#include "lz4.h"
size_t lz4raw_decode_buffer(uint8_t * __restrict dst_buffer, size_t dst_size,
const uint8_t * __restrict src_buffer, size_t src_size,
void * __restrict work __attribute__((unused)))
{
const uint8_t * src = src_buffer;
uint8_t * dst = dst_buffer;
#if LZ4_ENABLE_ASSEMBLY_DECODE
if (dst_size > LZ4_GOFAST_SAFETY_MARGIN && src_size > LZ4_GOFAST_SAFETY_MARGIN)
{
if (lz4_decode_asm(&dst, dst_buffer, dst_buffer + dst_size - LZ4_GOFAST_SAFETY_MARGIN, &src, src_buffer + src_size - LZ4_GOFAST_SAFETY_MARGIN))
return 0; }
#endif
if (lz4_decode(&dst, dst_buffer, dst_buffer + dst_size, &src, src_buffer + src_size))
return 0;
return (size_t)(dst - dst_buffer); }
#if LZ4DEBUG
#define DEBUG_LZ4_ENCODE_ERRORS (1)
#define DEBUG_LZ4_DECODE_ERRORS (1)
#endif
#if DEBUG_LZ4_ENCODE_ERRORS
#endif
#if !LZ4_ENABLE_ASSEMBLY_ENCODE
#if defined(__x86_64__) || defined(__x86_64h__)
# define LZ4_MATCH_SEARCH_INIT_SIZE 32
# define LZ4_MATCH_SEARCH_LOOP_SIZE 32
#else
# define LZ4_MATCH_SEARCH_INIT_SIZE 8
# define LZ4_MATCH_SEARCH_LOOP_SIZE 8
#endif
static inline uint32_t lz4_hash(uint32_t x) { return (x * 2654435761U) >> (32 - LZ4_COMPRESS_HASH_BITS); }
static inline void lz4_fill16(uint8_t * ptr)
{
store8(ptr,-1);
store8(ptr+8,-1);
}
static inline size_t lz4_nmatch4(const uint8_t * a,const uint8_t * b)
{
uint32_t x = load4(a) ^ load4(b);
return (x == 0)?4:(__builtin_ctzl(x) >> 3);
}
static inline size_t lz4_nmatch8(const uint8_t * a,const uint8_t * b)
{
uint64_t x = load8(a) ^ load8(b);
return (x == 0)?8:(__builtin_ctzll(x) >> 3);
}
static inline size_t lz4_nmatch16(const uint8_t * a,const uint8_t * b)
{
size_t n = lz4_nmatch8(a,b);
return (n == 8)?(8 + lz4_nmatch8(a+8,b+8)):n;
}
static inline size_t lz4_nmatch32(const uint8_t * a,const uint8_t * b)
{
size_t n = lz4_nmatch16(a,b);
return (n == 16)?(16 + lz4_nmatch16(a+16,b+16)):n;
}
static inline size_t lz4_nmatch64(const uint8_t * a,const uint8_t * b)
{
size_t n = lz4_nmatch32(a,b);
return (n == 32)?(32 + lz4_nmatch32(a+32,b+32)):n;
}
static inline size_t lz4_nmatch(int N, const uint8_t * a, const uint8_t * b)
{
switch (N) {
case 4: return lz4_nmatch4(a,b);
case 8: return lz4_nmatch8(a,b);
case 16: return lz4_nmatch16(a,b);
case 32: return lz4_nmatch32(a,b);
case 64: return lz4_nmatch64(a,b);
}
__builtin_trap(); }
static inline uint8_t *lz4_store_length(uint8_t * dst, const uint8_t * const end, uint32_t L) {
(void)end;
while (L >= 17*255) {
lz4_fill16(dst);
dst += 16;
L -= 16*255;
}
lz4_fill16(dst);
dst += L/255;
*dst++ = L%255;
return dst;
}
static inline uint32_t clamp(uint32_t x, uint32_t max) __attribute__((overloadable)) { return x > max ? max : x; }
static inline uint8_t *copy_literal(uint8_t *dst, const uint8_t * restrict src, uint32_t L) {
uint8_t *end = dst + L;
{ copy16(dst, src); dst += 16; src += 16; }
while (dst < end) { copy32(dst, src); dst += 32; src += 32; }
return end;
}
static uint8_t *lz4_emit_match(uint32_t L, uint32_t M, uint32_t D,
uint8_t * restrict dst,
const uint8_t * const end,
const uint8_t * restrict src) {
assert(M >= 4 && "LZ4 encoding requires that M is at least 4");
M -= 4;
assert(D <= USHRT_MAX && "LZ4 encoding requries that D can be stored in two bytes.");
*dst++ = clamp(L, 15) << 4 | clamp(M, 15);
if (L >= 15) {
dst = lz4_store_length(dst, end, L - 15);
if (dst == 0 || dst + L >= end) return NULL;
}
dst = copy_literal(dst, src, L);
store2(dst, D); dst += 2;
if (M >= 15) {
dst = lz4_store_length(dst, end, M - 15);
if (dst == 0) return NULL;
}
return dst;
}
#if LZ4_EARLY_ABORT
int lz4_do_early_abort = 1;
int lz4_early_aborts = 0;
#define LZ4_EARLY_ABORT_EVAL (448)
#define LZ4_EARLY_ABORT_MIN_COMPRESSION_FACTOR (20)
#endif
void lz4_encode_2gb(uint8_t ** dst_ptr,
size_t dst_size,
const uint8_t ** src_ptr,
const uint8_t * src_begin,
size_t src_size,
lz4_hash_entry_t hash_table[LZ4_COMPRESS_HASH_ENTRIES],
int skip_final_literals)
{
uint8_t *dst = *dst_ptr; uint8_t *end = dst + dst_size - LZ4_GOFAST_SAFETY_MARGIN;
const uint8_t *src = *src_ptr; const uint8_t *src_end = src + src_size - LZ4_GOFAST_SAFETY_MARGIN;
const uint8_t *match_begin = 0; const uint8_t *match_end = 0; #if LZ4_EARLY_ABORT
uint8_t * const dst_begin = dst;
uint32_t lz4_do_abort_eval = lz4_do_early_abort;
#endif
while (dst < end)
{
ptrdiff_t match_distance = 0;
for (match_begin = src; match_begin < src_end; match_begin += 1) {
const uint32_t pos = (uint32_t)(match_begin - src_begin);
const uint32_t w0 = load4(match_begin);
const uint32_t w1 = load4(match_begin + 1);
const uint32_t w2 = load4(match_begin + 2);
const uint32_t w3 = load4(match_begin + 3);
const int i0 = lz4_hash(w0);
const int i1 = lz4_hash(w1);
const int i2 = lz4_hash(w2);
const int i3 = lz4_hash(w3);
const uint8_t *c0 = src_begin + hash_table[i0].offset;
const uint8_t *c1 = src_begin + hash_table[i1].offset;
const uint8_t *c2 = src_begin + hash_table[i2].offset;
const uint8_t *c3 = src_begin + hash_table[i3].offset;
const uint32_t m0 = hash_table[i0].word;
const uint32_t m1 = hash_table[i1].word;
const uint32_t m2 = hash_table[i2].word;
const uint32_t m3 = hash_table[i3].word;
hash_table[i0].offset = pos;
hash_table[i0].word = w0;
hash_table[i1].offset = pos + 1;
hash_table[i1].word = w1;
hash_table[i2].offset = pos + 2;
hash_table[i2].word = w2;
hash_table[i3].offset = pos + 3;
hash_table[i3].word = w3;
match_distance = (match_begin - c0);
if (w0 == m0 && match_distance < 0x10000 && match_distance > 0) {
match_end = match_begin + 4;
goto EXPAND_FORWARD;
}
match_begin++;
match_distance = (match_begin - c1);
if (w1 == m1 && match_distance < 0x10000 && match_distance > 0) {
match_end = match_begin + 4;
goto EXPAND_FORWARD;
}
match_begin++;
match_distance = (match_begin - c2);
if (w2 == m2 && match_distance < 0x10000 && match_distance > 0) {
match_end = match_begin + 4;
goto EXPAND_FORWARD;
}
match_begin++;
match_distance = (match_begin - c3);
if (w3 == m3 && match_distance < 0x10000 && match_distance > 0) {
match_end = match_begin + 4;
goto EXPAND_FORWARD;
}
#if LZ4_EARLY_ABORT
if (lz4_do_abort_eval && ((pos) >= LZ4_EARLY_ABORT_EVAL)) {
ptrdiff_t dstd = dst - dst_begin;
if (dstd == 0) {
lz4_early_aborts++;
return;
}
lz4_do_abort_eval = 0;
}
#endif
}
if (skip_final_literals) { *src_ptr = src; *dst_ptr = dst; return; }
size_t src_remaining = src_end + LZ4_GOFAST_SAFETY_MARGIN - src;
if (src_remaining < 15) {
*dst++ = (uint8_t)(src_remaining << 4);
memcpy(dst, src, 16); dst += src_remaining;
} else {
*dst++ = 0xf0;
dst = lz4_store_length(dst, end, (uint32_t)(src_remaining - 15));
if (dst == 0 || dst + src_remaining >= end) return;
memcpy(dst, src, src_remaining); dst += src_remaining;
}
*dst_ptr = dst;
*src_ptr = src + src_remaining;
return;
EXPAND_FORWARD:
{
const uint8_t * ref_end = match_end - match_distance;
while (match_end < src_end)
{
size_t n = lz4_nmatch(LZ4_MATCH_SEARCH_LOOP_SIZE, ref_end, match_end);
if (n < LZ4_MATCH_SEARCH_LOOP_SIZE) { match_end += n; break; }
match_end += LZ4_MATCH_SEARCH_LOOP_SIZE;
ref_end += LZ4_MATCH_SEARCH_LOOP_SIZE;
}
}
{
const uint8_t * match_begin_min = src_begin + match_distance;
match_begin_min = (match_begin_min < src)?src:match_begin_min;
const uint8_t * ref_begin = match_begin - match_distance;
while (match_begin > match_begin_min && ref_begin[-1] == match_begin[-1] ) { match_begin -= 1; ref_begin -= 1; }
}
dst = lz4_emit_match((uint32_t)(match_begin - src), (uint32_t)(match_end - match_begin), (uint32_t)match_distance, dst, end, src);
if (!dst) return;
src = match_end;
*dst_ptr = dst;
*src_ptr = src;
}
}
#endif
size_t lz4raw_encode_buffer(uint8_t * __restrict dst_buffer, size_t dst_size,
const uint8_t * __restrict src_buffer, size_t src_size,
lz4_hash_entry_t hash_table[LZ4_COMPRESS_HASH_ENTRIES])
{
const lz4_hash_entry_t HASH_FILL = { .offset = 0x80000000, .word = 0x0 };
const uint8_t * src = src_buffer;
uint8_t * dst = dst_buffer;
const size_t BLOCK_SIZE = 0x7ffff000;
while (src_size > 0)
{
for (int i=0;i<LZ4_COMPRESS_HASH_ENTRIES;) {
hash_table[i++] = HASH_FILL;
hash_table[i++] = HASH_FILL;
hash_table[i++] = HASH_FILL;
hash_table[i++] = HASH_FILL;
}
const size_t src_to_encode = src_size > BLOCK_SIZE ? BLOCK_SIZE : src_size;
uint8_t * dst_start = dst;
const uint8_t * src_start = src;
lz4_encode_2gb(&dst, dst_size, &src, src, src_to_encode, hash_table, src_to_encode < src_size);
size_t dst_used = dst - dst_start;
size_t src_used = src - src_start; if (src_to_encode == src_size && src_used < src_to_encode) return 0;
if (src_to_encode < src_size && src_to_encode - src_used >= (1<<16)) return 0;
src_size -= src_used;
dst_size -= dst_used;
}
return (size_t)(dst - dst_buffer); }
#define likely(expr) __builtin_expect((expr) != 0, 1)
#define unlikely(expr) __builtin_expect((expr) != 0, 0)
typedef uint32_t lz4_uint128 __attribute__((ext_vector_type(4))) __attribute__((__aligned__(1)));
int lz4_decode(uint8_t ** dst_ptr,
uint8_t * dst_begin,
uint8_t * dst_end,
const uint8_t ** src_ptr,
const uint8_t * src_end)
{
uint8_t * dst = *dst_ptr;
const uint8_t * src = *src_ptr;
if (dst_end <= dst) goto OUT_FULL;
while (src < src_end)
{
*src_ptr = src;
*dst_ptr = dst;
uint8_t cmd = *src++; uint32_t literalLength = (cmd >> 4) & 15; uint32_t matchLength = 4 + (cmd & 15);
if (unlikely(literalLength == 15))
{
uint8_t s;
do {
#if DEBUG_LZ4_DECODE_ERRORS
if (unlikely(src >= src_end)) printf("Truncated SRC literal length\n");
#endif
if (unlikely(src >= src_end)) goto IN_FAIL; s = *src++;
literalLength += s;
} while (unlikely(s == 255));
}
#if DEBUG_LZ4_DECODE_ERRORS
if (unlikely(literalLength > (size_t)(src_end - src))) printf("Truncated SRC literal\n");
#endif
if (unlikely(literalLength > (size_t)(src_end - src))) goto IN_FAIL;
if (unlikely(literalLength > (size_t)(dst_end - dst))) {
literalLength = (uint32_t)(dst_end - dst);
memcpy(dst, src, literalLength);
dst += literalLength;
goto OUT_FULL;
}
memcpy(dst,src,literalLength);
src += literalLength;
dst += literalLength;
if (unlikely(src >= src_end)) goto OUT_FULL; #if DEBUG_LZ4_DECODE_ERRORS
if (unlikely(2 > (size_t)(src_end - src))) printf("Truncated SRC distance\n");
#endif
if (unlikely(2 > (size_t)(src_end - src))) goto IN_FAIL;
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wcast-align"
uint64_t matchDistance = *(const uint16_t *)src; #pragma clang diagnostic pop
src += 2;
#if DEBUG_LZ4_DECODE_ERRORS
if (matchDistance == 0) printf("Invalid match distance D = 0\n");
#endif
if (unlikely(matchDistance == 0)) goto IN_FAIL; uint8_t * ref = dst - matchDistance;
#if DEBUG_LZ4_DECODE_ERRORS
if (unlikely(ref < dst_begin)) printf("Invalid reference D=0x%llx dst_begin=%p dst=%p dst_end=%p\n",matchDistance,dst_begin,dst,dst_end);
#endif
if (unlikely(ref < dst_begin)) goto OUT_FAIL;
if (unlikely(matchLength == 19))
{
uint8_t s;
do {
#if DEBUG_LZ4_DECODE_ERRORS
if (unlikely(src >= src_end)) printf("Truncated SRC match length\n");
#endif
if (unlikely(src >= src_end)) goto IN_FAIL; s = *src++;
matchLength += s;
} while (unlikely(s == 255));
}
if (unlikely(matchLength > (size_t)(dst_end - dst))) {
matchLength = (uint32_t)(dst_end - dst);
for (uint32_t i=0; i<matchLength; ++i) dst[i] = ref[i];
dst += matchLength;
goto OUT_FULL;
}
for (uint64_t i=0;i<matchLength;i++) dst[i] = ref[i];
dst += matchLength;
}
OUT_FULL:
*dst_ptr = dst;
*src_ptr = src;
return 0;
OUT_FAIL:
IN_FAIL:
return 1; }