contrib/zstd/lib/common/entropy_common.c in extzstd-0.3.1 vs contrib/zstd/lib/common/entropy_common.c in extzstd-0.3.2
- old
+ new
@@ -36,79 +36,124 @@
/*-**************************************************************
* FSE NCount encoding-decoding
****************************************************************/
-size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
- const void* headerBuffer, size_t hbSize)
+static U32 FSE_ctz(U32 val)
{
+ assert(val != 0);
+ {
+# if defined(_MSC_VER) /* Visual */
+ unsigned long r=0;
+ return _BitScanForward(&r, val) ? (unsigned)r : 0;
+# elif defined(__GNUC__) && (__GNUC__ >= 3) /* GCC Intrinsic */
+ return __builtin_ctz(val);
+# elif defined(__ICCARM__) /* IAR Intrinsic */
+ return __CTZ(val);
+# else /* Software version */
+ U32 count = 0;
+ while ((val & 1) == 0) {
+ val >>= 1;
+ ++count;
+ }
+ return count;
+# endif
+ }
+}
+
+FORCE_INLINE_TEMPLATE
+size_t FSE_readNCount_body(short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
+ const void* headerBuffer, size_t hbSize)
+{
const BYTE* const istart = (const BYTE*) headerBuffer;
const BYTE* const iend = istart + hbSize;
const BYTE* ip = istart;
int nbBits;
int remaining;
int threshold;
U32 bitStream;
int bitCount;
unsigned charnum = 0;
+ unsigned const maxSV1 = *maxSVPtr + 1;
int previous0 = 0;
- if (hbSize < 4) {
- /* This function only works when hbSize >= 4 */
- char buffer[4];
- memset(buffer, 0, sizeof(buffer));
- memcpy(buffer, headerBuffer, hbSize);
+ if (hbSize < 8) {
+ /* This function only works when hbSize >= 8 */
+ char buffer[8] = {0};
+ ZSTD_memcpy(buffer, headerBuffer, hbSize);
{ size_t const countSize = FSE_readNCount(normalizedCounter, maxSVPtr, tableLogPtr,
buffer, sizeof(buffer));
if (FSE_isError(countSize)) return countSize;
if (countSize > hbSize) return ERROR(corruption_detected);
return countSize;
} }
- assert(hbSize >= 4);
+ assert(hbSize >= 8);
/* init */
- memset(normalizedCounter, 0, (*maxSVPtr+1) * sizeof(normalizedCounter[0])); /* all symbols not present in NCount have a frequency of 0 */
+ ZSTD_memset(normalizedCounter, 0, (*maxSVPtr+1) * sizeof(normalizedCounter[0])); /* all symbols not present in NCount have a frequency of 0 */
bitStream = MEM_readLE32(ip);
nbBits = (bitStream & 0xF) + FSE_MIN_TABLELOG; /* extract tableLog */
if (nbBits > FSE_TABLELOG_ABSOLUTE_MAX) return ERROR(tableLog_tooLarge);
bitStream >>= 4;
bitCount = 4;
*tableLogPtr = nbBits;
remaining = (1<<nbBits)+1;
threshold = 1<<nbBits;
nbBits++;
- while ((remaining>1) & (charnum<=*maxSVPtr)) {
+ for (;;) {
if (previous0) {
- unsigned n0 = charnum;
- while ((bitStream & 0xFFFF) == 0xFFFF) {
- n0 += 24;
- if (ip < iend-5) {
- ip += 2;
- bitStream = MEM_readLE32(ip) >> bitCount;
+ /* Count the number of repeats. Each time the
+ * 2-bit repeat code is 0b11 there is another
+ * repeat.
+ * Avoid UB by setting the high bit to 1.
+ */
+ int repeats = FSE_ctz(~bitStream | 0x80000000) >> 1;
+ while (repeats >= 12) {
+ charnum += 3 * 12;
+ if (LIKELY(ip <= iend-7)) {
+ ip += 3;
} else {
- bitStream >>= 16;
- bitCount += 16;
- } }
- while ((bitStream & 3) == 3) {
- n0 += 3;
- bitStream >>= 2;
- bitCount += 2;
+ bitCount -= (int)(8 * (iend - 7 - ip));
+ bitCount &= 31;
+ ip = iend - 4;
+ }
+ bitStream = MEM_readLE32(ip) >> bitCount;
+ repeats = FSE_ctz(~bitStream | 0x80000000) >> 1;
}
- n0 += bitStream & 3;
+ charnum += 3 * repeats;
+ bitStream >>= 2 * repeats;
+ bitCount += 2 * repeats;
+
+ /* Add the final repeat which isn't 0b11. */
+ assert((bitStream & 3) < 3);
+ charnum += bitStream & 3;
bitCount += 2;
- if (n0 > *maxSVPtr) return ERROR(maxSymbolValue_tooSmall);
- while (charnum < n0) normalizedCounter[charnum++] = 0;
- if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) {
+
+ /* This is an error, but break and return an error
+ * at the end, because returning out of a loop makes
+ * it harder for the compiler to optimize.
+ */
+ if (charnum >= maxSV1) break;
+
+ /* We don't need to set the normalized count to 0
+ * because we already memset the whole buffer to 0.
+ */
+
+ if (LIKELY(ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) {
assert((bitCount >> 3) <= 3); /* For first condition to work */
ip += bitCount>>3;
bitCount &= 7;
- bitStream = MEM_readLE32(ip) >> bitCount;
} else {
- bitStream >>= 2;
- } }
- { int const max = (2*threshold-1) - remaining;
+ bitCount -= (int)(8 * (iend - 4 - ip));
+ bitCount &= 31;
+ ip = iend - 4;
+ }
+ bitStream = MEM_readLE32(ip) >> bitCount;
+ }
+ {
+ int const max = (2*threshold-1) - remaining;
int count;
if ((bitStream & (threshold-1)) < (U32)max) {
count = bitStream & (threshold-1);
bitCount += nbBits-1;
@@ -117,36 +162,92 @@
if (count >= threshold) count -= max;
bitCount += nbBits;
}
count--; /* extra accuracy */
- remaining -= count < 0 ? -count : count; /* -1 means +1 */
+ /* When it matters (small blocks), this is a
+ * predictable branch, because we don't use -1.
+ */
+ if (count >= 0) {
+ remaining -= count;
+ } else {
+ assert(count == -1);
+ remaining += count;
+ }
normalizedCounter[charnum++] = (short)count;
previous0 = !count;
- while (remaining < threshold) {
- nbBits--;
- threshold >>= 1;
+
+ assert(threshold > 1);
+ if (remaining < threshold) {
+ /* This branch can be folded into the
+ * threshold update condition because we
+ * know that threshold > 1.
+ */
+ if (remaining <= 1) break;
+ nbBits = BIT_highbit32(remaining) + 1;
+ threshold = 1 << (nbBits - 1);
}
+ if (charnum >= maxSV1) break;
- if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) {
+ if (LIKELY(ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) {
ip += bitCount>>3;
bitCount &= 7;
} else {
bitCount -= (int)(8 * (iend - 4 - ip));
+ bitCount &= 31;
ip = iend - 4;
}
- bitStream = MEM_readLE32(ip) >> (bitCount & 31);
- } } /* while ((remaining>1) & (charnum<=*maxSVPtr)) */
+ bitStream = MEM_readLE32(ip) >> bitCount;
+ } }
if (remaining != 1) return ERROR(corruption_detected);
+ /* Only possible when there are too many zeros. */
+ if (charnum > maxSV1) return ERROR(maxSymbolValue_tooSmall);
if (bitCount > 32) return ERROR(corruption_detected);
*maxSVPtr = charnum-1;
ip += (bitCount+7)>>3;
return ip-istart;
}
+/* Avoids the FORCE_INLINE of the _body() function. */
+static size_t FSE_readNCount_body_default(
+ short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
+ const void* headerBuffer, size_t hbSize)
+{
+ return FSE_readNCount_body(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
+}
+#if DYNAMIC_BMI2
+TARGET_ATTRIBUTE("bmi2") static size_t FSE_readNCount_body_bmi2(
+ short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
+ const void* headerBuffer, size_t hbSize)
+{
+ return FSE_readNCount_body(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
+}
+#endif
+
+size_t FSE_readNCount_bmi2(
+ short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
+ const void* headerBuffer, size_t hbSize, int bmi2)
+{
+#if DYNAMIC_BMI2
+ if (bmi2) {
+ return FSE_readNCount_body_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
+ }
+#endif
+ (void)bmi2;
+ return FSE_readNCount_body_default(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
+}
+
+size_t FSE_readNCount(
+ short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
+ const void* headerBuffer, size_t hbSize)
+{
+ return FSE_readNCount_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize, /* bmi2 */ 0);
+}
+
+
/*! HUF_readStats() :
Read compact Huffman tree, saved by HUF_writeCTable().
`huffWeight` is destination buffer.
`rankStats` is assumed to be a table of at least HUF_TABLELOG_MAX U32.
@return : size read from `src` , or an error Code .
@@ -154,18 +255,29 @@
*/
size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, U32* rankStats,
U32* nbSymbolsPtr, U32* tableLogPtr,
const void* src, size_t srcSize)
{
+ U32 wksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
+ return HUF_readStats_wksp(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, wksp, sizeof(wksp), /* bmi2 */ 0);
+}
+
+FORCE_INLINE_TEMPLATE size_t
+HUF_readStats_body(BYTE* huffWeight, size_t hwSize, U32* rankStats,
+ U32* nbSymbolsPtr, U32* tableLogPtr,
+ const void* src, size_t srcSize,
+ void* workSpace, size_t wkspSize,
+ int bmi2)
+{
U32 weightTotal;
const BYTE* ip = (const BYTE*) src;
size_t iSize;
size_t oSize;
if (!srcSize) return ERROR(srcSize_wrong);
iSize = ip[0];
- /* memset(huffWeight, 0, hwSize); *//* is not necessary, even though some analyzer complain ... */
+ /* ZSTD_memset(huffWeight, 0, hwSize); *//* is not necessary, even though some analyzer complain ... */
if (iSize >= 128) { /* special header */
oSize = iSize - 127;
iSize = ((oSize+1)/2);
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
@@ -175,18 +287,18 @@
for (n=0; n<oSize; n+=2) {
huffWeight[n] = ip[n/2] >> 4;
huffWeight[n+1] = ip[n/2] & 15;
} } }
else { /* header compressed with FSE (normal case) */
- FSE_DTable fseWorkspace[FSE_DTABLE_SIZE_U32(6)]; /* 6 is max possible tableLog for HUF header (maybe even 5, to be tested) */
if (iSize+1 > srcSize) return ERROR(srcSize_wrong);
- oSize = FSE_decompress_wksp(huffWeight, hwSize-1, ip+1, iSize, fseWorkspace, 6); /* max (hwSize-1) values decoded, as last one is implied */
+ /* max (hwSize-1) values decoded, as last one is implied */
+ oSize = FSE_decompress_wksp_bmi2(huffWeight, hwSize-1, ip+1, iSize, 6, workSpace, wkspSize, bmi2);
if (FSE_isError(oSize)) return oSize;
}
/* collect weight stats */
- memset(rankStats, 0, (HUF_TABLELOG_MAX + 1) * sizeof(U32));
+ ZSTD_memset(rankStats, 0, (HUF_TABLELOG_MAX + 1) * sizeof(U32));
weightTotal = 0;
{ U32 n; for (n=0; n<oSize; n++) {
if (huffWeight[n] >= HUF_TABLELOG_MAX) return ERROR(corruption_detected);
rankStats[huffWeight[n]]++;
weightTotal += (1 << huffWeight[n]) >> 1;
@@ -211,6 +323,40 @@
if ((rankStats[1] < 2) || (rankStats[1] & 1)) return ERROR(corruption_detected); /* by construction : at least 2 elts of rank 1, must be even */
/* results */
*nbSymbolsPtr = (U32)(oSize+1);
return iSize+1;
+}
+
+/* Avoids the FORCE_INLINE of the _body() function. */
+static size_t HUF_readStats_body_default(BYTE* huffWeight, size_t hwSize, U32* rankStats,
+ U32* nbSymbolsPtr, U32* tableLogPtr,
+ const void* src, size_t srcSize,
+ void* workSpace, size_t wkspSize)
+{
+ return HUF_readStats_body(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize, 0);
+}
+
+#if DYNAMIC_BMI2
+static TARGET_ATTRIBUTE("bmi2") size_t HUF_readStats_body_bmi2(BYTE* huffWeight, size_t hwSize, U32* rankStats,
+ U32* nbSymbolsPtr, U32* tableLogPtr,
+ const void* src, size_t srcSize,
+ void* workSpace, size_t wkspSize)
+{
+ return HUF_readStats_body(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize, 1);
+}
+#endif
+
+size_t HUF_readStats_wksp(BYTE* huffWeight, size_t hwSize, U32* rankStats,
+ U32* nbSymbolsPtr, U32* tableLogPtr,
+ const void* src, size_t srcSize,
+ void* workSpace, size_t wkspSize,
+ int bmi2)
+{
+#if DYNAMIC_BMI2
+ if (bmi2) {
+ return HUF_readStats_body_bmi2(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize);
+ }
+#endif
+ (void)bmi2;
+ return HUF_readStats_body_default(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize);
}