ip < ip_limit))
ctrl = *ip++;
else
loop = 0;
if(ref == op)
{
/* optimize copy for a run */
flzuint8 b = ref[-1];
*op++ = b;
*op++ = b;
*op++ = b;
for(; len; --len)
*op++ = b;
}
else
{
#if !defined(FASTLZ_STRICT_ALIGN)
const flzuint16* p;
flzuint16* q;
#endif
/* copy from reference */
ref--;
*op++ = *ref++;
*op++ = *ref++;
*op++ = *ref++;
#if !defined(FASTLZ_STRICT_ALIGN)
/* copy a byte, so that now it's word aligned */
if(len & 1)
{
*op++ = *ref++;
len--;
}
/* copy 16-bit at once */
q = (flzuint16*) op;
op += len;
p = (const flzuint16*) ref;
for(len>>=1; len > 4; len-=4)
{
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
*q++ = *p++;
}
for(; len; --len)
*q++ = *p++;
#else
for(; len; --len)
*op++ = *ref++;
#endif
}
}
else
{
ctrl++;
#ifdef FASTLZ_SAFE
if (FASTLZ_UNEXPECT_CONDITIONAL(op + ctrl > op_limit))
return 0;
if (FASTLZ_UNEXPECT_CONDITIONAL(ip + ctrl > ip_limit))
return 0;
#endif
*op++ = *ip++;
for(--ctrl; ctrl; ctrl--)
*op++ = *ip++;
loop = FASTLZ_EXPECT_CONDITIONAL(ip < ip_limit);
if(loop)
ctrl = *ip++;
static void fastlz_memmove(uint8_t* dest, const uint8_t* src, uint32_t count) {
if ((count > 4) && (dest >= src + count)) {
memmove(dest, src, count);
} else {
switch (count) {
default:
do {
*dest++ = *src++;
} while (--count);
break;
case 3:
*dest++ = *src++;
case 2:
*dest++ = *src++;
case 1:
*dest++ = *src++;
case 0:
break;
}
}
while(FASTLZ_EXPECT_CONDITIONAL(loop));
return op - (flzuint8*)output;
}
#endif /* !defined(FASTLZ_COMPRESSOR) && !defined(FASTLZ_DECOMPRESSOR) */
static void fastlz_memcpy(uint8_t* dest, const uint8_t* src, uint32_t count) {
memcpy(dest, src, count);
}
#endif
int fastlz1_decompress(const void* input, int length, void* output,
int maxout) {
const uint8_t* ip = (const uint8_t*)input;
const uint8_t* ip_limit = ip + length;
const uint8_t* ip_bound = ip_limit - 2;
uint8_t* op = (uint8_t*)output;
uint8_t* op_limit = op + maxout;
uint32_t ctrl = (*ip++) & 31;
while (1) {
if (ctrl >= 32) {
uint32_t len = (ctrl >> 5) - 1;
uint32_t ofs = (ctrl & 31) << 8;
const uint8_t* ref = op - ofs - 1;
if (len == 7 - 1) {
FASTLZ_BOUND_CHECK(ip <= ip_bound);
len += *ip++;
}
ref -= *ip++;
len += 3;
FASTLZ_BOUND_CHECK(op + len <= op_limit);
FASTLZ_BOUND_CHECK(ref >= (uint8_t*)output);
fastlz_memmove(op, ref, len);
op += len;
} else {
ctrl++;
FASTLZ_BOUND_CHECK(op + ctrl <= op_limit);
FASTLZ_BOUND_CHECK(ip + ctrl <= ip_limit);
fastlz_memcpy(op, ip, ctrl);
ip += ctrl;
op += ctrl;
}
if (FASTLZ_UNLIKELY(ip > ip_bound)) break;
ctrl = *ip++;
}
return op - (uint8_t*)output;
}
int fastlz2_compress(const void* input, int length, void* output) {
const uint8_t* ip = (const uint8_t*)input;
const uint8_t* ip_bound = ip + length - 2;
const uint8_t* ip_limit = ip + length - 12 - 1;
uint8_t* op = (uint8_t*)output;
const uint8_t* htab[HASH_SIZE];
uint32_t hval;
uint32_t copy;
/* sanity check */
if (FASTLZ_UNLIKELY(length < 4)) {
if (length) {
/* create literal copy only */
*op++ = length - 1;
ip_bound++;
while (ip <= ip_bound) *op++ = *ip++;
return length + 1;
} else
return 0;
}
/* initializes hash table */
for (hval = 0; hval < HASH_SIZE; ++hval) htab[hval] = ip;
/* we start with literal copy */
copy = 2;
*op++ = MAX_COPY - 1;
*op++ = *ip++;
*op++ = *ip++;
/* main loop */
while (FASTLZ_LIKELY(ip < ip_limit)) {
const uint8_t* ref;
uint32_t distance;
/* minimum match length */
uint32_t len = 3;
/* comparison starting-point */
const uint8_t* anchor = ip;
/* check for a run */
if (ip[0] == ip[-1] && ip[0] == ip[1] && ip[1] == ip[2]) {
distance = 1;
ip += 3;
ref = anchor - 1 + 3;
goto match;
}
/* find potential match */
HASH_FUNCTION(hval, ip);
ref = htab[hval];
/* update hash table */
htab[hval] = anchor;
/* calculate distance to the match */
distance = anchor - ref;
/* is this a match? check the first 3 bytes */
if (distance == 0 || (distance >= MAX_FARDISTANCE) || *ref++ != *ip++ ||
*ref++ != *ip++ || *ref++ != *ip++)
goto literal;
/* far, needs at least 5-byte match */
if (distance >= MAX_L2_DISTANCE) {
if (*ip++ != *ref++ || *ip++ != *ref++) goto literal;
len += 2;
}
match:
/* last matched byte */
ip = anchor + len;
/* distance is biased */
distance--;
if (!distance) {
/* zero distance means a run */
uint8_t x = ip[-1];
while (ip < ip_bound)
if (*ref++ != x)
break;
else
ip++;
} else
for (;;) {
/* safe because the outer check against ip limit */
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
if (*ref++ != *ip++) break;
while (ip < ip_bound)
if (*ref++ != *ip++) break;
break;
}
/* if we have copied something, adjust the copy count */
if (copy) /* copy is biased, '0' means 1 byte copy */
*(op - copy - 1) = copy - 1;
else
/* back, to overwrite the copy count */
op--;
/* reset literal counter */
copy = 0;
/* length is biased, '1' means a match of 3 bytes */
ip -= 3;
len = ip - anchor;
/* encode the match */
if (distance < MAX_L2_DISTANCE) {
if (len < 7) {
*op++ = (len << 5) + (distance >> 8);
*op++ = (distance & 255);
} else {
*op++ = (7 << 5) + (distance >> 8);
for (len -= 7; len >= 255; len -= 255) *op++ = 255;
*op++ = len;
*op++ = (distance & 255);
}
} else {
/* far away, but not yet in the another galaxy... */
if (len < 7) {
distance -= MAX_L2_DISTANCE;
*op++ = (len << 5) + 31;
*op++ = 255;
*op++ = distance >> 8;
*op++ = distance & 255;
} else {
distance -= MAX_L2_DISTANCE;
*op++ = (7 << 5) + 31;
for (len -= 7; len >= 255; len -= 255) *op++ = 255;
*op++ = len;
*op++ = 255;
*op++ = distance >> 8;
*op++ = distance & 255;
}
}
/* update the hash at match boundary */
HASH_FUNCTION(hval, ip);
htab[hval] = ip++;
HASH_FUNCTION(hval, ip);
htab[hval] = ip++;
/* assuming literal copy */
*op++ = MAX_COPY - 1;
continue;
literal:
*op++ = *anchor++;
ip = anchor;
copy++;
if (FASTLZ_UNLIKELY(copy == MAX_COPY)) {
copy = 0;
*op++ = MAX_COPY - 1;
}
}
/* left-over as literal copy */
ip_bound++;
while (ip <= ip_bound) {
*op++ = *ip++;
copy++;
if (copy == MAX_COPY) {
copy = 0;
*op++ = MAX_COPY - 1;
}
}
/* if we have copied something, adjust the copy length */
if (copy)
*(op - copy - 1) = copy - 1;
else
op--;
/* marker for fastlz2 */
*(uint8_t*)output |= (1 << 5);
return op - (uint8_t*)output;
}
int fastlz2_decompress(const void* input, int length, void* output,
int maxout) {
const uint8_t* ip = (const uint8_t*)input;
const uint8_t* ip_limit = ip + length;
const uint8_t* ip_bound = ip_limit - 2;
uint8_t* op = (uint8_t*)output;
uint8_t* op_limit = op + maxout;
uint32_t ctrl = (*ip++) & 31;
while (1) {
if (ctrl >= 32) {
uint32_t len = (ctrl >> 5) - 1;
uint32_t ofs = (ctrl & 31) << 8;
const uint8_t* ref = op - ofs - 1;
uint8_t code;
if (len == 7 - 1) do {
FASTLZ_BOUND_CHECK(ip <= ip_bound);
code = *ip++;
len += code;
} while (code == 255);
code = *ip++;
ref -= code;
len += 3;
/* match from 16-bit distance */
if (FASTLZ_UNLIKELY(code == 255))
if (FASTLZ_LIKELY(ofs == (31 << 8))) {
FASTLZ_BOUND_CHECK(ip < ip_bound);
ofs = (*ip++) << 8;
ofs += *ip++;
ref = op - ofs - MAX_L2_DISTANCE - 1;
}
FASTLZ_BOUND_CHECK(op + len <= op_limit);
FASTLZ_BOUND_CHECK(ref >= (uint8_t*)output);
fastlz_memmove(op, ref, len);
op += len;
} else {
ctrl++;
FASTLZ_BOUND_CHECK(op + ctrl <= op_limit);
FASTLZ_BOUND_CHECK(ip + ctrl <= ip_limit);
fastlz_memcpy(op, ip, ctrl);
ip += ctrl;
op += ctrl;
}
if (FASTLZ_UNLIKELY(ip >= ip_limit)) break;
ctrl = *ip++;
}
return op - (uint8_t*)output;
}
int fastlz_compress(const void* input, int length, void* output) {
/* for short block, choose fastlz1 */
if (length < 65536) return fastlz1_compress(input, length, output);
/* else... */
return fastlz2_compress(input, length, output);
}
int fastlz_decompress(const void* input, int length, void* output, int maxout) {
/* magic identifier for compression level */
int level = ((*(const uint8_t*)input) >> 5) + 1;
if (level == 1) return fastlz1_decompress(input, length, output, maxout);
if (level == 2) return fastlz2_decompress(input, length, output, maxout);
/* unknown level, trigger error */
return 0;
}
int fastlz_compress_level(int level, const void* input, int length,
void* output) {
if (level == 1) return fastlz1_compress(input, length, output);
if (level == 2) return fastlz2_compress(input, length, output);
return 0;
}

View file

@ -1,9 +1,6 @@
/*
FastLZ - lightning-fast lossless compression library
Copyright (C) 2007 Ariya Hidayat (ariya@kde.org)
Copyright (C) 2006 Ariya Hidayat (ariya@kde.org)
Copyright (C) 2005 Ariya Hidayat (ariya@kde.org)
FastLZ - Byte-aligned LZ77 compression library
Copyright (C) 2005-2020 Ariya Hidayat <ariya.hidayat@gmail.com>
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
@ -27,48 +24,18 @@
#ifndef FASTLZ_H
#define FASTLZ_H
#define FASTLZ_VERSION 0x000100
#define FASTLZ_VERSION 0x000500
#define FASTLZ_VERSION_MAJOR 0
#define FASTLZ_VERSION_MINOR 0
#define FASTLZ_VERSION_REVISION 0
#define FASTLZ_VERSION_MAJOR 0
#define FASTLZ_VERSION_MINOR 5
#define FASTLZ_VERSION_REVISION 0
#define FASTLZ_VERSION_STRING "0.1.0"
#define FASTLZ_VERSION_STRING "0.5.0"
#if defined (__cplusplus)
#if defined(__cplusplus)
extern "C" {
#endif
/**
Compress a block of data in the input buffer and returns the size of
compressed block. The size of input buffer is specified by length. The
minimum input buffer size is 16.
The output buffer must be at least 5% larger than the input buffer
and can not be smaller than 66 bytes.
If the input is not compressible, the return value might be larger than
length (input buffer size).
The input buffer and the output buffer can not overlap.
*/
int fastlz_compress(const void* input, int length, void* output);
/**
Decompress a block of compressed data and returns the size of the
decompressed block. If error occurs, e.g. the compressed data is
corrupted or the output buffer is not large enough, then 0 (zero)
will be returned instead.
The input buffer and the output buffer can not overlap.
Decompression is memory safe and guaranteed not to write the output buffer
more than what is specified in maxout.
*/
int fastlz_decompress(const void* input, int length, void* output, int maxout);
/**
Compress a block of data in the input buffer and returns the size of
compressed block. The size of input buffer is specified by length. The
@ -88,12 +55,43 @@ int fastlz_decompress(const void* input, int length, void* output, int maxout);
Level 2 is slightly slower but it gives better compression ratio.
Note that the compressed data, regardless of the level, can always be
decompressed using the function fastlz_decompress above.
decompressed using the function fastlz_decompress below.
*/
int fastlz_compress_level(int level, const void* input, int length, void* output);
int fastlz_compress_level(int level, const void* input, int length,
void* output);
#if defined (__cplusplus)
/**
Decompress a block of compressed data and returns the size of the
decompressed block. If error occurs, e.g. the compressed data is
corrupted or the output buffer is not large enough, then 0 (zero)
will be returned instead.
The input buffer and the output buffer can not overlap.
Decompression is memory safe and guaranteed not to write the output buffer
more than what is specified in maxout.
Note that the decompression will always work, regardless of the
compression level specified in fastlz_compress_level above (when
producing the compressed block).
*/
int fastlz_decompress(const void* input, int length, void* output, int maxout);
/**
DEPRECATED.
This is similar to fastlz_compress_level above, but with the level
automatically chosen.
This function is deprecated and it will be completely removed in some future
version.
*/
int fastlz_compress(const void* input, int length, void* output);
#if defined(__cplusplus)
}
#endif