File size: 2,661 Bytes
f56a29b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 | function byteLength(string) {
let length = 0
for (let i = 0, n = string.length; i < n; i++) {
const code = string.charCodeAt(i)
if (code >= 0xd800 && code <= 0xdbff && i + 1 < n) {
const code = string.charCodeAt(i + 1)
if (code >= 0xdc00 && code <= 0xdfff) {
length += 4
i++
continue
}
}
if (code <= 0x7f) length += 1
else if (code <= 0x7ff) length += 2
else length += 3
}
return length
}
let toString
if (typeof TextDecoder !== 'undefined') {
const decoder = new TextDecoder()
toString = function toString(buffer) {
return decoder.decode(buffer)
}
} else {
toString = function toString(buffer) {
const len = buffer.byteLength
let output = ''
let i = 0
while (i < len) {
let byte = buffer[i]
if (byte <= 0x7f) {
output += String.fromCharCode(byte)
i++
continue
}
let bytesNeeded = 0
let codePoint = 0
if (byte <= 0xdf) {
bytesNeeded = 1
codePoint = byte & 0x1f
} else if (byte <= 0xef) {
bytesNeeded = 2
codePoint = byte & 0x0f
} else if (byte <= 0xf4) {
bytesNeeded = 3
codePoint = byte & 0x07
}
if (len - i - bytesNeeded > 0) {
let k = 0
while (k < bytesNeeded) {
byte = buffer[i + k + 1]
codePoint = (codePoint << 6) | (byte & 0x3f)
k += 1
}
} else {
codePoint = 0xfffd
bytesNeeded = len - i
}
output += String.fromCodePoint(codePoint)
i += bytesNeeded + 1
}
return output
}
}
let write
if (typeof TextEncoder !== 'undefined') {
const encoder = new TextEncoder()
write = function write(buffer, string) {
return encoder.encodeInto(string, buffer).written
}
} else {
write = function write(buffer, string) {
const len = buffer.byteLength
let i = 0
let j = 0
while (i < string.length) {
const code = string.codePointAt(i)
if (code <= 0x7f) {
buffer[j++] = code
i++
continue
}
let count = 0
let bits = 0
if (code <= 0x7ff) {
count = 6
bits = 0xc0
} else if (code <= 0xffff) {
count = 12
bits = 0xe0
} else if (code <= 0x1fffff) {
count = 18
bits = 0xf0
}
buffer[j++] = bits | (code >> count)
count -= 6
while (count >= 0) {
buffer[j++] = 0x80 | ((code >> count) & 0x3f)
count -= 6
}
i += code >= 0x10000 ? 2 : 1
}
return len
}
}
module.exports = {
byteLength,
toString,
write
}
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