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fixes for the huffman decoder

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This commit is contained in:
Andreas Gal 2011-05-11 16:30:30 -07:00
parent 9543128796
commit 2326832f49
1 changed files with 39 additions and 8 deletions
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47
pdf.js
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@ -117,6 +117,39 @@ var FlateStream = (function() {
[0, 258]
];
const distDecode = [
[0, 1],
[0, 2],
[0, 3],
[0, 4],
[1, 5],
[1, 7],
[2, 9],
[2, 13],
[3, 17],
[3, 25],
[4, 33],
[4, 49],
[5, 65],
[5, 97],
[6, 129],
[6, 193],
[7, 257],
[7, 385],
[8, 513],
[8, 769],
[9, 1025],
[9, 1537],
[10, 2049],
[10, 3073],
[11, 4097],
[11, 6145],
[12, 8193],
[12, 12289],
[13, 16385],
[13, 24577]
];
const fixedLitCodeTab = [[
[7, 0x0100],
[8, 0x0050],
@ -778,7 +811,7 @@ var FlateStream = (function() {
var size = 1 << maxLen;
var codes = new Array(size);
for (var len = 1, code = 0, skip = 2;
len < maxLen;
len <= maxLen;
++len, code <<= 1, skip <<= 1) {
for (var val = 0; val < n; ++val) {
if (lengths[val] == len) {
@ -854,8 +887,6 @@ var FlateStream = (function() {
var i = 0;
while (i < numCodeLenCodes)
codeLenCodeLengths[codeLenCodeMap[i++]] = this.getBits(3);
while (i < codeLenCodeMap.length)
codeLenCodeLengths[i++] = 0;
var codeLenCodeTab = this.generateHuffmanTable(codeLenCodeLengths);
// built the literal and distance code tables
@ -864,18 +895,18 @@ var FlateStream = (function() {
var codes = numLitCodes + numDistCodes;
var codeLengths = new Array(codes);
while (i < codes) {
function repeat(array, i, len, offset, what) {
var repeat = this.getBits(len) + offset;
function repeat(stream, array, i, len, offset, what) {
var repeat = stream.getBits(len) + offset;
while (repeat-- > 0)
array[i++] = what;
}
var code = this.getCode(codeLenCodeTab);
if (code == 16) {
repeat(codeLengths, i, 2, 3, len);
repeat(this, codeLengths, i, 2, 3, len);
} else if (code == 17) {
repeat(codeLengths, i, 3, 3, len = 0);
repeat(this, codeLengths, i, 3, 3, len = 0);
} else if (code == 18) {
repeat(codeLengths, i, 7, 11, len = 0);
repeat(this, codeLengths, i, 7, 11, len = 0);
} else {
codeLengths[i++] = len = code;
}