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