Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 1 | /* |
| 2 | * jchuff.c |
| 3 | * |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 4 | * Copyright (C) 1991-1997, Thomas G. Lane. |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 5 | * Copyright (C) 2009-2011, D. R. Commander. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 6 | * This file is part of the Independent JPEG Group's software. |
| 7 | * For conditions of distribution and use, see the accompanying README file. |
| 8 | * |
| 9 | * This file contains Huffman entropy encoding routines. |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 10 | * |
| 11 | * Much of the complexity here has to do with supporting output suspension. |
| 12 | * If the data destination module demands suspension, we want to be able to |
| 13 | * back up to the start of the current MCU. To do this, we copy state |
| 14 | * variables into local working storage, and update them back to the |
| 15 | * permanent JPEG objects only upon successful completion of an MCU. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 16 | */ |
| 17 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 18 | #define JPEG_INTERNALS |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 19 | #include "jinclude.h" |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 20 | #include "jpeglib.h" |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 21 | #include "jchuff.h" /* Declarations shared with jcphuff.c */ |
DRC | 8443e52 | 2009-07-30 08:35:06 +0000 | [diff] [blame] | 22 | #include <limits.h> |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 23 | |
DRC | ac906c5 | 2011-05-26 11:28:22 +0000 | [diff] [blame] | 24 | static unsigned char jpeg_nbits_table[65536]; |
| 25 | static int jpeg_nbits_table_init = 0; |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 26 | |
DRC | 3cba8db | 2009-03-16 23:58:30 +0000 | [diff] [blame] | 27 | #ifndef min |
| 28 | #define min(a,b) ((a)<(b)?(a):(b)) |
| 29 | #endif |
| 30 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 31 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 32 | /* Expanded entropy encoder object for Huffman encoding. |
| 33 | * |
| 34 | * The savable_state subrecord contains fields that change within an MCU, |
| 35 | * but must not be updated permanently until we complete the MCU. |
| 36 | */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 37 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 38 | typedef struct { |
DRC | 0489909 | 2010-02-26 23:01:19 +0000 | [diff] [blame] | 39 | size_t put_buffer; /* current bit-accumulation buffer */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 40 | int put_bits; /* # of bits now in it */ |
| 41 | int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */ |
| 42 | } savable_state; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 43 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 44 | /* This macro is to work around compilers with missing or broken |
| 45 | * structure assignment. You'll need to fix this code if you have |
| 46 | * such a compiler and you change MAX_COMPS_IN_SCAN. |
| 47 | */ |
| 48 | |
| 49 | #ifndef NO_STRUCT_ASSIGN |
| 50 | #define ASSIGN_STATE(dest,src) ((dest) = (src)) |
| 51 | #else |
| 52 | #if MAX_COMPS_IN_SCAN == 4 |
| 53 | #define ASSIGN_STATE(dest,src) \ |
| 54 | ((dest).put_buffer = (src).put_buffer, \ |
| 55 | (dest).put_bits = (src).put_bits, \ |
| 56 | (dest).last_dc_val[0] = (src).last_dc_val[0], \ |
| 57 | (dest).last_dc_val[1] = (src).last_dc_val[1], \ |
| 58 | (dest).last_dc_val[2] = (src).last_dc_val[2], \ |
| 59 | (dest).last_dc_val[3] = (src).last_dc_val[3]) |
| 60 | #endif |
| 61 | #endif |
| 62 | |
| 63 | |
| 64 | typedef struct { |
| 65 | struct jpeg_entropy_encoder pub; /* public fields */ |
| 66 | |
| 67 | savable_state saved; /* Bit buffer & DC state at start of MCU */ |
| 68 | |
| 69 | /* These fields are NOT loaded into local working state. */ |
| 70 | unsigned int restarts_to_go; /* MCUs left in this restart interval */ |
| 71 | int next_restart_num; /* next restart number to write (0-7) */ |
| 72 | |
| 73 | /* Pointers to derived tables (these workspaces have image lifespan) */ |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 74 | c_derived_tbl * dc_derived_tbls[NUM_HUFF_TBLS]; |
| 75 | c_derived_tbl * ac_derived_tbls[NUM_HUFF_TBLS]; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 76 | |
| 77 | #ifdef ENTROPY_OPT_SUPPORTED /* Statistics tables for optimization */ |
| 78 | long * dc_count_ptrs[NUM_HUFF_TBLS]; |
| 79 | long * ac_count_ptrs[NUM_HUFF_TBLS]; |
| 80 | #endif |
| 81 | } huff_entropy_encoder; |
| 82 | |
| 83 | typedef huff_entropy_encoder * huff_entropy_ptr; |
| 84 | |
| 85 | /* Working state while writing an MCU. |
| 86 | * This struct contains all the fields that are needed by subroutines. |
| 87 | */ |
| 88 | |
| 89 | typedef struct { |
| 90 | JOCTET * next_output_byte; /* => next byte to write in buffer */ |
| 91 | size_t free_in_buffer; /* # of byte spaces remaining in buffer */ |
| 92 | savable_state cur; /* Current bit buffer & DC state */ |
| 93 | j_compress_ptr cinfo; /* dump_buffer needs access to this */ |
| 94 | } working_state; |
| 95 | |
| 96 | |
| 97 | /* Forward declarations */ |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 98 | METHODDEF(boolean) encode_mcu_huff JPP((j_compress_ptr cinfo, |
| 99 | JBLOCKROW *MCU_data)); |
| 100 | METHODDEF(void) finish_pass_huff JPP((j_compress_ptr cinfo)); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 101 | #ifdef ENTROPY_OPT_SUPPORTED |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 102 | METHODDEF(boolean) encode_mcu_gather JPP((j_compress_ptr cinfo, |
| 103 | JBLOCKROW *MCU_data)); |
| 104 | METHODDEF(void) finish_pass_gather JPP((j_compress_ptr cinfo)); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 105 | #endif |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 106 | |
| 107 | |
| 108 | /* |
| 109 | * Initialize for a Huffman-compressed scan. |
| 110 | * If gather_statistics is TRUE, we do not output anything during the scan, |
| 111 | * just count the Huffman symbols used and generate Huffman code tables. |
| 112 | */ |
| 113 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 114 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 115 | start_pass_huff (j_compress_ptr cinfo, boolean gather_statistics) |
| 116 | { |
| 117 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; |
| 118 | int ci, dctbl, actbl; |
| 119 | jpeg_component_info * compptr; |
| 120 | |
| 121 | if (gather_statistics) { |
| 122 | #ifdef ENTROPY_OPT_SUPPORTED |
| 123 | entropy->pub.encode_mcu = encode_mcu_gather; |
| 124 | entropy->pub.finish_pass = finish_pass_gather; |
| 125 | #else |
| 126 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
| 127 | #endif |
| 128 | } else { |
| 129 | entropy->pub.encode_mcu = encode_mcu_huff; |
| 130 | entropy->pub.finish_pass = finish_pass_huff; |
| 131 | } |
| 132 | |
| 133 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
| 134 | compptr = cinfo->cur_comp_info[ci]; |
| 135 | dctbl = compptr->dc_tbl_no; |
| 136 | actbl = compptr->ac_tbl_no; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 137 | if (gather_statistics) { |
| 138 | #ifdef ENTROPY_OPT_SUPPORTED |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 139 | /* Check for invalid table indexes */ |
| 140 | /* (make_c_derived_tbl does this in the other path) */ |
| 141 | if (dctbl < 0 || dctbl >= NUM_HUFF_TBLS) |
| 142 | ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, dctbl); |
| 143 | if (actbl < 0 || actbl >= NUM_HUFF_TBLS) |
| 144 | ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, actbl); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 145 | /* Allocate and zero the statistics tables */ |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 146 | /* Note that jpeg_gen_optimal_table expects 257 entries in each table! */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 147 | if (entropy->dc_count_ptrs[dctbl] == NULL) |
| 148 | entropy->dc_count_ptrs[dctbl] = (long *) |
| 149 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 150 | 257 * SIZEOF(long)); |
| 151 | MEMZERO(entropy->dc_count_ptrs[dctbl], 257 * SIZEOF(long)); |
| 152 | if (entropy->ac_count_ptrs[actbl] == NULL) |
| 153 | entropy->ac_count_ptrs[actbl] = (long *) |
| 154 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 155 | 257 * SIZEOF(long)); |
| 156 | MEMZERO(entropy->ac_count_ptrs[actbl], 257 * SIZEOF(long)); |
| 157 | #endif |
| 158 | } else { |
| 159 | /* Compute derived values for Huffman tables */ |
| 160 | /* We may do this more than once for a table, but it's not expensive */ |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 161 | jpeg_make_c_derived_tbl(cinfo, TRUE, dctbl, |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 162 | & entropy->dc_derived_tbls[dctbl]); |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 163 | jpeg_make_c_derived_tbl(cinfo, FALSE, actbl, |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 164 | & entropy->ac_derived_tbls[actbl]); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 165 | } |
| 166 | /* Initialize DC predictions to 0 */ |
| 167 | entropy->saved.last_dc_val[ci] = 0; |
| 168 | } |
| 169 | |
| 170 | /* Initialize bit buffer to empty */ |
| 171 | entropy->saved.put_buffer = 0; |
| 172 | entropy->saved.put_bits = 0; |
| 173 | |
| 174 | /* Initialize restart stuff */ |
| 175 | entropy->restarts_to_go = cinfo->restart_interval; |
| 176 | entropy->next_restart_num = 0; |
| 177 | } |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 178 | |
| 179 | |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 180 | /* |
| 181 | * Compute the derived values for a Huffman table. |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 182 | * This routine also performs some validation checks on the table. |
| 183 | * |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 184 | * Note this is also used by jcphuff.c. |
| 185 | */ |
| 186 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 187 | GLOBAL(void) |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 188 | jpeg_make_c_derived_tbl (j_compress_ptr cinfo, boolean isDC, int tblno, |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 189 | c_derived_tbl ** pdtbl) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 190 | { |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 191 | JHUFF_TBL *htbl; |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 192 | c_derived_tbl *dtbl; |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 193 | int p, i, l, lastp, si, maxsymbol; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 194 | char huffsize[257]; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 195 | unsigned int huffcode[257]; |
| 196 | unsigned int code; |
| 197 | |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 198 | /* Note that huffsize[] and huffcode[] are filled in code-length order, |
| 199 | * paralleling the order of the symbols themselves in htbl->huffval[]. |
| 200 | */ |
| 201 | |
| 202 | /* Find the input Huffman table */ |
| 203 | if (tblno < 0 || tblno >= NUM_HUFF_TBLS) |
| 204 | ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno); |
| 205 | htbl = |
| 206 | isDC ? cinfo->dc_huff_tbl_ptrs[tblno] : cinfo->ac_huff_tbl_ptrs[tblno]; |
| 207 | if (htbl == NULL) |
| 208 | ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, tblno); |
| 209 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 210 | /* Allocate a workspace if we haven't already done so. */ |
| 211 | if (*pdtbl == NULL) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 212 | *pdtbl = (c_derived_tbl *) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 213 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 214 | SIZEOF(c_derived_tbl)); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 215 | dtbl = *pdtbl; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 216 | |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 217 | /* Figure C.1: make table of Huffman code length for each symbol */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 218 | |
| 219 | p = 0; |
| 220 | for (l = 1; l <= 16; l++) { |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 221 | i = (int) htbl->bits[l]; |
| 222 | if (i < 0 || p + i > 256) /* protect against table overrun */ |
| 223 | ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); |
| 224 | while (i--) |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 225 | huffsize[p++] = (char) l; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 226 | } |
| 227 | huffsize[p] = 0; |
| 228 | lastp = p; |
| 229 | |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 230 | /* Figure C.2: generate the codes themselves */ |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 231 | /* We also validate that the counts represent a legal Huffman code tree. */ |
| 232 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 233 | code = 0; |
| 234 | si = huffsize[0]; |
| 235 | p = 0; |
| 236 | while (huffsize[p]) { |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 237 | while (((int) huffsize[p]) == si) { |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 238 | huffcode[p++] = code; |
| 239 | code++; |
| 240 | } |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 241 | /* code is now 1 more than the last code used for codelength si; but |
| 242 | * it must still fit in si bits, since no code is allowed to be all ones. |
| 243 | */ |
| 244 | if (((INT32) code) >= (((INT32) 1) << si)) |
| 245 | ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 246 | code <<= 1; |
| 247 | si++; |
| 248 | } |
| 249 | |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 250 | /* Figure C.3: generate encoding tables */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 251 | /* These are code and size indexed by symbol value */ |
| 252 | |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 253 | /* Set all codeless symbols to have code length 0; |
| 254 | * this lets us detect duplicate VAL entries here, and later |
| 255 | * allows emit_bits to detect any attempt to emit such symbols. |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 256 | */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 257 | MEMZERO(dtbl->ehufsi, SIZEOF(dtbl->ehufsi)); |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 258 | |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 259 | /* This is also a convenient place to check for out-of-range |
| 260 | * and duplicated VAL entries. We allow 0..255 for AC symbols |
| 261 | * but only 0..15 for DC. (We could constrain them further |
| 262 | * based on data depth and mode, but this seems enough.) |
| 263 | */ |
| 264 | maxsymbol = isDC ? 15 : 255; |
| 265 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 266 | for (p = 0; p < lastp; p++) { |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 267 | i = htbl->huffval[p]; |
| 268 | if (i < 0 || i > maxsymbol || dtbl->ehufsi[i]) |
| 269 | ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); |
| 270 | dtbl->ehufco[i] = huffcode[p]; |
| 271 | dtbl->ehufsi[i] = huffsize[p]; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 272 | } |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 273 | |
DRC | ac906c5 | 2011-05-26 11:28:22 +0000 | [diff] [blame] | 274 | if(!jpeg_nbits_table_init) { |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 275 | for(i = 0; i < 65536; i++) { |
DRC | ac906c5 | 2011-05-26 11:28:22 +0000 | [diff] [blame] | 276 | int nbits = 0, temp = i; |
| 277 | while (temp) {temp >>= 1; nbits++;} |
| 278 | jpeg_nbits_table[i] = nbits; |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 279 | } |
DRC | ac906c5 | 2011-05-26 11:28:22 +0000 | [diff] [blame] | 280 | jpeg_nbits_table_init = 1; |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 281 | } |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 282 | } |
| 283 | |
| 284 | |
| 285 | /* Outputting bytes to the file */ |
| 286 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 287 | /* Emit a byte, taking 'action' if must suspend. */ |
| 288 | #define emit_byte(state,val,action) \ |
| 289 | { *(state)->next_output_byte++ = (JOCTET) (val); \ |
| 290 | if (--(state)->free_in_buffer == 0) \ |
| 291 | if (! dump_buffer(state)) \ |
| 292 | { action; } } |
| 293 | |
| 294 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 295 | LOCAL(boolean) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 296 | dump_buffer (working_state * state) |
| 297 | /* Empty the output buffer; return TRUE if successful, FALSE if must suspend */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 298 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 299 | struct jpeg_destination_mgr * dest = state->cinfo->dest; |
| 300 | |
DRC | 8629988 | 2009-03-14 01:21:13 +0000 | [diff] [blame] | 301 | dest->free_in_buffer = state->free_in_buffer; |
| 302 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 303 | if (! (*dest->empty_output_buffer) (state->cinfo)) |
| 304 | return FALSE; |
| 305 | /* After a successful buffer dump, must reset buffer pointers */ |
| 306 | state->next_output_byte = dest->next_output_byte; |
| 307 | state->free_in_buffer = dest->free_in_buffer; |
| 308 | return TRUE; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 309 | } |
| 310 | |
| 311 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 312 | /* Outputting bits to the file */ |
| 313 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 314 | /* These macros perform the same task as the emit_bits() function in the |
| 315 | * original libjpeg code. In addition to reducing overhead by explicitly |
| 316 | * inlining the code, additional performance is achieved by taking into |
| 317 | * account the size of the bit buffer and waiting until it is almost full |
| 318 | * before emptying it. This mostly benefits 64-bit platforms, since 6 |
| 319 | * bytes can be stored in a 64-bit bit buffer before it has to be emptied. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 320 | */ |
| 321 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 322 | #define EMIT_BYTE() { \ |
| 323 | JOCTET c; \ |
| 324 | put_bits -= 8; \ |
| 325 | c = (JOCTET)GETJOCTET(put_buffer >> put_bits); \ |
| 326 | *buffer++ = c; \ |
| 327 | if (c == 0xFF) /* need to stuff a zero byte? */ \ |
| 328 | *buffer++ = 0; \ |
DRC | 8443e52 | 2009-07-30 08:35:06 +0000 | [diff] [blame] | 329 | } |
| 330 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 331 | #define PUT_BITS(code, size) { \ |
| 332 | put_bits += size; \ |
| 333 | put_buffer = (put_buffer << size) | code; \ |
DRC | 8443e52 | 2009-07-30 08:35:06 +0000 | [diff] [blame] | 334 | } |
| 335 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 336 | #define CHECKBUF15() { \ |
| 337 | if (put_bits > 15) { \ |
| 338 | EMIT_BYTE() \ |
| 339 | EMIT_BYTE() \ |
| 340 | } \ |
DRC | 8443e52 | 2009-07-30 08:35:06 +0000 | [diff] [blame] | 341 | } |
| 342 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 343 | #define CHECKBUF31() { \ |
| 344 | if (put_bits > 31) { \ |
| 345 | EMIT_BYTE() \ |
| 346 | EMIT_BYTE() \ |
| 347 | EMIT_BYTE() \ |
| 348 | EMIT_BYTE() \ |
| 349 | } \ |
DRC | 8443e52 | 2009-07-30 08:35:06 +0000 | [diff] [blame] | 350 | } |
| 351 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 352 | #define CHECKBUF47() { \ |
| 353 | if (put_bits > 47) { \ |
| 354 | EMIT_BYTE() \ |
| 355 | EMIT_BYTE() \ |
| 356 | EMIT_BYTE() \ |
| 357 | EMIT_BYTE() \ |
| 358 | EMIT_BYTE() \ |
| 359 | EMIT_BYTE() \ |
| 360 | } \ |
| 361 | } |
DRC | 8443e52 | 2009-07-30 08:35:06 +0000 | [diff] [blame] | 362 | |
DRC | 830d5fc | 2010-04-20 21:13:26 +0000 | [diff] [blame] | 363 | #if __WORDSIZE==64 || defined(_WIN64) |
DRC | 8443e52 | 2009-07-30 08:35:06 +0000 | [diff] [blame] | 364 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 365 | #define EMIT_BITS(code, size) { \ |
| 366 | CHECKBUF47() \ |
| 367 | PUT_BITS(code, size) \ |
| 368 | } |
| 369 | |
| 370 | #define EMIT_CODE(code, size) { \ |
| 371 | temp2 &= (((INT32) 1)<<nbits) - 1; \ |
| 372 | CHECKBUF31() \ |
| 373 | PUT_BITS(code, size) \ |
| 374 | PUT_BITS(temp2, nbits) \ |
DRC | 8443e52 | 2009-07-30 08:35:06 +0000 | [diff] [blame] | 375 | } |
| 376 | |
| 377 | #else |
| 378 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 379 | #define EMIT_BITS(code, size) { \ |
| 380 | PUT_BITS(code, size) \ |
| 381 | CHECKBUF15() \ |
| 382 | } |
| 383 | |
| 384 | #define EMIT_CODE(code, size) { \ |
| 385 | temp2 &= (((INT32) 1)<<nbits) - 1; \ |
| 386 | PUT_BITS(code, size) \ |
| 387 | CHECKBUF15() \ |
| 388 | PUT_BITS(temp2, nbits) \ |
| 389 | CHECKBUF15() \ |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 390 | } |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 391 | |
DRC | 8443e52 | 2009-07-30 08:35:06 +0000 | [diff] [blame] | 392 | #endif |
| 393 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 394 | |
DRC | 3cba8db | 2009-03-16 23:58:30 +0000 | [diff] [blame] | 395 | #define BUFSIZE (DCTSIZE2 * 2) |
| 396 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 397 | #define LOAD_BUFFER() { \ |
| 398 | if (state->free_in_buffer < BUFSIZE) { \ |
| 399 | localbuf = 1; \ |
| 400 | buffer = _buffer; \ |
| 401 | } \ |
| 402 | else buffer = state->next_output_byte; \ |
DRC | 3cba8db | 2009-03-16 23:58:30 +0000 | [diff] [blame] | 403 | } |
| 404 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 405 | #define STORE_BUFFER() { \ |
| 406 | if (localbuf) { \ |
| 407 | bytes = buffer - _buffer; \ |
| 408 | buffer = _buffer; \ |
| 409 | while (bytes > 0) { \ |
| 410 | bytestocopy = min(bytes, state->free_in_buffer); \ |
| 411 | MEMCOPY(state->next_output_byte, buffer, bytestocopy); \ |
| 412 | state->next_output_byte += bytestocopy; \ |
| 413 | buffer += bytestocopy; \ |
| 414 | state->free_in_buffer -= bytestocopy; \ |
| 415 | if (state->free_in_buffer == 0) \ |
| 416 | if (! dump_buffer(state)) return FALSE; \ |
| 417 | bytes -= bytestocopy; \ |
| 418 | } \ |
| 419 | } \ |
| 420 | else { \ |
| 421 | state->free_in_buffer -= (buffer - state->next_output_byte); \ |
| 422 | state->next_output_byte = buffer; \ |
| 423 | } \ |
DRC | 3cba8db | 2009-03-16 23:58:30 +0000 | [diff] [blame] | 424 | } |
| 425 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 426 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 427 | LOCAL(boolean) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 428 | flush_bits (working_state * state) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 429 | { |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 430 | JOCTET _buffer[BUFSIZE], *buffer; |
DRC | 0489909 | 2010-02-26 23:01:19 +0000 | [diff] [blame] | 431 | size_t put_buffer; int put_bits; |
| 432 | size_t bytes, bytestocopy; int localbuf = 0; |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 433 | |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 434 | put_buffer = state->cur.put_buffer; |
| 435 | put_bits = state->cur.put_bits; |
DRC | 3cba8db | 2009-03-16 23:58:30 +0000 | [diff] [blame] | 436 | LOAD_BUFFER() |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 437 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 438 | /* fill any partial byte with ones */ |
| 439 | PUT_BITS(0x7F, 7) |
| 440 | while (put_bits >= 8) EMIT_BYTE() |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 441 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 442 | state->cur.put_buffer = 0; /* and reset bit-buffer to empty */ |
| 443 | state->cur.put_bits = 0; |
DRC | 3cba8db | 2009-03-16 23:58:30 +0000 | [diff] [blame] | 444 | STORE_BUFFER() |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 445 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 446 | return TRUE; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 447 | } |
| 448 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 449 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 450 | /* Encode a single block's worth of coefficients */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 451 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 452 | LOCAL(boolean) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 453 | encode_one_block (working_state * state, JCOEFPTR block, int last_dc_val, |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 454 | c_derived_tbl *dctbl, c_derived_tbl *actbl) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 455 | { |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 456 | int temp, temp2, temp3; |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 457 | int nbits; |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 458 | int r, code, size; |
| 459 | JOCTET _buffer[BUFSIZE], *buffer; |
DRC | 0489909 | 2010-02-26 23:01:19 +0000 | [diff] [blame] | 460 | size_t put_buffer; int put_bits; |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 461 | int code_0xf0 = actbl->ehufco[0xf0], size_0xf0 = actbl->ehufsi[0xf0]; |
DRC | 0489909 | 2010-02-26 23:01:19 +0000 | [diff] [blame] | 462 | size_t bytes, bytestocopy; int localbuf = 0; |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 463 | |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 464 | put_buffer = state->cur.put_buffer; |
| 465 | put_bits = state->cur.put_bits; |
DRC | 3cba8db | 2009-03-16 23:58:30 +0000 | [diff] [blame] | 466 | LOAD_BUFFER() |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 467 | |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 468 | /* Encode the DC coefficient difference per section F.1.2.1 */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 469 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 470 | temp = temp2 = block[0] - last_dc_val; |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 471 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 472 | /* This is a well-known technique for obtaining the absolute value without a |
| 473 | * branch. It is derived from an assembly language technique presented in |
| 474 | * "How to Optimize for the Pentium Processors", Copyright (c) 1996, 1997 by |
| 475 | * Agner Fog. |
| 476 | */ |
| 477 | temp3 = temp >> (CHAR_BIT * sizeof(int) - 1); |
| 478 | temp ^= temp3; |
| 479 | temp -= temp3; |
| 480 | |
| 481 | /* For a negative input, want temp2 = bitwise complement of abs(input) */ |
| 482 | /* This code assumes we are on a two's complement machine */ |
| 483 | temp2 += temp3; |
| 484 | |
| 485 | /* Find the number of bits needed for the magnitude of the coefficient */ |
DRC | ac906c5 | 2011-05-26 11:28:22 +0000 | [diff] [blame] | 486 | nbits = jpeg_nbits_table[temp]; |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 487 | |
| 488 | /* Emit the Huffman-coded symbol for the number of bits */ |
| 489 | code = dctbl->ehufco[nbits]; |
| 490 | size = dctbl->ehufsi[nbits]; |
| 491 | PUT_BITS(code, size) |
| 492 | CHECKBUF15() |
| 493 | |
| 494 | /* Mask off any extra bits in code */ |
| 495 | temp2 &= (((INT32) 1)<<nbits) - 1; |
| 496 | |
| 497 | /* Emit that number of bits of the value, if positive, */ |
| 498 | /* or the complement of its magnitude, if negative. */ |
| 499 | PUT_BITS(temp2, nbits) |
| 500 | CHECKBUF15() |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 501 | |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 502 | /* Encode the AC coefficients per section F.1.2.2 */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 503 | |
| 504 | r = 0; /* r = run length of zeros */ |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 505 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 506 | /* Manually unroll the k loop to eliminate the counter variable. This |
| 507 | * improves performance greatly on systems with a limited number of |
| 508 | * registers (such as x86.) |
| 509 | */ |
| 510 | #define kloop(jpeg_natural_order_of_k) { \ |
| 511 | if ((temp = block[jpeg_natural_order_of_k]) == 0) { \ |
| 512 | r++; \ |
| 513 | } else { \ |
| 514 | temp2 = temp; \ |
| 515 | /* Branch-less absolute value, bitwise complement, etc., same as above */ \ |
| 516 | temp3 = temp >> (CHAR_BIT * sizeof(int) - 1); \ |
| 517 | temp ^= temp3; \ |
| 518 | temp -= temp3; \ |
| 519 | temp2 += temp3; \ |
DRC | ac906c5 | 2011-05-26 11:28:22 +0000 | [diff] [blame] | 520 | nbits = jpeg_nbits_table[temp]; \ |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 521 | /* if run length > 15, must emit special run-length-16 codes (0xF0) */ \ |
| 522 | while (r > 15) { \ |
| 523 | EMIT_BITS(code_0xf0, size_0xf0) \ |
| 524 | r -= 16; \ |
| 525 | } \ |
| 526 | /* Emit Huffman symbol for run length / number of bits */ \ |
| 527 | temp3 = (r << 4) + nbits; \ |
| 528 | code = actbl->ehufco[temp3]; \ |
| 529 | size = actbl->ehufsi[temp3]; \ |
| 530 | EMIT_CODE(code, size) \ |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 531 | r = 0; \ |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 532 | } \ |
| 533 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 534 | |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 535 | /* One iteration for each value in jpeg_natural_order[] */ |
| 536 | kloop(1); kloop(8); kloop(16); kloop(9); kloop(2); kloop(3); |
| 537 | kloop(10); kloop(17); kloop(24); kloop(32); kloop(25); kloop(18); |
| 538 | kloop(11); kloop(4); kloop(5); kloop(12); kloop(19); kloop(26); |
| 539 | kloop(33); kloop(40); kloop(48); kloop(41); kloop(34); kloop(27); |
| 540 | kloop(20); kloop(13); kloop(6); kloop(7); kloop(14); kloop(21); |
| 541 | kloop(28); kloop(35); kloop(42); kloop(49); kloop(56); kloop(57); |
| 542 | kloop(50); kloop(43); kloop(36); kloop(29); kloop(22); kloop(15); |
| 543 | kloop(23); kloop(30); kloop(37); kloop(44); kloop(51); kloop(58); |
| 544 | kloop(59); kloop(52); kloop(45); kloop(38); kloop(31); kloop(39); |
| 545 | kloop(46); kloop(53); kloop(60); kloop(61); kloop(54); kloop(47); |
| 546 | kloop(55); kloop(62); kloop(63); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 547 | |
| 548 | /* If the last coef(s) were zero, emit an end-of-block code */ |
DRC | 6bb57b7 | 2011-04-26 22:08:31 +0000 | [diff] [blame] | 549 | if (r > 0) { |
| 550 | code = actbl->ehufco[0]; |
| 551 | size = actbl->ehufsi[0]; |
| 552 | EMIT_BITS(code, size) |
| 553 | } |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 554 | |
| 555 | state->cur.put_buffer = put_buffer; |
| 556 | state->cur.put_bits = put_bits; |
DRC | 3cba8db | 2009-03-16 23:58:30 +0000 | [diff] [blame] | 557 | STORE_BUFFER() |
DRC | 9931338 | 2009-03-12 17:24:27 +0000 | [diff] [blame] | 558 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 559 | return TRUE; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 560 | } |
| 561 | |
| 562 | |
| 563 | /* |
| 564 | * Emit a restart marker & resynchronize predictions. |
| 565 | */ |
| 566 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 567 | LOCAL(boolean) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 568 | emit_restart (working_state * state, int restart_num) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 569 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 570 | int ci; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 571 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 572 | if (! flush_bits(state)) |
| 573 | return FALSE; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 574 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 575 | emit_byte(state, 0xFF, return FALSE); |
| 576 | emit_byte(state, JPEG_RST0 + restart_num, return FALSE); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 577 | |
| 578 | /* Re-initialize DC predictions to 0 */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 579 | for (ci = 0; ci < state->cinfo->comps_in_scan; ci++) |
| 580 | state->cur.last_dc_val[ci] = 0; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 581 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 582 | /* The restart counter is not updated until we successfully write the MCU. */ |
| 583 | |
| 584 | return TRUE; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 585 | } |
| 586 | |
| 587 | |
| 588 | /* |
| 589 | * Encode and output one MCU's worth of Huffman-compressed coefficients. |
| 590 | */ |
| 591 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 592 | METHODDEF(boolean) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 593 | encode_mcu_huff (j_compress_ptr cinfo, JBLOCKROW *MCU_data) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 594 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 595 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; |
| 596 | working_state state; |
| 597 | int blkn, ci; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 598 | jpeg_component_info * compptr; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 599 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 600 | /* Load up working state */ |
| 601 | state.next_output_byte = cinfo->dest->next_output_byte; |
| 602 | state.free_in_buffer = cinfo->dest->free_in_buffer; |
| 603 | ASSIGN_STATE(state.cur, entropy->saved); |
| 604 | state.cinfo = cinfo; |
| 605 | |
| 606 | /* Emit restart marker if needed */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 607 | if (cinfo->restart_interval) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 608 | if (entropy->restarts_to_go == 0) |
| 609 | if (! emit_restart(&state, entropy->next_restart_num)) |
| 610 | return FALSE; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 611 | } |
| 612 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 613 | /* Encode the MCU data blocks */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 614 | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { |
| 615 | ci = cinfo->MCU_membership[blkn]; |
| 616 | compptr = cinfo->cur_comp_info[ci]; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 617 | if (! encode_one_block(&state, |
| 618 | MCU_data[blkn][0], state.cur.last_dc_val[ci], |
| 619 | entropy->dc_derived_tbls[compptr->dc_tbl_no], |
| 620 | entropy->ac_derived_tbls[compptr->ac_tbl_no])) |
| 621 | return FALSE; |
| 622 | /* Update last_dc_val */ |
| 623 | state.cur.last_dc_val[ci] = MCU_data[blkn][0][0]; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 624 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 625 | |
| 626 | /* Completed MCU, so update state */ |
| 627 | cinfo->dest->next_output_byte = state.next_output_byte; |
| 628 | cinfo->dest->free_in_buffer = state.free_in_buffer; |
| 629 | ASSIGN_STATE(entropy->saved, state.cur); |
| 630 | |
| 631 | /* Update restart-interval state too */ |
| 632 | if (cinfo->restart_interval) { |
| 633 | if (entropy->restarts_to_go == 0) { |
| 634 | entropy->restarts_to_go = cinfo->restart_interval; |
| 635 | entropy->next_restart_num++; |
| 636 | entropy->next_restart_num &= 7; |
| 637 | } |
| 638 | entropy->restarts_to_go--; |
| 639 | } |
| 640 | |
| 641 | return TRUE; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 642 | } |
| 643 | |
| 644 | |
| 645 | /* |
| 646 | * Finish up at the end of a Huffman-compressed scan. |
| 647 | */ |
| 648 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 649 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 650 | finish_pass_huff (j_compress_ptr cinfo) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 651 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 652 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; |
| 653 | working_state state; |
| 654 | |
| 655 | /* Load up working state ... flush_bits needs it */ |
| 656 | state.next_output_byte = cinfo->dest->next_output_byte; |
| 657 | state.free_in_buffer = cinfo->dest->free_in_buffer; |
| 658 | ASSIGN_STATE(state.cur, entropy->saved); |
| 659 | state.cinfo = cinfo; |
| 660 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 661 | /* Flush out the last data */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 662 | if (! flush_bits(&state)) |
| 663 | ERREXIT(cinfo, JERR_CANT_SUSPEND); |
| 664 | |
| 665 | /* Update state */ |
| 666 | cinfo->dest->next_output_byte = state.next_output_byte; |
| 667 | cinfo->dest->free_in_buffer = state.free_in_buffer; |
| 668 | ASSIGN_STATE(entropy->saved, state.cur); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 669 | } |
| 670 | |
| 671 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 672 | /* |
| 673 | * Huffman coding optimization. |
| 674 | * |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 675 | * We first scan the supplied data and count the number of uses of each symbol |
| 676 | * that is to be Huffman-coded. (This process MUST agree with the code above.) |
| 677 | * Then we build a Huffman coding tree for the observed counts. |
| 678 | * Symbols which are not needed at all for the particular image are not |
| 679 | * assigned any code, which saves space in the DHT marker as well as in |
| 680 | * the compressed data. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 681 | */ |
| 682 | |
| 683 | #ifdef ENTROPY_OPT_SUPPORTED |
| 684 | |
| 685 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 686 | /* Process a single block's worth of coefficients */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 687 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 688 | LOCAL(void) |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 689 | htest_one_block (j_compress_ptr cinfo, JCOEFPTR block, int last_dc_val, |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 690 | long dc_counts[], long ac_counts[]) |
| 691 | { |
| 692 | register int temp; |
| 693 | register int nbits; |
| 694 | register int k, r; |
| 695 | |
| 696 | /* Encode the DC coefficient difference per section F.1.2.1 */ |
| 697 | |
| 698 | temp = block[0] - last_dc_val; |
| 699 | if (temp < 0) |
| 700 | temp = -temp; |
| 701 | |
| 702 | /* Find the number of bits needed for the magnitude of the coefficient */ |
| 703 | nbits = 0; |
| 704 | while (temp) { |
| 705 | nbits++; |
| 706 | temp >>= 1; |
| 707 | } |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 708 | /* Check for out-of-range coefficient values. |
| 709 | * Since we're encoding a difference, the range limit is twice as much. |
| 710 | */ |
| 711 | if (nbits > MAX_COEF_BITS+1) |
| 712 | ERREXIT(cinfo, JERR_BAD_DCT_COEF); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 713 | |
| 714 | /* Count the Huffman symbol for the number of bits */ |
| 715 | dc_counts[nbits]++; |
| 716 | |
| 717 | /* Encode the AC coefficients per section F.1.2.2 */ |
| 718 | |
| 719 | r = 0; /* r = run length of zeros */ |
| 720 | |
| 721 | for (k = 1; k < DCTSIZE2; k++) { |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 722 | if ((temp = block[jpeg_natural_order[k]]) == 0) { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 723 | r++; |
| 724 | } else { |
| 725 | /* if run length > 15, must emit special run-length-16 codes (0xF0) */ |
| 726 | while (r > 15) { |
| 727 | ac_counts[0xF0]++; |
| 728 | r -= 16; |
| 729 | } |
| 730 | |
| 731 | /* Find the number of bits needed for the magnitude of the coefficient */ |
| 732 | if (temp < 0) |
| 733 | temp = -temp; |
| 734 | |
| 735 | /* Find the number of bits needed for the magnitude of the coefficient */ |
| 736 | nbits = 1; /* there must be at least one 1 bit */ |
| 737 | while ((temp >>= 1)) |
| 738 | nbits++; |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 739 | /* Check for out-of-range coefficient values */ |
| 740 | if (nbits > MAX_COEF_BITS) |
| 741 | ERREXIT(cinfo, JERR_BAD_DCT_COEF); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 742 | |
| 743 | /* Count Huffman symbol for run length / number of bits */ |
| 744 | ac_counts[(r << 4) + nbits]++; |
| 745 | |
| 746 | r = 0; |
| 747 | } |
| 748 | } |
| 749 | |
| 750 | /* If the last coef(s) were zero, emit an end-of-block code */ |
| 751 | if (r > 0) |
| 752 | ac_counts[0]++; |
| 753 | } |
| 754 | |
| 755 | |
| 756 | /* |
| 757 | * Trial-encode one MCU's worth of Huffman-compressed coefficients. |
| 758 | * No data is actually output, so no suspension return is possible. |
| 759 | */ |
| 760 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 761 | METHODDEF(boolean) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 762 | encode_mcu_gather (j_compress_ptr cinfo, JBLOCKROW *MCU_data) |
| 763 | { |
| 764 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; |
| 765 | int blkn, ci; |
| 766 | jpeg_component_info * compptr; |
| 767 | |
| 768 | /* Take care of restart intervals if needed */ |
| 769 | if (cinfo->restart_interval) { |
| 770 | if (entropy->restarts_to_go == 0) { |
| 771 | /* Re-initialize DC predictions to 0 */ |
| 772 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) |
| 773 | entropy->saved.last_dc_val[ci] = 0; |
| 774 | /* Update restart state */ |
| 775 | entropy->restarts_to_go = cinfo->restart_interval; |
| 776 | } |
| 777 | entropy->restarts_to_go--; |
| 778 | } |
| 779 | |
| 780 | for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) { |
| 781 | ci = cinfo->MCU_membership[blkn]; |
| 782 | compptr = cinfo->cur_comp_info[ci]; |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 783 | htest_one_block(cinfo, MCU_data[blkn][0], entropy->saved.last_dc_val[ci], |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 784 | entropy->dc_count_ptrs[compptr->dc_tbl_no], |
| 785 | entropy->ac_count_ptrs[compptr->ac_tbl_no]); |
| 786 | entropy->saved.last_dc_val[ci] = MCU_data[blkn][0][0]; |
| 787 | } |
| 788 | |
| 789 | return TRUE; |
| 790 | } |
| 791 | |
| 792 | |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 793 | /* |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 794 | * Generate the best Huffman code table for the given counts, fill htbl. |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 795 | * Note this is also used by jcphuff.c. |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 796 | * |
| 797 | * The JPEG standard requires that no symbol be assigned a codeword of all |
| 798 | * one bits (so that padding bits added at the end of a compressed segment |
| 799 | * can't look like a valid code). Because of the canonical ordering of |
| 800 | * codewords, this just means that there must be an unused slot in the |
| 801 | * longest codeword length category. Section K.2 of the JPEG spec suggests |
| 802 | * reserving such a slot by pretending that symbol 256 is a valid symbol |
| 803 | * with count 1. In theory that's not optimal; giving it count zero but |
| 804 | * including it in the symbol set anyway should give a better Huffman code. |
| 805 | * But the theoretically better code actually seems to come out worse in |
| 806 | * practice, because it produces more all-ones bytes (which incur stuffed |
| 807 | * zero bytes in the final file). In any case the difference is tiny. |
| 808 | * |
| 809 | * The JPEG standard requires Huffman codes to be no more than 16 bits long. |
| 810 | * If some symbols have a very small but nonzero probability, the Huffman tree |
| 811 | * must be adjusted to meet the code length restriction. We currently use |
| 812 | * the adjustment method suggested in JPEG section K.2. This method is *not* |
| 813 | * optimal; it may not choose the best possible limited-length code. But |
| 814 | * typically only very-low-frequency symbols will be given less-than-optimal |
| 815 | * lengths, so the code is almost optimal. Experimental comparisons against |
| 816 | * an optimal limited-length-code algorithm indicate that the difference is |
| 817 | * microscopic --- usually less than a hundredth of a percent of total size. |
| 818 | * So the extra complexity of an optimal algorithm doesn't seem worthwhile. |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 819 | */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 820 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 821 | GLOBAL(void) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 822 | jpeg_gen_optimal_table (j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[]) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 823 | { |
| 824 | #define MAX_CLEN 32 /* assumed maximum initial code length */ |
| 825 | UINT8 bits[MAX_CLEN+1]; /* bits[k] = # of symbols with code length k */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 826 | int codesize[257]; /* codesize[k] = code length of symbol k */ |
| 827 | int others[257]; /* next symbol in current branch of tree */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 828 | int c1, c2; |
| 829 | int p, i, j; |
| 830 | long v; |
| 831 | |
Thomas G. Lane | 4a6b730 | 1992-03-17 00:00:00 +0000 | [diff] [blame] | 832 | /* This algorithm is explained in section K.2 of the JPEG standard */ |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 833 | |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 834 | MEMZERO(bits, SIZEOF(bits)); |
| 835 | MEMZERO(codesize, SIZEOF(codesize)); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 836 | for (i = 0; i < 257; i++) |
| 837 | others[i] = -1; /* init links to empty */ |
| 838 | |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 839 | freq[256] = 1; /* make sure 256 has a nonzero count */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 840 | /* Including the pseudo-symbol 256 in the Huffman procedure guarantees |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 841 | * that no real symbol is given code-value of all ones, because 256 |
Thomas G. Lane | 5ead57a | 1998-03-27 00:00:00 +0000 | [diff] [blame] | 842 | * will be placed last in the largest codeword category. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 843 | */ |
| 844 | |
| 845 | /* Huffman's basic algorithm to assign optimal code lengths to symbols */ |
| 846 | |
| 847 | for (;;) { |
| 848 | /* Find the smallest nonzero frequency, set c1 = its symbol */ |
| 849 | /* In case of ties, take the larger symbol number */ |
| 850 | c1 = -1; |
| 851 | v = 1000000000L; |
| 852 | for (i = 0; i <= 256; i++) { |
| 853 | if (freq[i] && freq[i] <= v) { |
| 854 | v = freq[i]; |
| 855 | c1 = i; |
| 856 | } |
| 857 | } |
| 858 | |
| 859 | /* Find the next smallest nonzero frequency, set c2 = its symbol */ |
| 860 | /* In case of ties, take the larger symbol number */ |
| 861 | c2 = -1; |
| 862 | v = 1000000000L; |
| 863 | for (i = 0; i <= 256; i++) { |
| 864 | if (freq[i] && freq[i] <= v && i != c1) { |
| 865 | v = freq[i]; |
| 866 | c2 = i; |
| 867 | } |
| 868 | } |
| 869 | |
| 870 | /* Done if we've merged everything into one frequency */ |
| 871 | if (c2 < 0) |
| 872 | break; |
| 873 | |
| 874 | /* Else merge the two counts/trees */ |
| 875 | freq[c1] += freq[c2]; |
| 876 | freq[c2] = 0; |
| 877 | |
| 878 | /* Increment the codesize of everything in c1's tree branch */ |
| 879 | codesize[c1]++; |
| 880 | while (others[c1] >= 0) { |
| 881 | c1 = others[c1]; |
| 882 | codesize[c1]++; |
| 883 | } |
| 884 | |
| 885 | others[c1] = c2; /* chain c2 onto c1's tree branch */ |
| 886 | |
| 887 | /* Increment the codesize of everything in c2's tree branch */ |
| 888 | codesize[c2]++; |
| 889 | while (others[c2] >= 0) { |
| 890 | c2 = others[c2]; |
| 891 | codesize[c2]++; |
| 892 | } |
| 893 | } |
| 894 | |
| 895 | /* Now count the number of symbols of each code length */ |
| 896 | for (i = 0; i <= 256; i++) { |
| 897 | if (codesize[i]) { |
| 898 | /* The JPEG standard seems to think that this can't happen, */ |
| 899 | /* but I'm paranoid... */ |
| 900 | if (codesize[i] > MAX_CLEN) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 901 | ERREXIT(cinfo, JERR_HUFF_CLEN_OVERFLOW); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 902 | |
| 903 | bits[codesize[i]]++; |
| 904 | } |
| 905 | } |
| 906 | |
| 907 | /* JPEG doesn't allow symbols with code lengths over 16 bits, so if the pure |
| 908 | * Huffman procedure assigned any such lengths, we must adjust the coding. |
| 909 | * Here is what the JPEG spec says about how this next bit works: |
| 910 | * Since symbols are paired for the longest Huffman code, the symbols are |
| 911 | * removed from this length category two at a time. The prefix for the pair |
| 912 | * (which is one bit shorter) is allocated to one of the pair; then, |
| 913 | * skipping the BITS entry for that prefix length, a code word from the next |
| 914 | * shortest nonzero BITS entry is converted into a prefix for two code words |
| 915 | * one bit longer. |
| 916 | */ |
| 917 | |
| 918 | for (i = MAX_CLEN; i > 16; i--) { |
| 919 | while (bits[i] > 0) { |
| 920 | j = i - 2; /* find length of new prefix to be used */ |
| 921 | while (bits[j] == 0) |
| 922 | j--; |
| 923 | |
| 924 | bits[i] -= 2; /* remove two symbols */ |
| 925 | bits[i-1]++; /* one goes in this length */ |
| 926 | bits[j+1] += 2; /* two new symbols in this length */ |
| 927 | bits[j]--; /* symbol of this length is now a prefix */ |
| 928 | } |
| 929 | } |
| 930 | |
| 931 | /* Remove the count for the pseudo-symbol 256 from the largest codelength */ |
| 932 | while (bits[i] == 0) /* find largest codelength still in use */ |
| 933 | i--; |
| 934 | bits[i]--; |
| 935 | |
| 936 | /* Return final symbol counts (only for lengths 0..16) */ |
Thomas G. Lane | 88aeed4 | 1992-12-10 00:00:00 +0000 | [diff] [blame] | 937 | MEMCOPY(htbl->bits, bits, SIZEOF(htbl->bits)); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 938 | |
| 939 | /* Return a list of the symbols sorted by code length */ |
| 940 | /* It's not real clear to me why we don't need to consider the codelength |
| 941 | * changes made above, but the JPEG spec seems to think this works. |
| 942 | */ |
| 943 | p = 0; |
| 944 | for (i = 1; i <= MAX_CLEN; i++) { |
| 945 | for (j = 0; j <= 255; j++) { |
| 946 | if (codesize[j] == i) { |
Thomas G. Lane | bd543f0 | 1991-12-13 00:00:00 +0000 | [diff] [blame] | 947 | htbl->huffval[p] = (UINT8) j; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 948 | p++; |
| 949 | } |
| 950 | } |
| 951 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 952 | |
| 953 | /* Set sent_table FALSE so updated table will be written to JPEG file. */ |
| 954 | htbl->sent_table = FALSE; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 955 | } |
| 956 | |
| 957 | |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 958 | /* |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 959 | * Finish up a statistics-gathering pass and create the new Huffman tables. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 960 | */ |
| 961 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 962 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 963 | finish_pass_gather (j_compress_ptr cinfo) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 964 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 965 | huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy; |
| 966 | int ci, dctbl, actbl; |
| 967 | jpeg_component_info * compptr; |
| 968 | JHUFF_TBL **htblptr; |
| 969 | boolean did_dc[NUM_HUFF_TBLS]; |
| 970 | boolean did_ac[NUM_HUFF_TBLS]; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 971 | |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 972 | /* It's important not to apply jpeg_gen_optimal_table more than once |
| 973 | * per table, because it clobbers the input frequency counts! |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 974 | */ |
| 975 | MEMZERO(did_dc, SIZEOF(did_dc)); |
| 976 | MEMZERO(did_ac, SIZEOF(did_ac)); |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 977 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 978 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
| 979 | compptr = cinfo->cur_comp_info[ci]; |
| 980 | dctbl = compptr->dc_tbl_no; |
| 981 | actbl = compptr->ac_tbl_no; |
| 982 | if (! did_dc[dctbl]) { |
| 983 | htblptr = & cinfo->dc_huff_tbl_ptrs[dctbl]; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 984 | if (*htblptr == NULL) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 985 | *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 986 | jpeg_gen_optimal_table(cinfo, *htblptr, entropy->dc_count_ptrs[dctbl]); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 987 | did_dc[dctbl] = TRUE; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 988 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 989 | if (! did_ac[actbl]) { |
| 990 | htblptr = & cinfo->ac_huff_tbl_ptrs[actbl]; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 991 | if (*htblptr == NULL) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 992 | *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 993 | jpeg_gen_optimal_table(cinfo, *htblptr, entropy->ac_count_ptrs[actbl]); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 994 | did_ac[actbl] = TRUE; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 995 | } |
| 996 | } |
| 997 | } |
| 998 | |
| 999 | |
| 1000 | #endif /* ENTROPY_OPT_SUPPORTED */ |
| 1001 | |
| 1002 | |
| 1003 | /* |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 1004 | * Module initialization routine for Huffman entropy encoding. |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 1005 | */ |
| 1006 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 1007 | GLOBAL(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 1008 | jinit_huff_encoder (j_compress_ptr cinfo) |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 1009 | { |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 1010 | huff_entropy_ptr entropy; |
| 1011 | int i; |
| 1012 | |
| 1013 | entropy = (huff_entropy_ptr) |
| 1014 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 1015 | SIZEOF(huff_entropy_encoder)); |
| 1016 | cinfo->entropy = (struct jpeg_entropy_encoder *) entropy; |
| 1017 | entropy->pub.start_pass = start_pass_huff; |
| 1018 | |
| 1019 | /* Mark tables unallocated */ |
| 1020 | for (i = 0; i < NUM_HUFF_TBLS; i++) { |
| 1021 | entropy->dc_derived_tbls[i] = entropy->ac_derived_tbls[i] = NULL; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 1022 | #ifdef ENTROPY_OPT_SUPPORTED |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 1023 | entropy->dc_count_ptrs[i] = entropy->ac_count_ptrs[i] = NULL; |
Thomas G. Lane | 2cbeb8a | 1991-10-07 00:00:00 +0000 | [diff] [blame] | 1024 | #endif |
| 1025 | } |
| 1026 | } |