19e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project/* inftree9.c -- generate Huffman trees for efficient decoding 204351a92ecc8429c999acbfc5dfe5aa8bee1d19dElliott Hughes * Copyright (C) 1995-2013 Mark Adler 39e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project * For conditions of distribution and use, see copyright notice in zlib.h 49e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project */ 59e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 69e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project#include "zutil.h" 79e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project#include "inftree9.h" 89e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 99e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project#define MAXBITS 15 109e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 119e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Projectconst char inflate9_copyright[] = 1204351a92ecc8429c999acbfc5dfe5aa8bee1d19dElliott Hughes " inflate9 1.2.8 Copyright 1995-2013 Mark Adler "; 139e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project/* 149e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project If you use the zlib library in a product, an acknowledgment is welcome 159e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project in the documentation of your product. If for some reason you cannot 169e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project include such an acknowledgment, I would appreciate that you keep this 179e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project copyright string in the executable of your product. 189e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project */ 199e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 209e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project/* 219e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project Build a set of tables to decode the provided canonical Huffman code. 229e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project The code lengths are lens[0..codes-1]. The result starts at *table, 239e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project whose indices are 0..2^bits-1. work is a writable array of at least 249e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project lens shorts, which is used as a work area. type is the type of code 259e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project to be generated, CODES, LENS, or DISTS. On return, zero is success, 269e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project -1 is an invalid code, and +1 means that ENOUGH isn't enough. table 279e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project on return points to the next available entry's address. bits is the 289e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project requested root table index bits, and on return it is the actual root 299e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project table index bits. It will differ if the request is greater than the 309e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project longest code or if it is less than the shortest code. 319e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project */ 329e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Projectint inflate_table9(type, lens, codes, table, bits, work) 339e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Projectcodetype type; 349e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Projectunsigned short FAR *lens; 359e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Projectunsigned codes; 369e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Projectcode FAR * FAR *table; 379e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Projectunsigned FAR *bits; 389e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Projectunsigned short FAR *work; 399e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project{ 409e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned len; /* a code's length in bits */ 419e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned sym; /* index of code symbols */ 429e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned min, max; /* minimum and maximum code lengths */ 439e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned root; /* number of index bits for root table */ 449e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned curr; /* number of index bits for current table */ 459e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned drop; /* code bits to drop for sub-table */ 469e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project int left; /* number of prefix codes available */ 479e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned used; /* code entries in table used */ 489e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned huff; /* Huffman code */ 499e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned incr; /* for incrementing code, index */ 509e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned fill; /* index for replicating entries */ 519e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned low; /* low bits for current root entry */ 529e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned mask; /* mask for low root bits */ 539e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project code this; /* table entry for duplication */ 549e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project code FAR *next; /* next available space in table */ 559e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project const unsigned short FAR *base; /* base value table to use */ 569e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project const unsigned short FAR *extra; /* extra bits table to use */ 579e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project int end; /* use base and extra for symbol > end */ 589e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned short count[MAXBITS+1]; /* number of codes of each length */ 599e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project unsigned short offs[MAXBITS+1]; /* offsets in table for each length */ 609e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project static const unsigned short lbase[31] = { /* Length codes 257..285 base */ 619e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 629e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 639e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 131, 163, 195, 227, 3, 0, 0}; 649e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project static const unsigned short lext[31] = { /* Length codes 257..285 extra */ 659e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 128, 128, 128, 128, 128, 128, 128, 128, 129, 129, 129, 129, 669e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 130, 130, 130, 130, 131, 131, 131, 131, 132, 132, 132, 132, 6704351a92ecc8429c999acbfc5dfe5aa8bee1d19dElliott Hughes 133, 133, 133, 133, 144, 72, 78}; 689e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project static const unsigned short dbase[32] = { /* Distance codes 0..31 base */ 699e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 709e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 719e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 4097, 6145, 8193, 12289, 16385, 24577, 32769, 49153}; 729e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project static const unsigned short dext[32] = { /* Distance codes 0..31 extra */ 739e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 128, 128, 128, 128, 129, 129, 130, 130, 131, 131, 132, 132, 749e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 133, 133, 134, 134, 135, 135, 136, 136, 137, 137, 138, 138, 759e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 139, 139, 140, 140, 141, 141, 142, 142}; 769e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 779e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* 789e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project Process a set of code lengths to create a canonical Huffman code. The 799e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project code lengths are lens[0..codes-1]. Each length corresponds to the 809e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project symbols 0..codes-1. The Huffman code is generated by first sorting the 819e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project symbols by length from short to long, and retaining the symbol order 829e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project for codes with equal lengths. Then the code starts with all zero bits 839e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project for the first code of the shortest length, and the codes are integer 849e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project increments for the same length, and zeros are appended as the length 859e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project increases. For the deflate format, these bits are stored backwards 869e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project from their more natural integer increment ordering, and so when the 879e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project decoding tables are built in the large loop below, the integer codes 889e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project are incremented backwards. 899e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 909e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project This routine assumes, but does not check, that all of the entries in 919e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project lens[] are in the range 0..MAXBITS. The caller must assure this. 929e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1..MAXBITS is interpreted as that code length. zero means that that 939e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project symbol does not occur in this code. 949e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 959e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project The codes are sorted by computing a count of codes for each length, 969e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project creating from that a table of starting indices for each length in the 979e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project sorted table, and then entering the symbols in order in the sorted 989e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project table. The sorted table is work[], with that space being provided by 999e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project the caller. 1009e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1019e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project The length counts are used for other purposes as well, i.e. finding 1029e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project the minimum and maximum length codes, determining if there are any 1039e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project codes at all, checking for a valid set of lengths, and looking ahead 1049e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project at length counts to determine sub-table sizes when building the 1059e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project decoding tables. 1069e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project */ 1079e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1089e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* accumulate lengths for codes (assumes lens[] all in 0..MAXBITS) */ 1099e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project for (len = 0; len <= MAXBITS; len++) 1109e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project count[len] = 0; 1119e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project for (sym = 0; sym < codes; sym++) 1129e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project count[lens[sym]]++; 1139e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1149e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* bound code lengths, force root to be within code lengths */ 1159e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project root = *bits; 1169e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project for (max = MAXBITS; max >= 1; max--) 1179e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (count[max] != 0) break; 1189e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (root > max) root = max; 1199e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (max == 0) return -1; /* no codes! */ 1209e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project for (min = 1; min <= MAXBITS; min++) 1219e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (count[min] != 0) break; 1229e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (root < min) root = min; 1239e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1249e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* check for an over-subscribed or incomplete set of lengths */ 1259e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project left = 1; 1269e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project for (len = 1; len <= MAXBITS; len++) { 1279e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project left <<= 1; 1289e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project left -= count[len]; 1299e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (left < 0) return -1; /* over-subscribed */ 1309e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 1319e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (left > 0 && (type == CODES || max != 1)) 1329e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project return -1; /* incomplete set */ 1339e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1349e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* generate offsets into symbol table for each length for sorting */ 1359e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project offs[1] = 0; 1369e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project for (len = 1; len < MAXBITS; len++) 1379e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project offs[len + 1] = offs[len] + count[len]; 1389e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1399e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* sort symbols by length, by symbol order within each length */ 1409e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project for (sym = 0; sym < codes; sym++) 1419e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (lens[sym] != 0) work[offs[lens[sym]]++] = (unsigned short)sym; 1429e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1439e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* 1449e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project Create and fill in decoding tables. In this loop, the table being 1459e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project filled is at next and has curr index bits. The code being used is huff 1469e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project with length len. That code is converted to an index by dropping drop 1479e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project bits off of the bottom. For codes where len is less than drop + curr, 1489e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project those top drop + curr - len bits are incremented through all values to 1499e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project fill the table with replicated entries. 1509e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1519e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project root is the number of index bits for the root table. When len exceeds 1529e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project root, sub-tables are created pointed to by the root entry with an index 1539e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project of the low root bits of huff. This is saved in low to check for when a 1549e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project new sub-table should be started. drop is zero when the root table is 1559e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project being filled, and drop is root when sub-tables are being filled. 1569e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1579e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project When a new sub-table is needed, it is necessary to look ahead in the 1589e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project code lengths to determine what size sub-table is needed. The length 1599e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project counts are used for this, and so count[] is decremented as codes are 1609e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project entered in the tables. 1619e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1629e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project used keeps track of how many table entries have been allocated from the 163381716e9396b55b1adb8235b020c37344f60ab07Elliott Hughes provided *table space. It is checked for LENS and DIST tables against 164381716e9396b55b1adb8235b020c37344f60ab07Elliott Hughes the constants ENOUGH_LENS and ENOUGH_DISTS to guard against changes in 165381716e9396b55b1adb8235b020c37344f60ab07Elliott Hughes the initial root table size constants. See the comments in inftree9.h 166381716e9396b55b1adb8235b020c37344f60ab07Elliott Hughes for more information. 1679e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1689e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project sym increments through all symbols, and the loop terminates when 1699e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project all codes of length max, i.e. all codes, have been processed. This 1709e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project routine permits incomplete codes, so another loop after this one fills 1719e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project in the rest of the decoding tables with invalid code markers. 1729e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project */ 1739e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1749e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* set up for code type */ 1759e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project switch (type) { 1769e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project case CODES: 1779e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project base = extra = work; /* dummy value--not used */ 1789e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project end = 19; 1799e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project break; 1809e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project case LENS: 1819e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project base = lbase; 1829e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project base -= 257; 1839e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project extra = lext; 1849e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project extra -= 257; 1859e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project end = 256; 1869e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project break; 1879e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project default: /* DISTS */ 1889e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project base = dbase; 1899e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project extra = dext; 1909e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project end = -1; 1919e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 1929e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 1939e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* initialize state for loop */ 1949e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project huff = 0; /* starting code */ 1959e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project sym = 0; /* starting code symbol */ 1969e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project len = min; /* starting code length */ 1979e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project next = *table; /* current table to fill in */ 1989e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project curr = root; /* current table index bits */ 1999e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project drop = 0; /* current bits to drop from code for index */ 2009e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project low = (unsigned)(-1); /* trigger new sub-table when len > root */ 2019e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project used = 1U << root; /* use root table entries */ 2029e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project mask = used - 1; /* mask for comparing low */ 2039e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2049e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* check available table space */ 205381716e9396b55b1adb8235b020c37344f60ab07Elliott Hughes if ((type == LENS && used >= ENOUGH_LENS) || 206381716e9396b55b1adb8235b020c37344f60ab07Elliott Hughes (type == DISTS && used >= ENOUGH_DISTS)) 2079e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project return 1; 2089e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2099e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* process all codes and make table entries */ 2109e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project for (;;) { 2119e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* create table entry */ 2129e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.bits = (unsigned char)(len - drop); 2139e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if ((int)(work[sym]) < end) { 2149e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.op = (unsigned char)0; 2159e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.val = work[sym]; 2169e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 2179e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project else if ((int)(work[sym]) > end) { 2189e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.op = (unsigned char)(extra[work[sym]]); 2199e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.val = base[work[sym]]; 2209e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 2219e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project else { 2229e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.op = (unsigned char)(32 + 64); /* end of block */ 2239e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.val = 0; 2249e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 2259e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2269e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* replicate for those indices with low len bits equal to huff */ 2279e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project incr = 1U << (len - drop); 2289e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project fill = 1U << curr; 2299e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project do { 2309e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project fill -= incr; 2319e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project next[(huff >> drop) + fill] = this; 2329e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } while (fill != 0); 2339e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2349e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* backwards increment the len-bit code huff */ 2359e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project incr = 1U << (len - 1); 2369e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project while (huff & incr) 2379e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project incr >>= 1; 2389e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (incr != 0) { 2399e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project huff &= incr - 1; 2409e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project huff += incr; 2419e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 2429e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project else 2439e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project huff = 0; 2449e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2459e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* go to next symbol, update count, len */ 2469e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project sym++; 2479e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (--(count[len]) == 0) { 2489e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (len == max) break; 2499e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project len = lens[work[sym]]; 2509e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 2519e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2529e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* create new sub-table if needed */ 2539e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (len > root && (huff & mask) != low) { 2549e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* if first time, transition to sub-tables */ 2559e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (drop == 0) 2569e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project drop = root; 2579e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2589e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* increment past last table */ 2599e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project next += 1U << curr; 2609e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2619e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* determine length of next table */ 2629e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project curr = len - drop; 2639e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project left = (int)(1 << curr); 2649e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project while (curr + drop < max) { 2659e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project left -= count[curr + drop]; 2669e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (left <= 0) break; 2679e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project curr++; 2689e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project left <<= 1; 2699e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 2709e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2719e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* check for enough space */ 2729e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project used += 1U << curr; 273381716e9396b55b1adb8235b020c37344f60ab07Elliott Hughes if ((type == LENS && used >= ENOUGH_LENS) || 274381716e9396b55b1adb8235b020c37344f60ab07Elliott Hughes (type == DISTS && used >= ENOUGH_DISTS)) 2759e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project return 1; 2769e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2779e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* point entry in root table to sub-table */ 2789e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project low = huff & mask; 2799e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project (*table)[low].op = (unsigned char)curr; 2809e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project (*table)[low].bits = (unsigned char)root; 2819e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project (*table)[low].val = (unsigned short)(next - *table); 2829e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 2839e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 2849e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 2859e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* 2869e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project Fill in rest of table for incomplete codes. This loop is similar to the 2879e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project loop above in incrementing huff for table indices. It is assumed that 2889e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project len is equal to curr + drop, so there is no loop needed to increment 2899e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project through high index bits. When the current sub-table is filled, the loop 2909e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project drops back to the root table to fill in any remaining entries there. 2919e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project */ 2929e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.op = (unsigned char)64; /* invalid code marker */ 2939e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.bits = (unsigned char)(len - drop); 2949e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.val = (unsigned short)0; 2959e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project while (huff != 0) { 2969e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* when done with sub-table, drop back to root table */ 2979e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (drop != 0 && (huff & mask) != low) { 2989e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project drop = 0; 2999e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project len = root; 3009e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project next = *table; 3019e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project curr = root; 3029e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project this.bits = (unsigned char)len; 3039e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 3049e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 3059e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* put invalid code marker in table */ 3069e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project next[huff >> drop] = this; 3079e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 3089e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* backwards increment the len-bit code huff */ 3099e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project incr = 1U << (len - 1); 3109e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project while (huff & incr) 3119e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project incr >>= 1; 3129e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project if (incr != 0) { 3139e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project huff &= incr - 1; 3149e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project huff += incr; 3159e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 3169e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project else 3179e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project huff = 0; 3189e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project } 3199e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project 3209e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project /* set return parameters */ 3219e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project *table += used; 3229e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project *bits = root; 3239e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project return 0; 3249e38dfa2f95fce609707a0941f10af9a785288deThe Android Open Source Project} 325