riff-chunks.js ➔ getSubChunkIndex_ - Code Metrics - Inspection of "Solve mixed responsibilities between WaveFile, wav..." - rochars/wavefile - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Branch — v8.x (3f6847)

by Rafael S.

created 2018-07-10 22:10 UTC

riff-chunks.js ➔ getSubChunkIndex_ A

↳ Parent: vendor/riff-chunks.js

Complexity

Conditions	3
Paths	2

Size

Total Lines	20
Code Lines	16

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	3
eloc	16
nc	2
dl	0
loc	20
rs	9.6
c	0
b	0
f	0
nop	2

/*
 * riff-chunks: Read and write the chunks of RIFF and RIFX files.
 * https://github.com/rochars/riff-chunks
 *
 * Copyright (c) 2017-2018 Rafael da Silva Rocha.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

/**
 * @fileoverview The riff-chunks API.
 */

/** @module riffChunks */

import {unpackFrom, unpackString} from './byte-data.js';

/** @private */
const uInt32_ = {bits: 32};
/** @type {number} */
let head_ = 0;

/**
 * Return the chunks in a RIFF/RIFX file.
 * @param {!Uint8Array} buffer The file bytes.
 * @return {!Object} The RIFF chunks.
 */
export function riffChunks(buffer) {
    head_ = 0;
    let chunkId = getChunkId_(buffer, 0);
    uInt32_.be = chunkId == 'RIFX';
    let format = unpackString(buffer, 8, 4);
    head_ += 4;
    return {
        chunkId: chunkId,
        chunkSize: getChunkSize_(buffer, 0),
        format: format,
        subChunks: getSubChunksIndex_(buffer)
    };
}

/**
  * Find a chunk by its fourCC_ in a array of RIFF chunks.
  * @param {!Object} chunks The wav file chunks.
  * @param {string} chunkId The chunk fourCC_.
  * @param {boolean} multiple True if there may be multiple chunks
  *    with the same chunkId.
  * @return {?Array<!Object>}
  * @private
  */
export function findChunk_(chunks, chunkId, multiple=false) {
  /** @type {!Array<!Object>} */
  let chunk = [];
  for (let i=0; i<chunks.length; i++) {
    if (chunks[i].chunkId == chunkId) {
      if (multiple) {
        chunk.push(chunks[i]);
      } else {
        return chunks[i];
      }
    }
  }
  if (chunkId == 'LIST') {
    return chunk.length ? chunk : null;
  }
  return null;
}

/**
 * Return the sub chunks of a RIFF file.
 * @param {!Uint8Array} buffer the RIFF file bytes.
 * @return {!Array<Object>} The subchunks of a RIFF/RIFX or LIST chunk.
 * @private
 */
function getSubChunksIndex_(buffer) {
    let chunks = [];
    let i = head_;
    while(i <= buffer.length - 8) {
        chunks.push(getSubChunkIndex_(buffer, i));
        i += 8 + chunks[chunks.length - 1].chunkSize;
        i = i % 2 ? i + 1 : i;
    }
    return chunks;
}

/**
 * Return a sub chunk from a RIFF file.
 * @param {!Uint8Array} buffer the RIFF file bytes.
 * @param {number} index The start index of the chunk.
 * @return {!Object} A subchunk of a RIFF/RIFX or LIST chunk.
 * @private
 */
function getSubChunkIndex_(buffer, index) {
    let chunk = {
        chunkId: getChunkId_(buffer, index),
        chunkSize: getChunkSize_(buffer, index),
    };
    if (chunk.chunkId == 'LIST') {
        chunk.format = unpackString(buffer, index + 8, 4);
        head_ += 4;
        chunk.subChunks = getSubChunksIndex_(buffer);
    } else {
        let realChunkSize = chunk.chunkSize % 2 ?
            chunk.chunkSize + 1 : chunk.chunkSize;
        head_ = index + 8 + realChunkSize;
        chunk.chunkData = {
            start: index + 8,
            end: head_
        };
    }
    return chunk;
}

/**
 * Return the fourCC_ of a chunk.
 * @param {!Uint8Array} buffer the RIFF file bytes.
 * @param {number} index The start index of the chunk.
 * @return {string} The id of the chunk.
 * @private
 */
function getChunkId_(buffer, index) {
    head_ += 4;
    return unpackString(buffer, index, 4);
}

/**
 * Return the size of a chunk.
 * @param {!Uint8Array} buffer the RIFF file bytes.
 * @param {number} index The start index of the chunk.
 * @return {number} The size of the chunk without the id and size fields.
 * @private
 */
function getChunkSize_(buffer, index) {
    head_ += 4;
    return unpackFrom(buffer, uInt32_, index + 4);
}


1			/*
2			* riff-chunks: Read and write the chunks of RIFF and RIFX files.
3			* https://github.com/rochars/riff-chunks
4			*
5			* Copyright (c) 2017-2018 Rafael da Silva Rocha.
6			*
7			* Permission is hereby granted, free of charge, to any person obtaining
8			* a copy of this software and associated documentation files (the
9			* "Software"), to deal in the Software without restriction, including
10			* without limitation the rights to use, copy, modify, merge, publish,
11			* distribute, sublicense, and/or sell copies of the Software, and to
12			* permit persons to whom the Software is furnished to do so, subject to
13			* the following conditions:
14			*
15			* The above copyright notice and this permission notice shall be
16			* included in all copies or substantial portions of the Software.
17			*
18			* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19			* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20			* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21			* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
22			* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
23			* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
24			* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25			*
26			*/
27
28			/**
29			* @fileoverview The riff-chunks API.
30			*/
31
32			/** @module riffChunks */
33
34			import {unpackFrom, unpackString} from './byte-data.js';
35
36			/** @private */
37			const uInt32_ = {bits: 32};
38			/** @type {number} */
39			let head_ = 0;
40
41			/**
42			* Return the chunks in a RIFF/RIFX file.
43			* @param {!Uint8Array} buffer The file bytes.
44			* @return {!Object} The RIFF chunks.
45			*/
46			export function riffChunks(buffer) {
47			head_ = 0;
48			let chunkId = getChunkId_(buffer, 0);
49			uInt32_.be = chunkId == 'RIFX';
50			let format = unpackString(buffer, 8, 4);
51			head_ += 4;
52			return {
53			chunkId: chunkId,
54			chunkSize: getChunkSize_(buffer, 0),
55			format: format,
56			subChunks: getSubChunksIndex_(buffer)
57			};
58			}
59
60			/**
61			* Find a chunk by its fourCC_ in a array of RIFF chunks.
62			* @param {!Object} chunks The wav file chunks.
63			* @param {string} chunkId The chunk fourCC_.
64			* @param {boolean} multiple True if there may be multiple chunks
65			* with the same chunkId.
66			* @return {?Array<!Object>}
67			* @private
68			*/
69			export function findChunk_(chunks, chunkId, multiple=false) {
70			/** @type {!Array<!Object>} */
71			let chunk = [];
72			for (let i=0; i<chunks.length; i++) {
73			if (chunks[i].chunkId == chunkId) {
74			if (multiple) {
75			chunk.push(chunks[i]);
76			} else {
77			return chunks[i];
78			}
79			}
80			}
81			if (chunkId == 'LIST') {
82			return chunk.length ? chunk : null;
83			}
84			return null;
85			}
86
87			/**
88			* Return the sub chunks of a RIFF file.
89			* @param {!Uint8Array} buffer the RIFF file bytes.
90			* @return {!Array<Object>} The subchunks of a RIFF/RIFX or LIST chunk.
91			* @private
92			*/
93			function getSubChunksIndex_(buffer) {
94			let chunks = [];
95			let i = head_;
96			while(i <= buffer.length - 8) {
97			chunks.push(getSubChunkIndex_(buffer, i));
98			i += 8 + chunks[chunks.length - 1].chunkSize;
99			i = i % 2 ? i + 1 : i;
100			}
101			return chunks;
102			}
103
104			/**
105			* Return a sub chunk from a RIFF file.
106			* @param {!Uint8Array} buffer the RIFF file bytes.
107			* @param {number} index The start index of the chunk.
108			* @return {!Object} A subchunk of a RIFF/RIFX or LIST chunk.
109			* @private
110			*/
111			function getSubChunkIndex_(buffer, index) {
112			let chunk = {
113			chunkId: getChunkId_(buffer, index),
114			chunkSize: getChunkSize_(buffer, index),
115			};
116			if (chunk.chunkId == 'LIST') {
117			chunk.format = unpackString(buffer, index + 8, 4);
118			head_ += 4;
119			chunk.subChunks = getSubChunksIndex_(buffer);
120			} else {
121			let realChunkSize = chunk.chunkSize % 2 ?
122			chunk.chunkSize + 1 : chunk.chunkSize;
123			head_ = index + 8 + realChunkSize;
124			chunk.chunkData = {
125			start: index + 8,
126			end: head_
127			};
128			}
129			return chunk;
130			}
131
132			/**
133			* Return the fourCC_ of a chunk.
134			* @param {!Uint8Array} buffer the RIFF file bytes.
135			* @param {number} index The start index of the chunk.
136			* @return {string} The id of the chunk.
137			* @private
138			*/
139			function getChunkId_(buffer, index) {
140			head_ += 4;
141			return unpackString(buffer, index, 4);
142			}
143
144			/**
145			* Return the size of a chunk.
146			* @param {!Uint8Array} buffer the RIFF file bytes.
147			* @param {number} index The start index of the chunk.
148			* @return {number} The size of the chunk without the id and size fields.
149			* @private
150			*/
151			function getChunkSize_(buffer, index) {
152			head_ += 4;
153			return unpackFrom(buffer, uInt32_, index + 4);
154			}
155

rochars / wavefile

Branch — v8.x (3f6847)

riff-chunks.js ➔ getSubChunkIndex_ A

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