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Diffstat (limited to 'webclients/novnc/vendor/pako/lib/zlib/inftrees.js')
| -rw-r--r-- | webclients/novnc/vendor/pako/lib/zlib/inftrees.js | 322 |
1 files changed, 322 insertions, 0 deletions
diff --git a/webclients/novnc/vendor/pako/lib/zlib/inftrees.js b/webclients/novnc/vendor/pako/lib/zlib/inftrees.js new file mode 100644 index 0000000..78b7c9e --- /dev/null +++ b/webclients/novnc/vendor/pako/lib/zlib/inftrees.js @@ -0,0 +1,322 @@ +import * as utils from "../utils/common.js"; + +var MAXBITS = 15; +var ENOUGH_LENS = 852; +var ENOUGH_DISTS = 592; +//var ENOUGH = (ENOUGH_LENS+ENOUGH_DISTS); + +var CODES = 0; +var LENS = 1; +var DISTS = 2; + +var lbase = [ /* Length codes 257..285 base */ + 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, + 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0 +]; + +var lext = [ /* Length codes 257..285 extra */ + 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, + 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 16, 72, 78 +]; + +var dbase = [ /* Distance codes 0..29 base */ + 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, + 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, + 8193, 12289, 16385, 24577, 0, 0 +]; + +var dext = [ /* Distance codes 0..29 extra */ + 16, 16, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 22, 22, + 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, + 28, 28, 29, 29, 64, 64 +]; + +export default function inflate_table(type, lens, lens_index, codes, table, table_index, work, opts) +{ + var bits = opts.bits; + //here = opts.here; /* table entry for duplication */ + + var len = 0; /* a code's length in bits */ + var sym = 0; /* index of code symbols */ + var min = 0, max = 0; /* minimum and maximum code lengths */ + var root = 0; /* number of index bits for root table */ + var curr = 0; /* number of index bits for current table */ + var drop = 0; /* code bits to drop for sub-table */ + var left = 0; /* number of prefix codes available */ + var used = 0; /* code entries in table used */ + var huff = 0; /* Huffman code */ + var incr; /* for incrementing code, index */ + var fill; /* index for replicating entries */ + var low; /* low bits for current root entry */ + var mask; /* mask for low root bits */ + var next; /* next available space in table */ + var base = null; /* base value table to use */ + var base_index = 0; +// var shoextra; /* extra bits table to use */ + var end; /* use base and extra for symbol > end */ + var count = new utils.Buf16(MAXBITS + 1); //[MAXBITS+1]; /* number of codes of each length */ + var offs = new utils.Buf16(MAXBITS + 1); //[MAXBITS+1]; /* offsets in table for each length */ + var extra = null; + var extra_index = 0; + + var here_bits, here_op, here_val; + + /* + Process a set of code lengths to create a canonical Huffman code. The + code lengths are lens[0..codes-1]. Each length corresponds to the + symbols 0..codes-1. The Huffman code is generated by first sorting the + symbols by length from short to long, and retaining the symbol order + for codes with equal lengths. Then the code starts with all zero bits + for the first code of the shortest length, and the codes are integer + increments for the same length, and zeros are appended as the length + increases. For the deflate format, these bits are stored backwards + from their more natural integer increment ordering, and so when the + decoding tables are built in the large loop below, the integer codes + are incremented backwards. + + This routine assumes, but does not check, that all of the entries in + lens[] are in the range 0..MAXBITS. The caller must assure this. + 1..MAXBITS is interpreted as that code length. zero means that that + symbol does not occur in this code. + + The codes are sorted by computing a count of codes for each length, + creating from that a table of starting indices for each length in the + sorted table, and then entering the symbols in order in the sorted + table. The sorted table is work[], with that space being provided by + the caller. + + The length counts are used for other purposes as well, i.e. finding + the minimum and maximum length codes, determining if there are any + codes at all, checking for a valid set of lengths, and looking ahead + at length counts to determine sub-table sizes when building the + decoding tables. + */ + + /* accumulate lengths for codes (assumes lens[] all in 0..MAXBITS) */ + for (len = 0; len <= MAXBITS; len++) { + count[len] = 0; + } + for (sym = 0; sym < codes; sym++) { + count[lens[lens_index + sym]]++; + } + + /* bound code lengths, force root to be within code lengths */ + root = bits; + for (max = MAXBITS; max >= 1; max--) { + if (count[max] !== 0) { break; } + } + if (root > max) { + root = max; + } + if (max === 0) { /* no symbols to code at all */ + //table.op[opts.table_index] = 64; //here.op = (var char)64; /* invalid code marker */ + //table.bits[opts.table_index] = 1; //here.bits = (var char)1; + //table.val[opts.table_index++] = 0; //here.val = (var short)0; + table[table_index++] = (1 << 24) | (64 << 16) | 0; + + + //table.op[opts.table_index] = 64; + //table.bits[opts.table_index] = 1; + //table.val[opts.table_index++] = 0; + table[table_index++] = (1 << 24) | (64 << 16) | 0; + + opts.bits = 1; + return 0; /* no symbols, but wait for decoding to report error */ + } + for (min = 1; min < max; min++) { + if (count[min] !== 0) { break; } + } + if (root < min) { + root = min; + } + + /* check for an over-subscribed or incomplete set of lengths */ + left = 1; + for (len = 1; len <= MAXBITS; len++) { + left <<= 1; + left -= count[len]; + if (left < 0) { + return -1; + } /* over-subscribed */ + } + if (left > 0 && (type === CODES || max !== 1)) { + return -1; /* incomplete set */ + } + + /* generate offsets into symbol table for each length for sorting */ + offs[1] = 0; + for (len = 1; len < MAXBITS; len++) { + offs[len + 1] = offs[len] + count[len]; + } + + /* sort symbols by length, by symbol order within each length */ + for (sym = 0; sym < codes; sym++) { + if (lens[lens_index + sym] !== 0) { + work[offs[lens[lens_index + sym]]++] = sym; + } + } + + /* + Create and fill in decoding tables. In this loop, the table being + filled is at next and has curr index bits. The code being used is huff + with length len. That code is converted to an index by dropping drop + bits off of the bottom. For codes where len is less than drop + curr, + those top drop + curr - len bits are incremented through all values to + fill the table with replicated entries. + + root is the number of index bits for the root table. When len exceeds + root, sub-tables are created pointed to by the root entry with an index + of the low root bits of huff. This is saved in low to check for when a + new sub-table should be started. drop is zero when the root table is + being filled, and drop is root when sub-tables are being filled. + + When a new sub-table is needed, it is necessary to look ahead in the + code lengths to determine what size sub-table is needed. The length + counts are used for this, and so count[] is decremented as codes are + entered in the tables. + + used keeps track of how many table entries have been allocated from the + provided *table space. It is checked for LENS and DIST tables against + the constants ENOUGH_LENS and ENOUGH_DISTS to guard against changes in + the initial root table size constants. See the comments in inftrees.h + for more information. + + sym increments through all symbols, and the loop terminates when + all codes of length max, i.e. all codes, have been processed. This + routine permits incomplete codes, so another loop after this one fills + in the rest of the decoding tables with invalid code markers. + */ + + /* set up for code type */ + // poor man optimization - use if-else instead of switch, + // to avoid deopts in old v8 + if (type === CODES) { + base = extra = work; /* dummy value--not used */ + end = 19; + + } else if (type === LENS) { + base = lbase; + base_index -= 257; + extra = lext; + extra_index -= 257; + end = 256; + + } else { /* DISTS */ + base = dbase; + extra = dext; + end = -1; + } + + /* initialize opts for loop */ + huff = 0; /* starting code */ + sym = 0; /* starting code symbol */ + len = min; /* starting code length */ + next = table_index; /* current table to fill in */ + curr = root; /* current table index bits */ + drop = 0; /* current bits to drop from code for index */ + low = -1; /* trigger new sub-table when len > root */ + used = 1 << root; /* use root table entries */ + mask = used - 1; /* mask for comparing low */ + + /* check available table space */ + if ((type === LENS && used > ENOUGH_LENS) || + (type === DISTS && used > ENOUGH_DISTS)) { + return 1; + } + + /* process all codes and make table entries */ + for (;;) { + /* create table entry */ + here_bits = len - drop; + if (work[sym] < end) { + here_op = 0; + here_val = work[sym]; + } + else if (work[sym] > end) { + here_op = extra[extra_index + work[sym]]; + here_val = base[base_index + work[sym]]; + } + else { + here_op = 32 + 64; /* end of block */ + here_val = 0; + } + + /* replicate for those indices with low len bits equal to huff */ + incr = 1 << (len - drop); + fill = 1 << curr; + min = fill; /* save offset to next table */ + do { + fill -= incr; + table[next + (huff >> drop) + fill] = (here_bits << 24) | (here_op << 16) | here_val |0; + } while (fill !== 0); + + /* backwards increment the len-bit code huff */ + incr = 1 << (len - 1); + while (huff & incr) { + incr >>= 1; + } + if (incr !== 0) { + huff &= incr - 1; + huff += incr; + } else { + huff = 0; + } + + /* go to next symbol, update count, len */ + sym++; + if (--count[len] === 0) { + if (len === max) { break; } + len = lens[lens_index + work[sym]]; + } + + /* create new sub-table if needed */ + if (len > root && (huff & mask) !== low) { + /* if first time, transition to sub-tables */ + if (drop === 0) { + drop = root; + } + + /* increment past last table */ + next += min; /* here min is 1 << curr */ + + /* determine length of next table */ + curr = len - drop; + left = 1 << curr; + while (curr + drop < max) { + left -= count[curr + drop]; + if (left <= 0) { break; } + curr++; + left <<= 1; + } + + /* check for enough space */ + used += 1 << curr; + if ((type === LENS && used > ENOUGH_LENS) || + (type === DISTS && used > ENOUGH_DISTS)) { + return 1; + } + + /* point entry in root table to sub-table */ + low = huff & mask; + /*table.op[low] = curr; + table.bits[low] = root; + table.val[low] = next - opts.table_index;*/ + table[low] = (root << 24) | (curr << 16) | (next - table_index) |0; + } + } + + /* fill in remaining table entry if code is incomplete (guaranteed to have + at most one remaining entry, since if the code is incomplete, the + maximum code length that was allowed to get this far is one bit) */ + if (huff !== 0) { + //table.op[next + huff] = 64; /* invalid code marker */ + //table.bits[next + huff] = len - drop; + //table.val[next + huff] = 0; + table[next + huff] = ((len - drop) << 24) | (64 << 16) |0; + } + + /* set return parameters */ + //opts.table_index += used; + opts.bits = root; + return 0; +}; |