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annotate contrib/python-zstandard/zstd/common/bitstream.h @ 48674:f7086f6173f8 stable

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dirstate-v2: rename the configuration to enable the format The rename of the old experimental name was overlooked before the 6.0 release. We rename everything to use the new name (and keep the released name as an alias for compatibility). Differential Revision: https://phab.mercurial-scm.org/D12129
author Pierre-Yves David <pierre-yves.david@octobus.net>
date Tue, 01 Feb 2022 16:36:20 +0100
parents de7838053207
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1 /* ******************************************************************
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2 bitstream
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3 Part of FSE library
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4 Copyright (C) 2013-present, Yann Collet.
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5
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6 BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
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7
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8 Redistribution and use in source and binary forms, with or without
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9 modification, are permitted provided that the following conditions are
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10 met:
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11
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12 * Redistributions of source code must retain the above copyright
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13 notice, this list of conditions and the following disclaimer.
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14 * Redistributions in binary form must reproduce the above
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15 copyright notice, this list of conditions and the following disclaimer
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16 in the documentation and/or other materials provided with the
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17 distribution.
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18
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19 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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20 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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21 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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22 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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23 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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24 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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25 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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26 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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27 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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28 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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29 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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30
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31 You can contact the author at :
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32 - Source repository : https://github.com/Cyan4973/FiniteStateEntropy
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33 ****************************************************************** */
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34 #ifndef BITSTREAM_H_MODULE
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35 #define BITSTREAM_H_MODULE
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36
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37 #if defined (__cplusplus)
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38 extern "C" {
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39 #endif
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40
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41 /*
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42 * This API consists of small unitary functions, which must be inlined for best performance.
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43 * Since link-time-optimization is not available for all compilers,
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44 * these functions are defined into a .h to be included.
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45 */
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46
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47 /*-****************************************
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48 * Dependencies
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49 ******************************************/
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50 #include "mem.h" /* unaligned access routines */
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51 #include "debug.h" /* assert(), DEBUGLOG(), RAWLOG() */
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52 #include "error_private.h" /* error codes and messages */
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53
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54
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55 /*=========================================
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56 * Target specific
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57 =========================================*/
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58 #if defined(__BMI__) && defined(__GNUC__)
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59 # include <immintrin.h> /* support for bextr (experimental) */
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60 #elif defined(__ICCARM__)
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61 # include <intrinsics.h>
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62 #endif
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63
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64 #define STREAM_ACCUMULATOR_MIN_32 25
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65 #define STREAM_ACCUMULATOR_MIN_64 57
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66 #define STREAM_ACCUMULATOR_MIN ((U32)(MEM_32bits() ? STREAM_ACCUMULATOR_MIN_32 : STREAM_ACCUMULATOR_MIN_64))
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67
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68
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69 /*-******************************************
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70 * bitStream encoding API (write forward)
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71 ********************************************/
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72 /* bitStream can mix input from multiple sources.
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73 * A critical property of these streams is that they encode and decode in **reverse** direction.
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74 * So the first bit sequence you add will be the last to be read, like a LIFO stack.
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75 */
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76 typedef struct {
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77 size_t bitContainer;
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78 unsigned bitPos;
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79 char* startPtr;
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80 char* ptr;
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81 char* endPtr;
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82 } BIT_CStream_t;
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83
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84 MEM_STATIC size_t BIT_initCStream(BIT_CStream_t* bitC, void* dstBuffer, size_t dstCapacity);
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85 MEM_STATIC void BIT_addBits(BIT_CStream_t* bitC, size_t value, unsigned nbBits);
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86 MEM_STATIC void BIT_flushBits(BIT_CStream_t* bitC);
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87 MEM_STATIC size_t BIT_closeCStream(BIT_CStream_t* bitC);
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88
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89 /* Start with initCStream, providing the size of buffer to write into.
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90 * bitStream will never write outside of this buffer.
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91 * `dstCapacity` must be >= sizeof(bitD->bitContainer), otherwise @return will be an error code.
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92 *
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93 * bits are first added to a local register.
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94 * Local register is size_t, hence 64-bits on 64-bits systems, or 32-bits on 32-bits systems.
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95 * Writing data into memory is an explicit operation, performed by the flushBits function.
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96 * Hence keep track how many bits are potentially stored into local register to avoid register overflow.
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97 * After a flushBits, a maximum of 7 bits might still be stored into local register.
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98 *
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99 * Avoid storing elements of more than 24 bits if you want compatibility with 32-bits bitstream readers.
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100 *
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101 * Last operation is to close the bitStream.
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102 * The function returns the final size of CStream in bytes.
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103 * If data couldn't fit into `dstBuffer`, it will return a 0 ( == not storable)
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104 */
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105
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106
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107 /*-********************************************
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108 * bitStream decoding API (read backward)
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109 **********************************************/
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110 typedef struct {
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111 size_t bitContainer;
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112 unsigned bitsConsumed;
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113 const char* ptr;
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114 const char* start;
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115 const char* limitPtr;
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116 } BIT_DStream_t;
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117
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118 typedef enum { BIT_DStream_unfinished = 0,
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119 BIT_DStream_endOfBuffer = 1,
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120 BIT_DStream_completed = 2,
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121 BIT_DStream_overflow = 3 } BIT_DStream_status; /* result of BIT_reloadDStream() */
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122 /* 1,2,4,8 would be better for bitmap combinations, but slows down performance a bit ... :( */
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123
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124 MEM_STATIC size_t BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize);
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125 MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, unsigned nbBits);
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126 MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD);
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127 MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* bitD);
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128
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129
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
130 /* Start by invoking BIT_initDStream().
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
131 * A chunk of the bitStream is then stored into a local register.
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
132 * Local register size is 64-bits on 64-bits systems, 32-bits on 32-bits systems (size_t).
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
133 * You can then retrieve bitFields stored into the local register, **in reverse order**.
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
134 * Local register is explicitly reloaded from memory by the BIT_reloadDStream() method.
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
135 * A reload guarantee a minimum of ((8*sizeof(bitD->bitContainer))-7) bits when its result is BIT_DStream_unfinished.
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
136 * Otherwise, it can be less than that, so proceed accordingly.
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
137 * Checking if DStream has reached its end can be performed with BIT_endOfDStream().
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
138 */
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
139
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
140
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
141 /*-****************************************
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
142 * unsafe API
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
143 ******************************************/
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
144 MEM_STATIC void BIT_addBitsFast(BIT_CStream_t* bitC, size_t value, unsigned nbBits);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
145 /* faster, but works only if value is "clean", meaning all high bits above nbBits are 0 */
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
146
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
147 MEM_STATIC void BIT_flushBitsFast(BIT_CStream_t* bitC);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
148 /* unsafe version; does not check buffer overflow */
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
149
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
150 MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, unsigned nbBits);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
151 /* faster, but works only if nbBits >= 1 */
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
152
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
153
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
154
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
155 /*-**************************************************************
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
156 * Internal functions
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
157 ****************************************************************/
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
158 MEM_STATIC unsigned BIT_highbit32 (U32 val)
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
159 {
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
160 assert(val != 0);
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
161 {
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
162 # if defined(_MSC_VER) /* Visual */
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
163 unsigned long r=0;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
164 _BitScanReverse ( &r, val );
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
165 return (unsigned) r;
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
166 # elif defined(__GNUC__) && (__GNUC__ >= 3) /* Use GCC Intrinsic */
43994
de7838053207 zstandard: vendor python-zstandard 0.13.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 42937
diff changeset
167 return __builtin_clz (val) ^ 31;
42937
69de49c4e39c zstandard: vendor python-zstandard 0.12
Gregory Szorc <gregory.szorc@gmail.com>
parents: 42070
diff changeset
168 # elif defined(__ICCARM__) /* IAR Intrinsic */
69de49c4e39c zstandard: vendor python-zstandard 0.12
Gregory Szorc <gregory.szorc@gmail.com>
parents: 42070
diff changeset
169 return 31 - __CLZ(val);
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
170 # else /* Software version */
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
171 static const unsigned DeBruijnClz[32] = { 0, 9, 1, 10, 13, 21, 2, 29,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
172 11, 14, 16, 18, 22, 25, 3, 30,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
173 8, 12, 20, 28, 15, 17, 24, 7,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
174 19, 27, 23, 6, 26, 5, 4, 31 };
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
175 U32 v = val;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
176 v |= v >> 1;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
177 v |= v >> 2;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
178 v |= v >> 4;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
179 v |= v >> 8;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
180 v |= v >> 16;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
181 return DeBruijnClz[ (U32) (v * 0x07C4ACDDU) >> 27];
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
182 # endif
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
183 }
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
184 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
185
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
186 /*===== Local Constants =====*/
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
187 static const unsigned BIT_mask[] = {
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
188 0, 1, 3, 7, 0xF, 0x1F,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
189 0x3F, 0x7F, 0xFF, 0x1FF, 0x3FF, 0x7FF,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
190 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF, 0x1FFFF,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
191 0x3FFFF, 0x7FFFF, 0xFFFFF, 0x1FFFFF, 0x3FFFFF, 0x7FFFFF,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
192 0xFFFFFF, 0x1FFFFFF, 0x3FFFFFF, 0x7FFFFFF, 0xFFFFFFF, 0x1FFFFFFF,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
193 0x3FFFFFFF, 0x7FFFFFFF}; /* up to 31 bits */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
194 #define BIT_MASK_SIZE (sizeof(BIT_mask) / sizeof(BIT_mask[0]))
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
195
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
196 /*-**************************************************************
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
197 * bitStream encoding
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
198 ****************************************************************/
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
199 /*! BIT_initCStream() :
37495
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Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
200 * `dstCapacity` must be > sizeof(size_t)
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
201 * @return : 0 if success,
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
202 * otherwise an error code (can be tested using ERR_isError()) */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
203 MEM_STATIC size_t BIT_initCStream(BIT_CStream_t* bitC,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
204 void* startPtr, size_t dstCapacity)
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
205 {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
206 bitC->bitContainer = 0;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
207 bitC->bitPos = 0;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
208 bitC->startPtr = (char*)startPtr;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
209 bitC->ptr = bitC->startPtr;
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
210 bitC->endPtr = bitC->startPtr + dstCapacity - sizeof(bitC->bitContainer);
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
211 if (dstCapacity <= sizeof(bitC->bitContainer)) return ERROR(dstSize_tooSmall);
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
212 return 0;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
213 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
214
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
215 /*! BIT_addBits() :
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
216 * can add up to 31 bits into `bitC`.
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
217 * Note : does not check for register overflow ! */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
218 MEM_STATIC void BIT_addBits(BIT_CStream_t* bitC,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
219 size_t value, unsigned nbBits)
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
220 {
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
221 MEM_STATIC_ASSERT(BIT_MASK_SIZE == 32);
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
222 assert(nbBits < BIT_MASK_SIZE);
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
223 assert(nbBits + bitC->bitPos < sizeof(bitC->bitContainer) * 8);
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
224 bitC->bitContainer |= (value & BIT_mask[nbBits]) << bitC->bitPos;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
225 bitC->bitPos += nbBits;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
226 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
227
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
228 /*! BIT_addBitsFast() :
40121
73fef626dae3 zstandard: vendor python-zstandard 0.10.1
Gregory Szorc <gregory.szorc@gmail.com>
parents: 37495
diff changeset
229 * works only if `value` is _clean_,
73fef626dae3 zstandard: vendor python-zstandard 0.10.1
Gregory Szorc <gregory.szorc@gmail.com>
parents: 37495
diff changeset
230 * meaning all high bits above nbBits are 0 */
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
231 MEM_STATIC void BIT_addBitsFast(BIT_CStream_t* bitC,
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
232 size_t value, unsigned nbBits)
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
233 {
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
234 assert((value>>nbBits) == 0);
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
235 assert(nbBits + bitC->bitPos < sizeof(bitC->bitContainer) * 8);
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
236 bitC->bitContainer |= value << bitC->bitPos;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
237 bitC->bitPos += nbBits;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
238 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
239
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
240 /*! BIT_flushBitsFast() :
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
241 * assumption : bitContainer has not overflowed
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
242 * unsafe version; does not check buffer overflow */
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
243 MEM_STATIC void BIT_flushBitsFast(BIT_CStream_t* bitC)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
244 {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
245 size_t const nbBytes = bitC->bitPos >> 3;
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
246 assert(bitC->bitPos < sizeof(bitC->bitContainer) * 8);
43994
de7838053207 zstandard: vendor python-zstandard 0.13.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 42937
diff changeset
247 assert(bitC->ptr <= bitC->endPtr);
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
248 MEM_writeLEST(bitC->ptr, bitC->bitContainer);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
249 bitC->ptr += nbBytes;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
250 bitC->bitPos &= 7;
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
251 bitC->bitContainer >>= nbBytes*8;
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
252 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
253
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
254 /*! BIT_flushBits() :
37495
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Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
255 * assumption : bitContainer has not overflowed
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
256 * safe version; check for buffer overflow, and prevents it.
37495
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Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
257 * note : does not signal buffer overflow.
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
258 * overflow will be revealed later on using BIT_closeCStream() */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
259 MEM_STATIC void BIT_flushBits(BIT_CStream_t* bitC)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
260 {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
261 size_t const nbBytes = bitC->bitPos >> 3;
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
262 assert(bitC->bitPos < sizeof(bitC->bitContainer) * 8);
43994
de7838053207 zstandard: vendor python-zstandard 0.13.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 42937
diff changeset
263 assert(bitC->ptr <= bitC->endPtr);
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
264 MEM_writeLEST(bitC->ptr, bitC->bitContainer);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
265 bitC->ptr += nbBytes;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
266 if (bitC->ptr > bitC->endPtr) bitC->ptr = bitC->endPtr;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
267 bitC->bitPos &= 7;
37495
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Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
268 bitC->bitContainer >>= nbBytes*8;
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
269 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
270
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
271 /*! BIT_closeCStream() :
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
272 * @return : size of CStream, in bytes,
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
273 * or 0 if it could not fit into dstBuffer */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
274 MEM_STATIC size_t BIT_closeCStream(BIT_CStream_t* bitC)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
275 {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
276 BIT_addBitsFast(bitC, 1, 1); /* endMark */
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
277 BIT_flushBits(bitC);
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
278 if (bitC->ptr >= bitC->endPtr) return 0; /* overflow detected */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
279 return (bitC->ptr - bitC->startPtr) + (bitC->bitPos > 0);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
280 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
281
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
282
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
283 /*-********************************************************
37495
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Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
284 * bitStream decoding
30434
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Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
285 **********************************************************/
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
286 /*! BIT_initDStream() :
37495
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Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
287 * Initialize a BIT_DStream_t.
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
288 * `bitD` : a pointer to an already allocated BIT_DStream_t structure.
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
289 * `srcSize` must be the *exact* size of the bitStream, in bytes.
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
290 * @return : size of stream (== srcSize), or an errorCode if a problem is detected
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
291 */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
292 MEM_STATIC size_t BIT_initDStream(BIT_DStream_t* bitD, const void* srcBuffer, size_t srcSize)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
293 {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
294 if (srcSize < 1) { memset(bitD, 0, sizeof(*bitD)); return ERROR(srcSize_wrong); }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
295
37495
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Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
296 bitD->start = (const char*)srcBuffer;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
297 bitD->limitPtr = bitD->start + sizeof(bitD->bitContainer);
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
298
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
299 if (srcSize >= sizeof(bitD->bitContainer)) { /* normal case */
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
300 bitD->ptr = (const char*)srcBuffer + srcSize - sizeof(bitD->bitContainer);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
301 bitD->bitContainer = MEM_readLEST(bitD->ptr);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
302 { BYTE const lastByte = ((const BYTE*)srcBuffer)[srcSize-1];
30822
b54a2984cdd4 zstd: vendor python-zstandard 0.6.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30434
diff changeset
303 bitD->bitsConsumed = lastByte ? 8 - BIT_highbit32(lastByte) : 0; /* ensures bitsConsumed is always set */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
304 if (lastByte == 0) return ERROR(GENERIC); /* endMark not present */ }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
305 } else {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
306 bitD->ptr = bitD->start;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
307 bitD->bitContainer = *(const BYTE*)(bitD->start);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
308 switch(srcSize)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
309 {
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
310 case 7: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[6]) << (sizeof(bitD->bitContainer)*8 - 16);
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
311 /* fall-through */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
312
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
313 case 6: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[5]) << (sizeof(bitD->bitContainer)*8 - 24);
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
314 /* fall-through */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
315
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
316 case 5: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[4]) << (sizeof(bitD->bitContainer)*8 - 32);
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
317 /* fall-through */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
318
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
319 case 4: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[3]) << 24;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
320 /* fall-through */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
321
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
322 case 3: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[2]) << 16;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
323 /* fall-through */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
324
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
325 case 2: bitD->bitContainer += (size_t)(((const BYTE*)(srcBuffer))[1]) << 8;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
326 /* fall-through */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
327
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
328 default: break;
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
329 }
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
330 { BYTE const lastByte = ((const BYTE*)srcBuffer)[srcSize-1];
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
331 bitD->bitsConsumed = lastByte ? 8 - BIT_highbit32(lastByte) : 0;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
332 if (lastByte == 0) return ERROR(corruption_detected); /* endMark not present */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
333 }
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
334 bitD->bitsConsumed += (U32)(sizeof(bitD->bitContainer) - srcSize)*8;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
335 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
336
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
337 return srcSize;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
338 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
339
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
340 MEM_STATIC size_t BIT_getUpperBits(size_t bitContainer, U32 const start)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
341 {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
342 return bitContainer >> start;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
343 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
344
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
345 MEM_STATIC size_t BIT_getMiddleBits(size_t bitContainer, U32 const start, U32 const nbBits)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
346 {
42070
675775c33ab6 zstandard: vendor python-zstandard 0.11
Gregory Szorc <gregory.szorc@gmail.com>
parents: 40121
diff changeset
347 U32 const regMask = sizeof(bitContainer)*8 - 1;
675775c33ab6 zstandard: vendor python-zstandard 0.11
Gregory Szorc <gregory.szorc@gmail.com>
parents: 40121
diff changeset
348 /* if start > regMask, bitstream is corrupted, and result is undefined */
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
349 assert(nbBits < BIT_MASK_SIZE);
42070
675775c33ab6 zstandard: vendor python-zstandard 0.11
Gregory Szorc <gregory.szorc@gmail.com>
parents: 40121
diff changeset
350 return (bitContainer >> (start & regMask)) & BIT_mask[nbBits];
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
351 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
352
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
353 MEM_STATIC size_t BIT_getLowerBits(size_t bitContainer, U32 const nbBits)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
354 {
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
355 assert(nbBits < BIT_MASK_SIZE);
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
356 return bitContainer & BIT_mask[nbBits];
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
357 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
358
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
359 /*! BIT_lookBits() :
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
360 * Provides next n bits from local register.
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
361 * local register is not modified.
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
362 * On 32-bits, maxNbBits==24.
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
363 * On 64-bits, maxNbBits==56.
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
364 * @return : value extracted */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
365 MEM_STATIC size_t BIT_lookBits(const BIT_DStream_t* bitD, U32 nbBits)
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
366 {
42070
675775c33ab6 zstandard: vendor python-zstandard 0.11
Gregory Szorc <gregory.szorc@gmail.com>
parents: 40121
diff changeset
367 /* arbitrate between double-shift and shift+mask */
675775c33ab6 zstandard: vendor python-zstandard 0.11
Gregory Szorc <gregory.szorc@gmail.com>
parents: 40121
diff changeset
368 #if 1
675775c33ab6 zstandard: vendor python-zstandard 0.11
Gregory Szorc <gregory.szorc@gmail.com>
parents: 40121
diff changeset
369 /* if bitD->bitsConsumed + nbBits > sizeof(bitD->bitContainer)*8,
675775c33ab6 zstandard: vendor python-zstandard 0.11
Gregory Szorc <gregory.szorc@gmail.com>
parents: 40121
diff changeset
370 * bitstream is likely corrupted, and result is undefined */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
371 return BIT_getMiddleBits(bitD->bitContainer, (sizeof(bitD->bitContainer)*8) - bitD->bitsConsumed - nbBits, nbBits);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
372 #else
42070
675775c33ab6 zstandard: vendor python-zstandard 0.11
Gregory Szorc <gregory.szorc@gmail.com>
parents: 40121
diff changeset
373 /* this code path is slower on my os-x laptop */
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
374 U32 const regMask = sizeof(bitD->bitContainer)*8 - 1;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
375 return ((bitD->bitContainer << (bitD->bitsConsumed & regMask)) >> 1) >> ((regMask-nbBits) & regMask);
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
376 #endif
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
377 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
378
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
379 /*! BIT_lookBitsFast() :
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
380 * unsafe version; only works if nbBits >= 1 */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
381 MEM_STATIC size_t BIT_lookBitsFast(const BIT_DStream_t* bitD, U32 nbBits)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
382 {
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
383 U32 const regMask = sizeof(bitD->bitContainer)*8 - 1;
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
384 assert(nbBits >= 1);
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
385 return (bitD->bitContainer << (bitD->bitsConsumed & regMask)) >> (((regMask+1)-nbBits) & regMask);
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
386 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
387
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
388 MEM_STATIC void BIT_skipBits(BIT_DStream_t* bitD, U32 nbBits)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
389 {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
390 bitD->bitsConsumed += nbBits;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
391 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
392
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
393 /*! BIT_readBits() :
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
394 * Read (consume) next n bits from local register and update.
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
395 * Pay attention to not read more than nbBits contained into local register.
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
396 * @return : extracted value. */
42070
675775c33ab6 zstandard: vendor python-zstandard 0.11
Gregory Szorc <gregory.szorc@gmail.com>
parents: 40121
diff changeset
397 MEM_STATIC size_t BIT_readBits(BIT_DStream_t* bitD, unsigned nbBits)
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
398 {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
399 size_t const value = BIT_lookBits(bitD, nbBits);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
400 BIT_skipBits(bitD, nbBits);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
401 return value;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
402 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
403
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
404 /*! BIT_readBitsFast() :
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
405 * unsafe version; only works only if nbBits >= 1 */
42070
675775c33ab6 zstandard: vendor python-zstandard 0.11
Gregory Szorc <gregory.szorc@gmail.com>
parents: 40121
diff changeset
406 MEM_STATIC size_t BIT_readBitsFast(BIT_DStream_t* bitD, unsigned nbBits)
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
407 {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
408 size_t const value = BIT_lookBitsFast(bitD, nbBits);
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
409 assert(nbBits >= 1);
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
410 BIT_skipBits(bitD, nbBits);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
411 return value;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
412 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
413
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
414 /*! BIT_reloadDStream() :
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
415 * Refill `bitD` from buffer previously set in BIT_initDStream() .
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
416 * This function is safe, it guarantees it will not read beyond src buffer.
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
417 * @return : status of `BIT_DStream_t` internal register.
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
418 * when status == BIT_DStream_unfinished, internal register is filled with at least 25 or 57 bits */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
419 MEM_STATIC BIT_DStream_status BIT_reloadDStream(BIT_DStream_t* bitD)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
420 {
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
421 if (bitD->bitsConsumed > (sizeof(bitD->bitContainer)*8)) /* overflow detected, like end of stream */
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
422 return BIT_DStream_overflow;
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
423
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
424 if (bitD->ptr >= bitD->limitPtr) {
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
425 bitD->ptr -= bitD->bitsConsumed >> 3;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
426 bitD->bitsConsumed &= 7;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
427 bitD->bitContainer = MEM_readLEST(bitD->ptr);
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
428 return BIT_DStream_unfinished;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
429 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
430 if (bitD->ptr == bitD->start) {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
431 if (bitD->bitsConsumed < sizeof(bitD->bitContainer)*8) return BIT_DStream_endOfBuffer;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
432 return BIT_DStream_completed;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
433 }
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
434 /* start < ptr < limitPtr */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
435 { U32 nbBytes = bitD->bitsConsumed >> 3;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
436 BIT_DStream_status result = BIT_DStream_unfinished;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
437 if (bitD->ptr - nbBytes < bitD->start) {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
438 nbBytes = (U32)(bitD->ptr - bitD->start); /* ptr > start */
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
439 result = BIT_DStream_endOfBuffer;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
440 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
441 bitD->ptr -= nbBytes;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
442 bitD->bitsConsumed -= nbBytes*8;
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
443 bitD->bitContainer = MEM_readLEST(bitD->ptr); /* reminder : srcSize > sizeof(bitD->bitContainer), otherwise bitD->ptr == bitD->start */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
444 return result;
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
445 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
446 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
447
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
448 /*! BIT_endOfDStream() :
37495
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
449 * @return : 1 if DStream has _exactly_ reached its end (all bits consumed).
b1fb341d8a61 zstandard: vendor python-zstandard 0.9.0
Gregory Szorc <gregory.szorc@gmail.com>
parents: 30822
diff changeset
450 */
30434
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
451 MEM_STATIC unsigned BIT_endOfDStream(const BIT_DStream_t* DStream)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
452 {
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
453 return ((DStream->ptr == DStream->start) && (DStream->bitsConsumed == sizeof(DStream->bitContainer)*8));
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
454 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
455
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
456 #if defined (__cplusplus)
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
457 }
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
458 #endif
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
459
2e484bdea8c4 zstd: vendor zstd 1.1.1
Gregory Szorc <gregory.szorc@gmail.com>
parents:
diff changeset
460 #endif /* BITSTREAM_H_MODULE */