forked from zhurui/management
117 lines
3.0 KiB
JavaScript
117 lines
3.0 KiB
JavaScript
var inherits = require('inherits');
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var Reporter = require('../base').Reporter;
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var Buffer = require('buffer').Buffer;
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function DecoderBuffer(base, options) {
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Reporter.call(this, options);
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if (!Buffer.isBuffer(base)) {
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this.error('Input not Buffer');
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return;
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}
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this.base = base;
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this.offset = 0;
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this.length = base.length;
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}
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inherits(DecoderBuffer, Reporter);
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exports.DecoderBuffer = DecoderBuffer;
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DecoderBuffer.prototype.save = function save() {
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return { offset: this.offset, reporter: Reporter.prototype.save.call(this) };
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};
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DecoderBuffer.prototype.restore = function restore(save) {
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// Return skipped data
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var res = new DecoderBuffer(this.base);
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res.offset = save.offset;
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res.length = this.offset;
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this.offset = save.offset;
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Reporter.prototype.restore.call(this, save.reporter);
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return res;
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};
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DecoderBuffer.prototype.isEmpty = function isEmpty() {
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return this.offset === this.length;
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};
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DecoderBuffer.prototype.readUInt8 = function readUInt8(fail) {
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if (this.offset + 1 <= this.length)
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return this.base.readUInt8(this.offset++, true);
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else
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return this.error(fail || 'DecoderBuffer overrun');
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}
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DecoderBuffer.prototype.skip = function skip(bytes, fail) {
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if (!(this.offset + bytes <= this.length))
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return this.error(fail || 'DecoderBuffer overrun');
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var res = new DecoderBuffer(this.base);
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// Share reporter state
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res._reporterState = this._reporterState;
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res.offset = this.offset;
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res.length = this.offset + bytes;
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this.offset += bytes;
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return res;
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}
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DecoderBuffer.prototype.raw = function raw(save) {
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return this.base.slice(save ? save.offset : this.offset, this.length);
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}
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function EncoderBuffer(value, reporter) {
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if (Array.isArray(value)) {
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this.length = 0;
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this.value = value.map(function(item) {
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if (!(item instanceof EncoderBuffer))
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item = new EncoderBuffer(item, reporter);
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this.length += item.length;
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return item;
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}, this);
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} else if (typeof value === 'number') {
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if (!(0 <= value && value <= 0xff))
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return reporter.error('non-byte EncoderBuffer value');
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this.value = value;
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this.length = 1;
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} else if (typeof value === 'string') {
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this.value = value;
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this.length = Buffer.byteLength(value);
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} else if (Buffer.isBuffer(value)) {
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this.value = value;
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this.length = value.length;
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} else {
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return reporter.error('Unsupported type: ' + typeof value);
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}
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}
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exports.EncoderBuffer = EncoderBuffer;
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EncoderBuffer.prototype.join = function join(out, offset) {
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if (!out)
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out = new Buffer(this.length);
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if (!offset)
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offset = 0;
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if (this.length === 0)
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return out;
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if (Array.isArray(this.value)) {
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this.value.forEach(function(item) {
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item.join(out, offset);
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offset += item.length;
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});
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} else {
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if (typeof this.value === 'number')
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out[offset] = this.value;
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else if (typeof this.value === 'string')
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out.write(this.value, offset);
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else if (Buffer.isBuffer(this.value))
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this.value.copy(out, offset);
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offset += this.length;
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}
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return out;
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};
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