BitWriter.write64BitFloat - Code Metrics - Inspection of "removed int-bits dependecy" - rochars/byte-data - Measure and Improve Code Quality continuously with Scrutinizer

Passed

Push — master ( 56b7f2...fe4dd1 )

by Rafael S.

created 2017-12-06 02:18 UTC

BitWriter.write64BitFloat A

↳ Parent: src/bit-parser.js

Complexity

Conditions	1
Paths	1

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

Metric	Value
cc	1
c	1
b	0
f	0
nc	1
nop	3
dl	0
loc	5
rs	9.4285

/**
 * bit-parser: Functions to read and write bytes.
 * Copyright (c) 2017 Rafael da Silva Rocha.
 * https://github.com/rochars/byte-data
 * Float32 based on int-bits: https://github.com/Jam3/int-bits
 */

const helpers = require("../src/helpers.js");
const floats = require("../src/floats.js");
let i8 = new Int8Array(4);
let i32 = new Int32Array(i8.buffer, 0, 1);
let f32 = new Float32Array(i8.buffer, 0, 1);

/**
 * Read a group of bytes by turning it to bits.
 * Useful for 40 & 48-bit, but underperform.
 * @param {!Array<number>|Uint8Array} bytes An array of bytes.
 * @param {number} i The index to read.
 * @param {number} numBytes The number of bytes
 *      (1 for 8-bit, 2 for 16-bit, etc).
 * @return {number}
 */
function readBytesAsBits(bytes, i, numBytes) {
    let j = numBytes-1;
    let bits = "";
    while (j >= 0) {
        bits += helpers.bytePadding(bytes[j + i].toString(2), 2);
        j--;
    }
    return parseInt(bits, 2);
}

let BitReader = {

    /**
     * Read 1 8-bit int from from bytes.
     * @param {!Array<number>|Uint8Array} bytes An array of bytes.
     * @param {number} i The index to read.
     * @return {number}
     */
    "read8Bit": function (bytes, i) {
        return bytes[i];
    },

    /**
     * Read 1 16-bit int from from bytes.
     * @param {!Array<number>|Uint8Array} bytes An array of bytes.
     * @param {number} i The index to read.
     * @return {number}
     */
    "read16Bit": function (bytes, i) {
        return bytes[1 + i] << 8 | bytes[i];
    },

    /**
     * Read 1 16-bit float from from bytes.
     * @param {!Array<number>|Uint8Array} bytes An array of bytes.
     * @param {number} i The index to read.
     * @return {number}
     */
    "read16BitFloat": function (bytes, i) {
        return floats.decodeFloat16(bytes.slice(i,i+2));
    },

    /**
     * Read 1 24-bit int from from bytes.
     * @param {!Array<number>|Uint8Array} bytes An array of bytes.
     * @param {number} i The index to read.
     * @return {number}
     */
    "read24Bit": function (bytes, i) {
        return bytes[2 + i] << 16 | BitReader["read16Bit"](bytes, i);
    },

    /**
     * Read 1 32-bit int from from bytes.
     * @param {!Array<number>|Uint8Array} bytes An array of bytes.
     * @param {number} i The index to read.
     * @return {number}
     */
    "read32Bit": function (bytes, i) {
        return (bytes[3 + i] << 24 |
            BitReader["read24Bit"](bytes, i)) >>> 0;
    },

    /**
     * Read 1 32-bit float from from bytes.
     * @param {!Array<number>|Uint8Array} bytes An array of bytes.
     * @param {number} i The index to read.
     * @return {number}
     */
    "read32BitFloat": function (bytes, i) {
        i32[0] = BitReader["read32Bit"](bytes, i);
        return f32[0];
    },

    /**
     * Read 1 40-bit int from from bytes.
     * @param {!Array<number>|Uint8Array} bytes An array of bytes.
     * @param {number} i The index to read.
     * @return {number}
     */
    "read40Bit": function (bytes, i) {
        return readBytesAsBits(bytes, i, 5);
    },

    /**
     * Read 1 48-bit int from bytes.
     * @param {!Array<number>|Uint8Array} bytes An array of bytes.
     * @param {number} i The index to read.
     * @return {number}
     */
    "read48Bit": function (bytes, i) {
        return readBytesAsBits(bytes, i, 6);
    },

    /**
     * Read 1 64-bit double from bytes.
     * @param {!Array<number>|Uint8Array} bytes An array of bytes.
     * @param {number} i The index to read.
     * @return {number}
     */
    "read64BitFloat": function (bytes, i) {
        return floats.decodeFloat64(bytes.slice(i,i+8));
    },

    /**
     * Read 1 char from bytes.
     * @param {!Array<number>|Uint8Array} bytes An array of bytes.
     * @param {number} i The index to read.
     * @return {string}
     */
    "readChar": function (bytes, i, type) {
        let chrs = "";
        let j = 0;
        let len = type.bits / 8;
        while(j < len) {
            chrs += String.fromCharCode(bytes[i+j]);
            j++;
        }
        return chrs;
    }
};

let BitWriter = {

    "write64BitFloat": function(bytes, number, j) {
        let bits = floats.toFloat64(number);
        j = BitWriter["write32Bit"](bytes, bits[1], j);
        return BitWriter["write32Bit"](bytes, bits[0], j);
    },

    // Thanks https://github.com/majimboo/c-struct
    "write48Bit": function (bytes, number, j) {
        j = BitWriter["write40Bit"](bytes, number, j);
        bytes[j++] = number / 0x10000000000 & 0xFF;
        return j;
    },

    // Thanks https://github.com/majimboo/c-struct
    "write40Bit": function (bytes, number, j) {
        j = BitWriter["write32Bit"](bytes, number, j);
        bytes[j++] = number / 0x100000000 & 0xFF;
        return j;
    },

    "write32BitFloat": function (bytes, number, j) {
        f32[0] = number;
        j = BitWriter["write32Bit"](bytes, i32[0], j);
        return j;
    },

    "write32Bit": function (bytes, number, j) {
        j = BitWriter["write24Bit"](bytes, number, j);
        bytes[j++] = number >>> 24 & 0xFF;
        return j;
    },

    "write24Bit": function (bytes, number, j) {
        j = BitWriter["write16Bit"](bytes, number, j);
        bytes[j++] = number >>> 16 & 0xFF;
        return j;
    },

    "write16Bit": function (bytes, number, j) {
        bytes[j++] = number & 0xFF;
        bytes[j++] = number >>> 8 & 0xFF;
        return j;
    },

    "write16BitFloat": function (bytes, number, j) {
        let bits = floats.toHalf(number);
        bytes[j++] = bits >>> 8 & 0xFF;
        bytes[j++] = bits & 0xFF;
        return j;
    },

    "write8Bit": function (bytes, number, j) {
        bytes[j++] = number & 0xFF;
        return j;
    },

    "write4Bit": function (bytes, number, j) {
        bytes[j++] = number & 0xF;
        return j;
    },

    "write2Bit": function (bytes, number, j) {
        bytes[j++] = number < 0 ? number + 4 : number;
        return j;
    },

    "write1Bit": function (bytes, number, j) {
        bytes[j++] = number ? 1 : 0;
        return j;
    },

    "writeString": function (bytes, string, j) {
        bytes[j++] = string.charCodeAt(0);
        return j;
    }
};

module.exports.BitWriter = BitWriter;
module.exports.BitReader = BitReader;


1			/**
2			* bit-parser: Functions to read and write bytes.
3			* Copyright (c) 2017 Rafael da Silva Rocha.
4			* https://github.com/rochars/byte-data
5			* Float32 based on int-bits: https://github.com/Jam3/int-bits
6			*/
7
8			const helpers = require("../src/helpers.js");
9			const floats = require("../src/floats.js");
10			let i8 = new Int8Array(4);
11			let i32 = new Int32Array(i8.buffer, 0, 1);
12			let f32 = new Float32Array(i8.buffer, 0, 1);
13
14			/**
15			* Read a group of bytes by turning it to bits.
16			* Useful for 40 & 48-bit, but underperform.
17			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
18			* @param {number} i The index to read.
19			* @param {number} numBytes The number of bytes
20			* (1 for 8-bit, 2 for 16-bit, etc).
21			* @return {number}
22			*/
23			function readBytesAsBits(bytes, i, numBytes) {
24			let j = numBytes-1;
25			let bits = "";
26			while (j >= 0) {
27			bits += helpers.bytePadding(bytes[j + i].toString(2), 2);
28			j--;
29			}
30			return parseInt(bits, 2);
31			}
32
33			let BitReader = {
34
35			/**
36			* Read 1 8-bit int from from bytes.
37			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
38			* @param {number} i The index to read.
39			* @return {number}
40			*/
41			"read8Bit": function (bytes, i) {
42			return bytes[i];
43			},
44
45			/**
46			* Read 1 16-bit int from from bytes.
47			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
48			* @param {number} i The index to read.
49			* @return {number}
50			*/
51			"read16Bit": function (bytes, i) {
52			return bytes[1 + i] << 8 \| bytes[i];
53			},
54
55			/**
56			* Read 1 16-bit float from from bytes.
57			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
58			* @param {number} i The index to read.
59			* @return {number}
60			*/
61			"read16BitFloat": function (bytes, i) {
62			return floats.decodeFloat16(bytes.slice(i,i+2));
63			},
64
65			/**
66			* Read 1 24-bit int from from bytes.
67			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
68			* @param {number} i The index to read.
69			* @return {number}
70			*/
71			"read24Bit": function (bytes, i) {
72			return bytes[2 + i] << 16 \| BitReader["read16Bit"](bytes, i);
73			},
74
75			/**
76			* Read 1 32-bit int from from bytes.
77			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
78			* @param {number} i The index to read.
79			* @return {number}
80			*/
81			"read32Bit": function (bytes, i) {
82			return (bytes[3 + i] << 24 \|
83			BitReader["read24Bit"](bytes, i)) >>> 0;
84			},
85
86			/**
87			* Read 1 32-bit float from from bytes.
88			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
89			* @param {number} i The index to read.
90			* @return {number}
91			*/
92			"read32BitFloat": function (bytes, i) {
93			i32[0] = BitReader["read32Bit"](bytes, i);
94			return f32[0];
95			},
96
97			/**
98			* Read 1 40-bit int from from bytes.
99			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
100			* @param {number} i The index to read.
101			* @return {number}
102			*/
103			"read40Bit": function (bytes, i) {
104			return readBytesAsBits(bytes, i, 5);
105			},
106
107			/**
108			* Read 1 48-bit int from bytes.
109			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
110			* @param {number} i The index to read.
111			* @return {number}
112			*/
113			"read48Bit": function (bytes, i) {
114			return readBytesAsBits(bytes, i, 6);
115			},
116
117			/**
118			* Read 1 64-bit double from bytes.
119			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
120			* @param {number} i The index to read.
121			* @return {number}
122			*/
123			"read64BitFloat": function (bytes, i) {
124			return floats.decodeFloat64(bytes.slice(i,i+8));
125			},
126
127			/**
128			* Read 1 char from bytes.
129			* @param {!Array<number>\|Uint8Array} bytes An array of bytes.
130			* @param {number} i The index to read.
131			* @return {string}
132			*/
133			"readChar": function (bytes, i, type) {
134			let chrs = "";
135			let j = 0;
136			let len = type.bits / 8;
137			while(j < len) {
138			chrs += String.fromCharCode(bytes[i+j]);
139			j++;
140			}
141			return chrs;
142			}
143			};
144
145			let BitWriter = {
146
147			"write64BitFloat": function(bytes, number, j) {
148			let bits = floats.toFloat64(number);
149			j = BitWriter["write32Bit"](bytes, bits[1], j);
150			return BitWriter["write32Bit"](bytes, bits[0], j);
151			},
152
153			// Thanks https://github.com/majimboo/c-struct
154			"write48Bit": function (bytes, number, j) {
155			j = BitWriter["write40Bit"](bytes, number, j);
156			bytes[j++] = number / 0x10000000000 & 0xFF;
157			return j;
158			},
159
160			// Thanks https://github.com/majimboo/c-struct
161			"write40Bit": function (bytes, number, j) {
162			j = BitWriter["write32Bit"](bytes, number, j);
163			bytes[j++] = number / 0x100000000 & 0xFF;
164			return j;
165			},
166
167			"write32BitFloat": function (bytes, number, j) {
168			f32[0] = number;
169			j = BitWriter["write32Bit"](bytes, i32[0], j);
170			return j;
171			},
172
173			"write32Bit": function (bytes, number, j) {
174			j = BitWriter["write24Bit"](bytes, number, j);
175			bytes[j++] = number >>> 24 & 0xFF;
176			return j;
177			},
178
179			"write24Bit": function (bytes, number, j) {
180			j = BitWriter["write16Bit"](bytes, number, j);
181			bytes[j++] = number >>> 16 & 0xFF;
182			return j;
183			},
184
185			"write16Bit": function (bytes, number, j) {
186			bytes[j++] = number & 0xFF;
187			bytes[j++] = number >>> 8 & 0xFF;
188			return j;
189			},
190
191			"write16BitFloat": function (bytes, number, j) {
192			let bits = floats.toHalf(number);
193			bytes[j++] = bits >>> 8 & 0xFF;
194			bytes[j++] = bits & 0xFF;
195			return j;
196			},
197
198			"write8Bit": function (bytes, number, j) {
199			bytes[j++] = number & 0xFF;
200			return j;
201			},
202
203			"write4Bit": function (bytes, number, j) {
204			bytes[j++] = number & 0xF;
205			return j;
206			},
207
208			"write2Bit": function (bytes, number, j) {
209			bytes[j++] = number < 0 ? number + 4 : number;
210			return j;
211			},
212
213			"write1Bit": function (bytes, number, j) {
214			bytes[j++] = number ? 1 : 0;
215			return j;
216			},
217
218			"writeString": function (bytes, string, j) {
219			bytes[j++] = string.charCodeAt(0);
220			return j;
221			}
222			};
223
224			module.exports.BitWriter = BitWriter;
225			module.exports.BitReader = BitReader;
226

rochars / byte-data

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