inikep | 63ecd74 | 2016-05-13 11:27:56 +0200 | [diff] [blame] | 1 | /* |
| 2 | Common functions of New Generation Entropy library |
| 3 | Copyright (C) 2016, Yann Collet. |
| 4 | |
| 5 | BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) |
| 6 | |
| 7 | Redistribution and use in source and binary forms, with or without |
| 8 | modification, are permitted provided that the following conditions are |
| 9 | met: |
| 10 | |
| 11 | * Redistributions of source code must retain the above copyright |
| 12 | notice, this list of conditions and the following disclaimer. |
| 13 | * Redistributions in binary form must reproduce the above |
| 14 | copyright notice, this list of conditions and the following disclaimer |
| 15 | in the documentation and/or other materials provided with the |
| 16 | distribution. |
| 17 | |
| 18 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 19 | "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 20 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 21 | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 22 | OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 23 | SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 24 | LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 25 | DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 26 | THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 27 | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 28 | OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 29 | |
| 30 | You can contact the author at : |
| 31 | - FSE+HUF source repository : https://github.com/Cyan4973/FiniteStateEntropy |
| 32 | - Public forum : https://groups.google.com/forum/#!forum/lz4c |
| 33 | *************************************************************************** */ |
| 34 | |
| 35 | /* ************************************* |
| 36 | * Dependencies |
| 37 | ***************************************/ |
| 38 | #include <stdlib.h> |
| 39 | #include "mem.h" |
Yann Collet | d0e2cd1 | 2016-06-05 00:58:01 +0200 | [diff] [blame^] | 40 | #define FSE_STATIC_LINKING_ONLY /* FSE_MIN_TABLELOG */ |
| 41 | #include "fse.h" |
inikep | 63ecd74 | 2016-05-13 11:27:56 +0200 | [diff] [blame] | 42 | #include "error_private.h" |
| 43 | #include "fse.h" /* declaration of FSE_isError, FSE_getErrorName */ |
| 44 | #include "huf.h" /* declaration of HUF_isError, HUF_getErrorName */ |
| 45 | |
| 46 | |
| 47 | |
| 48 | /*-**************************************** |
| 49 | * FSE Error Management |
| 50 | ******************************************/ |
| 51 | unsigned FSE_isError(size_t code) { return ERR_isError(code); } |
| 52 | |
| 53 | const char* FSE_getErrorName(size_t code) { return ERR_getErrorName(code); } |
| 54 | |
| 55 | |
| 56 | /* ************************************************************** |
| 57 | * HUF Error Management |
| 58 | ****************************************************************/ |
| 59 | unsigned HUF_isError(size_t code) { return ERR_isError(code); } |
| 60 | |
| 61 | const char* HUF_getErrorName(size_t code) { return ERR_getErrorName(code); } |
| 62 | |
| 63 | |
| 64 | /*-************************************************************** |
| 65 | * FSE NCount encoding-decoding |
| 66 | ****************************************************************/ |
| 67 | static short FSE_abs(short a) { return a<0 ? -a : a; } |
| 68 | |
| 69 | size_t FSE_readNCount (short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr, |
| 70 | const void* headerBuffer, size_t hbSize) |
| 71 | { |
| 72 | const BYTE* const istart = (const BYTE*) headerBuffer; |
| 73 | const BYTE* const iend = istart + hbSize; |
| 74 | const BYTE* ip = istart; |
| 75 | int nbBits; |
| 76 | int remaining; |
| 77 | int threshold; |
| 78 | U32 bitStream; |
| 79 | int bitCount; |
| 80 | unsigned charnum = 0; |
| 81 | int previous0 = 0; |
| 82 | |
| 83 | if (hbSize < 4) return ERROR(srcSize_wrong); |
| 84 | bitStream = MEM_readLE32(ip); |
| 85 | nbBits = (bitStream & 0xF) + FSE_MIN_TABLELOG; /* extract tableLog */ |
| 86 | if (nbBits > FSE_TABLELOG_ABSOLUTE_MAX) return ERROR(tableLog_tooLarge); |
| 87 | bitStream >>= 4; |
| 88 | bitCount = 4; |
| 89 | *tableLogPtr = nbBits; |
| 90 | remaining = (1<<nbBits)+1; |
| 91 | threshold = 1<<nbBits; |
| 92 | nbBits++; |
| 93 | |
| 94 | while ((remaining>1) && (charnum<=*maxSVPtr)) { |
| 95 | if (previous0) { |
| 96 | unsigned n0 = charnum; |
| 97 | while ((bitStream & 0xFFFF) == 0xFFFF) { |
| 98 | n0+=24; |
| 99 | if (ip < iend-5) { |
| 100 | ip+=2; |
| 101 | bitStream = MEM_readLE32(ip) >> bitCount; |
| 102 | } else { |
| 103 | bitStream >>= 16; |
| 104 | bitCount+=16; |
| 105 | } } |
| 106 | while ((bitStream & 3) == 3) { |
| 107 | n0+=3; |
| 108 | bitStream>>=2; |
| 109 | bitCount+=2; |
| 110 | } |
| 111 | n0 += bitStream & 3; |
| 112 | bitCount += 2; |
| 113 | if (n0 > *maxSVPtr) return ERROR(maxSymbolValue_tooSmall); |
| 114 | while (charnum < n0) normalizedCounter[charnum++] = 0; |
| 115 | if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) { |
| 116 | ip += bitCount>>3; |
| 117 | bitCount &= 7; |
| 118 | bitStream = MEM_readLE32(ip) >> bitCount; |
| 119 | } |
| 120 | else |
| 121 | bitStream >>= 2; |
| 122 | } |
| 123 | { short const max = (short)((2*threshold-1)-remaining); |
| 124 | short count; |
| 125 | |
| 126 | if ((bitStream & (threshold-1)) < (U32)max) { |
| 127 | count = (short)(bitStream & (threshold-1)); |
| 128 | bitCount += nbBits-1; |
| 129 | } else { |
| 130 | count = (short)(bitStream & (2*threshold-1)); |
| 131 | if (count >= threshold) count -= max; |
| 132 | bitCount += nbBits; |
| 133 | } |
| 134 | |
| 135 | count--; /* extra accuracy */ |
| 136 | remaining -= FSE_abs(count); |
| 137 | normalizedCounter[charnum++] = count; |
| 138 | previous0 = !count; |
| 139 | while (remaining < threshold) { |
| 140 | nbBits--; |
| 141 | threshold >>= 1; |
| 142 | } |
| 143 | |
| 144 | if ((ip <= iend-7) || (ip + (bitCount>>3) <= iend-4)) { |
| 145 | ip += bitCount>>3; |
| 146 | bitCount &= 7; |
| 147 | } else { |
| 148 | bitCount -= (int)(8 * (iend - 4 - ip)); |
| 149 | ip = iend - 4; |
| 150 | } |
| 151 | bitStream = MEM_readLE32(ip) >> (bitCount & 31); |
| 152 | } } /* while ((remaining>1) && (charnum<=*maxSVPtr)) */ |
| 153 | if (remaining != 1) return ERROR(GENERIC); |
| 154 | *maxSVPtr = charnum-1; |
| 155 | |
| 156 | ip += (bitCount+7)>>3; |
| 157 | if ((size_t)(ip-istart) > hbSize) return ERROR(srcSize_wrong); |
| 158 | return ip-istart; |
| 159 | } |