[Files.app] Split the JavaScript files into subdirectories: common, background, and foreground

chrome/browser/resources/file_manager/js/metadata/byte_reader.js

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-'use strict';
-
-/**
- * @constructor
- * @param {ArrayBuffer} arrayBuffer  // TODO(JSDOC).
- * @param {number=} opt_offset  // TODO(JSDOC).
- * @param {number=} opt_length  // TODO(JSDOC).
- */
-function ByteReader(arrayBuffer, opt_offset, opt_length) {
-  opt_offset = opt_offset || 0;
-  opt_length = opt_length || (arrayBuffer.byteLength - opt_offset);
-  this.view_ = new DataView(arrayBuffer, opt_offset, opt_length);
-  this.pos_ = 0;
-  this.seekStack_ = [];
-  this.setByteOrder(ByteReader.BIG_ENDIAN);
-}
-
-// Static constants and methods.
-
-/**
- * Intel, 0x1234 is [0x34, 0x12]
- * @const
- * @type {number}
- */
-ByteReader.LITTLE_ENDIAN = 0;
-/**
- * Motorola, 0x1234 is [0x12, 0x34]
- * @const
- * @type {number}
- */
-ByteReader.BIG_ENDIAN = 1;
-
-/**
- * Seek relative to the beginning of the buffer.
- * @const
- * @type {number}
- */
-ByteReader.SEEK_BEG = 0;
-/**
- * Seek relative to the current position.
- * @const
- * @type {number}
- */
-ByteReader.SEEK_CUR = 1;
-/**
- * Seek relative to the end of the buffer.
- * @const
- * @type {number}
- */
-ByteReader.SEEK_END = 2;
-
-/**
- * Throw an error if (0 > pos >= end) or if (pos + size > end).
- *
- * Static utility function.
- *
- * @param {number} pos  // TODO(JSDOC).
- * @param {number} size  // TODO(JSDOC).
- * @param {number} end  // TODO(JSDOC).
- */
-ByteReader.validateRead = function(pos, size, end) {
-  if (pos < 0 || pos >= end)
-    throw new Error('Invalid read position');
-
-  if (pos + size > end)
-    throw new Error('Read past end of buffer');
-};
-
-/**
- * Read as a sequence of characters, returning them as a single string.
- *
- * This is a static utility function.  There is a member function with the
- * same name which side-effects the current read position.
- *
- * @param {DataView} dataView  // TODO(JSDOC).
- * @param {number} pos  // TODO(JSDOC).
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.readString = function(dataView, pos, size, opt_end) {
-  ByteReader.validateRead(pos, size, opt_end || dataView.byteLength);
-
-  var codes = [];
-
-  for (var i = 0; i < size; ++i)
-    codes.push(dataView.getUint8(pos + i));
-
-  return String.fromCharCode.apply(null, codes);
-};
-
-/**
- * Read as a sequence of characters, returning them as a single string.
- *
- * This is a static utility function.  There is a member function with the
- * same name which side-effects the current read position.
- *
- * @param {DataView} dataView  // TODO(JSDOC).
- * @param {number} pos  // TODO(JSDOC).
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.readNullTerminatedString = function(dataView, pos, size, opt_end) {
-  ByteReader.validateRead(pos, size, opt_end || dataView.byteLength);
-
-  var codes = [];
-
-  for (var i = 0; i < size; ++i) {
-    var code = dataView.getUint8(pos + i);
-    if (code == 0) break;
-    codes.push(code);
-  }
-
-  return String.fromCharCode.apply(null, codes);
-};
-
-/**
- * Read as a sequence of UTF16 characters, returning them as a single string.
- *
- * This is a static utility function.  There is a member function with the
- * same name which side-effects the current read position.
- *
- * @param {DataView} dataView  // TODO(JSDOC).
- * @param {number} pos  // TODO(JSDOC).
- * @param {boolean} bom  // TODO(JSDOC).
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.readNullTerminatedStringUTF16 = function(
-    dataView, pos, bom, size, opt_end) {
-  ByteReader.validateRead(pos, size, opt_end || dataView.byteLength);
-
-  var littleEndian = false;
-  var start = 0;
-
-  if (bom) {
-    littleEndian = (dataView.getUint8(pos) == 0xFF);
-    start = 2;
-  }
-
-  var codes = [];
-
-  for (var i = start; i < size; i += 2) {
-    var code = dataView.getUint16(pos + i, littleEndian);
-    if (code == 0) break;
-    codes.push(code);
-  }
-
-  return String.fromCharCode.apply(null, codes);
-};
-
-/**
- * @const
- * @type {Array.<string>}
- * @private
- */
-ByteReader.base64Alphabet_ =
-    ('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/').
-    split('');
-
-/**
- * Read as a sequence of bytes, returning them as a single base64 encoded
- * string.
- *
- * This is a static utility function.  There is a member function with the
- * same name which side-effects the current read position.
- *
- * @param {DataView} dataView  // TODO(JSDOC).
- * @param {number} pos  // TODO(JSDOC).
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.readBase64 = function(dataView, pos, size, opt_end) {
-  ByteReader.validateRead(pos, size, opt_end || dataView.byteLength);
-
-  var rv = [];
-  var chars = [];
-  var padding = 0;
-
-  for (var i = 0; i < size; /* incremented inside */) {
-    var bits = dataView.getUint8(pos + (i++)) << 16;
-
-    if (i < size) {
-      bits |= dataView.getUint8(pos + (i++)) << 8;
-
-      if (i < size) {
-        bits |= dataView.getUint8(pos + (i++));
-      } else {
-        padding = 1;
-      }
-    } else {
-      padding = 2;
-    }
-
-    chars[3] = ByteReader.base64Alphabet_[bits & 63];
-    chars[2] = ByteReader.base64Alphabet_[(bits >> 6) & 63];
-    chars[1] = ByteReader.base64Alphabet_[(bits >> 12) & 63];
-    chars[0] = ByteReader.base64Alphabet_[(bits >> 18) & 63];
-
-    rv.push.apply(rv, chars);
-  }
-
-  if (padding > 0)
-    rv[rv.length - 1] = '=';
-  if (padding > 1)
-    rv[rv.length - 2] = '=';
-
-  return rv.join('');
-};
-
-/**
- * Read as an image encoded in a data url.
- *
- * This is a static utility function.  There is a member function with the
- * same name which side-effects the current read position.
- *
- * @param {DataView} dataView  // TODO(JSDOC).
- * @param {number} pos  // TODO(JSDOC).
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.readImage = function(dataView, pos, size, opt_end) {
-  opt_end = opt_end || dataView.byteLength;
-  ByteReader.validateRead(pos, size, opt_end);
-
-  // Two bytes is enough to identify the mime type.
-  var prefixToMime = {
-     '\x89P' : 'png',
-     '\xFF\xD8' : 'jpeg',
-     'BM' : 'bmp',
-     'GI' : 'gif'
-  };
-
-  var prefix = ByteReader.readString(dataView, pos, 2, opt_end);
-  var mime = prefixToMime[prefix] ||
-      dataView.getUint16(pos, false).toString(16);  // For debugging.
-
-  var b64 = ByteReader.readBase64(dataView, pos, size, opt_end);
-  return 'data:image/' + mime + ';base64,' + b64;
-};
-
-// Instance methods.
-
-/**
- * Return true if the requested number of bytes can be read from the buffer.
- *
- * @param {number} size  // TODO(JSDOC).
- * @return {boolean}  // TODO(JSDOC).
- */
-ByteReader.prototype.canRead = function(size) {
-   return this.pos_ + size <= this.view_.byteLength;
-};
-
-/**
- * Return true if the current position is past the end of the buffer.
- * @return {boolean}  // TODO(JSDOC).
- */
-ByteReader.prototype.eof = function() {
-  return this.pos_ >= this.view_.byteLength;
-};
-
-/**
- * Return true if the current position is before the beginning of the buffer.
- * @return {boolean}  // TODO(JSDOC).
- */
-ByteReader.prototype.bof = function() {
-  return this.pos_ < 0;
-};
-
-/**
- * Return true if the current position is outside the buffer.
- * @return {boolean}  // TODO(JSDOC).
- */
-ByteReader.prototype.beof = function() {
-  return this.pos_ >= this.view_.byteLength || this.pos_ < 0;
-};
-
-/**
- * Set the expected byte ordering for future reads.
- * @param {number} order  // TODO(JSDOC).
- */
-ByteReader.prototype.setByteOrder = function(order) {
-  this.littleEndian_ = order == ByteReader.LITTLE_ENDIAN;
-};
-
-/**
- * Throw an error if the reader is at an invalid position, or if a read a read
- * of |size| would put it in one.
- *
- * You may optionally pass opt_end to override what is considered to be the
- * end of the buffer.
- *
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- */
-ByteReader.prototype.validateRead = function(size, opt_end) {
-  if (typeof opt_end == 'undefined')
-    opt_end = this.view_.byteLength;
-
-  ByteReader.validateRead(this.view_, this.pos_, size, opt_end);
-};
-
-/**
- * @param {number} width  // TODO(JSDOC).
- * @param {boolean=} opt_signed  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.prototype.readScalar = function(width, opt_signed, opt_end) {
-  var method = opt_signed ? 'getInt' : 'getUint';
-
-  switch (width) {
-    case 1:
-      method += '8';
-      break;
-
-    case 2:
-      method += '16';
-      break;
-
-    case 4:
-      method += '32';
-      break;
-
-    case 8:
-      method += '64';
-      break;
-
-    default:
-      throw new Error('Invalid width: ' + width);
-      break;
-  }
-
-  this.validateRead(width, opt_end);
-  var rv = this.view_[method](this.pos_, this.littleEndian_);
-  this.pos_ += width;
-  return rv;
-};
-
-/**
- * Read as a sequence of characters, returning them as a single string.
- *
- * Adjusts the current position on success.  Throws an exception if the
- * read would go past the end of the buffer.
- *
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.prototype.readString = function(size, opt_end) {
-  var rv = ByteReader.readString(this.view_, this.pos_, size, opt_end);
-  this.pos_ += size;
-  return rv;
-};
-
-
-/**
- * Read as a sequence of characters, returning them as a single string.
- *
- * Adjusts the current position on success.  Throws an exception if the
- * read would go past the end of the buffer.
- *
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.prototype.readNullTerminatedString = function(size, opt_end) {
-  var rv = ByteReader.readNullTerminatedString(this.view_,
-                                               this.pos_,
-                                               size,
-                                               opt_end);
-  this.pos_ += rv.length;
-
-  if (rv.length < size) {
-    // If we've stopped reading because we found '0' but didn't hit size limit
-    // then we should skip additional '0' character
-    this.pos_++;
-  }
-
-  return rv;
-};
-
-
-/**
- * Read as a sequence of UTF16 characters, returning them as a single string.
- *
- * Adjusts the current position on success.  Throws an exception if the
- * read would go past the end of the buffer.
- *
- * @param {boolean} bom  // TODO(JSDOC).
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.prototype.readNullTerminatedStringUTF16 =
-    function(bom, size, opt_end) {
-  var rv = ByteReader.readNullTerminatedStringUTF16(
-      this.view_, this.pos_, bom, size, opt_end);
-
-  if (bom) {
-    // If the BOM word was present advance the position.
-    this.pos_ += 2;
-  }
-
-  this.pos_ += rv.length;
-
-  if (rv.length < size) {
-    // If we've stopped reading because we found '0' but didn't hit size limit
-    // then we should skip additional '0' character
-    this.pos_ += 2;
-  }
-
-  return rv;
-};
-
-
-/**
- * Read as an array of numbers.
- *
- * Adjusts the current position on success.  Throws an exception if the
- * read would go past the end of the buffer.
- *
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @param {function(new:Array.<*>)=} opt_arrayConstructor  // TODO(JSDOC).
- * @return {Array.<*>}  // TODO(JSDOC).
- */
-ByteReader.prototype.readSlice = function(size, opt_end,
-                                          opt_arrayConstructor) {
-  this.validateRead(size, opt_end);
-
-  var arrayConstructor = opt_arrayConstructor || Uint8Array;
-  var slice = new arrayConstructor(
-      this.view_.buffer, this.view_.byteOffset + this.pos, size);
-  this.pos_ += size;
-
-  return slice;
-};
-
-/**
- * Read as a sequence of bytes, returning them as a single base64 encoded
- * string.
- *
- * Adjusts the current position on success.  Throws an exception if the
- * read would go past the end of the buffer.
- *
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.prototype.readBase64 = function(size, opt_end) {
-  var rv = ByteReader.readBase64(this.view_, this.pos_, size, opt_end);
-  this.pos_ += size;
-  return rv;
-};
-
-/**
- * Read an image returning it as a data url.
- *
- * Adjusts the current position on success.  Throws an exception if the
- * read would go past the end of the buffer.
- *
- * @param {number} size  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- * @return {string}  // TODO(JSDOC).
- */
-ByteReader.prototype.readImage = function(size, opt_end) {
-  var rv = ByteReader.readImage(this.view_, this.pos_, size, opt_end);
-  this.pos_ += size;
-  return rv;
-};
-
-/**
- * Seek to a give position relative to opt_seekStart.
- *
- * @param {number} pos  // TODO(JSDOC).
- * @param {number=} opt_seekStart  // TODO(JSDOC).
- * @param {number=} opt_end  // TODO(JSDOC).
- */
-ByteReader.prototype.seek = function(pos, opt_seekStart, opt_end) {
-  opt_end = opt_end || this.view_.byteLength;
-
-  var newPos;
-  if (opt_seekStart == ByteReader.SEEK_CUR) {
-    newPos = this.pos_ + pos;
-  } else if (opt_seekStart == ByteReader.SEEK_END) {
-    newPos = opt_end + pos;
-  } else {
-    newPos = pos;
-  }
-
-  if (newPos < 0 || newPos > this.view_.byteLength)
-    throw new Error('Seek outside of buffer: ' + (newPos - opt_end));
-
-  this.pos_ = newPos;
-};
-
-/**
- * Seek to a given position relative to opt_seekStart, saving the current
- * position.
- *
- * Recover the current position with a call to seekPop.
- *
- * @param {number} pos  // TODO(JSDOC).
- * @param {number=} opt_seekStart  // TODO(JSDOC).
- */
-ByteReader.prototype.pushSeek = function(pos, opt_seekStart) {
-  var oldPos = this.pos_;
-  this.seek(pos, opt_seekStart);
-  // Alter the seekStack_ after the call to seek(), in case it throws.
-  this.seekStack_.push(oldPos);
-};
-
-/**
- * Undo a previous seekPush.
- */
-ByteReader.prototype.popSeek = function() {
-  this.seek(this.seekStack_.pop());
-};
-
-/**
- * Return the current read position.
- * @return {number}  // TODO(JSDOC).
- */
-ByteReader.prototype.tell = function() {
-  return this.pos_;
-};