|
1
|
|
|
/* |
|
2
|
|
|
* helpers: functions to work with bytes and byte arrays. |
|
3
|
|
|
* Copyright (c) 2017 Rafael da Silva Rocha. |
|
4
|
|
|
* https://github.com/rochars/byte-data |
|
5
|
|
|
*/ |
|
6
|
|
|
|
|
7
|
|
|
const endianness = require("endianness"); |
|
8
|
|
|
const bitDepths = require("../src/bit-depth.js"); |
|
9
|
|
|
|
|
10
|
|
|
/** |
|
11
|
|
|
* Padding for binary strings. |
|
12
|
|
|
* @param {!Array<string>} bytes The bytes as binary strings. |
|
13
|
|
|
* @param {number} base The base. |
|
14
|
|
|
* @param {number} index The byte to pad. |
|
15
|
|
|
*/ |
|
16
|
|
|
function padding(bytes, base, index) { |
|
17
|
|
|
bytes[index] = bytePadding(bytes[index], base); |
|
18
|
|
|
} |
|
19
|
|
|
|
|
20
|
|
|
/** |
|
21
|
|
|
* Padding with 0s for byte strings. |
|
22
|
|
|
* @param {string} theByte The byte as a binary or hex string. |
|
23
|
|
|
* @param {number} base The base. |
|
24
|
|
|
* @returns {string} The padded byte. |
|
25
|
|
|
*/ |
|
26
|
|
|
function bytePadding(theByte, base) { |
|
27
|
|
|
let offset = theByte.length + 1; |
|
28
|
|
|
if (base == 2) { |
|
29
|
|
|
offset = 8; |
|
30
|
|
|
} else if (base == 16) { |
|
31
|
|
|
offset = 2; |
|
32
|
|
|
} |
|
33
|
|
|
return lPadZeros(theByte, offset); |
|
34
|
|
|
} |
|
35
|
|
|
|
|
36
|
|
|
/** |
|
37
|
|
|
* Fix the size of nibbles. |
|
38
|
|
|
* @param {!Array<string>} nibbles The nibble as a binary or hex string. |
|
39
|
|
|
* @param {number} base The base. |
|
40
|
|
|
* @param {number} index The nibble offset. |
|
41
|
|
|
*/ |
|
42
|
|
|
function paddingNibble(nibbles, base, index) { |
|
43
|
|
|
if (base == 2 && nibbles[index].length < 4) { |
|
44
|
|
|
nibbles[index] = |
|
45
|
|
|
new Array((5 - nibbles[index].length)).join("0") + nibbles[index]; |
|
46
|
|
|
} |
|
47
|
|
|
} |
|
48
|
|
|
|
|
49
|
|
|
/** |
|
50
|
|
|
* Fix the size of crumbs. |
|
51
|
|
|
* @param {!Array<string>} crumbs The nibble as a binary or hex string. |
|
52
|
|
|
* @param {number} base The base. |
|
53
|
|
|
* @param {number} index The nibble offset. |
|
54
|
|
|
*/ |
|
55
|
|
|
function paddingCrumb(crumbs, base, index) { |
|
56
|
|
|
if ((base == 2 || base == 16) && crumbs[index].length < 2) { |
|
57
|
|
|
crumbs[index] = '0' + crumbs[index]; |
|
58
|
|
|
} |
|
59
|
|
|
} |
|
60
|
|
|
|
|
61
|
|
|
/** |
|
62
|
|
|
* Pad a string with zeros to the left. |
|
63
|
|
|
* TODO: This should support both arrays and strings. |
|
64
|
|
|
* @param {string} value The string (representing a binary or hex value). |
|
65
|
|
|
* @param {number} numZeros the max number of zeros. |
|
66
|
|
|
* For 1 binary byte string it should be 8. |
|
67
|
|
|
*/ |
|
68
|
|
|
function lPadZeros(value, numZeros) { |
|
69
|
|
|
while (value.length < numZeros) { |
|
70
|
|
|
value = '0' + value; |
|
71
|
|
|
} |
|
72
|
|
|
return value; |
|
73
|
|
|
} |
|
74
|
|
|
|
|
75
|
|
|
/** |
|
76
|
|
|
* Pad a array with zeros to the right. |
|
77
|
|
|
* @param {!Array<number>} byteArray The array. |
|
78
|
|
|
* @param {number} numZeros the max number of zeros. |
|
79
|
|
|
* For 1 binary byte string it should be 8. |
|
80
|
|
|
* TODO: better explanation of numZeros |
|
81
|
|
|
*/ |
|
82
|
|
|
function fixByteArraySize(byteArray, numZeros) { |
|
83
|
|
|
let i = 0; |
|
84
|
|
|
let fix = byteArray.length % numZeros; |
|
85
|
|
|
if (fix) { |
|
86
|
|
|
fix = (fix - numZeros) * -1; |
|
87
|
|
|
while(i < fix) { |
|
88
|
|
|
byteArray.push(0); |
|
89
|
|
|
i++; |
|
90
|
|
|
} |
|
91
|
|
|
} |
|
92
|
|
|
} |
|
93
|
|
|
|
|
94
|
|
|
/** |
|
95
|
|
|
* Swap the endianness to big endian. |
|
96
|
|
|
* @param {!Array<number>} bytes The values. |
|
97
|
|
|
* @param {boolean} isBigEndian True if the bytes should be big endian. |
|
98
|
|
|
* @param {number} bitDepth The bitDepth of the data. |
|
99
|
|
|
*/ |
|
100
|
|
|
function makeBigEndian(bytes, isBigEndian, bitDepth) { |
|
101
|
|
|
if (isBigEndian) { |
|
102
|
|
|
endianness(bytes, bitDepths.BitDepthOffsets[bitDepth]); |
|
103
|
|
|
} |
|
104
|
|
|
} |
|
105
|
|
|
|
|
106
|
|
|
/** |
|
107
|
|
|
* Turn bytes to base 2, 10 or 16. |
|
108
|
|
|
* @param {!Array<string>|!Array<number>} bytes The bytes. |
|
109
|
|
|
* @param {number} base The base. |
|
110
|
|
|
* @param {Function} padFunction The function to use for padding. |
|
111
|
|
|
*/ |
|
112
|
|
|
function bytesToBase(bytes, base, padFunction=padding) { |
|
113
|
|
|
if (base != 10) { |
|
114
|
|
|
let i = 0; |
|
115
|
|
|
let len = bytes.length; |
|
116
|
|
|
while (i < len) { |
|
117
|
|
|
bytes[i] = bytes[i].toString(base); |
|
118
|
|
|
padFunction(bytes, base, i); |
|
119
|
|
|
i++; |
|
120
|
|
|
} |
|
121
|
|
|
} |
|
122
|
|
|
} |
|
123
|
|
|
|
|
124
|
|
|
/** |
|
125
|
|
|
* Turn the output to the correct base. |
|
126
|
|
|
* @param {!Array<number>} bytes The bytes. |
|
127
|
|
|
* @param {number} bitDepth The bit depth of the data. |
|
128
|
|
|
* @param {number} base The desired base for the output data. |
|
129
|
|
|
*/ |
|
130
|
|
|
function outputToBase(bytes, bitDepth, base) { |
|
131
|
|
|
if (bitDepth == 4) { |
|
132
|
|
|
bytesToBase(bytes, base, paddingNibble); |
|
133
|
|
|
} else if (bitDepth == 2) { |
|
134
|
|
|
bytesToBase(bytes, base, paddingCrumb); |
|
135
|
|
|
} else if(bitDepth == 1) { |
|
136
|
|
|
bytesToBase(bytes, base, function(){}); |
|
137
|
|
|
}else { |
|
138
|
|
|
bytesToBase(bytes, base); |
|
139
|
|
|
} |
|
140
|
|
|
} |
|
141
|
|
|
|
|
142
|
|
|
/** |
|
143
|
|
|
* Make a single value an array in case it is not. |
|
144
|
|
|
* If the value is a string it stays a string. |
|
145
|
|
|
* @param {!Array<number>|number|string} values The value or values. |
|
146
|
|
|
* @return {!Array<number>|string} |
|
147
|
|
|
*/ |
|
148
|
|
|
function turnToArray(values) { |
|
149
|
|
|
if (!Array.isArray(values) && typeof values != "string") { |
|
150
|
|
|
values = [values]; |
|
151
|
|
|
} |
|
152
|
|
|
return values; |
|
153
|
|
|
} |
|
154
|
|
|
|
|
155
|
|
|
/** |
|
156
|
|
|
* Turn a unsigned number to a signed number. |
|
157
|
|
|
* @param {number} num The number. |
|
158
|
|
|
* @param {number} maxValue The max range for the number bit depth. |
|
159
|
|
|
*/ |
|
160
|
|
|
function signed(num, maxValue) { |
|
161
|
|
|
if (num > parseInt(maxValue / 2, 10) - 1) { |
|
162
|
|
|
num -= maxValue; |
|
163
|
|
|
} |
|
164
|
|
|
return num; |
|
165
|
|
|
} |
|
166
|
|
|
|
|
167
|
|
|
/** |
|
168
|
|
|
* Fix the endianness of float16 bytes (r/w is always big-endian). |
|
169
|
|
|
* @param {!Array<number>|Uint8Array} bytes The bytes. |
|
170
|
|
|
* @param {Object} options The type. |
|
171
|
|
|
*/ |
|
172
|
|
|
function fixFloat16Endianness(bytes, options) { |
|
173
|
|
|
if (options.float && options.bits == 16) { |
|
174
|
|
|
endianness(bytes, 2); |
|
175
|
|
|
} |
|
176
|
|
|
} |
|
177
|
|
|
|
|
178
|
|
|
/** |
|
179
|
|
|
* Build a type based on the arguments. |
|
180
|
|
|
* @param {Object} options The type. |
|
181
|
|
|
* @param {number} bitDepth The bit depth. |
|
182
|
|
|
*/ |
|
183
|
|
|
function buildType(options, bitDepth) { |
|
184
|
|
|
if (bitDepth == 64) { |
|
185
|
|
|
options.float = true; |
|
186
|
|
|
} |
|
187
|
|
|
if (options.float) { |
|
188
|
|
|
options.signed = true; |
|
189
|
|
|
} |
|
190
|
|
|
options.bits = bitDepth; |
|
191
|
|
|
} |
|
192
|
|
|
|
|
193
|
|
|
module.exports.makeBigEndian = makeBigEndian; |
|
194
|
|
|
module.exports.bytesToBase = bytesToBase; |
|
195
|
|
|
module.exports.outputToBase = outputToBase; |
|
196
|
|
|
module.exports.turnToArray = turnToArray; |
|
197
|
|
|
module.exports.signed = signed; |
|
198
|
|
|
module.exports.fixByteArraySize = fixByteArraySize; |
|
199
|
|
|
module.exports.padding = padding; |
|
200
|
|
|
module.exports.paddingNibble = paddingNibble; |
|
201
|
|
|
module.exports.paddingCrumb = paddingCrumb; |
|
202
|
|
|
module.exports.bytePadding = bytePadding; |
|
203
|
|
|
module.exports.lPadZeros = lPadZeros; |
|
204
|
|
|
module.exports.fixFloat16Endianness = fixFloat16Endianness; |
|
205
|
|
|
module.exports.buildType = buildType; |
|
206
|
|
|
|