| Current File : /home/tradevaly/www/node_modules/jszip/lib/utf8.js |
'use strict';
var utils = require('./utils');
var support = require('./support');
var nodejsUtils = require('./nodejsUtils');
var GenericWorker = require('./stream/GenericWorker');
/**
* The following functions come from pako, from pako/lib/utils/strings
* released under the MIT license, see pako https://github.com/nodeca/pako/
*/
// Table with utf8 lengths (calculated by first byte of sequence)
// Note, that 5 & 6-byte values and some 4-byte values can not be represented in JS,
// because max possible codepoint is 0x10ffff
var _utf8len = new Array(256);
for (var i=0; i<256; i++) {
_utf8len[i] = (i >= 252 ? 6 : i >= 248 ? 5 : i >= 240 ? 4 : i >= 224 ? 3 : i >= 192 ? 2 : 1);
}
_utf8len[254]=_utf8len[254]=1; // Invalid sequence start
// convert string to array (typed, when possible)
var string2buf = function (str) {
var buf, c, c2, m_pos, i, str_len = str.length, buf_len = 0;
// count binary size
for (m_pos = 0; m_pos < str_len; m_pos++) {
c = str.charCodeAt(m_pos);
if ((c & 0xfc00) === 0xd800 && (m_pos+1 < str_len)) {
c2 = str.charCodeAt(m_pos+1);
if ((c2 & 0xfc00) === 0xdc00) {
c = 0x10000 + ((c - 0xd800) << 10) + (c2 - 0xdc00);
m_pos++;
}
}
buf_len += c < 0x80 ? 1 : c < 0x800 ? 2 : c < 0x10000 ? 3 : 4;
}
// allocate buffer
if (support.uint8array) {
buf = new Uint8Array(buf_len);
} else {
buf = new Array(buf_len);
}
// convert
for (i=0, m_pos = 0; i < buf_len; m_pos++) {
c = str.charCodeAt(m_pos);
if ((c & 0xfc00) === 0xd800 && (m_pos+1 < str_len)) {
c2 = str.charCodeAt(m_pos+1);
if ((c2 & 0xfc00) === 0xdc00) {
c = 0x10000 + ((c - 0xd800) << 10) + (c2 - 0xdc00);
m_pos++;
}
}
if (c < 0x80) {
/* one byte */
buf[i++] = c;
} else if (c < 0x800) {
/* two bytes */
buf[i++] = 0xC0 | (c >>> 6);
buf[i++] = 0x80 | (c & 0x3f);
} else if (c < 0x10000) {
/* three bytes */
buf[i++] = 0xE0 | (c >>> 12);
buf[i++] = 0x80 | (c >>> 6 & 0x3f);
buf[i++] = 0x80 | (c & 0x3f);
} else {
/* four bytes */
buf[i++] = 0xf0 | (c >>> 18);
buf[i++] = 0x80 | (c >>> 12 & 0x3f);
buf[i++] = 0x80 | (c >>> 6 & 0x3f);
buf[i++] = 0x80 | (c & 0x3f);
}
}
return buf;
};
// Calculate max possible position in utf8 buffer,
// that will not break sequence. If that's not possible
// - (very small limits) return max size as is.
//
// buf[] - utf8 bytes array
// max - length limit (mandatory);
var utf8border = function(buf, max) {
var pos;
max = max || buf.length;
if (max > buf.length) { max = buf.length; }
// go back from last position, until start of sequence found
pos = max-1;
while (pos >= 0 && (buf[pos] & 0xC0) === 0x80) { pos--; }
// Fuckup - very small and broken sequence,
// return max, because we should return something anyway.
if (pos < 0) { return max; }
// If we came to start of buffer - that means vuffer is too small,
// return max too.
if (pos === 0) { return max; }
return (pos + _utf8len[buf[pos]] > max) ? pos : max;
};
// convert array to string
var buf2string = function (buf) {
var str, i, out, c, c_len;
var len = buf.length;
// Reserve max possible length (2 words per char)
// NB: by unknown reasons, Array is significantly faster for
// String.fromCharCode.apply than Uint16Array.
var utf16buf = new Array(len*2);
for (out=0, i=0; i<len;) {
c = buf[i++];
// quick process ascii
if (c < 0x80) { utf16buf[out++] = c; continue; }
c_len = _utf8len[c];
// skip 5 & 6 byte codes
if (c_len > 4) { utf16buf[out++] = 0xfffd; i += c_len-1; continue; }
// apply mask on first byte
c &= c_len === 2 ? 0x1f : c_len === 3 ? 0x0f : 0x07;
// join the rest
while (c_len > 1 && i < len) {
c = (c << 6) | (buf[i++] & 0x3f);
c_len--;
}
// terminated by end of string?
if (c_len > 1) { utf16buf[out++] = 0xfffd; continue; }
if (c < 0x10000) {
utf16buf[out++] = c;
} else {
c -= 0x10000;
utf16buf[out++] = 0xd800 | ((c >> 10) & 0x3ff);
utf16buf[out++] = 0xdc00 | (c & 0x3ff);
}
}
// shrinkBuf(utf16buf, out)
if (utf16buf.length !== out) {
if(utf16buf.subarray) {
utf16buf = utf16buf.subarray(0, out);
} else {
utf16buf.length = out;
}
}
// return String.fromCharCode.apply(null, utf16buf);
return utils.applyFromCharCode(utf16buf);
};
// That's all for the pako functions.
/**
* Transform a javascript string into an array (typed if possible) of bytes,
* UTF-8 encoded.
* @param {String} str the string to encode
* @return {Array|Uint8Array|Buffer} the UTF-8 encoded string.
*/
exports.utf8encode = function utf8encode(str) {
if (support.nodebuffer) {
return nodejsUtils.newBufferFrom(str, "utf-8");
}
return string2buf(str);
};
/**
* Transform a bytes array (or a representation) representing an UTF-8 encoded
* string into a javascript string.
* @param {Array|Uint8Array|Buffer} buf the data de decode
* @return {String} the decoded string.
*/
exports.utf8decode = function utf8decode(buf) {
if (support.nodebuffer) {
return utils.transformTo("nodebuffer", buf).toString("utf-8");
}
buf = utils.transformTo(support.uint8array ? "uint8array" : "array", buf);
return buf2string(buf);
};
/**
* A worker to decode utf8 encoded binary chunks into string chunks.
* @constructor
*/
function Utf8DecodeWorker() {
GenericWorker.call(this, "utf-8 decode");
// the last bytes if a chunk didn't end with a complete codepoint.
this.leftOver = null;
}
utils.inherits(Utf8DecodeWorker, GenericWorker);
/**
* @see GenericWorker.processChunk
*/
Utf8DecodeWorker.prototype.processChunk = function (chunk) {
var data = utils.transformTo(support.uint8array ? "uint8array" : "array", chunk.data);
// 1st step, re-use what's left of the previous chunk
if (this.leftOver && this.leftOver.length) {
if(support.uint8array) {
var previousData = data;
data = new Uint8Array(previousData.length + this.leftOver.length);
data.set(this.leftOver, 0);
data.set(previousData, this.leftOver.length);
} else {
data = this.leftOver.concat(data);
}
this.leftOver = null;
}
var nextBoundary = utf8border(data);
var usableData = data;
if (nextBoundary !== data.length) {
if (support.uint8array) {
usableData = data.subarray(0, nextBoundary);
this.leftOver = data.subarray(nextBoundary, data.length);
} else {
usableData = data.slice(0, nextBoundary);
this.leftOver = data.slice(nextBoundary, data.length);
}
}
this.push({
data : exports.utf8decode(usableData),
meta : chunk.meta
});
};
/**
* @see GenericWorker.flush
*/
Utf8DecodeWorker.prototype.flush = function () {
if(this.leftOver && this.leftOver.length) {
this.push({
data : exports.utf8decode(this.leftOver),
meta : {}
});
this.leftOver = null;
}
};
exports.Utf8DecodeWorker = Utf8DecodeWorker;
/**
* A worker to endcode string chunks into utf8 encoded binary chunks.
* @constructor
*/
function Utf8EncodeWorker() {
GenericWorker.call(this, "utf-8 encode");
}
utils.inherits(Utf8EncodeWorker, GenericWorker);
/**
* @see GenericWorker.processChunk
*/
Utf8EncodeWorker.prototype.processChunk = function (chunk) {
this.push({
data : exports.utf8encode(chunk.data),
meta : chunk.meta
});
};
exports.Utf8EncodeWorker = Utf8EncodeWorker;