--- /dev/null
+/*
+ * Common functions of New Generation Entropy library
+ * Copyright (C) 2016, Yann Collet.
+ *
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation. This program is dual-licensed; you may select
+ * either version 2 of the GNU General Public License ("GPL") or BSD license
+ * ("BSD").
+ *
+ * You can contact the author at :
+ * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
+ */
+
+/* *************************************
+* Dependencies
+***************************************/
+#include "error_private.h" /* ERR_*, ERROR */
+#include "fse.h"
+#include "huf.h"
+#include "mem.h"
+
+/*=== Version ===*/
+unsigned FSE_versionNumber(void) { return FSE_VERSION_NUMBER; }
+
+/*=== Error Management ===*/
+unsigned FSE_isError(size_t code) { return ERR_isError(code); }
+
+unsigned HUF_isError(size_t code) { return ERR_isError(code); }
+
+/*-**************************************************************
+* FSE NCount encoding-decoding
+****************************************************************/
+size_t FSE_readNCount(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;
+ int previous0 = 0;
+
+ if (hbSize < 4)
+ return ERROR(srcSize_wrong);
+ bitStream = ZSTD_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)) {
+ if (previous0) {
+ unsigned n0 = charnum;
+ while ((bitStream & 0xFFFF) == 0xFFFF) {
+ n0 += 24;
+ if (ip < iend - 5) {
+ ip += 2;
+ bitStream = ZSTD_readLE32(ip) >> bitCount;
+ } else {
+ bitStream >>= 16;
+ bitCount += 16;
+ }
+ }
+ while ((bitStream & 3) == 3) {
+ n0 += 3;
+ bitStream >>= 2;
+ bitCount += 2;
+ }
+ n0 += 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)) {
+ ip += bitCount >> 3;
+ bitCount &= 7;
+ bitStream = ZSTD_readLE32(ip) >> bitCount;
+ } else {
+ bitStream >>= 2;
+ }
+ }
+ {
+ int const max = (2 * threshold - 1) - remaining;
+ int count;
+
+ if ((bitStream & (threshold - 1)) < (U32)max) {
+ count = bitStream & (threshold - 1);
+ bitCount += nbBits - 1;
+ } else {
+ count = bitStream & (2 * threshold - 1);
+ if (count >= threshold)
+ count -= max;
+ bitCount += nbBits;
+ }
+
+ count--; /* extra accuracy */
+ remaining -= count < 0 ? -count : count; /* -1 means +1 */
+ normalizedCounter[charnum++] = (short)count;
+ previous0 = !count;
+ while (remaining < threshold) {
+ nbBits--;
+ threshold >>= 1;
+ }
+
+ if ((ip <= iend - 7) || (ip + (bitCount >> 3) <= iend - 4)) {
+ ip += bitCount >> 3;
+ bitCount &= 7;
+ } else {
+ bitCount -= (int)(8 * (iend - 4 - ip));
+ ip = iend - 4;
+ }
+ bitStream = ZSTD_readLE32(ip) >> (bitCount & 31);
+ }
+ } /* while ((remaining>1) & (charnum<=*maxSVPtr)) */
+ if (remaining != 1)
+ return ERROR(corruption_detected);
+ if (bitCount > 32)
+ return ERROR(corruption_detected);
+ *maxSVPtr = charnum - 1;
+
+ ip += (bitCount + 7) >> 3;
+ return ip - istart;
+}
+
+/*! 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 .
+ Note : Needed by HUF_readCTable() and HUF_readDTableX?() .
+*/
+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 workspaceSize)
+{
+ 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 ... */
+
+ if (iSize >= 128) { /* special header */
+ oSize = iSize - 127;
+ iSize = ((oSize + 1) / 2);
+ if (iSize + 1 > srcSize)
+ return ERROR(srcSize_wrong);
+ if (oSize >= hwSize)
+ return ERROR(corruption_detected);
+ ip += 1;
+ {
+ U32 n;
+ 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) */
+ if (iSize + 1 > srcSize)
+ return ERROR(srcSize_wrong);
+ oSize = FSE_decompress_wksp(huffWeight, hwSize - 1, ip + 1, iSize, 6, workspace, workspaceSize); /* max (hwSize-1) values decoded, as last one is implied */
+ if (FSE_isError(oSize))
+ return oSize;
+ }
+
+ /* collect weight stats */
+ 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;
+ }
+ }
+ if (weightTotal == 0)
+ return ERROR(corruption_detected);
+
+ /* get last non-null symbol weight (implied, total must be 2^n) */
+ {
+ U32 const tableLog = BIT_highbit32(weightTotal) + 1;
+ if (tableLog > HUF_TABLELOG_MAX)
+ return ERROR(corruption_detected);
+ *tableLogPtr = tableLog;
+ /* determine last weight */
+ {
+ U32 const total = 1 << tableLog;
+ U32 const rest = total - weightTotal;
+ U32 const verif = 1 << BIT_highbit32(rest);
+ U32 const lastWeight = BIT_highbit32(rest) + 1;
+ if (verif != rest)
+ return ERROR(corruption_detected); /* last value must be a clean power of 2 */
+ huffWeight[oSize] = (BYTE)lastWeight;
+ rankStats[lastWeight]++;
+ }
+ }
+
+ /* check tree construction validity */
+ 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;
+}
projects / ceph.git / blobdiff