| inftrees.c (180208) | inftrees.c (205471) |
|---|---|
| 1/* inftrees.c -- generate Huffman trees for efficient decoding | 1/* inftrees.c -- generate Huffman trees for efficient decoding |
| 2 * Copyright (C) 1995-2005 Mark Adler | 2 * Copyright (C) 1995-2010 Mark Adler |
| 3 * For conditions of distribution and use, see copyright notice in zlib.h 4 */ 5 6#include "zutil.h" 7#include "inftrees.h" 8 9#define MAXBITS 15 10 11const char inflate_copyright[] = | 3 * For conditions of distribution and use, see copyright notice in zlib.h 4 */ 5 6#include "zutil.h" 7#include "inftrees.h" 8 9#define MAXBITS 15 10 11const char inflate_copyright[] = |
| 12 " inflate 1.2.3 Copyright 1995-2005 Mark Adler "; | 12 " inflate 1.2.4 Copyright 1995-2010 Mark Adler "; |
| 13/* 14 If you use the zlib library in a product, an acknowledgment is welcome 15 in the documentation of your product. If for some reason you cannot 16 include such an acknowledgment, I would appreciate that you keep this 17 copyright string in the executable of your product. 18 */ 19 20/* --- 24 unchanged lines hidden (view full) --- 45 unsigned drop; /* code bits to drop for sub-table */ 46 int left; /* number of prefix codes available */ 47 unsigned used; /* code entries in table used */ 48 unsigned huff; /* Huffman code */ 49 unsigned incr; /* for incrementing code, index */ 50 unsigned fill; /* index for replicating entries */ 51 unsigned low; /* low bits for current root entry */ 52 unsigned mask; /* mask for low root bits */ | 13/* 14 If you use the zlib library in a product, an acknowledgment is welcome 15 in the documentation of your product. If for some reason you cannot 16 include such an acknowledgment, I would appreciate that you keep this 17 copyright string in the executable of your product. 18 */ 19 20/* --- 24 unchanged lines hidden (view full) --- 45 unsigned drop; /* code bits to drop for sub-table */ 46 int left; /* number of prefix codes available */ 47 unsigned used; /* code entries in table used */ 48 unsigned huff; /* Huffman code */ 49 unsigned incr; /* for incrementing code, index */ 50 unsigned fill; /* index for replicating entries */ 51 unsigned low; /* low bits for current root entry */ 52 unsigned mask; /* mask for low root bits */ |
| 53 code this; /* table entry for duplication */ | 53 code here; /* table entry for duplication */ |
| 54 code FAR *next; /* next available space in table */ 55 const unsigned short FAR *base; /* base value table to use */ 56 const unsigned short FAR *extra; /* extra bits table to use */ 57 int end; /* use base and extra for symbol > end */ 58 unsigned short count[MAXBITS+1]; /* number of codes of each length */ 59 unsigned short offs[MAXBITS+1]; /* offsets in table for each length */ 60 static const unsigned short lbase[31] = { /* Length codes 257..285 base */ 61 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 62 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0}; 63 static const unsigned short lext[31] = { /* Length codes 257..285 extra */ 64 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, | 54 code FAR *next; /* next available space in table */ 55 const unsigned short FAR *base; /* base value table to use */ 56 const unsigned short FAR *extra; /* extra bits table to use */ 57 int end; /* use base and extra for symbol > end */ 58 unsigned short count[MAXBITS+1]; /* number of codes of each length */ 59 unsigned short offs[MAXBITS+1]; /* offsets in table for each length */ 60 static const unsigned short lbase[31] = { /* Length codes 257..285 base */ 61 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 62 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0}; 63 static const unsigned short lext[31] = { /* Length codes 257..285 extra */ 64 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, |
| 65 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 201, 196}; | 65 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 64, 195}; |
| 66 static const unsigned short dbase[32] = { /* Distance codes 0..29 base */ 67 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 68 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 69 8193, 12289, 16385, 24577, 0, 0}; 70 static const unsigned short dext[32] = { /* Distance codes 0..29 extra */ 71 16, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 72 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 73 28, 28, 29, 29, 64, 64}; --- 36 unchanged lines hidden (view full) --- 110 count[lens[sym]]++; 111 112 /* bound code lengths, force root to be within code lengths */ 113 root = *bits; 114 for (max = MAXBITS; max >= 1; max--) 115 if (count[max] != 0) break; 116 if (root > max) root = max; 117 if (max == 0) { /* no symbols to code at all */ | 66 static const unsigned short dbase[32] = { /* Distance codes 0..29 base */ 67 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 68 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 69 8193, 12289, 16385, 24577, 0, 0}; 70 static const unsigned short dext[32] = { /* Distance codes 0..29 extra */ 71 16, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, 72 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 73 28, 28, 29, 29, 64, 64}; --- 36 unchanged lines hidden (view full) --- 110 count[lens[sym]]++; 111 112 /* bound code lengths, force root to be within code lengths */ 113 root = *bits; 114 for (max = MAXBITS; max >= 1; max--) 115 if (count[max] != 0) break; 116 if (root > max) root = max; 117 if (max == 0) { /* no symbols to code at all */ |
| 118 this.op = (unsigned char)64; /* invalid code marker */ 119 this.bits = (unsigned char)1; 120 this.val = (unsigned short)0; 121 *(*table)++ = this; /* make a table to force an error */ 122 *(*table)++ = this; | 118 here.op = (unsigned char)64; /* invalid code marker */ 119 here.bits = (unsigned char)1; 120 here.val = (unsigned short)0; 121 *(*table)++ = here; /* make a table to force an error */ 122 *(*table)++ = here; |
| 123 *bits = 1; 124 return 0; /* no symbols, but wait for decoding to report error */ 125 } | 123 *bits = 1; 124 return 0; /* no symbols, but wait for decoding to report error */ 125 } |
| 126 for (min = 1; min <= MAXBITS; min++) | 126 for (min = 1; min < max; min++) |
| 127 if (count[min] != 0) break; 128 if (root < min) root = min; 129 130 /* check for an over-subscribed or incomplete set of lengths */ 131 left = 1; 132 for (len = 1; len <= MAXBITS; len++) { 133 left <<= 1; 134 left -= count[len]; --- 26 unchanged lines hidden (view full) --- 161 being filled, and drop is root when sub-tables are being filled. 162 163 When a new sub-table is needed, it is necessary to look ahead in the 164 code lengths to determine what size sub-table is needed. The length 165 counts are used for this, and so count[] is decremented as codes are 166 entered in the tables. 167 168 used keeps track of how many table entries have been allocated from the | 127 if (count[min] != 0) break; 128 if (root < min) root = min; 129 130 /* check for an over-subscribed or incomplete set of lengths */ 131 left = 1; 132 for (len = 1; len <= MAXBITS; len++) { 133 left <<= 1; 134 left -= count[len]; --- 26 unchanged lines hidden (view full) --- 161 being filled, and drop is root when sub-tables are being filled. 162 163 When a new sub-table is needed, it is necessary to look ahead in the 164 code lengths to determine what size sub-table is needed. The length 165 counts are used for this, and so count[] is decremented as codes are 166 entered in the tables. 167 168 used keeps track of how many table entries have been allocated from the |
| 169 provided *table space. It is checked when a LENS table is being made 170 against the space in *table, ENOUGH, minus the maximum space needed by 171 the worst case distance code, MAXD. This should never happen, but the 172 sufficiency of ENOUGH has not been proven exhaustively, hence the check. 173 This assumes that when type == LENS, bits == 9. | 169 provided *table space. It is checked for LENS and DIST tables against 170 the constants ENOUGH_LENS and ENOUGH_DISTS to guard against changes in 171 the initial root table size constants. See the comments in inftrees.h 172 for more information. |
| 174 175 sym increments through all symbols, and the loop terminates when 176 all codes of length max, i.e. all codes, have been processed. This 177 routine permits incomplete codes, so another loop after this one fills 178 in the rest of the decoding tables with invalid code markers. 179 */ 180 181 /* set up for code type */ --- 22 unchanged lines hidden (view full) --- 204 next = *table; /* current table to fill in */ 205 curr = root; /* current table index bits */ 206 drop = 0; /* current bits to drop from code for index */ 207 low = (unsigned)(-1); /* trigger new sub-table when len > root */ 208 used = 1U << root; /* use root table entries */ 209 mask = used - 1; /* mask for comparing low */ 210 211 /* check available table space */ | 173 174 sym increments through all symbols, and the loop terminates when 175 all codes of length max, i.e. all codes, have been processed. This 176 routine permits incomplete codes, so another loop after this one fills 177 in the rest of the decoding tables with invalid code markers. 178 */ 179 180 /* set up for code type */ --- 22 unchanged lines hidden (view full) --- 203 next = *table; /* current table to fill in */ 204 curr = root; /* current table index bits */ 205 drop = 0; /* current bits to drop from code for index */ 206 low = (unsigned)(-1); /* trigger new sub-table when len > root */ 207 used = 1U << root; /* use root table entries */ 208 mask = used - 1; /* mask for comparing low */ 209 210 /* check available table space */ |
| 212 if (type == LENS && used >= ENOUGH - MAXD) | 211 if ((type == LENS && used >= ENOUGH_LENS) || 212 (type == DISTS && used >= ENOUGH_DISTS)) |
| 213 return 1; 214 215 /* process all codes and make table entries */ 216 for (;;) { 217 /* create table entry */ | 213 return 1; 214 215 /* process all codes and make table entries */ 216 for (;;) { 217 /* create table entry */ |
| 218 this.bits = (unsigned char)(len - drop); | 218 here.bits = (unsigned char)(len - drop); |
| 219 if ((int)(work[sym]) < end) { | 219 if ((int)(work[sym]) < end) { |
| 220 this.op = (unsigned char)0; 221 this.val = work[sym]; | 220 here.op = (unsigned char)0; 221 here.val = work[sym]; |
| 222 } 223 else if ((int)(work[sym]) > end) { | 222 } 223 else if ((int)(work[sym]) > end) { |
| 224 this.op = (unsigned char)(extra[work[sym]]); 225 this.val = base[work[sym]]; | 224 here.op = (unsigned char)(extra[work[sym]]); 225 here.val = base[work[sym]]; |
| 226 } 227 else { | 226 } 227 else { |
| 228 this.op = (unsigned char)(32 + 64); /* end of block */ 229 this.val = 0; | 228 here.op = (unsigned char)(32 + 64); /* end of block */ 229 here.val = 0; |
| 230 } 231 232 /* replicate for those indices with low len bits equal to huff */ 233 incr = 1U << (len - drop); 234 fill = 1U << curr; 235 min = fill; /* save offset to next table */ 236 do { 237 fill -= incr; | 230 } 231 232 /* replicate for those indices with low len bits equal to huff */ 233 incr = 1U << (len - drop); 234 fill = 1U << curr; 235 min = fill; /* save offset to next table */ 236 do { 237 fill -= incr; |
| 238 next[(huff >> drop) + fill] = this; | 238 next[(huff >> drop) + fill] = here; |
| 239 } while (fill != 0); 240 241 /* backwards increment the len-bit code huff */ 242 incr = 1U << (len - 1); 243 while (huff & incr) 244 incr >>= 1; 245 if (incr != 0) { 246 huff &= incr - 1; --- 25 unchanged lines hidden (view full) --- 272 left -= count[curr + drop]; 273 if (left <= 0) break; 274 curr++; 275 left <<= 1; 276 } 277 278 /* check for enough space */ 279 used += 1U << curr; | 239 } while (fill != 0); 240 241 /* backwards increment the len-bit code huff */ 242 incr = 1U << (len - 1); 243 while (huff & incr) 244 incr >>= 1; 245 if (incr != 0) { 246 huff &= incr - 1; --- 25 unchanged lines hidden (view full) --- 272 left -= count[curr + drop]; 273 if (left <= 0) break; 274 curr++; 275 left <<= 1; 276 } 277 278 /* check for enough space */ 279 used += 1U << curr; |
| 280 if (type == LENS && used >= ENOUGH - MAXD) | 280 if ((type == LENS && used >= ENOUGH_LENS) || 281 (type == DISTS && used >= ENOUGH_DISTS)) |
| 281 return 1; 282 283 /* point entry in root table to sub-table */ 284 low = huff & mask; 285 (*table)[low].op = (unsigned char)curr; 286 (*table)[low].bits = (unsigned char)root; 287 (*table)[low].val = (unsigned short)(next - *table); 288 } 289 } 290 291 /* 292 Fill in rest of table for incomplete codes. This loop is similar to the 293 loop above in incrementing huff for table indices. It is assumed that 294 len is equal to curr + drop, so there is no loop needed to increment 295 through high index bits. When the current sub-table is filled, the loop 296 drops back to the root table to fill in any remaining entries there. 297 */ | 282 return 1; 283 284 /* point entry in root table to sub-table */ 285 low = huff & mask; 286 (*table)[low].op = (unsigned char)curr; 287 (*table)[low].bits = (unsigned char)root; 288 (*table)[low].val = (unsigned short)(next - *table); 289 } 290 } 291 292 /* 293 Fill in rest of table for incomplete codes. This loop is similar to the 294 loop above in incrementing huff for table indices. It is assumed that 295 len is equal to curr + drop, so there is no loop needed to increment 296 through high index bits. When the current sub-table is filled, the loop 297 drops back to the root table to fill in any remaining entries there. 298 */ |
| 298 this.op = (unsigned char)64; /* invalid code marker */ 299 this.bits = (unsigned char)(len - drop); 300 this.val = (unsigned short)0; | 299 here.op = (unsigned char)64; /* invalid code marker */ 300 here.bits = (unsigned char)(len - drop); 301 here.val = (unsigned short)0; |
| 301 while (huff != 0) { 302 /* when done with sub-table, drop back to root table */ 303 if (drop != 0 && (huff & mask) != low) { 304 drop = 0; 305 len = root; 306 next = *table; | 302 while (huff != 0) { 303 /* when done with sub-table, drop back to root table */ 304 if (drop != 0 && (huff & mask) != low) { 305 drop = 0; 306 len = root; 307 next = *table; |
| 307 this.bits = (unsigned char)len; | 308 here.bits = (unsigned char)len; |
| 308 } 309 310 /* put invalid code marker in table */ | 309 } 310 311 /* put invalid code marker in table */ |
| 311 next[huff >> drop] = this; | 312 next[huff >> drop] = here; |
| 312 313 /* backwards increment the len-bit code huff */ 314 incr = 1U << (len - 1); 315 while (huff & incr) 316 incr >>= 1; 317 if (incr != 0) { 318 huff &= incr - 1; 319 huff += incr; 320 } 321 else 322 huff = 0; 323 } 324 325 /* set return parameters */ 326 *table += used; 327 *bits = root; 328 return 0; 329} | 313 314 /* backwards increment the len-bit code huff */ 315 incr = 1U << (len - 1); 316 while (huff & incr) 317 incr >>= 1; 318 if (incr != 0) { 319 huff &= incr - 1; 320 huff += incr; 321 } 322 else 323 huff = 0; 324 } 325 326 /* set return parameters */ 327 *table += used; 328 *bits = root; 329 return 0; 330} |