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cleanup; rename vars; fix deflate

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rolux 2012-05-25 10:37:48 +02:00
parent a393591741
commit ad3b50cb82
1 changed files with 354 additions and 387 deletions
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343
source/Ox/js/Encoding.js
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@ -1,91 +1,50 @@
'use strict';
(function() {
function cap(width, height) {
// returns maximum encoding capacity of an image
return parseInt(width * height * 3/8) - 4;
}
function seek(data, px) {
// returns this, or the next, opaque pixel
while (data[px * 4 + 3] < 255) {
if (++px * 4 == data.length) {
throwPNGError('de');
}
}
return px;
}
function xor(byte) {
// returns "1"-bits-in-byte % 2
// use: num.toString(2).replace(/0/g, '').length % 2
var xor = 0;
Ox.range(8).forEach(function(i) {
xor ^= byte >> i & 1;
});
return xor;
}
function throwPNGError(str) {
throw new RangeError(
'PNG codec can\'t ' +
(str == 'en' ? 'encode data' : 'decode image')
);
}
function throwUTF8Error(byte, pos) {
throw new RangeError(
'UTF-8 codec can\'t decode byte 0x' +
byte.toString(16).toUpperCase() + ' at position ' + pos
);
}
/*@
Ox.encodeBase26 <b> Encode a number as bijective base26
/*@
Ox.encodeBase26 <b> Encode a number as bijective base26
See <a href="http://en.wikipedia.org/wiki/Bijective_numeration">
Bijective numeration</a>.
> Ox.encodeBase26(4461)
'FOO'
@*/
Ox.encodeBase26 = function(num) {
var ret = '';
while (num) {
ret = String.fromCharCode(64 + num % 26) + ret;
num = parseInt(num / 26);
@*/
Ox.encodeBase26 = function(number) {
var string = '';
while (number) {
string = String.fromCharCode(64 + number % 26) + string;
number = parseInt(number / 26);
}
return ret;
};
return string;
};
/*@
Ox.decodeBase26 <f> Decodes a bijective base26-encoded number
/*@
Ox.decodeBase26 <f> Decodes a bijective base26-encoded number
See <a href="http://en.wikipedia.org/wiki/Bijective_numeration">
Bijective numeration</a>.
> Ox.decodeBase26('foo')
4461
@*/
Ox.decodeBase26 = function(str) {
return str.toUpperCase().split('').reverse().reduce(function(p, v, i) {
return p + (v.charCodeAt(0) - 64) * Math.pow(26, i);
@*/
Ox.decodeBase26 = function(string) {
return string.toUpperCase().split('').reverse().reduce(function(p, c, i) {
return p + (c.charCodeAt(0) - 64) * Math.pow(26, i);
}, 0);
};
};
/*@
Ox.encodeBase32 <b> Encode a number as base32
/*@
Ox.encodeBase32 <b> Encode a number as base32
See <a href="http://www.crockford.com/wrmg/base32.html">Base 32</a>.
> Ox.encodeBase32(15360)
'F00'
> Ox.encodeBase32(33819)
'110V'
@*/
Ox.encodeBase32 = function(num) {
return Ox.map(num.toString(32), function(char) {
return Ox.BASE_32_DIGITS[parseInt(char, 32)];
@*/
Ox.encodeBase32 = function(number) {
return Ox.map(number.toString(32), function(character) {
return Ox.BASE_32_DIGITS[parseInt(character, 32)];
});
};
};
/*@
Ox.decodeBase32 <f> Decodes a base32-encoded number
/*@
Ox.decodeBase32 <f> Decodes a base32-encoded number
See <a href="http://www.crockford.com/wrmg/base32.html">Base 32</a>.
> Ox.decodeBase32('foo')
15360
@ -93,86 +52,86 @@
33819
> Ox.decodeBase32('?').toString()
'NaN'
@*/
Ox.decodeBase32 = function(str) {
return parseInt(Ox.map(str.toUpperCase(), function(char) {
@*/
Ox.decodeBase32 = function(string) {
return parseInt(Ox.map(string.toUpperCase(), function(character) {
var index = Ox.BASE_32_DIGITS.indexOf(
Ox.BASE_32_ALIASES[char] || char
Ox.BASE_32_ALIASES[character] || character
);
return (index == -1 ? ' ' : index).toString(32);
}), 32);
};
};
/*@
Ox.encodeBase64 <f> Encode a number as base64
/*@
Ox.encodeBase64 <f> Encode a number as base64
> Ox.encodeBase64(32394)
'foo'
@*/
Ox.encodeBase64 = function(num) {
return btoa(Ox.encodeBase256(num)).replace(/=/g, '');
};
@*/
Ox.encodeBase64 = function(number) {
return btoa(Ox.encodeBase256(number)).replace(/=/g, '');
};
/*@
Ox.decodeBase64 <f> Decodes a base64-encoded number
/*@
Ox.decodeBase64 <f> Decodes a base64-encoded number
> Ox.decodeBase64('foo')
32394
@*/
Ox.decodeBase64 = function(str) {
return Ox.decodeBase256(atob(str));
};
@*/
Ox.decodeBase64 = function(string) {
return Ox.decodeBase256(atob(string));
};
/*@
Ox.encodeBase128 <f> Encode a number as base128
/*@
Ox.encodeBase128 <f> Encode a number as base128
> Ox.encodeBase128(1685487)
'foo'
@*/
Ox.encodeBase128 = function(num) {
var str = '';
while (num) {
str = Ox.char(num & 127) + str;
num >>= 7;
@*/
Ox.encodeBase128 = function(number) {
var string = '';
while (number) {
string = Ox.char(number & 127) + string;
number >>= 7;
}
return str;
};
return string;
};
/*@
Ox.decodeBase128 <f> Decode a base128-encoded number
/*@
Ox.decodeBase128 <f> Decode a base128-encoded number
> Ox.decodeBase128('foo')
1685487
@*/
Ox.decodeBase128 = function(str) {
return str.split('').reverse().reduce(function(p, v, i) {
return p + (v.charCodeAt(0) << i * 7);
@*/
Ox.decodeBase128 = function(string) {
return string.split('').reverse().reduce(function(p, c, i) {
return p + (c.charCodeAt(0) << i * 7);
}, 0);
};
};
/*@
Ox.encodeBase256 <f> Encode a number as base256
/*@
Ox.encodeBase256 <f> Encode a number as base256
> Ox.encodeBase256(6713199)
'foo'
@*/
Ox.encodeBase256 = function(num) {
var str = '';
while (num) {
str = Ox.char(num & 255) + str;
num >>= 8;
@*/
Ox.encodeBase256 = function(number) {
var string = '';
while (number) {
string = Ox.char(number & 255) + string;
number >>= 8;
}
return str;
};
return string;
};
/*@
Ox.decodeBase256 <f> Decode a base256-encoded number
/*@
Ox.decodeBase256 <f> Decode a base256-encoded number
> Ox.decodeBase256('foo')
6713199
@*/
Ox.decodeBase256 = function(str) {
return str.split('').reverse().reduce(function(p, v, i) {
return p + (v.charCodeAt(0) << i * 8);
@*/
Ox.decodeBase256 = function(string) {
return string.split('').reverse().reduce(function(p, c, i) {
return p + (c.charCodeAt(0) << i * 8);
}, 0);
};
};
/*@
Ox.encodeDeflate <f> Encodes a string, using deflate
/*@
Ox.encodeDeflate <f> Encodes a string, using deflate
Since PNGs are deflate-encoded, the <code>canvas</code> object's
<code>toDataURL</code> method provides an efficient implementation.
The string is encoded as UTF-8 and written to the RGB channels of a
@ -181,44 +140,47 @@
(str) -> <s> The encoded string
str <s> The string to be encoded
# Test with: Ox.decodeDeflate(Ox.encodeDeflate('foo'), alert)
@*/
@*/
Ox.encodeDeflate = function(str, callback) {
Ox.encodeDeflate = function(string, callback) {
// Make sure we can encode the full unicode range of characters.
str = Ox.encodeUTF8(str);
string = Ox.encodeUTF8(string);
// We can only safely write to RGB, so we need 1 pixel for 3 bytes.
// The string length may not be a multiple of 3, so we need to encode
// the number of padding bytes (1 byte), the string, and non-0-bytes
// as padding, so that the combined length becomes a multiple of 3.
var len = 1 + str.length, c = Ox.canvas(Math.ceil(len / 3), 1),
data, idat, pad = (3 - len % 3) % 3;
str = Ox.char(pad) + str + Ox.repeat('\u00FF', pad);
var length = 1 + string.length, c = Ox.canvas(Math.ceil(length / 3), 1),
data, idat, pad = (3 - length % 3) % 3;
string = Ox.char(pad) + string + Ox.repeat('\u00FF', pad);
Ox.loop(c.data.length, function(i) {
// Write character codes into RGB, and 255 into ALPHA
c.data[i] = i % 4 < 3 ? str.charCodeAt(i - parseInt(i / 4)) : 255;
c.data[i] = i % 4 < 3 ? string.charCodeAt(i - parseInt(i / 4)) : 255;
});
c.context.putImageData(c.imageData, 0, 0);
// Get the PNG data from the data URL and decode it from base64.
str = atob(c.canvas.toDataURL().split(',')[1]);
string = atob(c.canvas.toDataURL().split(',')[1]);
// Discard bytes 0 to 15 (8 bytes PNG signature, 4 bytes IHDR length, 4
// bytes IHDR name), keep bytes 16 to 19 (width), discard bytes 20 to 29
// (4 bytes height, 5 bytes flags), keep bytes 29 to 32 (IHDR checksum),
// keep the rest (IDAT chunks), discard the last 12 bytes (IEND chunk).
data = str.slice(16, 20) + str.slice(29, 33);
idat = str.slice(33, -45);
data = string.slice(16, 20) + string.slice(29, 33);
idat = string.slice(33, -12);
while (idat) {
// Each IDAT chunk is 4 bytes length, 4 bytes name, length bytes
// data and 4 bytes checksum. We can discard the name parts.
len = idat.slice(0, 4);
data += len + idat.slice(8, 12 + (len = Ox.decodeBase256(len)));
idat = idat.slice(12 + len);
length = idat.slice(0, 4);
data += length + idat.slice(8, 12 + (
length = Ox.decodeBase256(length)
));
idat = idat.slice(12 + length);
}
// Allow for async use, symmetrical to Ox.decodeDeflate
callback && callback(data);
return data;
};
};
/*@
Ox.decodeDeflate <f> Decodes an deflate-encoded string
/*@
Ox.decodeDeflate <f> Decodes an deflate-encoded string
Since PNGs are deflate-encoded, the <code>canvas</code> object's
<code>drawImage</code> method provides an efficient implementation. The
string will be wrapped as a PNG dataURL, encoded as base64, and drawn
@ -228,65 +190,67 @@
str <s> The string to be decoded
callback <f> Callback function
str <s> The decoded string
@*/
@*/
Ox.decodeDeflate = function(str, callback) {
Ox.decodeDeflate = function(string, callback) {
var image = new Image(),
// PNG file signature and IHDR chunk
data = '\u0089PNG\r\n\u001A\n\u0000\u0000\u0000\u000DIHDR'
+ str.slice(0, 4) + '\u0000\u0000\u0000\u0001'
+ '\u0008\u0006\u0000\u0000\u0000' + str.slice(4, 8),
+ string.slice(0, 4) + '\u0000\u0000\u0000\u0001'
+ '\u0008\u0006\u0000\u0000\u0000' + string.slice(4, 8),
// IDAT chunks
idat = str.slice(8), len;
idat = string.slice(8), length;
function error() {
throw new RangeError('Deflate codec can\'t decode data.');
}
while (idat) {
// Reinsert the IDAT chunk names
len = idat.slice(0, 4);
data += len + 'IDAT' + idat.slice(4, 8 + (len = Ox.decodeBase256(len)));
idat = idat.slice(8 + len);
length = idat.slice(0, 4);
data += length + 'IDAT' + idat.slice(4, 8 + (
length = Ox.decodeBase256(length)
));
idat = idat.slice(8 + length);
}
// IEND chunk
data += '\u0000\u0000\u0000\u0000IEND\u00AE\u0042\u0060\u0082';
// Unfortunately, we can't synchronously set the source of an image,
// draw it onto a canvas, and read its data.
image.onload = function() {
str = Ox.toArray(Ox.canvas(image).data).map(function(v, i) {
string = Ox.toArray(Ox.canvas(image).data).map(function(value, index) {
// Read one character per RGB byte, ignore ALPHA.
return i % 4 < 3 ? Ox.char(v) : '';
return index % 4 < 3 ? Ox.char(value) : '';
}).join('');
try {
// Parse the first byte as number of bytes to chop at the end,
// and the rest, without these bytes, as an UTF8-encoded string.
str = Ox.decodeUTF8(str.slice(1, -str.CharCodeAt(0)));
string = Ox.decodeUTF8(string.slice(1, -string.charCodeAt(0)));
} catch (e) {
error();
}
callback(str);
callback(string);
}
image.onerror = error;
image.src = 'data:image/png;base64,' + btoa(data);
};
};
/*@
Ox.encodeHTML <f> HTML-encodes a string
/*@
Ox.encodeHTML <f> HTML-encodes a string
> Ox.encodeHTML('\'<"&">\'')
'&apos;&lt;&quot;&amp;&quot;&gt;&apos;'
> Ox.encodeHTML('äbçdê')
'&#x00E4;b&#x00E7;d&#x00EA;'
@*/
Ox.encodeHTML = function(str) {
@*/
Ox.encodeHTML = function(str) {
return Ox.map(str.toString(), function(v) {
var code = v.charCodeAt(0);
return code < 128
? (v in Ox.HTML_ENTITIES ? Ox.HTML_ENTITIES[v] : v)
: '&#x' + Ox.pad(code.toString(16).toUpperCase(), 4) + ';';
});
};
};
/*@
Ox.decodeHTML <f> Decodes an HTML-encoded string
/*@
Ox.decodeHTML <f> Decodes an HTML-encoded string
> Ox.decodeHTML('&apos;&lt;&quot;&amp;&quot;&gt;&apos;')
'\'<"&">\''
> Ox.decodeHTML('&#x0027;&#x003C;&#x0022;&#x0026;&#x0022;&#x003E;&#x0027;')
@ -297,33 +261,33 @@
'äbçdê'
> Ox.decodeHTML('<b>bold</b>')
'<b>bold</b>'
@*/
Ox.decodeHTML = function(str) {
@*/
Ox.decodeHTML = function(str) {
// relies on dom, but shorter than using this:
// http://www.w3.org/TR/html5/named-character-references.html
return Ox.decodeHTMLEntities(Ox.element('<div>').html(str).html());
};
};
Ox.encodeHTMLEntities = function(str) {
Ox.encodeHTMLEntities = function(str) {
return str.replace(
new RegExp('(' + Object.keys(Ox.HTML_ENTITIES).join('|') + ')', 'g'),
function(match) {
return Ox.HTML_ENTITIES[match];
}
);
};
};
Ox.decodeHTMLEntities = function(str) {
Ox.decodeHTMLEntities = function(str) {
return str.replace(
new RegExp('(' + Ox.values(Ox.HTML_ENTITIES).join('|') + ')', 'g'),
function(match) {
return Ox.keyOf(Ox.HTML_ENTITIES, match);
}
);
};
};
/*@
Ox.encodeUTF8 <f> Encodes a string as UTF-8
/*@
Ox.encodeUTF8 <f> Encodes a string as UTF-8
see http://en.wikipedia.org/wiki/UTF-8
(string) -> <s> UTF-8 encoded string
string <s> Any string
@ -331,8 +295,8 @@
"YES"
> Ox.encodeUTF8("¥€$")
"\u00C2\u00A5\u00E2\u0082\u00AC\u0024"
@*/
Ox.encodeUTF8 = function(str) {
@*/
Ox.encodeUTF8 = function(str) {
return Ox.map(str, function(chr) {
var code = chr.charCodeAt(0),
str = '';
@ -348,10 +312,10 @@
}
return str;
});
};
};
/*@
Ox.decodeUTF8 <f> Decodes an UTF-8-encoded string
/*@
Ox.decodeUTF8 <f> Decodes an UTF-8-encoded string
see http://en.wikipedia.org/wiki/UTF-8
(utf8) -> <s> string
utf8 <s> Any UTF-8-encoded string
@ -359,22 +323,27 @@
'YES'
> Ox.decodeUTF8('\u00C2\u00A5\u00E2\u0082\u00AC\u0024')
'¥€$'
@*/
Ox.decodeUTF8 = function(str) {
var code,
i = 0,
len = str.length,
ret = '';
while (i < len) {
code = Ox.range(3).map(function(o) {
return str.charCodeAt(i + o);
});
@*/
Ox.decodeUTF8 = function(string) {
var code, i = 0, length = string.length, ret = '';
function error(byte, position) {
throw new RangeError(
'UTF-8 codec can\'t decode byte 0x' +
byte.toString(16).toUpperCase() + ' at position ' + position
);
}
while (i < length) {
code = [
string.charCodeAt(i),
string.charCodeAt(i + 1),
string.charCodeAt(i + 2)
];
if (code[0] <= 128) {
ret += str[i];
ret += string[i];
i++;
} else if (
code[0] >= 192 && code[0] < 240
&& i < len - (code[0] < 224 ? 1 : 2)
&& i < length - (code[0] < 224 ? 1 : 2)
) {
if (code[1] >= 128 && code[1] < 192) {
if (code[0] < 224) {
@ -389,16 +358,14 @@
);
i += 3;
} else {
throwUTF8Error(code[2], i + 2);
error(code[2], i + 2);
}
} else {
throwUTF8Error(code[1], i + 1);
error(code[1], i + 1);
}
} else {
throwUTF8Error(code[0], i);
error(code[0], i);
}
}
return ret;
};
})();
};