Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(172)

Side by Side Diff: jdhuff.h

Issue 1953443002: Update to libjpeg_turbo 1.4.90 (Closed) Base URL: https://chromium.googlesource.com/chromium/deps/libjpeg_turbo.git@master
Patch Set: Created 4 years, 7 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View unified diff | Download patch
« no previous file with comments | « jddctmgr.c ('k') | jdhuff.c » ('j') | no next file with comments »
Toggle Intra-line Diffs ('i') | Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
OLDNEW
1 /* 1 /*
2 * jdhuff.h 2 * jdhuff.h
3 * 3 *
4 * This file was part of the Independent JPEG Group's software: 4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1997, Thomas G. Lane. 5 * Copyright (C) 1991-1997, Thomas G. Lane.
6 * Modifications: 6 * libjpeg-turbo Modifications:
7 * Copyright (C) 2010-2011, D. R. Commander. 7 * Copyright (C) 2010-2011, 2015-2016, D. R. Commander.
8 * For conditions of distribution and use, see the accompanying README file. 8 * For conditions of distribution and use, see the accompanying README.ijg
9 * file.
9 * 10 *
10 * This file contains declarations for Huffman entropy decoding routines 11 * This file contains declarations for Huffman entropy decoding routines
11 * that are shared between the sequential decoder (jdhuff.c) and the 12 * that are shared between the sequential decoder (jdhuff.c) and the
12 * progressive decoder (jdphuff.c). No other modules need to see these. 13 * progressive decoder (jdphuff.c). No other modules need to see these.
13 */ 14 */
14 15
15 /* Short forms of external names for systems with brain-damaged linkers. */ 16 #include "jconfigint.h"
16
17 #ifdef NEED_SHORT_EXTERNAL_NAMES
18 #define jpeg_make_d_derived_tbl»jMkDDerived
19 #define jpeg_fill_bit_buffer» jFilBitBuf
20 #define jpeg_huff_decode» jHufDecode
21 #endif /* NEED_SHORT_EXTERNAL_NAMES */
22 17
23 18
24 /* Derived data constructed for each Huffman table */ 19 /* Derived data constructed for each Huffman table */
25 20
26 #define HUFF_LOOKAHEAD» 8» /* # of bits of lookahead */ 21 #define HUFF_LOOKAHEAD 8 /* # of bits of lookahead */
27 22
28 typedef struct { 23 typedef struct {
29 /* Basic tables: (element [0] of each array is unused) */ 24 /* Basic tables: (element [0] of each array is unused) */
30 INT32 maxcode[18];» » /* largest code of length k (-1 if none) */ 25 JLONG maxcode[18]; /* largest code of length k (-1 if none) */
31 /* (maxcode[17] is a sentinel to ensure jpeg_huff_decode terminates) */ 26 /* (maxcode[17] is a sentinel to ensure jpeg_huff_decode terminates) */
32 INT32 valoffset[18];» » /* huffval[] offset for codes of length k */ 27 JLONG valoffset[18]; /* huffval[] offset for codes of length k */
33 /* valoffset[k] = huffval[] index of 1st symbol of code length k, less 28 /* valoffset[k] = huffval[] index of 1st symbol of code length k, less
34 * the smallest code of length k; so given a code of length k, the 29 * the smallest code of length k; so given a code of length k, the
35 * corresponding symbol is huffval[code + valoffset[k]] 30 * corresponding symbol is huffval[code + valoffset[k]]
36 */ 31 */
37 32
38 /* Link to public Huffman table (needed only in jpeg_huff_decode) */ 33 /* Link to public Huffman table (needed only in jpeg_huff_decode) */
39 JHUFF_TBL *pub; 34 JHUFF_TBL *pub;
40 35
41 /* Lookahead table: indexed by the next HUFF_LOOKAHEAD bits of 36 /* Lookahead table: indexed by the next HUFF_LOOKAHEAD bits of
42 * the input data stream. If the next Huffman code is no more 37 * the input data stream. If the next Huffman code is no more
43 * than HUFF_LOOKAHEAD bits long, we can obtain its length and 38 * than HUFF_LOOKAHEAD bits long, we can obtain its length and
44 * the corresponding symbol directly from this tables. 39 * the corresponding symbol directly from this tables.
45 * 40 *
46 * The lower 8 bits of each table entry contain the number of 41 * The lower 8 bits of each table entry contain the number of
47 * bits in the corresponding Huffman code, or HUFF_LOOKAHEAD + 1 42 * bits in the corresponding Huffman code, or HUFF_LOOKAHEAD + 1
48 * if too long. The next 8 bits of each entry contain the 43 * if too long. The next 8 bits of each entry contain the
49 * symbol. 44 * symbol.
50 */ 45 */
51 int lookup[1<<HUFF_LOOKAHEAD]; 46 int lookup[1<<HUFF_LOOKAHEAD];
52 } d_derived_tbl; 47 } d_derived_tbl;
53 48
54 /* Expand a Huffman table definition into the derived format */ 49 /* Expand a Huffman table definition into the derived format */
55 EXTERN(void) jpeg_make_d_derived_tbl 50 EXTERN(void) jpeg_make_d_derived_tbl
56 » JPP((j_decompress_ptr cinfo, boolean isDC, int tblno, 51 (j_decompress_ptr cinfo, boolean isDC, int tblno,
57 » d_derived_tbl ** pdtbl)); 52 d_derived_tbl ** pdtbl);
58 53
59 54
60 /* 55 /*
61 * Fetching the next N bits from the input stream is a time-critical operation 56 * Fetching the next N bits from the input stream is a time-critical operation
62 * for the Huffman decoders. We implement it with a combination of inline 57 * for the Huffman decoders. We implement it with a combination of inline
63 * macros and out-of-line subroutines. Note that N (the number of bits 58 * macros and out-of-line subroutines. Note that N (the number of bits
64 * demanded at one time) never exceeds 15 for JPEG use. 59 * demanded at one time) never exceeds 15 for JPEG use.
65 * 60 *
66 * We read source bytes into get_buffer and dole out bits as needed. 61 * We read source bytes into get_buffer and dole out bits as needed.
67 * If get_buffer already contains enough bits, they are fetched in-line 62 * If get_buffer already contains enough bits, they are fetched in-line
68 * by the macros CHECK_BIT_BUFFER and GET_BITS. When there aren't enough 63 * by the macros CHECK_BIT_BUFFER and GET_BITS. When there aren't enough
69 * bits, jpeg_fill_bit_buffer is called; it will attempt to fill get_buffer 64 * bits, jpeg_fill_bit_buffer is called; it will attempt to fill get_buffer
70 * as full as possible (not just to the number of bits needed; this 65 * as full as possible (not just to the number of bits needed; this
71 * prefetching reduces the overhead cost of calling jpeg_fill_bit_buffer). 66 * prefetching reduces the overhead cost of calling jpeg_fill_bit_buffer).
72 * Note that jpeg_fill_bit_buffer may return FALSE to indicate suspension. 67 * Note that jpeg_fill_bit_buffer may return FALSE to indicate suspension.
73 * On TRUE return, jpeg_fill_bit_buffer guarantees that get_buffer contains 68 * On TRUE return, jpeg_fill_bit_buffer guarantees that get_buffer contains
74 * at least the requested number of bits --- dummy zeroes are inserted if 69 * at least the requested number of bits --- dummy zeroes are inserted if
75 * necessary. 70 * necessary.
76 */ 71 */
77 72
78 #if __WORDSIZE == 64 || defined(_WIN64) 73 #if !defined(_WIN32) && !defined(SIZEOF_SIZE_T)
74 #error Cannot determine word size
75 #endif
79 76
80 typedef size_t bit_buf_type;» /* type of bit-extraction buffer */ 77 #if SIZEOF_SIZE_T==8 || defined(_WIN64)
81 #define BIT_BUF_SIZE 64» » /* size of buffer in bits */ 78
79 typedef size_t bit_buf_type; /* type of bit-extraction buffer */
80 #define BIT_BUF_SIZE 64 /* size of buffer in bits */
82 81
83 #else 82 #else
84 83
85 typedef INT32 bit_buf_type;» /* type of bit-extraction buffer */ 84 typedef unsigned long bit_buf_type; /* type of bit-extraction buffer */
86 #define BIT_BUF_SIZE 32» » /* size of buffer in bits */ 85 #define BIT_BUF_SIZE 32 /* size of buffer in bits */
87 86
88 #endif 87 #endif
89 88
90 /* If long is > 32 bits on your machine, and shifting/masking longs is 89 /* If long is > 32 bits on your machine, and shifting/masking longs is
91 * reasonably fast, making bit_buf_type be long and setting BIT_BUF_SIZE 90 * reasonably fast, making bit_buf_type be long and setting BIT_BUF_SIZE
92 * appropriately should be a win. Unfortunately we can't define the size 91 * appropriately should be a win. Unfortunately we can't define the size
93 * with something like #define BIT_BUF_SIZE (sizeof(bit_buf_type)*8) 92 * with something like #define BIT_BUF_SIZE (sizeof(bit_buf_type)*8)
94 * because not all machines measure sizeof in 8-bit bytes. 93 * because not all machines measure sizeof in 8-bit bytes.
95 */ 94 */
96 95
97 typedef struct {» » /* Bitreading state saved across MCUs */ 96 typedef struct { /* Bitreading state saved across MCUs */
98 bit_buf_type get_buffer;» /* current bit-extraction buffer */ 97 bit_buf_type get_buffer; /* current bit-extraction buffer */
99 int bits_left;» » /* # of unused bits in it */ 98 int bits_left; /* # of unused bits in it */
100 } bitread_perm_state; 99 } bitread_perm_state;
101 100
102 typedef struct {» » /* Bitreading working state within an MCU */ 101 typedef struct { /* Bitreading working state within an MCU */
103 /* Current data source location */ 102 /* Current data source location */
104 /* We need a copy, rather than munging the original, in case of suspension */ 103 /* We need a copy, rather than munging the original, in case of suspension */
105 const JOCTET * next_input_byte; /* => next byte to read from source */ 104 const JOCTET *next_input_byte; /* => next byte to read from source */
106 size_t bytes_in_buffer;» /* # of bytes remaining in source buffer */ 105 size_t bytes_in_buffer; /* # of bytes remaining in source buffer */
107 /* Bit input buffer --- note these values are kept in register variables, 106 /* Bit input buffer --- note these values are kept in register variables,
108 * not in this struct, inside the inner loops. 107 * not in this struct, inside the inner loops.
109 */ 108 */
110 bit_buf_type get_buffer;» /* current bit-extraction buffer */ 109 bit_buf_type get_buffer; /* current bit-extraction buffer */
111 int bits_left;» » /* # of unused bits in it */ 110 int bits_left; /* # of unused bits in it */
112 /* Pointer needed by jpeg_fill_bit_buffer. */ 111 /* Pointer needed by jpeg_fill_bit_buffer. */
113 j_decompress_ptr cinfo;» /* back link to decompress master record */ 112 j_decompress_ptr cinfo; /* back link to decompress master record */
114 } bitread_working_state; 113 } bitread_working_state;
115 114
116 /* Macros to declare and load/save bitread local variables. */ 115 /* Macros to declare and load/save bitread local variables. */
117 #define BITREAD_STATE_VARS \ 116 #define BITREAD_STATE_VARS \
118 » register bit_buf_type get_buffer; \ 117 register bit_buf_type get_buffer; \
119 » register int bits_left; \ 118 register int bits_left; \
120 » bitread_working_state br_state 119 bitread_working_state br_state
121 120
122 #define BITREAD_LOAD_STATE(cinfop,permstate) \ 121 #define BITREAD_LOAD_STATE(cinfop,permstate) \
123 » br_state.cinfo = cinfop; \ 122 br_state.cinfo = cinfop; \
124 » br_state.next_input_byte = cinfop->src->next_input_byte; \ 123 br_state.next_input_byte = cinfop->src->next_input_byte; \
125 » br_state.bytes_in_buffer = cinfop->src->bytes_in_buffer; \ 124 br_state.bytes_in_buffer = cinfop->src->bytes_in_buffer; \
126 » get_buffer = permstate.get_buffer; \ 125 get_buffer = permstate.get_buffer; \
127 » bits_left = permstate.bits_left; 126 bits_left = permstate.bits_left;
128 127
129 #define BITREAD_SAVE_STATE(cinfop,permstate) \ 128 #define BITREAD_SAVE_STATE(cinfop,permstate) \
130 » cinfop->src->next_input_byte = br_state.next_input_byte; \ 129 cinfop->src->next_input_byte = br_state.next_input_byte; \
131 » cinfop->src->bytes_in_buffer = br_state.bytes_in_buffer; \ 130 cinfop->src->bytes_in_buffer = br_state.bytes_in_buffer; \
132 » permstate.get_buffer = get_buffer; \ 131 permstate.get_buffer = get_buffer; \
133 » permstate.bits_left = bits_left 132 permstate.bits_left = bits_left
134 133
135 /* 134 /*
136 * These macros provide the in-line portion of bit fetching. 135 * These macros provide the in-line portion of bit fetching.
137 * Use CHECK_BIT_BUFFER to ensure there are N bits in get_buffer 136 * Use CHECK_BIT_BUFFER to ensure there are N bits in get_buffer
138 * before using GET_BITS, PEEK_BITS, or DROP_BITS. 137 * before using GET_BITS, PEEK_BITS, or DROP_BITS.
139 * The variables get_buffer and bits_left are assumed to be locals, 138 * The variables get_buffer and bits_left are assumed to be locals,
140 * but the state struct might not be (jpeg_huff_decode needs this). 139 * but the state struct might not be (jpeg_huff_decode needs this).
141 *» CHECK_BIT_BUFFER(state,n,action); 140 * CHECK_BIT_BUFFER(state,n,action);
142 *» » Ensure there are N bits in get_buffer; if suspend, take action. 141 * Ensure there are N bits in get_buffer; if suspend, take action.
143 * val = GET_BITS(n); 142 * val = GET_BITS(n);
144 *» » Fetch next N bits. 143 * Fetch next N bits.
145 * val = PEEK_BITS(n); 144 * val = PEEK_BITS(n);
146 *» » Fetch next N bits without removing them from the buffer. 145 * Fetch next N bits without removing them from the buffer.
147 *» DROP_BITS(n); 146 * DROP_BITS(n);
148 *» » Discard next N bits. 147 * Discard next N bits.
149 * The value N should be a simple variable, not an expression, because it 148 * The value N should be a simple variable, not an expression, because it
150 * is evaluated multiple times. 149 * is evaluated multiple times.
151 */ 150 */
152 151
153 #define CHECK_BIT_BUFFER(state,nbits,action) \ 152 #define CHECK_BIT_BUFFER(state,nbits,action) \
154 » { if (bits_left < (nbits)) { \ 153 { if (bits_left < (nbits)) { \
155 » if (! jpeg_fill_bit_buffer(&(state),get_buffer,bits_left,nbits)) \ 154 if (! jpeg_fill_bit_buffer(&(state),get_buffer,bits_left,nbits)) \
156 » { action; } \ 155 { action; } \
157 » get_buffer = (state).get_buffer; bits_left = (state).bits_left; } } 156 get_buffer = (state).get_buffer; bits_left = (state).bits_left; } }
158 157
159 #define GET_BITS(nbits) \ 158 #define GET_BITS(nbits) \
160 » (((int) (get_buffer >> (bits_left -= (nbits)))) & ((1<<(nbits))-1)) 159 (((int) (get_buffer >> (bits_left -= (nbits)))) & ((1<<(nbits))-1))
161 160
162 #define PEEK_BITS(nbits) \ 161 #define PEEK_BITS(nbits) \
163 » (((int) (get_buffer >> (bits_left - (nbits)))) & ((1<<(nbits))-1)) 162 (((int) (get_buffer >> (bits_left - (nbits)))) & ((1<<(nbits))-1))
164 163
165 #define DROP_BITS(nbits) \ 164 #define DROP_BITS(nbits) \
166 » (bits_left -= (nbits)) 165 (bits_left -= (nbits))
167 166
168 /* Load up the bit buffer to a depth of at least nbits */ 167 /* Load up the bit buffer to a depth of at least nbits */
169 EXTERN(boolean) jpeg_fill_bit_buffer 168 EXTERN(boolean) jpeg_fill_bit_buffer
170 » JPP((bitread_working_state * state, register bit_buf_type get_buffer, 169 (bitread_working_state *state, register bit_buf_type get_buffer,
171 » register int bits_left, int nbits)); 170 register int bits_left, int nbits);
172 171
173 172
174 /* 173 /*
175 * Code for extracting next Huffman-coded symbol from input bit stream. 174 * Code for extracting next Huffman-coded symbol from input bit stream.
176 * Again, this is time-critical and we make the main paths be macros. 175 * Again, this is time-critical and we make the main paths be macros.
177 * 176 *
178 * We use a lookahead table to process codes of up to HUFF_LOOKAHEAD bits 177 * We use a lookahead table to process codes of up to HUFF_LOOKAHEAD bits
179 * without looping. Usually, more than 95% of the Huffman codes will be 8 178 * without looping. Usually, more than 95% of the Huffman codes will be 8
180 * or fewer bits long. The few overlength codes are handled with a loop, 179 * or fewer bits long. The few overlength codes are handled with a loop,
181 * which need not be inline code. 180 * which need not be inline code.
(...skipping 15 matching lines...) Expand all
197 nb = 1; goto slowlabel; \ 196 nb = 1; goto slowlabel; \
198 } \ 197 } \
199 } \ 198 } \
200 look = PEEK_BITS(HUFF_LOOKAHEAD); \ 199 look = PEEK_BITS(HUFF_LOOKAHEAD); \
201 if ((nb = (htbl->lookup[look] >> HUFF_LOOKAHEAD)) <= HUFF_LOOKAHEAD) { \ 200 if ((nb = (htbl->lookup[look] >> HUFF_LOOKAHEAD)) <= HUFF_LOOKAHEAD) { \
202 DROP_BITS(nb); \ 201 DROP_BITS(nb); \
203 result = htbl->lookup[look] & ((1 << HUFF_LOOKAHEAD) - 1); \ 202 result = htbl->lookup[look] & ((1 << HUFF_LOOKAHEAD) - 1); \
204 } else { \ 203 } else { \
205 slowlabel: \ 204 slowlabel: \
206 if ((result=jpeg_huff_decode(&state,get_buffer,bits_left,htbl,nb)) < 0) \ 205 if ((result=jpeg_huff_decode(&state,get_buffer,bits_left,htbl,nb)) < 0) \
207 » { failaction; } \ 206 { failaction; } \
208 get_buffer = state.get_buffer; bits_left = state.bits_left; \ 207 get_buffer = state.get_buffer; bits_left = state.bits_left; \
209 } \ 208 } \
210 } 209 }
211 210
212 #define HUFF_DECODE_FAST(s,nb,htbl,slowlabel) \ 211 #define HUFF_DECODE_FAST(s,nb,htbl,slowlabel) \
213 FILL_BIT_BUFFER_FAST; \ 212 FILL_BIT_BUFFER_FAST; \
214 s = PEEK_BITS(HUFF_LOOKAHEAD); \ 213 s = PEEK_BITS(HUFF_LOOKAHEAD); \
215 s = htbl->lookup[s]; \ 214 s = htbl->lookup[s]; \
216 nb = s >> HUFF_LOOKAHEAD; \ 215 nb = s >> HUFF_LOOKAHEAD; \
217 /* Pre-execute the common case of nb <= HUFF_LOOKAHEAD */ \ 216 /* Pre-execute the common case of nb <= HUFF_LOOKAHEAD */ \
218 DROP_BITS(nb); \ 217 DROP_BITS(nb); \
219 s = s & ((1 << HUFF_LOOKAHEAD) - 1); \ 218 s = s & ((1 << HUFF_LOOKAHEAD) - 1); \
220 if (nb > HUFF_LOOKAHEAD) { \ 219 if (nb > HUFF_LOOKAHEAD) { \
221 /* Equivalent of jpeg_huff_decode() */ \ 220 /* Equivalent of jpeg_huff_decode() */ \
222 /* Don't use GET_BITS() here because we don't want to modify bits_left */ \ 221 /* Don't use GET_BITS() here because we don't want to modify bits_left */ \
223 s = (get_buffer >> bits_left) & ((1 << (nb)) - 1); \ 222 s = (get_buffer >> bits_left) & ((1 << (nb)) - 1); \
224 while (s > htbl->maxcode[nb]) { \ 223 while (s > htbl->maxcode[nb]) { \
225 s <<= 1; \ 224 s <<= 1; \
226 s |= GET_BITS(1); \ 225 s |= GET_BITS(1); \
227 nb++; \ 226 nb++; \
228 } \ 227 } \
229 if (nb > 16) \ 228 if (nb > 16) \
230 goto slowlabel; \ 229 goto slowlabel; \
231 s = htbl->pub->huffval[ (int) (s + htbl->valoffset[nb]) ]; \ 230 s = htbl->pub->huffval[ (int) (s + htbl->valoffset[nb]) ]; \
232 } 231 }
233 232
234 /* Out-of-line case for Huffman code fetching */ 233 /* Out-of-line case for Huffman code fetching */
235 EXTERN(int) jpeg_huff_decode 234 EXTERN(int) jpeg_huff_decode
236 » JPP((bitread_working_state * state, register bit_buf_type get_buffer, 235 (bitread_working_state *state, register bit_buf_type get_buffer,
237 » register int bits_left, d_derived_tbl * htbl, int min_bits)); 236 register int bits_left, d_derived_tbl *htbl, int min_bits);
OLDNEW
« no previous file with comments | « jddctmgr.c ('k') | jdhuff.c » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698