112 lines
3.0 KiB
JavaScript
112 lines
3.0 KiB
JavaScript
var Iconv = require('iconv').Iconv;
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var Iconv_converters = {};
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function getIconv(from) {
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var to = 'utf-8';
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var key = from+'---'+to;
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if(!(key in Iconv_converters)) {
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Iconv_converters[key] = new Iconv(from, to);
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}
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return Iconv_converters[key];
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}
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function Reader(query,buffer) {
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this.query = query;
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this.buffer = buffer;
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this.i = 0;
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}
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Reader.prototype = {
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offset: function() { return this.i; },
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skip: function(i) { this.i += i; },
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string: function() {
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var args = Array.prototype.slice.call(arguments);
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var options = {};
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if(args.length == 0) {
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options = {};
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} else if(args.length == 1) {
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if(typeof args[0] == 'string') options = { delimiter: args[0] };
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else if(typeof args[0] == 'number') options = { length: args[0] };
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else options = args[0];
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}
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options.encoding = options.encoding || this.query.encoding;
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if(options.encoding == 'latin1') options.encoding = 'windows-1252';
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var start = this.i+0;
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var end = start;
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if(!('length' in options)) {
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// terminated by the delimiter
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var delim = options.delimiter || this.query.delimiter;
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if(typeof delim == 'string') delim = delim.charCodeAt(0);
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while(true) {
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if(end >= this.buffer.length) return '';
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if(this.buffer.readUInt8(end) == delim) break;
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end++;
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}
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this.i = end+1;
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} else {
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end = start+options.length;
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if(end > this.buffer.length) return '';
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this.i = end;
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if(options.stripnull && this.buffer.readUInt8(end-1) == 0) end--;
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}
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var out = this.buffer.slice(start, end);
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var enc = options.encoding;
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if(enc == 'utf8' || enc == 'ucs2' || enc == 'binary') {
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out = out.toString(enc);
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} else {
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var converter = getIconv(enc);
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out = converter.convert(out).toString();
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}
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return out;
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},
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uint: function(bytes) {
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var r = 0;
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if(this.i+bytes <= this.buffer.length) {
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if(this.query.byteorder == 'be') {
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if(bytes == 1) r = this.buffer.readUInt8(this.i);
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else if(bytes == 2) r = this.buffer.readUInt16BE(this.i);
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else if(bytes == 4) r = this.buffer.readUInt32BE(this.i);
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else if(bytes == 8) r = Bignum.fromBuffer(this.buffer.slice(this.i,this.i+8),{endian:'big',size:'auto'});
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} else {
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if(bytes == 1) r = this.buffer.readUInt8(this.i);
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else if(bytes == 2) r = this.buffer.readUInt16LE(this.i);
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else if(bytes == 4) r = this.buffer.readUInt32LE(this.i);
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else if(bytes == 8) r = Bignum.fromBuffer(this.buffer.slice(this.i,this.i+8),{endian:'little',size:'auto'});
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}
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}
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this.i += bytes;
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return r;
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},
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float: function() {
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var r = 0;
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if(this.i+4 <= this.buffer.length) {
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if(this.query.byteorder == 'be') r = this.buffer.readFloatBE(this.i);
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else r = this.buffer.readFloatLE(this.i);
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}
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this.i += 4;
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return r;
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},
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pascal: function(enc) {
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if(this.i >= this.buffer.length) return '';
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var length = this.buffer.readUInt8(this.i);
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this.i++;
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return this.string({
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encoding: enc,
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length: length,
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stripnull: true
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});
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},
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done: function() {
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return this.i >= this.buffer.length;
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}
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};
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module.exports = Reader;
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