Decompress bzip data in the browser

This commit is contained in:
Marcin Kulik 2012-03-03 19:43:38 +01:00
parent b3e8fbb7df
commit 1062aa3d01
5 changed files with 446 additions and 5 deletions

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@ -9,7 +9,6 @@ gem 'confstruct'
gem 'omniauth'
gem 'omniauth-twitter'
gem 'omniauth-github'
gem 'bzip2-ruby'
# Gems used only for assets and not required
# in production environments by default.

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@ -33,7 +33,6 @@ GEM
arel (3.0.0)
awesome_print (0.4.0)
builder (3.0.0)
bzip2-ruby (0.2.7)
capybara (1.1.2)
mime-types (>= 1.16)
nokogiri (>= 1.3.3)
@ -205,7 +204,6 @@ PLATFORMS
DEPENDENCIES
awesome_print
bzip2-ruby
capybara
carrierwave
coffee-rails

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@ -33,7 +33,10 @@ class AsciiIo.Movie
data: ->
unless @_data
@_data = eval "'" + @model.get('escaped_stdout_data') + "'"
d = @model.get('escaped_stdout_data')
d = eval "'" + d + "'"
d = ArchUtils.bz2.decode(d)
@_data = d
@_data

441
app/assets/javascripts/vendor/bzip2.js vendored Normal file
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@ -0,0 +1,441 @@
/**
* this is a port of pyflate
* @url http://www.paul.sladen.org/projects/pyflate/
* @author kirilloid
* @license CC-SA 3.0
* @usage ArchUtils.bz2.decode(str)
* @example ArchUtils.bz2.decode(
* "BZh91AY&SYN\xEC\xE86\0\0\2Q\x80\0\x10@\0\6D\x90\x80 " +
* "\x001\6LA\1\xA7\xA9\xA5\x80\xBB\x941\xF8\xBB\x92)\xC2\x84\x82wgA\xB0"
* ) == "hello world\n";
*/
var ArchUtils = (function(){
'use strict';
// python functions
function ord(c) { return String(c).charCodeAt(); }
function chr(n) { return String.fromCharCode(n); }
function sum(l) { return l.reduce(function(a,b){return a+b}, 0); }
// NOTE: for in loop works another way in js and iterates over keys
// therefore you can't use for (x in range(...)) the same way as in python
function range(start, stop, step) {
switch(arguments.length) {
case 0: return [];
case 1: stop = start; start = 0; step = 1; break;
case 2: step = 1;
}
if ((stop - start) * step < 0) return [];
var a = [];
if (start < stop) {
for (var i = start; i < stop; i += step) { a.push(i); }
} else {
for (var i = start; i > stop; i += step) { a.push(i); }
}
return a;
}
/**
* bwt_reverse code from wikipedia (slightly modified)
* @url http://en.wikipedia.org/wiki/Burrows%E2%80%93Wheeler_transform
* @license: CC-SA 3.0
*/
function bwt_reverse(src, primary) {
var len = src.length;
if (primary >= len) throw RangeError("Out of bound");
if (primary < 0) throw RangeError("Out of bound");
if (typeof src == 'string') {
var A = src.split('');
} else {
var A = src;
src = src.join('');
}
A.sort();
var start = {};
for (var i = len-1; i >= 0; i--) start[A[i]] = i;
var links = [];
for (i = 0; i < len; i++) links.push(start[src[i]]++);
var i, first = A[i = primary], ret = [];
//while (i != primary) {
for (var j = 1; j < len; j++) {
ret.push(A[i = links[i]]);
}
return first + ret.reverse().join('');
}
function move_to_front(a, c) {
var v = a[c];
for (var i = c; i > 0; a[i] = a[--i]);
a[0] = v;
}
/**
* @class BitfieldBase
* base class for bit-precision reading from stream
*/
var BitfieldBase = function() {
// init
this.init = function(x) {
this._masks = [];
for (var i = 0; i < 31; i++) this._masks[i] = (1 << i) - 1;
this._masks[31] = -0x80000000;
if (x instanceof BitfieldBase) {
this.f = x.f;
this.bits = x.bits;
this.bitfield = x.bitfield;
this.count = x.count;
} else {
this.f = x;
this.bits = 0;
this.bitfield = 0x0;
this.count = 0;
}
}
// FIXME: this will throw an Exception when one tries to read zero-length string
this._read = function(n) {
var s = this.f.substr(this.count, n);
if (!s) throw RangeError("Length Error");
this.count += s.length;
return s;
}
this._readByte = function _readByte() {
return this.f.charCodeAt(this.count++);
}
this.needbits = function(n) {
do { this._more() } while (this.bits < n);
}
this.toskip = function() {
return this.bits & 0x7;
}
this.align = function() {
this.readbits(this.toskip());
}
this.dropbits = function(n) {
if (typeof n == 'undefined') n = 8;
while (n >= this.bits && n > 7) {
n -= this.bits;
this.bits = 0;
n -= (this.f._read(n >> 3)).length << 3;
}
if (n) this.readbits(n);
}
this.dropbytes = function(n) {
if (typeof n == 'undefined') n = 1;
this.dropbits(n << 3);
}
// some function for debugging
this.tell = function() {
return [this.count - ((this.bits+7) >> 3), 7 - ((this.bits-1) & 0x7)];
}
}
// not used after all
/* ìar Bitfield = function() {
this._more = function() {
this.bitfield += this._readByte() << this.bits;
this.bits += 8;
}
this.readbits = function(n) {
if (typeof n == 'undefined') n = 8;
if (n >= 32) {
var n2 = n >> 1;
return this.readbits(n2) * (1 << n2) + this.readbits(n - n2);
}
if (n > this.bits)
this.needbits(n);
var r = this.bitfield & this._masks[n];
this.bits -= n;
this.bitfield >>= n;
return r;
}
}
Bitfield.prototype = new BitfieldBase();*/
/**
* @class BitfieldBase
* right-sided bitfield for reading bits in byte from right to left
*/
var RBitfield = function() {
this._more = function() {
this.bitfield = (this.bitfield << 8) + this._readByte();
this.bits += 8;
}
// since js truncate args to int32 with bit operators
// we need to specific processing for n >= 32 bits reading
// separate function is created for optimization purposes
this.readbits2 = function readbits2(n) {
if (n >= 32) {
var n2 = n >> 1;
return this.readbits(n2) * (1 << n2) + this.readbits(n - n2);
} else {
return this.readbits(n);
}
}
this.readbits = function readbits(n) {
//if (n > this.bits) this.needbits(n);
// INLINED: needbits
while (this.bits < n) {
this.bitfield = (this.bitfield << 8) + this._readByte();
this.bits += 8;
}
var m = this._masks[n];
var r = (this.bitfield >> (this.bits - n)) & m;
this.bits -= n;
this.bitfield &= ~(m << this.bits);
return r;
}
}
RBitfield.prototype = new BitfieldBase();
/**
* @class HuffmanLength
* utility class, used for comparison of huffman codes
*/
var HuffmanLength = function(code, bits) {
if (typeof bits == "undefined") bits = 0;
this.code = code;
this.bits = bits;
this.symbol = undefined;
this.toString = function() {
return [this.code, this.bits, this.symbol/*, this.reverse_symbol*/];
}
this.valueOf = function() {
return this.bits * 1000 + this.code;
}
}
/**
* @class HuffmanLength
* utility class for working with huffman table
*/
var HuffmanTable = function() {
this.init = function initHuffmanTable(bootstrap) {
var l = [];
var b = bootstrap[0];
var start = b[0], bits = b[1];
for (var p = 1; p < bootstrap.length; p++) {
var finish = bootstrap[p][0], endbits = bootstrap[p][1];
if (bits)
for (var code = start; code < finish; code++)
l.push(new HuffmanLength(code, bits));
start = finish;
bits = endbits;
if (endbits == -1) break;
}
l.sort(function cmpHuffmanTable(a, b){
return (a.bits - b.bits) || (a.code - b.code);
});
this.table = l;
}
this.populate_huffman_symbols = function() {
var bits = 0;
var symbol = -1;
// faht = Fast Access Huffman Table
this.faht = [];
var cb = null;
for (var i = 0; i < this.table.length; i++) {
var x = this.table[i];
symbol += 1;
if (x.bits != bits) {
symbol <<= x.bits - bits;
cb = this.faht[bits = x.bits] = {};
}
cb[x.symbol = symbol] = x;
}
}
this.min_max_bits = function() {
this.min_bits = 16;
this.max_bits = -1;
this.table.forEach(function(x){
if (x.bits < this.min_bits) this.min_bits = x.bits;
if (x.bits > this.max_bits) this.max_bits = x.bits;
}, this);
}
}
var OrderedHuffmanTable = function() {
this.init = function(lengths) {
var l = lengths.length;
var z = [];
for (var i = 0; i < l; i++) {
z.push([i, lengths[i]]);
}
z.push([l, -1]);
OrderedHuffmanTable.prototype.init.call(this, z);
}
}
OrderedHuffmanTable.prototype = new HuffmanTable();
// unpackedSize is ignored here but added for uniformity
// this param simplifies Java (applet) implementation of bzip decoder
return ({ bz2: { decode: function(input, unpackedSize) {
var b = new RBitfield();
b.init(input);
b.readbits(16);
var method = b.readbits(8);
if (method != ord('h')) {
throw "Unknown (not type 'h'uffman Bzip2) compression method";
}
var blocksize = b.readbits(8);
if (ord('1') <= blocksize
&& blocksize <= ord('9')) {
blocksize -= ord('0');
} else {
throw "Unknown (not size '0'-'9') Bzip2 blocksize";
}
function getUsedCharTable(b) {
var a = [];
var used_groups = b.readbits(16);
for (var m1 = 1 << 15; m1 > 0; m1 >>= 1) {
if (!(used_groups & m1)) {
for (var i = 0; i < 16; i++) a.push(false);
continue;
}
var used_chars = b.readbits(16);
for (var m2 = 1 << 15; m2 > 0; m2 >>= 1) {
a.push( Boolean(used_chars & m2) );
}
}
return a;
}
var out = [];
// TODO: I hope exection may me splitted into chunks
// and run with them in background
function main_loop() { while (true) {
var blocktype = b.readbits2(48);
var crc = b.readbits2(32);
if (blocktype == 0x314159265359) { // (pi)
if (b.readbits(1)) throw "Bzip2 randomised support not implemented";
var pointer = b.readbits(24);
var used = getUsedCharTable(b);
var huffman_groups = b.readbits(3);
if (2 > huffman_groups || huffman_groups > 6)
throw RangeError("Bzip2: Number of Huffman groups not in range 2..6");
var mtf = range(huffman_groups);
var selectors_list = [];
for (var i = 0, selectors_used = b.readbits(15); i < selectors_used; i++) {
// zero-terminated bit runs (0..62) of MTF'ed huffman table
var c = 0;
while (b.readbits(1)) {
if (c++ >= huffman_groups)
throw RangeError("More than max ("+huffman_groups+") groups");
}
move_to_front(mtf, c);
selectors_list.push(mtf[0]);
}
var groups_lengths = [];
var symbols_in_use = sum(used) + 2 // remember RUN[AB] RLE symbols
for (var j = 0; j < huffman_groups; j++) {
var length = b.readbits(5);
var lengths = [];
for (var i = 0; i < symbols_in_use; i++) {
if (length < 0 || length > 20)
throw RangeError("Bzip2 Huffman length code outside range 0..20");
while (b.readbits(1)) length -= (b.readbits(1) * 2) - 1;
lengths.push(length);
}
groups_lengths.push(lengths);
}
var tables = [];
for (var g = 0; g < groups_lengths.length; g++) {
var codes = new OrderedHuffmanTable();
codes.init(groups_lengths[g]);
codes.populate_huffman_symbols();
codes.min_max_bits();
tables.push(codes);
}
var favourites = [];
for (var c = used.length - 1; c >= 0; c--) {
if (used[c]) favourites.push(chr(c));
}
favourites.reverse();
var selector_pointer = 0;
var decoded = 0;
var t;
// Main Huffman loop
var repeat = 0;
var repeat_power = 0;
var buffer = [], r;
while (true) {
if (--decoded <= 0) {
decoded = 50;
if (selector_pointer <= selectors_list.length)
t = tables[selectors_list[selector_pointer++]];
}
// INLINED: find_next_symbol
for (var bb in t.faht) {
if (b.bits < bb) {
b.bitfield = (b.bitfield << 8) + b.f.charCodeAt(b.count++);
b.bits += 8;
}
if (r = t.faht[bb][ b.bitfield >> (b.bits - bb) ]) {
b.bitfield &= b._masks[b.bits -= bb];
r = r.code;
break;
}
}
if (0 <= r && r <= 1) {
if (repeat == 0) repeat_power = 1;
repeat += repeat_power << r;
repeat_power <<= 1;
continue;
} else {
var v = favourites[0];
for ( ; repeat > 0; repeat--) buffer.push(v);
}
if (r == symbols_in_use - 1) { // eof symbol
break;
} else {
// INLINED: move_to_front
var v = favourites[r-1];
for (var i = r-1; i > 0; favourites[i] = favourites[--i]);
buffer.push(favourites[0] = v);
}
}
var nt = bwt_reverse(buffer, pointer);
var done = [];
var i = 0;
var len = nt.length;
// RLE decoding
while (i < len) {
var c = nt.charCodeAt(i);
if ((i < len - 4)
&& nt.charCodeAt(i+1) == c
&& nt.charCodeAt(i+2) == c
&& nt.charCodeAt(i+3) == c) {
var c = nt.charAt(i);
var rep = nt.charCodeAt(i+4)+4;
for (; rep > 0; rep--) done.push(c);
i += 5;
} else {
done.push(nt[i++]);
}
}
out.push(done.join(''));
} else if (blocktype == 0x177245385090) { // sqrt(pi)
b.align();
break;
} else {
throw "Illegal Bzip2 blocktype = 0x" + blocktype.toString(16);
}
} }
main_loop();
return out.join('');
} } });
})();

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@ -27,7 +27,7 @@ class Asciicast < ActiveRecord::Base
def escaped_stdout_data
if data = stdout.read
Bzip2.uncompress(data).bytes.map { |b| '\x' + format('%02x', b) }.join
data.bytes.map { |b| '\x' + format('%02x', b) }.join
else
nil
end