Passed
Push — master ( 2f7ce0...4f126f )
by Rafael S.
02:01
created

utf8-buffer.js ➔ unpack   F

Complexity

Conditions 20
Paths 1684

Size

Total Lines 62
Code Lines 44

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
cc 20
eloc 44
c 0
b 0
f 0
nc 1684
nop 3
dl 0
loc 62
rs 0

How to fix   Long Method    Complexity   

Long Method

Small methods make your code easier to understand, in particular if combined with a good name. Besides, if your method is small, finding a good name is usually much easier.

For example, if you find yourself adding comments to a method's body, this is usually a good sign to extract the commented part to a new method, and use the comment as a starting point when coming up with a good name for this new method.

Commonly applied refactorings include:

Complexity

Complex classes like utf8-buffer.js ➔ unpack often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.

Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.

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/*
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 * Copyright (c) 2018 Rafael da Silva Rocha.
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 *
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 * Permission is hereby granted, free of charge, to any person obtaining
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 * a copy of this software and associated documentation files (the
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 * "Software"), to deal in the Software without restriction, including
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 * without limitation the rights to use, copy, modify, merge, publish,
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 * distribute, sublicense, and/or sell copies of the Software, and to
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 * permit persons to whom the Software is furnished to do so, subject to
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 * the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be
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 * included in all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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 *
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 */
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/**
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 * @fileoverview Functions to serialize and deserialize UTF-8 strings.
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 * @see https://github.com/rochars/utf8-buffer
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 * @see https://encoding.spec.whatwg.org/#the-encoding
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 * @see https://encoding.spec.whatwg.org/#utf-8-encoder
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 */
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import utf8BufferSize from 'utf8-buffer-size';
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/**
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 * Read a string of UTF-8 characters from a byte buffer.
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 * Invalid characters are replaced with 'REPLACEMENT CHARACTER' (U+FFFD).
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 * @see https://encoding.spec.whatwg.org/#the-encoding
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 * @see https://stackoverflow.com/a/34926911
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 * @param {!Uint8Array|!Array<!number>} buffer A byte buffer.
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 * @param {number=} index The index to read.
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 * @param {?number=} len The number of bytes to read.
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 *    If len is undefined will read until the end of the buffer.
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 * @return {string}
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 */
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export function unpack(buffer, index=0, len=undefined) {
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  len = len !== undefined ? index + len : buffer.length;
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  /** @type {string} */
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  let str = "";
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  while(index < len) {
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    /** @type {number} */
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    let lowerBoundary = 0x80;
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    /** @type {number} */
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    let upperBoundary = 0xBF;
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    /** @type {boolean} */
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    let replace = false;
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    /** @type {number} */
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    let charCode = buffer[index++];
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    if (charCode >= 0x00 && charCode <= 0x7F) {
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      str += String.fromCharCode(charCode);
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    } else {
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      /** @type {number} */
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      let count = 0;
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      if (charCode >= 0xC2 && charCode <= 0xDF) {
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        count = 1;
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      } else if (charCode >= 0xE0 && charCode <= 0xEF ) {
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        count = 2;
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        if (buffer[index] === 0xE0) {
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          lowerBoundary = 0xA0;
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        }
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        if (buffer[index] === 0xED) {
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          upperBoundary = 0x9F;
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        }
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      } else if (charCode >= 0xF0 && charCode <= 0xF4 ) {
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        count = 3;
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        if (buffer[index] === 0xF0) {
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          lowerBoundary = 0x90;
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        }
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        if (buffer[index] === 0xF4) {
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          upperBoundary = 0x8F;
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        }
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      } else {
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        replace = true;
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      }
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      charCode = charCode & (1 << (8 - count - 1)) - 1;
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      for (let i = 0; i < count; i++) {
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        if (buffer[index] < lowerBoundary || buffer[index] > upperBoundary) {
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          replace = true;
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        }
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        charCode = (charCode << 6) | (buffer[index] & 0x3f);
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        index++;
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      }
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      if (replace) {
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        str += String.fromCharCode(0xFFFD);
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      } 
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      else if (charCode <= 0xffff) {
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        str += String.fromCharCode(charCode);
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      } else {
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        charCode -= 0x10000;
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        str += String.fromCharCode(
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          ((charCode >> 10) & 0x3ff) + 0xd800,
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          (charCode & 0x3ff) + 0xdc00);
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      }
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    }
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  }
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  return str;
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}
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/**
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 * Write a string of UTF-8 characters as a byte buffer.
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 * @see https://encoding.spec.whatwg.org/#utf-8-encoder
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 * @param {string} str The string to pack.
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 * @return {!Uint8Array} The packed string.
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 * @suppress {checkTypes}
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 */
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export function pack(str) {
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  /** @type {!Uint8Array} */
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  let bytes;
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  if (typeof Uint8Array != 'undefined') {
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    bytes = new Uint8Array(utf8BufferSize(str));
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  } else {
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    bytes = [];
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  }
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  let bufferIndex = 0;
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  for (let i = 0, len = str.length; i < len; i++) {
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    /** @type {number} */
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    let codePoint = str.codePointAt(i);
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    if (codePoint < 128) {
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      bytes[bufferIndex] = codePoint;
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      bufferIndex++;
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    } else {
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      /** @type {number} */
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      let count = 0;
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      /** @type {number} */
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      let offset = 0;
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      if (codePoint <= 0x07FF) {
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        count = 1;
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        offset = 0xC0;
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      } else if(codePoint <= 0xFFFF) {
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        count = 2;
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        offset = 0xE0;
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      } else if(codePoint <= 0x10FFFF) {
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        count = 3;
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        offset = 0xF0;
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        i++;
0 ignored issues
show
Complexity Coding Style introduced by Rafael Rocha
You seem to be assigning a new value to the loop variable i here. Please check if this was indeed your intention. Even if it was, consider using another kind of loop instead.
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      }
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      bytes[bufferIndex] = (codePoint >> (6 * count)) + offset;
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      bufferIndex++;
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      while (count > 0) {
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        bytes[bufferIndex] = 0x80 | (codePoint >> (6 * (count - 1)) & 0x3F);
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        bufferIndex++;
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        count--;
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      }
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    }
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  }
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  return bytes;
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}
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