| 1 | import * as utils from "../utils/common.js"; |
| 2 | |
| 3 | /* Public constants ==========================================================*/ |
| 4 | /* ===========================================================================*/ |
| 5 | |
| 6 | |
| 7 | //var Z_FILTERED = 1; |
| 8 | //var Z_HUFFMAN_ONLY = 2; |
| 9 | //var Z_RLE = 3; |
| 10 | var Z_FIXED = 4; |
| 11 | //var Z_DEFAULT_STRATEGY = 0; |
| 12 | |
| 13 | /* Possible values of the data_type field (though see inflate()) */ |
| 14 | var Z_BINARY = 0; |
| 15 | var Z_TEXT = 1; |
| 16 | //var Z_ASCII = 1; // = Z_TEXT |
| 17 | var Z_UNKNOWN = 2; |
| 18 | |
| 19 | /*============================================================================*/ |
| 20 | |
| 21 | |
| 22 | function zero(buf) { var len = buf.length; while (--len >= 0) { buf[len] = 0; } } |
| 23 | |
| 24 | // From zutil.h |
| 25 | |
| 26 | var STORED_BLOCK = 0; |
| 27 | var STATIC_TREES = 1; |
| 28 | var DYN_TREES = 2; |
| 29 | /* The three kinds of block type */ |
| 30 | |
| 31 | var MIN_MATCH = 3; |
| 32 | var MAX_MATCH = 258; |
| 33 | /* The minimum and maximum match lengths */ |
| 34 | |
| 35 | // From deflate.h |
| 36 | /* =========================================================================== |
| 37 | * Internal compression state. |
| 38 | */ |
| 39 | |
| 40 | var LENGTH_CODES = 29; |
| 41 | /* number of length codes, not counting the special END_BLOCK code */ |
| 42 | |
| 43 | var LITERALS = 256; |
| 44 | /* number of literal bytes 0..255 */ |
| 45 | |
| 46 | var L_CODES = LITERALS + 1 + LENGTH_CODES; |
| 47 | /* number of Literal or Length codes, including the END_BLOCK code */ |
| 48 | |
| 49 | var D_CODES = 30; |
| 50 | /* number of distance codes */ |
| 51 | |
| 52 | var BL_CODES = 19; |
| 53 | /* number of codes used to transfer the bit lengths */ |
| 54 | |
| 55 | var HEAP_SIZE = 2 * L_CODES + 1; |
| 56 | /* maximum heap size */ |
| 57 | |
| 58 | var MAX_BITS = 15; |
| 59 | /* All codes must not exceed MAX_BITS bits */ |
| 60 | |
| 61 | var Buf_size = 16; |
| 62 | /* size of bit buffer in bi_buf */ |
| 63 | |
| 64 | |
| 65 | /* =========================================================================== |
| 66 | * Constants |
| 67 | */ |
| 68 | |
| 69 | var MAX_BL_BITS = 7; |
| 70 | /* Bit length codes must not exceed MAX_BL_BITS bits */ |
| 71 | |
| 72 | var END_BLOCK = 256; |
| 73 | /* end of block literal code */ |
| 74 | |
| 75 | var REP_3_6 = 16; |
| 76 | /* repeat previous bit length 3-6 times (2 bits of repeat count) */ |
| 77 | |
| 78 | var REPZ_3_10 = 17; |
| 79 | /* repeat a zero length 3-10 times (3 bits of repeat count) */ |
| 80 | |
| 81 | var REPZ_11_138 = 18; |
| 82 | /* repeat a zero length 11-138 times (7 bits of repeat count) */ |
| 83 | |
| 84 | /* eslint-disable comma-spacing,array-bracket-spacing */ |
| 85 | var extra_lbits = /* extra bits for each length code */ |
| 86 | [0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0]; |
| 87 | |
| 88 | var extra_dbits = /* extra bits for each distance code */ |
| 89 | [0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13]; |
| 90 | |
| 91 | var extra_blbits = /* extra bits for each bit length code */ |
| 92 | [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7]; |
| 93 | |
| 94 | var bl_order = |
| 95 | [16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15]; |
| 96 | /* eslint-enable comma-spacing,array-bracket-spacing */ |
| 97 | |
| 98 | /* The lengths of the bit length codes are sent in order of decreasing |
| 99 | * probability, to avoid transmitting the lengths for unused bit length codes. |
| 100 | */ |
| 101 | |
| 102 | /* =========================================================================== |
| 103 | * Local data. These are initialized only once. |
| 104 | */ |
| 105 | |
| 106 | // We pre-fill arrays with 0 to avoid uninitialized gaps |
| 107 | |
| 108 | var DIST_CODE_LEN = 512; /* see definition of array dist_code below */ |
| 109 | |
| 110 | // !!!! Use flat array insdead of structure, Freq = i*2, Len = i*2+1 |
| 111 | var static_ltree = new Array((L_CODES + 2) * 2); |
| 112 | zero(static_ltree); |
| 113 | /* The static literal tree. Since the bit lengths are imposed, there is no |
| 114 | * need for the L_CODES extra codes used during heap construction. However |
| 115 | * The codes 286 and 287 are needed to build a canonical tree (see _tr_init |
| 116 | * below). |
| 117 | */ |
| 118 | |
| 119 | var static_dtree = new Array(D_CODES * 2); |
| 120 | zero(static_dtree); |
| 121 | /* The static distance tree. (Actually a trivial tree since all codes use |
| 122 | * 5 bits.) |
| 123 | */ |
| 124 | |
| 125 | var _dist_code = new Array(DIST_CODE_LEN); |
| 126 | zero(_dist_code); |
| 127 | /* Distance codes. The first 256 values correspond to the distances |
| 128 | * 3 .. 258, the last 256 values correspond to the top 8 bits of |
| 129 | * the 15 bit distances. |
| 130 | */ |
| 131 | |
| 132 | var _length_code = new Array(MAX_MATCH - MIN_MATCH + 1); |
| 133 | zero(_length_code); |
| 134 | /* length code for each normalized match length (0 == MIN_MATCH) */ |
| 135 | |
| 136 | var base_length = new Array(LENGTH_CODES); |
| 137 | zero(base_length); |
| 138 | /* First normalized length for each code (0 = MIN_MATCH) */ |
| 139 | |
| 140 | var base_dist = new Array(D_CODES); |
| 141 | zero(base_dist); |
| 142 | /* First normalized distance for each code (0 = distance of 1) */ |
| 143 | |
| 144 | |
| 145 | function StaticTreeDesc(static_tree, extra_bits, extra_base, elems, max_length) { |
| 146 | |
| 147 | this.static_tree = static_tree; /* static tree or NULL */ |
| 148 | this.extra_bits = extra_bits; /* extra bits for each code or NULL */ |
| 149 | this.extra_base = extra_base; /* base index for extra_bits */ |
| 150 | this.elems = elems; /* max number of elements in the tree */ |
| 151 | this.max_length = max_length; /* max bit length for the codes */ |
| 152 | |
| 153 | // show if `static_tree` has data or dummy - needed for monomorphic objects |
| 154 | this.has_stree = static_tree && static_tree.length; |
| 155 | } |
| 156 | |
| 157 | |
| 158 | var static_l_desc; |
| 159 | var static_d_desc; |
| 160 | var static_bl_desc; |
| 161 | |
| 162 | |
| 163 | function TreeDesc(dyn_tree, stat_desc) { |
| 164 | this.dyn_tree = dyn_tree; /* the dynamic tree */ |
| 165 | this.max_code = 0; /* largest code with non zero frequency */ |
| 166 | this.stat_desc = stat_desc; /* the corresponding static tree */ |
| 167 | } |
| 168 | |
| 169 | |
| 170 | |
| 171 | function d_code(dist) { |
| 172 | return dist < 256 ? _dist_code[dist] : _dist_code[256 + (dist >>> 7)]; |
| 173 | } |
| 174 | |
| 175 | |
| 176 | /* =========================================================================== |
| 177 | * Output a short LSB first on the stream. |
| 178 | * IN assertion: there is enough room in pendingBuf. |
| 179 | */ |
| 180 | function put_short(s, w) { |
| 181 | // put_byte(s, (uch)((w) & 0xff)); |
| 182 | // put_byte(s, (uch)((ush)(w) >> 8)); |
| 183 | s.pending_buf[s.pending++] = (w) & 0xff; |
| 184 | s.pending_buf[s.pending++] = (w >>> 8) & 0xff; |
| 185 | } |
| 186 | |
| 187 | |
| 188 | /* =========================================================================== |
| 189 | * Send a value on a given number of bits. |
| 190 | * IN assertion: length <= 16 and value fits in length bits. |
| 191 | */ |
| 192 | function send_bits(s, value, length) { |
| 193 | if (s.bi_valid > (Buf_size - length)) { |
| 194 | s.bi_buf |= (value << s.bi_valid) & 0xffff; |
| 195 | put_short(s, s.bi_buf); |
| 196 | s.bi_buf = value >> (Buf_size - s.bi_valid); |
| 197 | s.bi_valid += length - Buf_size; |
| 198 | } else { |
| 199 | s.bi_buf |= (value << s.bi_valid) & 0xffff; |
| 200 | s.bi_valid += length; |
| 201 | } |
| 202 | } |
| 203 | |
| 204 | |
| 205 | function send_code(s, c, tree) { |
| 206 | send_bits(s, tree[c * 2]/*.Code*/, tree[c * 2 + 1]/*.Len*/); |
| 207 | } |
| 208 | |
| 209 | |
| 210 | /* =========================================================================== |
| 211 | * Reverse the first len bits of a code, using straightforward code (a faster |
| 212 | * method would use a table) |
| 213 | * IN assertion: 1 <= len <= 15 |
| 214 | */ |
| 215 | function bi_reverse(code, len) { |
| 216 | var res = 0; |
| 217 | do { |
| 218 | res |= code & 1; |
| 219 | code >>>= 1; |
| 220 | res <<= 1; |
| 221 | } while (--len > 0); |
| 222 | return res >>> 1; |
| 223 | } |
| 224 | |
| 225 | |
| 226 | /* =========================================================================== |
| 227 | * Flush the bit buffer, keeping at most 7 bits in it. |
| 228 | */ |
| 229 | function bi_flush(s) { |
| 230 | if (s.bi_valid === 16) { |
| 231 | put_short(s, s.bi_buf); |
| 232 | s.bi_buf = 0; |
| 233 | s.bi_valid = 0; |
| 234 | |
| 235 | } else if (s.bi_valid >= 8) { |
| 236 | s.pending_buf[s.pending++] = s.bi_buf & 0xff; |
| 237 | s.bi_buf >>= 8; |
| 238 | s.bi_valid -= 8; |
| 239 | } |
| 240 | } |
| 241 | |
| 242 | |
| 243 | /* =========================================================================== |
| 244 | * Compute the optimal bit lengths for a tree and update the total bit length |
| 245 | * for the current block. |
| 246 | * IN assertion: the fields freq and dad are set, heap[heap_max] and |
| 247 | * above are the tree nodes sorted by increasing frequency. |
| 248 | * OUT assertions: the field len is set to the optimal bit length, the |
| 249 | * array bl_count contains the frequencies for each bit length. |
| 250 | * The length opt_len is updated; static_len is also updated if stree is |
| 251 | * not null. |
| 252 | */ |
| 253 | function gen_bitlen(s, desc) |
| 254 | // deflate_state *s; |
| 255 | // tree_desc *desc; /* the tree descriptor */ |
| 256 | { |
| 257 | var tree = desc.dyn_tree; |
| 258 | var max_code = desc.max_code; |
| 259 | var stree = desc.stat_desc.static_tree; |
| 260 | var has_stree = desc.stat_desc.has_stree; |
| 261 | var extra = desc.stat_desc.extra_bits; |
| 262 | var base = desc.stat_desc.extra_base; |
| 263 | var max_length = desc.stat_desc.max_length; |
| 264 | var h; /* heap index */ |
| 265 | var n, m; /* iterate over the tree elements */ |
| 266 | var bits; /* bit length */ |
| 267 | var xbits; /* extra bits */ |
| 268 | var f; /* frequency */ |
| 269 | var overflow = 0; /* number of elements with bit length too large */ |
| 270 | |
| 271 | for (bits = 0; bits <= MAX_BITS; bits++) { |
| 272 | s.bl_count[bits] = 0; |
| 273 | } |
| 274 | |
| 275 | /* In a first pass, compute the optimal bit lengths (which may |
| 276 | * overflow in the case of the bit length tree). |
| 277 | */ |
| 278 | tree[s.heap[s.heap_max] * 2 + 1]/*.Len*/ = 0; /* root of the heap */ |
| 279 | |
| 280 | for (h = s.heap_max + 1; h < HEAP_SIZE; h++) { |
| 281 | n = s.heap[h]; |
| 282 | bits = tree[tree[n * 2 + 1]/*.Dad*/ * 2 + 1]/*.Len*/ + 1; |
| 283 | if (bits > max_length) { |
| 284 | bits = max_length; |
| 285 | overflow++; |
| 286 | } |
| 287 | tree[n * 2 + 1]/*.Len*/ = bits; |
| 288 | /* We overwrite tree[n].Dad which is no longer needed */ |
| 289 | |
| 290 | if (n > max_code) { continue; } /* not a leaf node */ |
| 291 | |
| 292 | s.bl_count[bits]++; |
| 293 | xbits = 0; |
| 294 | if (n >= base) { |
| 295 | xbits = extra[n - base]; |
| 296 | } |
| 297 | f = tree[n * 2]/*.Freq*/; |
| 298 | s.opt_len += f * (bits + xbits); |
| 299 | if (has_stree) { |
| 300 | s.static_len += f * (stree[n * 2 + 1]/*.Len*/ + xbits); |
| 301 | } |
| 302 | } |
| 303 | if (overflow === 0) { return; } |
| 304 | |
| 305 | // Trace((stderr,"\nbit length overflow\n")); |
| 306 | /* This happens for example on obj2 and pic of the Calgary corpus */ |
| 307 | |
| 308 | /* Find the first bit length which could increase: */ |
| 309 | do { |
| 310 | bits = max_length - 1; |
| 311 | while (s.bl_count[bits] === 0) { bits--; } |
| 312 | s.bl_count[bits]--; /* move one leaf down the tree */ |
| 313 | s.bl_count[bits + 1] += 2; /* move one overflow item as its brother */ |
| 314 | s.bl_count[max_length]--; |
| 315 | /* The brother of the overflow item also moves one step up, |
| 316 | * but this does not affect bl_count[max_length] |
| 317 | */ |
| 318 | overflow -= 2; |
| 319 | } while (overflow > 0); |
| 320 | |
| 321 | /* Now recompute all bit lengths, scanning in increasing frequency. |
| 322 | * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all |
| 323 | * lengths instead of fixing only the wrong ones. This idea is taken |
| 324 | * from 'ar' written by Haruhiko Okumura.) |
| 325 | */ |
| 326 | for (bits = max_length; bits !== 0; bits--) { |
| 327 | n = s.bl_count[bits]; |
| 328 | while (n !== 0) { |
| 329 | m = s.heap[--h]; |
| 330 | if (m > max_code) { continue; } |
| 331 | if (tree[m * 2 + 1]/*.Len*/ !== bits) { |
| 332 | // Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); |
| 333 | s.opt_len += (bits - tree[m * 2 + 1]/*.Len*/) * tree[m * 2]/*.Freq*/; |
| 334 | tree[m * 2 + 1]/*.Len*/ = bits; |
| 335 | } |
| 336 | n--; |
| 337 | } |
| 338 | } |
| 339 | } |
| 340 | |
| 341 | |
| 342 | /* =========================================================================== |
| 343 | * Generate the codes for a given tree and bit counts (which need not be |
| 344 | * optimal). |
| 345 | * IN assertion: the array bl_count contains the bit length statistics for |
| 346 | * the given tree and the field len is set for all tree elements. |
| 347 | * OUT assertion: the field code is set for all tree elements of non |
| 348 | * zero code length. |
| 349 | */ |
| 350 | function gen_codes(tree, max_code, bl_count) |
| 351 | // ct_data *tree; /* the tree to decorate */ |
| 352 | // int max_code; /* largest code with non zero frequency */ |
| 353 | // ushf *bl_count; /* number of codes at each bit length */ |
| 354 | { |
| 355 | var next_code = new Array(MAX_BITS + 1); /* next code value for each bit length */ |
| 356 | var code = 0; /* running code value */ |
| 357 | var bits; /* bit index */ |
| 358 | var n; /* code index */ |
| 359 | |
| 360 | /* The distribution counts are first used to generate the code values |
| 361 | * without bit reversal. |
| 362 | */ |
| 363 | for (bits = 1; bits <= MAX_BITS; bits++) { |
| 364 | next_code[bits] = code = (code + bl_count[bits - 1]) << 1; |
| 365 | } |
| 366 | /* Check that the bit counts in bl_count are consistent. The last code |
| 367 | * must be all ones. |
| 368 | */ |
| 369 | //Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, |
| 370 | // "inconsistent bit counts"); |
| 371 | //Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); |
| 372 | |
| 373 | for (n = 0; n <= max_code; n++) { |
| 374 | var len = tree[n * 2 + 1]/*.Len*/; |
| 375 | if (len === 0) { continue; } |
| 376 | /* Now reverse the bits */ |
| 377 | tree[n * 2]/*.Code*/ = bi_reverse(next_code[len]++, len); |
| 378 | |
| 379 | //Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", |
| 380 | // n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); |
| 381 | } |
| 382 | } |
| 383 | |
| 384 | |
| 385 | /* =========================================================================== |
| 386 | * Initialize the various 'constant' tables. |
| 387 | */ |
| 388 | function tr_static_init() { |
| 389 | var n; /* iterates over tree elements */ |
| 390 | var bits; /* bit counter */ |
| 391 | var length; /* length value */ |
| 392 | var code; /* code value */ |
| 393 | var dist; /* distance index */ |
| 394 | var bl_count = new Array(MAX_BITS + 1); |
| 395 | /* number of codes at each bit length for an optimal tree */ |
| 396 | |
| 397 | // do check in _tr_init() |
| 398 | //if (static_init_done) return; |
| 399 | |
| 400 | /* For some embedded targets, global variables are not initialized: */ |
| 401 | /*#ifdef NO_INIT_GLOBAL_POINTERS |
| 402 | static_l_desc.static_tree = static_ltree; |
| 403 | static_l_desc.extra_bits = extra_lbits; |
| 404 | static_d_desc.static_tree = static_dtree; |
| 405 | static_d_desc.extra_bits = extra_dbits; |
| 406 | static_bl_desc.extra_bits = extra_blbits; |
| 407 | #endif*/ |
| 408 | |
| 409 | /* Initialize the mapping length (0..255) -> length code (0..28) */ |
| 410 | length = 0; |
| 411 | for (code = 0; code < LENGTH_CODES - 1; code++) { |
| 412 | base_length[code] = length; |
| 413 | for (n = 0; n < (1 << extra_lbits[code]); n++) { |
| 414 | _length_code[length++] = code; |
| 415 | } |
| 416 | } |
| 417 | //Assert (length == 256, "tr_static_init: length != 256"); |
| 418 | /* Note that the length 255 (match length 258) can be represented |
| 419 | * in two different ways: code 284 + 5 bits or code 285, so we |
| 420 | * overwrite length_code[255] to use the best encoding: |
| 421 | */ |
| 422 | _length_code[length - 1] = code; |
| 423 | |
| 424 | /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ |
| 425 | dist = 0; |
| 426 | for (code = 0; code < 16; code++) { |
| 427 | base_dist[code] = dist; |
| 428 | for (n = 0; n < (1 << extra_dbits[code]); n++) { |
| 429 | _dist_code[dist++] = code; |
| 430 | } |
| 431 | } |
| 432 | //Assert (dist == 256, "tr_static_init: dist != 256"); |
| 433 | dist >>= 7; /* from now on, all distances are divided by 128 */ |
| 434 | for (; code < D_CODES; code++) { |
| 435 | base_dist[code] = dist << 7; |
| 436 | for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) { |
| 437 | _dist_code[256 + dist++] = code; |
| 438 | } |
| 439 | } |
| 440 | //Assert (dist == 256, "tr_static_init: 256+dist != 512"); |
| 441 | |
| 442 | /* Construct the codes of the static literal tree */ |
| 443 | for (bits = 0; bits <= MAX_BITS; bits++) { |
| 444 | bl_count[bits] = 0; |
| 445 | } |
| 446 | |
| 447 | n = 0; |
| 448 | while (n <= 143) { |
| 449 | static_ltree[n * 2 + 1]/*.Len*/ = 8; |
| 450 | n++; |
| 451 | bl_count[8]++; |
| 452 | } |
| 453 | while (n <= 255) { |
| 454 | static_ltree[n * 2 + 1]/*.Len*/ = 9; |
| 455 | n++; |
| 456 | bl_count[9]++; |
| 457 | } |
| 458 | while (n <= 279) { |
| 459 | static_ltree[n * 2 + 1]/*.Len*/ = 7; |
| 460 | n++; |
| 461 | bl_count[7]++; |
| 462 | } |
| 463 | while (n <= 287) { |
| 464 | static_ltree[n * 2 + 1]/*.Len*/ = 8; |
| 465 | n++; |
| 466 | bl_count[8]++; |
| 467 | } |
| 468 | /* Codes 286 and 287 do not exist, but we must include them in the |
| 469 | * tree construction to get a canonical Huffman tree (longest code |
| 470 | * all ones) |
| 471 | */ |
| 472 | gen_codes(static_ltree, L_CODES + 1, bl_count); |
| 473 | |
| 474 | /* The static distance tree is trivial: */ |
| 475 | for (n = 0; n < D_CODES; n++) { |
| 476 | static_dtree[n * 2 + 1]/*.Len*/ = 5; |
| 477 | static_dtree[n * 2]/*.Code*/ = bi_reverse(n, 5); |
| 478 | } |
| 479 | |
| 480 | // Now data ready and we can init static trees |
| 481 | static_l_desc = new StaticTreeDesc(static_ltree, extra_lbits, LITERALS + 1, L_CODES, MAX_BITS); |
| 482 | static_d_desc = new StaticTreeDesc(static_dtree, extra_dbits, 0, D_CODES, MAX_BITS); |
| 483 | static_bl_desc = new StaticTreeDesc(new Array(0), extra_blbits, 0, BL_CODES, MAX_BL_BITS); |
| 484 | |
| 485 | //static_init_done = true; |
| 486 | } |
| 487 | |
| 488 | |
| 489 | /* =========================================================================== |
| 490 | * Initialize a new block. |
| 491 | */ |
| 492 | function init_block(s) { |
| 493 | var n; /* iterates over tree elements */ |
| 494 | |
| 495 | /* Initialize the trees. */ |
| 496 | for (n = 0; n < L_CODES; n++) { s.dyn_ltree[n * 2]/*.Freq*/ = 0; } |
| 497 | for (n = 0; n < D_CODES; n++) { s.dyn_dtree[n * 2]/*.Freq*/ = 0; } |
| 498 | for (n = 0; n < BL_CODES; n++) { s.bl_tree[n * 2]/*.Freq*/ = 0; } |
| 499 | |
| 500 | s.dyn_ltree[END_BLOCK * 2]/*.Freq*/ = 1; |
| 501 | s.opt_len = s.static_len = 0; |
| 502 | s.last_lit = s.matches = 0; |
| 503 | } |
| 504 | |
| 505 | |
| 506 | /* =========================================================================== |
| 507 | * Flush the bit buffer and align the output on a byte boundary |
| 508 | */ |
| 509 | function bi_windup(s) |
| 510 | { |
| 511 | if (s.bi_valid > 8) { |
| 512 | put_short(s, s.bi_buf); |
| 513 | } else if (s.bi_valid > 0) { |
| 514 | //put_byte(s, (Byte)s->bi_buf); |
| 515 | s.pending_buf[s.pending++] = s.bi_buf; |
| 516 | } |
| 517 | s.bi_buf = 0; |
| 518 | s.bi_valid = 0; |
| 519 | } |
| 520 | |
| 521 | /* =========================================================================== |
| 522 | * Copy a stored block, storing first the length and its |
| 523 | * one's complement if requested. |
| 524 | */ |
| 525 | function copy_block(s, buf, len, header) |
| 526 | //DeflateState *s; |
| 527 | //charf *buf; /* the input data */ |
| 528 | //unsigned len; /* its length */ |
| 529 | //int header; /* true if block header must be written */ |
| 530 | { |
| 531 | bi_windup(s); /* align on byte boundary */ |
| 532 | |
| 533 | if (header) { |
| 534 | put_short(s, len); |
| 535 | put_short(s, ~len); |
| 536 | } |
| 537 | // while (len--) { |
| 538 | // put_byte(s, *buf++); |
| 539 | // } |
| 540 | utils.arraySet(s.pending_buf, s.window, buf, len, s.pending); |
| 541 | s.pending += len; |
| 542 | } |
| 543 | |
| 544 | /* =========================================================================== |
| 545 | * Compares to subtrees, using the tree depth as tie breaker when |
| 546 | * the subtrees have equal frequency. This minimizes the worst case length. |
| 547 | */ |
| 548 | function smaller(tree, n, m, depth) { |
| 549 | var _n2 = n * 2; |
| 550 | var _m2 = m * 2; |
| 551 | return (tree[_n2]/*.Freq*/ < tree[_m2]/*.Freq*/ || |
| 552 | (tree[_n2]/*.Freq*/ === tree[_m2]/*.Freq*/ && depth[n] <= depth[m])); |
| 553 | } |
| 554 | |
| 555 | /* =========================================================================== |
| 556 | * Restore the heap property by moving down the tree starting at node k, |
| 557 | * exchanging a node with the smallest of its two sons if necessary, stopping |
| 558 | * when the heap property is re-established (each father smaller than its |
| 559 | * two sons). |
| 560 | */ |
| 561 | function pqdownheap(s, tree, k) |
| 562 | // deflate_state *s; |
| 563 | // ct_data *tree; /* the tree to restore */ |
| 564 | // int k; /* node to move down */ |
| 565 | { |
| 566 | var v = s.heap[k]; |
| 567 | var j = k << 1; /* left son of k */ |
| 568 | while (j <= s.heap_len) { |
| 569 | /* Set j to the smallest of the two sons: */ |
| 570 | if (j < s.heap_len && |
| 571 | smaller(tree, s.heap[j + 1], s.heap[j], s.depth)) { |
| 572 | j++; |
| 573 | } |
| 574 | /* Exit if v is smaller than both sons */ |
| 575 | if (smaller(tree, v, s.heap[j], s.depth)) { break; } |
| 576 | |
| 577 | /* Exchange v with the smallest son */ |
| 578 | s.heap[k] = s.heap[j]; |
| 579 | k = j; |
| 580 | |
| 581 | /* And continue down the tree, setting j to the left son of k */ |
| 582 | j <<= 1; |
| 583 | } |
| 584 | s.heap[k] = v; |
| 585 | } |
| 586 | |
| 587 | |
| 588 | // inlined manually |
| 589 | // var SMALLEST = 1; |
| 590 | |
| 591 | /* =========================================================================== |
| 592 | * Send the block data compressed using the given Huffman trees |
| 593 | */ |
| 594 | function compress_block(s, ltree, dtree) |
| 595 | // deflate_state *s; |
| 596 | // const ct_data *ltree; /* literal tree */ |
| 597 | // const ct_data *dtree; /* distance tree */ |
| 598 | { |
| 599 | var dist; /* distance of matched string */ |
| 600 | var lc; /* match length or unmatched char (if dist == 0) */ |
| 601 | var lx = 0; /* running index in l_buf */ |
| 602 | var code; /* the code to send */ |
| 603 | var extra; /* number of extra bits to send */ |
| 604 | |
| 605 | if (s.last_lit !== 0) { |
| 606 | do { |
| 607 | dist = (s.pending_buf[s.d_buf + lx * 2] << 8) | (s.pending_buf[s.d_buf + lx * 2 + 1]); |
| 608 | lc = s.pending_buf[s.l_buf + lx]; |
| 609 | lx++; |
| 610 | |
| 611 | if (dist === 0) { |
| 612 | send_code(s, lc, ltree); /* send a literal byte */ |
| 613 | //Tracecv(isgraph(lc), (stderr," '%c' ", lc)); |
| 614 | } else { |
| 615 | /* Here, lc is the match length - MIN_MATCH */ |
| 616 | code = _length_code[lc]; |
| 617 | send_code(s, code + LITERALS + 1, ltree); /* send the length code */ |
| 618 | extra = extra_lbits[code]; |
| 619 | if (extra !== 0) { |
| 620 | lc -= base_length[code]; |
| 621 | send_bits(s, lc, extra); /* send the extra length bits */ |
| 622 | } |
| 623 | dist--; /* dist is now the match distance - 1 */ |
| 624 | code = d_code(dist); |
| 625 | //Assert (code < D_CODES, "bad d_code"); |
| 626 | |
| 627 | send_code(s, code, dtree); /* send the distance code */ |
| 628 | extra = extra_dbits[code]; |
| 629 | if (extra !== 0) { |
| 630 | dist -= base_dist[code]; |
| 631 | send_bits(s, dist, extra); /* send the extra distance bits */ |
| 632 | } |
| 633 | } /* literal or match pair ? */ |
| 634 | |
| 635 | /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ |
| 636 | //Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, |
| 637 | // "pendingBuf overflow"); |
| 638 | |
| 639 | } while (lx < s.last_lit); |
| 640 | } |
| 641 | |
| 642 | send_code(s, END_BLOCK, ltree); |
| 643 | } |
| 644 | |
| 645 | |
| 646 | /* =========================================================================== |
| 647 | * Construct one Huffman tree and assigns the code bit strings and lengths. |
| 648 | * Update the total bit length for the current block. |
| 649 | * IN assertion: the field freq is set for all tree elements. |
| 650 | * OUT assertions: the fields len and code are set to the optimal bit length |
| 651 | * and corresponding code. The length opt_len is updated; static_len is |
| 652 | * also updated if stree is not null. The field max_code is set. |
| 653 | */ |
| 654 | function build_tree(s, desc) |
| 655 | // deflate_state *s; |
| 656 | // tree_desc *desc; /* the tree descriptor */ |
| 657 | { |
| 658 | var tree = desc.dyn_tree; |
| 659 | var stree = desc.stat_desc.static_tree; |
| 660 | var has_stree = desc.stat_desc.has_stree; |
| 661 | var elems = desc.stat_desc.elems; |
| 662 | var n, m; /* iterate over heap elements */ |
| 663 | var max_code = -1; /* largest code with non zero frequency */ |
| 664 | var node; /* new node being created */ |
| 665 | |
| 666 | /* Construct the initial heap, with least frequent element in |
| 667 | * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. |
| 668 | * heap[0] is not used. |
| 669 | */ |
| 670 | s.heap_len = 0; |
| 671 | s.heap_max = HEAP_SIZE; |
| 672 | |
| 673 | for (n = 0; n < elems; n++) { |
| 674 | if (tree[n * 2]/*.Freq*/ !== 0) { |
| 675 | s.heap[++s.heap_len] = max_code = n; |
| 676 | s.depth[n] = 0; |
| 677 | |
| 678 | } else { |
| 679 | tree[n * 2 + 1]/*.Len*/ = 0; |
| 680 | } |
| 681 | } |
| 682 | |
| 683 | /* The pkzip format requires that at least one distance code exists, |
| 684 | * and that at least one bit should be sent even if there is only one |
| 685 | * possible code. So to avoid special checks later on we force at least |
| 686 | * two codes of non zero frequency. |
| 687 | */ |
| 688 | while (s.heap_len < 2) { |
| 689 | node = s.heap[++s.heap_len] = (max_code < 2 ? ++max_code : 0); |
| 690 | tree[node * 2]/*.Freq*/ = 1; |
| 691 | s.depth[node] = 0; |
| 692 | s.opt_len--; |
| 693 | |
| 694 | if (has_stree) { |
| 695 | s.static_len -= stree[node * 2 + 1]/*.Len*/; |
| 696 | } |
| 697 | /* node is 0 or 1 so it does not have extra bits */ |
| 698 | } |
| 699 | desc.max_code = max_code; |
| 700 | |
| 701 | /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, |
| 702 | * establish sub-heaps of increasing lengths: |
| 703 | */ |
| 704 | for (n = (s.heap_len >> 1/*int /2*/); n >= 1; n--) { pqdownheap(s, tree, n); } |
| 705 | |
| 706 | /* Construct the Huffman tree by repeatedly combining the least two |
| 707 | * frequent nodes. |
| 708 | */ |
| 709 | node = elems; /* next internal node of the tree */ |
| 710 | do { |
| 711 | //pqremove(s, tree, n); /* n = node of least frequency */ |
| 712 | /*** pqremove ***/ |
| 713 | n = s.heap[1/*SMALLEST*/]; |
| 714 | s.heap[1/*SMALLEST*/] = s.heap[s.heap_len--]; |
| 715 | pqdownheap(s, tree, 1/*SMALLEST*/); |
| 716 | /***/ |
| 717 | |
| 718 | m = s.heap[1/*SMALLEST*/]; /* m = node of next least frequency */ |
| 719 | |
| 720 | s.heap[--s.heap_max] = n; /* keep the nodes sorted by frequency */ |
| 721 | s.heap[--s.heap_max] = m; |
| 722 | |
| 723 | /* Create a new node father of n and m */ |
| 724 | tree[node * 2]/*.Freq*/ = tree[n * 2]/*.Freq*/ + tree[m * 2]/*.Freq*/; |
| 725 | s.depth[node] = (s.depth[n] >= s.depth[m] ? s.depth[n] : s.depth[m]) + 1; |
| 726 | tree[n * 2 + 1]/*.Dad*/ = tree[m * 2 + 1]/*.Dad*/ = node; |
| 727 | |
| 728 | /* and insert the new node in the heap */ |
| 729 | s.heap[1/*SMALLEST*/] = node++; |
| 730 | pqdownheap(s, tree, 1/*SMALLEST*/); |
| 731 | |
| 732 | } while (s.heap_len >= 2); |
| 733 | |
| 734 | s.heap[--s.heap_max] = s.heap[1/*SMALLEST*/]; |
| 735 | |
| 736 | /* At this point, the fields freq and dad are set. We can now |
| 737 | * generate the bit lengths. |
| 738 | */ |
| 739 | gen_bitlen(s, desc); |
| 740 | |
| 741 | /* The field len is now set, we can generate the bit codes */ |
| 742 | gen_codes(tree, max_code, s.bl_count); |
| 743 | } |
| 744 | |
| 745 | |
| 746 | /* =========================================================================== |
| 747 | * Scan a literal or distance tree to determine the frequencies of the codes |
| 748 | * in the bit length tree. |
| 749 | */ |
| 750 | function scan_tree(s, tree, max_code) |
| 751 | // deflate_state *s; |
| 752 | // ct_data *tree; /* the tree to be scanned */ |
| 753 | // int max_code; /* and its largest code of non zero frequency */ |
| 754 | { |
| 755 | var n; /* iterates over all tree elements */ |
| 756 | var prevlen = -1; /* last emitted length */ |
| 757 | var curlen; /* length of current code */ |
| 758 | |
| 759 | var nextlen = tree[0 * 2 + 1]/*.Len*/; /* length of next code */ |
| 760 | |
| 761 | var count = 0; /* repeat count of the current code */ |
| 762 | var max_count = 7; /* max repeat count */ |
| 763 | var min_count = 4; /* min repeat count */ |
| 764 | |
| 765 | if (nextlen === 0) { |
| 766 | max_count = 138; |
| 767 | min_count = 3; |
| 768 | } |
| 769 | tree[(max_code + 1) * 2 + 1]/*.Len*/ = 0xffff; /* guard */ |
| 770 | |
| 771 | for (n = 0; n <= max_code; n++) { |
| 772 | curlen = nextlen; |
| 773 | nextlen = tree[(n + 1) * 2 + 1]/*.Len*/; |
| 774 | |
| 775 | if (++count < max_count && curlen === nextlen) { |
| 776 | continue; |
| 777 | |
| 778 | } else if (count < min_count) { |
| 779 | s.bl_tree[curlen * 2]/*.Freq*/ += count; |
| 780 | |
| 781 | } else if (curlen !== 0) { |
| 782 | |
| 783 | if (curlen !== prevlen) { s.bl_tree[curlen * 2]/*.Freq*/++; } |
| 784 | s.bl_tree[REP_3_6 * 2]/*.Freq*/++; |
| 785 | |
| 786 | } else if (count <= 10) { |
| 787 | s.bl_tree[REPZ_3_10 * 2]/*.Freq*/++; |
| 788 | |
| 789 | } else { |
| 790 | s.bl_tree[REPZ_11_138 * 2]/*.Freq*/++; |
| 791 | } |
| 792 | |
| 793 | count = 0; |
| 794 | prevlen = curlen; |
| 795 | |
| 796 | if (nextlen === 0) { |
| 797 | max_count = 138; |
| 798 | min_count = 3; |
| 799 | |
| 800 | } else if (curlen === nextlen) { |
| 801 | max_count = 6; |
| 802 | min_count = 3; |
| 803 | |
| 804 | } else { |
| 805 | max_count = 7; |
| 806 | min_count = 4; |
| 807 | } |
| 808 | } |
| 809 | } |
| 810 | |
| 811 | |
| 812 | /* =========================================================================== |
| 813 | * Send a literal or distance tree in compressed form, using the codes in |
| 814 | * bl_tree. |
| 815 | */ |
| 816 | function send_tree(s, tree, max_code) |
| 817 | // deflate_state *s; |
| 818 | // ct_data *tree; /* the tree to be scanned */ |
| 819 | // int max_code; /* and its largest code of non zero frequency */ |
| 820 | { |
| 821 | var n; /* iterates over all tree elements */ |
| 822 | var prevlen = -1; /* last emitted length */ |
| 823 | var curlen; /* length of current code */ |
| 824 | |
| 825 | var nextlen = tree[0 * 2 + 1]/*.Len*/; /* length of next code */ |
| 826 | |
| 827 | var count = 0; /* repeat count of the current code */ |
| 828 | var max_count = 7; /* max repeat count */ |
| 829 | var min_count = 4; /* min repeat count */ |
| 830 | |
| 831 | /* tree[max_code+1].Len = -1; */ /* guard already set */ |
| 832 | if (nextlen === 0) { |
| 833 | max_count = 138; |
| 834 | min_count = 3; |
| 835 | } |
| 836 | |
| 837 | for (n = 0; n <= max_code; n++) { |
| 838 | curlen = nextlen; |
| 839 | nextlen = tree[(n + 1) * 2 + 1]/*.Len*/; |
| 840 | |
| 841 | if (++count < max_count && curlen === nextlen) { |
| 842 | continue; |
| 843 | |
| 844 | } else if (count < min_count) { |
| 845 | do { send_code(s, curlen, s.bl_tree); } while (--count !== 0); |
| 846 | |
| 847 | } else if (curlen !== 0) { |
| 848 | if (curlen !== prevlen) { |
| 849 | send_code(s, curlen, s.bl_tree); |
| 850 | count--; |
| 851 | } |
| 852 | //Assert(count >= 3 && count <= 6, " 3_6?"); |
| 853 | send_code(s, REP_3_6, s.bl_tree); |
| 854 | send_bits(s, count - 3, 2); |
| 855 | |
| 856 | } else if (count <= 10) { |
| 857 | send_code(s, REPZ_3_10, s.bl_tree); |
| 858 | send_bits(s, count - 3, 3); |
| 859 | |
| 860 | } else { |
| 861 | send_code(s, REPZ_11_138, s.bl_tree); |
| 862 | send_bits(s, count - 11, 7); |
| 863 | } |
| 864 | |
| 865 | count = 0; |
| 866 | prevlen = curlen; |
| 867 | if (nextlen === 0) { |
| 868 | max_count = 138; |
| 869 | min_count = 3; |
| 870 | |
| 871 | } else if (curlen === nextlen) { |
| 872 | max_count = 6; |
| 873 | min_count = 3; |
| 874 | |
| 875 | } else { |
| 876 | max_count = 7; |
| 877 | min_count = 4; |
| 878 | } |
| 879 | } |
| 880 | } |
| 881 | |
| 882 | |
| 883 | /* =========================================================================== |
| 884 | * Construct the Huffman tree for the bit lengths and return the index in |
| 885 | * bl_order of the last bit length code to send. |
| 886 | */ |
| 887 | function build_bl_tree(s) { |
| 888 | var max_blindex; /* index of last bit length code of non zero freq */ |
| 889 | |
| 890 | /* Determine the bit length frequencies for literal and distance trees */ |
| 891 | scan_tree(s, s.dyn_ltree, s.l_desc.max_code); |
| 892 | scan_tree(s, s.dyn_dtree, s.d_desc.max_code); |
| 893 | |
| 894 | /* Build the bit length tree: */ |
| 895 | build_tree(s, s.bl_desc); |
| 896 | /* opt_len now includes the length of the tree representations, except |
| 897 | * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. |
| 898 | */ |
| 899 | |
| 900 | /* Determine the number of bit length codes to send. The pkzip format |
| 901 | * requires that at least 4 bit length codes be sent. (appnote.txt says |
| 902 | * 3 but the actual value used is 4.) |
| 903 | */ |
| 904 | for (max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--) { |
| 905 | if (s.bl_tree[bl_order[max_blindex] * 2 + 1]/*.Len*/ !== 0) { |
| 906 | break; |
| 907 | } |
| 908 | } |
| 909 | /* Update opt_len to include the bit length tree and counts */ |
| 910 | s.opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4; |
| 911 | //Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", |
| 912 | // s->opt_len, s->static_len)); |
| 913 | |
| 914 | return max_blindex; |
| 915 | } |
| 916 | |
| 917 | |
| 918 | /* =========================================================================== |
| 919 | * Send the header for a block using dynamic Huffman trees: the counts, the |
| 920 | * lengths of the bit length codes, the literal tree and the distance tree. |
| 921 | * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. |
| 922 | */ |
| 923 | function send_all_trees(s, lcodes, dcodes, blcodes) |
| 924 | // deflate_state *s; |
| 925 | // int lcodes, dcodes, blcodes; /* number of codes for each tree */ |
| 926 | { |
| 927 | var rank; /* index in bl_order */ |
| 928 | |
| 929 | //Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); |
| 930 | //Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, |
| 931 | // "too many codes"); |
| 932 | //Tracev((stderr, "\nbl counts: ")); |
| 933 | send_bits(s, lcodes - 257, 5); /* not +255 as stated in appnote.txt */ |
| 934 | send_bits(s, dcodes - 1, 5); |
| 935 | send_bits(s, blcodes - 4, 4); /* not -3 as stated in appnote.txt */ |
| 936 | for (rank = 0; rank < blcodes; rank++) { |
| 937 | //Tracev((stderr, "\nbl code %2d ", bl_order[rank])); |
| 938 | send_bits(s, s.bl_tree[bl_order[rank] * 2 + 1]/*.Len*/, 3); |
| 939 | } |
| 940 | //Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); |
| 941 | |
| 942 | send_tree(s, s.dyn_ltree, lcodes - 1); /* literal tree */ |
| 943 | //Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); |
| 944 | |
| 945 | send_tree(s, s.dyn_dtree, dcodes - 1); /* distance tree */ |
| 946 | //Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); |
| 947 | } |
| 948 | |
| 949 | |
| 950 | /* =========================================================================== |
| 951 | * Check if the data type is TEXT or BINARY, using the following algorithm: |
| 952 | * - TEXT if the two conditions below are satisfied: |
| 953 | * a) There are no non-portable control characters belonging to the |
| 954 | * "black list" (0..6, 14..25, 28..31). |
| 955 | * b) There is at least one printable character belonging to the |
| 956 | * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255). |
| 957 | * - BINARY otherwise. |
| 958 | * - The following partially-portable control characters form a |
| 959 | * "gray list" that is ignored in this detection algorithm: |
| 960 | * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}). |
| 961 | * IN assertion: the fields Freq of dyn_ltree are set. |
| 962 | */ |
| 963 | function detect_data_type(s) { |
| 964 | /* black_mask is the bit mask of black-listed bytes |
| 965 | * set bits 0..6, 14..25, and 28..31 |
| 966 | * 0xf3ffc07f = binary 11110011111111111100000001111111 |
| 967 | */ |
| 968 | var black_mask = 0xf3ffc07f; |
| 969 | var n; |
| 970 | |
| 971 | /* Check for non-textual ("black-listed") bytes. */ |
| 972 | for (n = 0; n <= 31; n++, black_mask >>>= 1) { |
| 973 | if ((black_mask & 1) && (s.dyn_ltree[n * 2]/*.Freq*/ !== 0)) { |
| 974 | return Z_BINARY; |
| 975 | } |
| 976 | } |
| 977 | |
| 978 | /* Check for textual ("white-listed") bytes. */ |
| 979 | if (s.dyn_ltree[9 * 2]/*.Freq*/ !== 0 || s.dyn_ltree[10 * 2]/*.Freq*/ !== 0 || |
| 980 | s.dyn_ltree[13 * 2]/*.Freq*/ !== 0) { |
| 981 | return Z_TEXT; |
| 982 | } |
| 983 | for (n = 32; n < LITERALS; n++) { |
| 984 | if (s.dyn_ltree[n * 2]/*.Freq*/ !== 0) { |
| 985 | return Z_TEXT; |
| 986 | } |
| 987 | } |
| 988 | |
| 989 | /* There are no "black-listed" or "white-listed" bytes: |
| 990 | * this stream either is empty or has tolerated ("gray-listed") bytes only. |
| 991 | */ |
| 992 | return Z_BINARY; |
| 993 | } |
| 994 | |
| 995 | |
| 996 | var static_init_done = false; |
| 997 | |
| 998 | /* =========================================================================== |
| 999 | * Initialize the tree data structures for a new zlib stream. |
| 1000 | */ |
| 1001 | function _tr_init(s) |
| 1002 | { |
| 1003 | |
| 1004 | if (!static_init_done) { |
| 1005 | tr_static_init(); |
| 1006 | static_init_done = true; |
| 1007 | } |
| 1008 | |
| 1009 | s.l_desc = new TreeDesc(s.dyn_ltree, static_l_desc); |
| 1010 | s.d_desc = new TreeDesc(s.dyn_dtree, static_d_desc); |
| 1011 | s.bl_desc = new TreeDesc(s.bl_tree, static_bl_desc); |
| 1012 | |
| 1013 | s.bi_buf = 0; |
| 1014 | s.bi_valid = 0; |
| 1015 | |
| 1016 | /* Initialize the first block of the first file: */ |
| 1017 | init_block(s); |
| 1018 | } |
| 1019 | |
| 1020 | |
| 1021 | /* =========================================================================== |
| 1022 | * Send a stored block |
| 1023 | */ |
| 1024 | function _tr_stored_block(s, buf, stored_len, last) |
| 1025 | //DeflateState *s; |
| 1026 | //charf *buf; /* input block */ |
| 1027 | //ulg stored_len; /* length of input block */ |
| 1028 | //int last; /* one if this is the last block for a file */ |
| 1029 | { |
| 1030 | send_bits(s, (STORED_BLOCK << 1) + (last ? 1 : 0), 3); /* send block type */ |
| 1031 | copy_block(s, buf, stored_len, true); /* with header */ |
| 1032 | } |
| 1033 | |
| 1034 | |
| 1035 | /* =========================================================================== |
| 1036 | * Send one empty static block to give enough lookahead for inflate. |
| 1037 | * This takes 10 bits, of which 7 may remain in the bit buffer. |
| 1038 | */ |
| 1039 | function _tr_align(s) { |
| 1040 | send_bits(s, STATIC_TREES << 1, 3); |
| 1041 | send_code(s, END_BLOCK, static_ltree); |
| 1042 | bi_flush(s); |
| 1043 | } |
| 1044 | |
| 1045 | |
| 1046 | /* =========================================================================== |
| 1047 | * Determine the best encoding for the current block: dynamic trees, static |
| 1048 | * trees or store, and output the encoded block to the zip file. |
| 1049 | */ |
| 1050 | function _tr_flush_block(s, buf, stored_len, last) |
| 1051 | //DeflateState *s; |
| 1052 | //charf *buf; /* input block, or NULL if too old */ |
| 1053 | //ulg stored_len; /* length of input block */ |
| 1054 | //int last; /* one if this is the last block for a file */ |
| 1055 | { |
| 1056 | var opt_lenb, static_lenb; /* opt_len and static_len in bytes */ |
| 1057 | var max_blindex = 0; /* index of last bit length code of non zero freq */ |
| 1058 | |
| 1059 | /* Build the Huffman trees unless a stored block is forced */ |
| 1060 | if (s.level > 0) { |
| 1061 | |
| 1062 | /* Check if the file is binary or text */ |
| 1063 | if (s.strm.data_type === Z_UNKNOWN) { |
| 1064 | s.strm.data_type = detect_data_type(s); |
| 1065 | } |
| 1066 | |
| 1067 | /* Construct the literal and distance trees */ |
| 1068 | build_tree(s, s.l_desc); |
| 1069 | // Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, |
| 1070 | // s->static_len)); |
| 1071 | |
| 1072 | build_tree(s, s.d_desc); |
| 1073 | // Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, |
| 1074 | // s->static_len)); |
| 1075 | /* At this point, opt_len and static_len are the total bit lengths of |
| 1076 | * the compressed block data, excluding the tree representations. |
| 1077 | */ |
| 1078 | |
| 1079 | /* Build the bit length tree for the above two trees, and get the index |
| 1080 | * in bl_order of the last bit length code to send. |
| 1081 | */ |
| 1082 | max_blindex = build_bl_tree(s); |
| 1083 | |
| 1084 | /* Determine the best encoding. Compute the block lengths in bytes. */ |
| 1085 | opt_lenb = (s.opt_len + 3 + 7) >>> 3; |
| 1086 | static_lenb = (s.static_len + 3 + 7) >>> 3; |
| 1087 | |
| 1088 | // Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", |
| 1089 | // opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, |
| 1090 | // s->last_lit)); |
| 1091 | |
| 1092 | if (static_lenb <= opt_lenb) { opt_lenb = static_lenb; } |
| 1093 | |
| 1094 | } else { |
| 1095 | // Assert(buf != (char*)0, "lost buf"); |
| 1096 | opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ |
| 1097 | } |
| 1098 | |
| 1099 | if ((stored_len + 4 <= opt_lenb) && (buf !== -1)) { |
| 1100 | /* 4: two words for the lengths */ |
| 1101 | |
| 1102 | /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. |
| 1103 | * Otherwise we can't have processed more than WSIZE input bytes since |
| 1104 | * the last block flush, because compression would have been |
| 1105 | * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to |
| 1106 | * transform a block into a stored block. |
| 1107 | */ |
| 1108 | _tr_stored_block(s, buf, stored_len, last); |
| 1109 | |
| 1110 | } else if (s.strategy === Z_FIXED || static_lenb === opt_lenb) { |
| 1111 | |
| 1112 | send_bits(s, (STATIC_TREES << 1) + (last ? 1 : 0), 3); |
| 1113 | compress_block(s, static_ltree, static_dtree); |
| 1114 | |
| 1115 | } else { |
| 1116 | send_bits(s, (DYN_TREES << 1) + (last ? 1 : 0), 3); |
| 1117 | send_all_trees(s, s.l_desc.max_code + 1, s.d_desc.max_code + 1, max_blindex + 1); |
| 1118 | compress_block(s, s.dyn_ltree, s.dyn_dtree); |
| 1119 | } |
| 1120 | // Assert (s->compressed_len == s->bits_sent, "bad compressed size"); |
| 1121 | /* The above check is made mod 2^32, for files larger than 512 MB |
| 1122 | * and uLong implemented on 32 bits. |
| 1123 | */ |
| 1124 | init_block(s); |
| 1125 | |
| 1126 | if (last) { |
| 1127 | bi_windup(s); |
| 1128 | } |
| 1129 | // Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, |
| 1130 | // s->compressed_len-7*last)); |
| 1131 | } |
| 1132 | |
| 1133 | /* =========================================================================== |
| 1134 | * Save the match info and tally the frequency counts. Return true if |
| 1135 | * the current block must be flushed. |
| 1136 | */ |
| 1137 | function _tr_tally(s, dist, lc) |
| 1138 | // deflate_state *s; |
| 1139 | // unsigned dist; /* distance of matched string */ |
| 1140 | // unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ |
| 1141 | { |
| 1142 | //var out_length, in_length, dcode; |
| 1143 | |
| 1144 | s.pending_buf[s.d_buf + s.last_lit * 2] = (dist >>> 8) & 0xff; |
| 1145 | s.pending_buf[s.d_buf + s.last_lit * 2 + 1] = dist & 0xff; |
| 1146 | |
| 1147 | s.pending_buf[s.l_buf + s.last_lit] = lc & 0xff; |
| 1148 | s.last_lit++; |
| 1149 | |
| 1150 | if (dist === 0) { |
| 1151 | /* lc is the unmatched char */ |
| 1152 | s.dyn_ltree[lc * 2]/*.Freq*/++; |
| 1153 | } else { |
| 1154 | s.matches++; |
| 1155 | /* Here, lc is the match length - MIN_MATCH */ |
| 1156 | dist--; /* dist = match distance - 1 */ |
| 1157 | //Assert((ush)dist < (ush)MAX_DIST(s) && |
| 1158 | // (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && |
| 1159 | // (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); |
| 1160 | |
| 1161 | s.dyn_ltree[(_length_code[lc] + LITERALS + 1) * 2]/*.Freq*/++; |
| 1162 | s.dyn_dtree[d_code(dist) * 2]/*.Freq*/++; |
| 1163 | } |
| 1164 | |
| 1165 | // (!) This block is disabled in zlib defailts, |
| 1166 | // don't enable it for binary compatibility |
| 1167 | |
| 1168 | //#ifdef TRUNCATE_BLOCK |
| 1169 | // /* Try to guess if it is profitable to stop the current block here */ |
| 1170 | // if ((s.last_lit & 0x1fff) === 0 && s.level > 2) { |
| 1171 | // /* Compute an upper bound for the compressed length */ |
| 1172 | // out_length = s.last_lit*8; |
| 1173 | // in_length = s.strstart - s.block_start; |
| 1174 | // |
| 1175 | // for (dcode = 0; dcode < D_CODES; dcode++) { |
| 1176 | // out_length += s.dyn_dtree[dcode*2]/*.Freq*/ * (5 + extra_dbits[dcode]); |
| 1177 | // } |
| 1178 | // out_length >>>= 3; |
| 1179 | // //Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", |
| 1180 | // // s->last_lit, in_length, out_length, |
| 1181 | // // 100L - out_length*100L/in_length)); |
| 1182 | // if (s.matches < (s.last_lit>>1)/*int /2*/ && out_length < (in_length>>1)/*int /2*/) { |
| 1183 | // return true; |
| 1184 | // } |
| 1185 | // } |
| 1186 | //#endif |
| 1187 | |
| 1188 | return (s.last_lit === s.lit_bufsize - 1); |
| 1189 | /* We avoid equality with lit_bufsize because of wraparound at 64K |
| 1190 | * on 16 bit machines and because stored blocks are restricted to |
| 1191 | * 64K-1 bytes. |
| 1192 | */ |
| 1193 | } |
| 1194 | |
| 1195 | export { _tr_init, _tr_stored_block, _tr_flush_block, _tr_tally, _tr_align }; |