52 lines
1.1 KiB
JavaScript
52 lines
1.1 KiB
JavaScript
function byteLength (string) {
|
|
return string.length >>> 1
|
|
}
|
|
|
|
function toString (buffer) {
|
|
const len = buffer.byteLength
|
|
|
|
buffer = new DataView(buffer.buffer, buffer.byteOffset, len)
|
|
|
|
let result = ''
|
|
let i = 0
|
|
|
|
for (let n = len - (len % 4); i < n; i += 4) {
|
|
result += buffer.getUint32(i).toString(16).padStart(8, '0')
|
|
}
|
|
|
|
for (; i < len; i++) {
|
|
result += buffer.getUint8(i).toString(16).padStart(2, '0')
|
|
}
|
|
|
|
return result
|
|
}
|
|
|
|
function write (buffer, string, offset = 0, length = byteLength(string)) {
|
|
const len = Math.min(length, buffer.byteLength - offset)
|
|
|
|
for (let i = 0; i < len; i++) {
|
|
const a = hexValue(string.charCodeAt(i * 2))
|
|
const b = hexValue(string.charCodeAt(i * 2 + 1))
|
|
|
|
if (a === undefined || b === undefined) {
|
|
return buffer.subarray(0, i)
|
|
}
|
|
|
|
buffer[offset + i] = (a << 4) | b
|
|
}
|
|
|
|
return len
|
|
}
|
|
|
|
module.exports = {
|
|
byteLength,
|
|
toString,
|
|
write
|
|
}
|
|
|
|
function hexValue (char) {
|
|
if (char >= 0x30 && char <= 0x39) return char - 0x30
|
|
if (char >= 0x41 && char <= 0x46) return char - 0x41 + 10
|
|
if (char >= 0x61 && char <= 0x66) return char - 0x61 + 10
|
|
}
|