PromoCursed/node_modules/@leichtgewicht/ip-codec/index.mjs
2024-08-20 23:25:37 +04:00

202 lines
5.9 KiB
JavaScript

const v4Regex = /^(\d{1,3}\.){3,3}\d{1,3}$/
const v4Size = 4
const v6Regex = /^(::)?(((\d{1,3}\.){3}(\d{1,3}){1})?([0-9a-f]){0,4}:{0,2}){1,8}(::)?$/i
const v6Size = 16
export const v4 = {
name: 'v4',
size: v4Size,
isFormat: ip => v4Regex.test(ip),
encode (ip, buff, offset) {
offset = ~~offset
buff = buff || new Uint8Array(offset + v4Size)
const max = ip.length
let n = 0
for (let i = 0; i < max;) {
const c = ip.charCodeAt(i++)
if (c === 46) { // "."
buff[offset++] = n
n = 0
} else {
n = n * 10 + (c - 48)
}
}
buff[offset] = n
return buff
},
decode (buff, offset) {
offset = ~~offset
return `${buff[offset++]}.${buff[offset++]}.${buff[offset++]}.${buff[offset]}`
}
}
export const v6 = {
name: 'v6',
size: v6Size,
isFormat: ip => ip.length > 0 && v6Regex.test(ip),
encode (ip, buff, offset) {
offset = ~~offset
let end = offset + v6Size
let fill = -1
let hexN = 0
let decN = 0
let prevColon = true
let useDec = false
buff = buff || new Uint8Array(offset + v6Size)
// Note: This algorithm needs to check if the offset
// could exceed the buffer boundaries as it supports
// non-standard compliant encodings that may go beyond
// the boundary limits. if (offset < end) checks should
// not be necessary...
for (let i = 0; i < ip.length; i++) {
let c = ip.charCodeAt(i)
if (c === 58) { // :
if (prevColon) {
if (fill !== -1) {
// Not Standard! (standard doesn't allow multiple ::)
// We need to treat
if (offset < end) buff[offset] = 0
if (offset < end - 1) buff[offset + 1] = 0
offset += 2
} else if (offset < end) {
// :: in the middle
fill = offset
}
} else {
// : ends the previous number
if (useDec === true) {
// Non-standard! (ipv4 should be at end only)
// A ipv4 address should not be found anywhere else but at
// the end. This codec also support putting characters
// after the ipv4 address..
if (offset < end) buff[offset] = decN
offset++
} else {
if (offset < end) buff[offset] = hexN >> 8
if (offset < end - 1) buff[offset + 1] = hexN & 0xff
offset += 2
}
hexN = 0
decN = 0
}
prevColon = true
useDec = false
} else if (c === 46) { // . indicates IPV4 notation
if (offset < end) buff[offset] = decN
offset++
decN = 0
hexN = 0
prevColon = false
useDec = true
} else {
prevColon = false
if (c >= 97) {
c -= 87 // a-f ... 97~102 -87 => 10~15
} else if (c >= 65) {
c -= 55 // A-F ... 65~70 -55 => 10~15
} else {
c -= 48 // 0-9 ... starting from charCode 48
decN = decN * 10 + c
}
// We don't know yet if its a dec or hex number
hexN = (hexN << 4) + c
}
}
if (prevColon === false) {
// Commiting last number
if (useDec === true) {
if (offset < end) buff[offset] = decN
offset++
} else {
if (offset < end) buff[offset] = hexN >> 8
if (offset < end - 1) buff[offset + 1] = hexN & 0xff
offset += 2
}
} else if (fill === 0) {
// Not Standard! (standard doesn't allow multiple ::)
// This means that a : was found at the start AND end which means the
// end needs to be treated as 0 entry...
if (offset < end) buff[offset] = 0
if (offset < end - 1) buff[offset + 1] = 0
offset += 2
} else if (fill !== -1) {
// Non-standard! (standard doens't allow multiple ::)
// Here we find that there has been a :: somewhere in the middle
// and the end. To treat the end with priority we need to move all
// written data two bytes to the right.
offset += 2
for (let i = Math.min(offset - 1, end - 1); i >= fill + 2; i--) {
buff[i] = buff[i - 2]
}
buff[fill] = 0
buff[fill + 1] = 0
fill = offset
}
if (fill !== offset && fill !== -1) {
// Move the written numbers to the end while filling the everything
// "fill" to the bytes with zeros.
if (offset > end - 2) {
// Non Standard support, when the cursor exceeds bounds.
offset = end - 2
}
while (end > fill) {
buff[--end] = offset < end && offset > fill ? buff[--offset] : 0
}
} else {
// Fill the rest with zeros
while (offset < end) {
buff[offset++] = 0
}
}
return buff
},
decode (buff, offset) {
offset = ~~offset
let result = ''
for (let i = 0; i < v6Size; i += 2) {
if (i !== 0) {
result += ':'
}
result += (buff[offset + i] << 8 | buff[offset + i + 1]).toString(16)
}
return result
.replace(/(^|:)0(:0)*:0(:|$)/, '$1::$3')
.replace(/:{3,4}/, '::')
}
}
export const name = 'ip'
export function sizeOf (ip) {
if (v4.isFormat(ip)) return v4.size
if (v6.isFormat(ip)) return v6.size
throw Error(`Invalid ip address: ${ip}`)
}
export function familyOf (string) {
return sizeOf(string) === v4.size ? 1 : 2
}
export function encode (ip, buff, offset) {
offset = ~~offset
const size = sizeOf(ip)
if (typeof buff === 'function') {
buff = buff(offset + size)
}
if (size === v4.size) {
return v4.encode(ip, buff, offset)
}
return v6.encode(ip, buff, offset)
}
export function decode (buff, offset, length) {
offset = ~~offset
length = length || (buff.length - offset)
if (length === v4.size) {
return v4.decode(buff, offset, length)
}
if (length === v6.size) {
return v6.decode(buff, offset, length)
}
throw Error(`Invalid buffer size needs to be ${v4.size} for v4 or ${v6.size} for v6.`)
}