cafe-grader-web

Location: cafe-grader-web/node_modules/tiny-inflate/index.js - annotation

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Commit Description:
prevent multiple place login using uuid cookie
Commit Description:
prevent multiple place login using uuid cookie
References:
r883:327f656f4545 algo
File last commit:
r789:8cd7e8db7e38 default
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node_modules/tiny-inflate/index.js | 375 lines | 9.0 KiB | application/javascript | JavascriptLexer |
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move datatable to yarn
 r789 var TINF_OK = 0;
var TINF_DATA_ERROR = -3;
function Tree() {
this.table = new Uint16Array(16); /* table of code length counts */
this.trans = new Uint16Array(288); /* code -> symbol translation table */
}
function Data(source, dest) {
this.source = source;
this.sourceIndex = 0;
this.tag = 0;
this.bitcount = 0;
this.dest = dest;
this.destLen = 0;
this.ltree = new Tree(); /* dynamic length/symbol tree */
this.dtree = new Tree(); /* dynamic distance tree */
}
/* --------------------------------------------------- *
* -- uninitialized global data (static structures) -- *
* --------------------------------------------------- */
var sltree = new Tree();
var sdtree = new Tree();
/* extra bits and base tables for length codes */
var length_bits = new Uint8Array(30);
var length_base = new Uint16Array(30);
/* extra bits and base tables for distance codes */
var dist_bits = new Uint8Array(30);
var dist_base = new Uint16Array(30);
/* special ordering of code length codes */
var clcidx = new Uint8Array([
16, 17, 18, 0, 8, 7, 9, 6,
10, 5, 11, 4, 12, 3, 13, 2,
14, 1, 15
]);
/* used by tinf_decode_trees, avoids allocations every call */
var code_tree = new Tree();
var lengths = new Uint8Array(288 + 32);
/* ----------------------- *
* -- utility functions -- *
* ----------------------- */
/* build extra bits and base tables */
function tinf_build_bits_base(bits, base, delta, first) {
var i, sum;
/* build bits table */
for (i = 0; i < delta; ++i) bits[i] = 0;
for (i = 0; i < 30 - delta; ++i) bits[i + delta] = i / delta | 0;
/* build base table */
for (sum = first, i = 0; i < 30; ++i) {
base[i] = sum;
sum += 1 << bits[i];
}
}
/* build the fixed huffman trees */
function tinf_build_fixed_trees(lt, dt) {
var i;
/* build fixed length tree */
for (i = 0; i < 7; ++i) lt.table[i] = 0;
lt.table[7] = 24;
lt.table[8] = 152;
lt.table[9] = 112;
for (i = 0; i < 24; ++i) lt.trans[i] = 256 + i;
for (i = 0; i < 144; ++i) lt.trans[24 + i] = i;
for (i = 0; i < 8; ++i) lt.trans[24 + 144 + i] = 280 + i;
for (i = 0; i < 112; ++i) lt.trans[24 + 144 + 8 + i] = 144 + i;
/* build fixed distance tree */
for (i = 0; i < 5; ++i) dt.table[i] = 0;
dt.table[5] = 32;
for (i = 0; i < 32; ++i) dt.trans[i] = i;
}
/* given an array of code lengths, build a tree */
var offs = new Uint16Array(16);
function tinf_build_tree(t, lengths, off, num) {
var i, sum;
/* clear code length count table */
for (i = 0; i < 16; ++i) t.table[i] = 0;
/* scan symbol lengths, and sum code length counts */
for (i = 0; i < num; ++i) t.table[lengths[off + i]]++;
t.table[0] = 0;
/* compute offset table for distribution sort */
for (sum = 0, i = 0; i < 16; ++i) {
offs[i] = sum;
sum += t.table[i];
}
/* create code->symbol translation table (symbols sorted by code) */
for (i = 0; i < num; ++i) {
if (lengths[off + i]) t.trans[offs[lengths[off + i]]++] = i;
}
}
/* ---------------------- *
* -- decode functions -- *
* ---------------------- */
/* get one bit from source stream */
function tinf_getbit(d) {
/* check if tag is empty */
if (!d.bitcount--) {
/* load next tag */
d.tag = d.source[d.sourceIndex++];
d.bitcount = 7;
}
/* shift bit out of tag */
var bit = d.tag & 1;
d.tag >>>= 1;
return bit;
}
/* read a num bit value from a stream and add base */
function tinf_read_bits(d, num, base) {
if (!num)
return base;
while (d.bitcount < 24) {
d.tag |= d.source[d.sourceIndex++] << d.bitcount;
d.bitcount += 8;
}
var val = d.tag & (0xffff >>> (16 - num));
d.tag >>>= num;
d.bitcount -= num;
return val + base;
}
/* given a data stream and a tree, decode a symbol */
function tinf_decode_symbol(d, t) {
while (d.bitcount < 24) {
d.tag |= d.source[d.sourceIndex++] << d.bitcount;
d.bitcount += 8;
}
var sum = 0, cur = 0, len = 0;
var tag = d.tag;
/* get more bits while code value is above sum */
do {
cur = 2 * cur + (tag & 1);
tag >>>= 1;
++len;
sum += t.table[len];
cur -= t.table[len];
} while (cur >= 0);
d.tag = tag;
d.bitcount -= len;
return t.trans[sum + cur];
}
/* given a data stream, decode dynamic trees from it */
function tinf_decode_trees(d, lt, dt) {
var hlit, hdist, hclen;
var i, num, length;
/* get 5 bits HLIT (257-286) */
hlit = tinf_read_bits(d, 5, 257);
/* get 5 bits HDIST (1-32) */
hdist = tinf_read_bits(d, 5, 1);
/* get 4 bits HCLEN (4-19) */
hclen = tinf_read_bits(d, 4, 4);
for (i = 0; i < 19; ++i) lengths[i] = 0;
/* read code lengths for code length alphabet */
for (i = 0; i < hclen; ++i) {
/* get 3 bits code length (0-7) */
var clen = tinf_read_bits(d, 3, 0);
lengths[clcidx[i]] = clen;
}
/* build code length tree */
tinf_build_tree(code_tree, lengths, 0, 19);
/* decode code lengths for the dynamic trees */
for (num = 0; num < hlit + hdist;) {
var sym = tinf_decode_symbol(d, code_tree);
switch (sym) {
case 16:
/* copy previous code length 3-6 times (read 2 bits) */
var prev = lengths[num - 1];
for (length = tinf_read_bits(d, 2, 3); length; --length) {
lengths[num++] = prev;
}
break;
case 17:
/* repeat code length 0 for 3-10 times (read 3 bits) */
for (length = tinf_read_bits(d, 3, 3); length; --length) {
lengths[num++] = 0;
}
break;
case 18:
/* repeat code length 0 for 11-138 times (read 7 bits) */
for (length = tinf_read_bits(d, 7, 11); length; --length) {
lengths[num++] = 0;
}
break;
default:
/* values 0-15 represent the actual code lengths */
lengths[num++] = sym;
break;
}
}
/* build dynamic trees */
tinf_build_tree(lt, lengths, 0, hlit);
tinf_build_tree(dt, lengths, hlit, hdist);
}
/* ----------------------------- *
* -- block inflate functions -- *
* ----------------------------- */
/* given a stream and two trees, inflate a block of data */
function tinf_inflate_block_data(d, lt, dt) {
while (1) {
var sym = tinf_decode_symbol(d, lt);
/* check for end of block */
if (sym === 256) {
return TINF_OK;
}
if (sym < 256) {
d.dest[d.destLen++] = sym;
} else {
var length, dist, offs;
var i;
sym -= 257;
/* possibly get more bits from length code */
length = tinf_read_bits(d, length_bits[sym], length_base[sym]);
dist = tinf_decode_symbol(d, dt);
/* possibly get more bits from distance code */
offs = d.destLen - tinf_read_bits(d, dist_bits[dist], dist_base[dist]);
/* copy match */
for (i = offs; i < offs + length; ++i) {
d.dest[d.destLen++] = d.dest[i];
}
}
}
}
/* inflate an uncompressed block of data */
function tinf_inflate_uncompressed_block(d) {
var length, invlength;
var i;
/* unread from bitbuffer */
while (d.bitcount > 8) {
d.sourceIndex--;
d.bitcount -= 8;
}
/* get length */
length = d.source[d.sourceIndex + 1];
length = 256 * length + d.source[d.sourceIndex];
/* get one's complement of length */
invlength = d.source[d.sourceIndex + 3];
invlength = 256 * invlength + d.source[d.sourceIndex + 2];
/* check length */
if (length !== (~invlength & 0x0000ffff))
return TINF_DATA_ERROR;
d.sourceIndex += 4;
/* copy block */
for (i = length; i; --i)
d.dest[d.destLen++] = d.source[d.sourceIndex++];
/* make sure we start next block on a byte boundary */
d.bitcount = 0;
return TINF_OK;
}
/* inflate stream from source to dest */
function tinf_uncompress(source, dest) {
var d = new Data(source, dest);
var bfinal, btype, res;
do {
/* read final block flag */
bfinal = tinf_getbit(d);
/* read block type (2 bits) */
btype = tinf_read_bits(d, 2, 0);
/* decompress block */
switch (btype) {
case 0:
/* decompress uncompressed block */
res = tinf_inflate_uncompressed_block(d);
break;
case 1:
/* decompress block with fixed huffman trees */
res = tinf_inflate_block_data(d, sltree, sdtree);
break;
case 2:
/* decompress block with dynamic huffman trees */
tinf_decode_trees(d, d.ltree, d.dtree);
res = tinf_inflate_block_data(d, d.ltree, d.dtree);
break;
default:
res = TINF_DATA_ERROR;
}
if (res !== TINF_OK)
throw new Error('Data error');
} while (!bfinal);
if (d.destLen < d.dest.length) {
if (typeof d.dest.slice === 'function')
return d.dest.slice(0, d.destLen);
else
return d.dest.subarray(0, d.destLen);
}
return d.dest;
}
/* -------------------- *
* -- initialization -- *
* -------------------- */
/* build fixed huffman trees */
tinf_build_fixed_trees(sltree, sdtree);
/* build extra bits and base tables */
tinf_build_bits_base(length_bits, length_base, 4, 3);
tinf_build_bits_base(dist_bits, dist_base, 2, 1);
/* fix a special case */
length_bits[28] = 0;
length_base[28] = 258;
module.exports = tinf_uncompress;