89 lines
2.6 KiB
JavaScript
89 lines
2.6 KiB
JavaScript
function BufferStream(buffer, offset, length, bigEndian) {
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this.buffer = buffer;
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this.offset = offset || 0;
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length = typeof length === 'number' ? length : buffer.length;
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this.endPosition = this.offset + length;
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this.setBigEndian(bigEndian);
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}
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BufferStream.prototype = {
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setBigEndian: function(bigEndian) {
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this.bigEndian = !!bigEndian;
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},
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nextUInt8: function() {
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var value = this.buffer.readUInt8(this.offset);
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this.offset += 1;
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return value;
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},
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nextInt8: function() {
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var value = this.buffer.readInt8(this.offset);
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this.offset += 1;
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return value;
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},
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nextUInt16: function() {
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var value = this.bigEndian ? this.buffer.readUInt16BE(this.offset) : this.buffer.readUInt16LE(this.offset);
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this.offset += 2;
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return value;
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},
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nextUInt32: function() {
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var value = this.bigEndian ? this.buffer.readUInt32BE(this.offset) : this.buffer.readUInt32LE(this.offset);
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this.offset += 4;
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return value;
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},
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nextInt16: function() {
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var value = this.bigEndian ? this.buffer.readInt16BE(this.offset) : this.buffer.readInt16LE(this.offset);
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this.offset += 2;
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return value;
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},
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nextInt32: function() {
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var value = this.bigEndian ? this.buffer.readInt32BE(this.offset) : this.buffer.readInt32LE(this.offset);
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this.offset += 4;
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return value;
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},
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nextFloat: function() {
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var value = this.bigEndian ? this.buffer.readFloatBE(this.offset) : this.buffer.readFloatLE(this.offset);
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this.offset += 4;
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return value;
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},
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nextDouble: function() {
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var value = this.bigEndian ? this.buffer.readDoubleBE(this.offset) : this.buffer.readDoubleLE(this.offset);
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this.offset += 8;
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return value;
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},
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nextBuffer: function(length) {
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var value = this.buffer.slice(this.offset, this.offset + length);
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this.offset += length;
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return value;
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},
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remainingLength: function() {
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return this.endPosition - this.offset;
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},
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nextString: function(length) {
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var value = this.buffer.toString('utf8', this.offset, this.offset + length);
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this.offset += length;
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return value;
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},
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mark: function() {
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var self = this;
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return {
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openWithOffset: function(offset) {
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offset = (offset || 0) + this.offset;
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return new BufferStream(self.buffer, offset, self.endPosition - offset, self.bigEndian);
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},
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offset: this.offset
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};
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},
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offsetFrom: function(marker) {
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return this.offset - marker.offset;
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},
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skip: function(amount) {
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this.offset += amount;
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},
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branch: function(offset, length) {
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length = typeof length === 'number' ? length : this.endPosition - (this.offset + offset);
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return new BufferStream(this.buffer, this.offset + offset, length, this.bigEndian);
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}
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};
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module.exports = BufferStream;
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