protobufjs/src/reader_buffer.js

Protocol Buffers for JavaScript & TypeScript.

"use strict";
module.exports = BufferReader;

// extends Reader
var Reader = require("./reader");
(BufferReader.prototype = Object.create(Reader.prototype)).constructor = BufferReader;

var util = require("./util/minimal");

/**
 * Constructs a new buffer reader instance.
 * @classdesc Wire format reader using node buffers.
 * @extends Reader
 * @constructor
 * @param {Buffer} buffer Buffer to read from
 */
function BufferReader(buffer) {
    Reader.call(this, buffer);

    /**
     * Read buffer.
     * @name BufferReader#buf
     * @type {Buffer}
     */
}

BufferReader._configure = function () {
    /* istanbul ignore else */
    if (util.Buffer)
        BufferReader.prototype._slice = util.Buffer.prototype.slice;
};

/**
 * Returns raw bytes from the backing buffer without advancing the reader.
 * @name BufferReader#raw
 * @function
 * @param {number} start Start offset
 * @param {number} end End offset
 * @returns {Buffer} Raw bytes
 */
BufferReader.prototype.raw = function read_raw_buffer(start, end) {
    if (start === end)
        return util.Buffer.alloc(0);
    return this._slice.call(this.buf, start, end);
};

/**
 * @override
 */
BufferReader.prototype.string = function read_string_buffer() {
    var len = this.uint32(), // modifies pos
        start = this.pos,
        end = this.pos + len;

    /* istanbul ignore if */
    if (end > this.len)
        throw RangeError("index out of range: " + this.pos + " + " + len + " > " + this.len);

    this.pos = end;
    return this.buf.utf8Slice
        ? this.buf.utf8Slice(start, end)
        : this.buf.toString("utf-8", start, end);
};

/**
 * Reads a sequence of bytes preceeded by its length as a varint.
 * @name BufferReader#bytes
 * @function
 * @returns {Buffer} Value read
 */

BufferReader._configure();