Repository files navigation

Tools to work with IPv4 and IPv6 CIDR, but 20x faster thancidr-tools, and isnot Pure ESM (publish both CommonJS and ESM).

RequiresBigInt supports.

import{ip2bigint,// support both IPv4 and IPv6bigint2ip,// support both IPv4 and IPv6contains,exclude,expand,merge,overlap}from'fast-cidr-tools';contains(['1.0.0.0/24','2.0.0.0/24'],['1.0.0.1'])//=> trueexclude(['::1/127'],['::1/128'])//=> ['::/128']expand(['2001:db8::/126'])//=> ['2001:db8::', '2001:db8::1', '2001:db8::2', '2001:db8::3']merge(['1.0.0.0/24'],['1.0.1.0/24']);//=> ['1.0.0.0/23']overlap(['1.0.0.0/24'],['1.0.0.128/25'])//=> true

fast-cidr-tools is very fast, and is specfically optimized for IPv4. In some cases, it can be 20x faster thancidr-tools.fast-cidr-tools acheive this performance by:

• Doing less things, E.g.:
  • cidr-tools will cast input to an array if it is string (cidrTools.merge('1.0.0.0/24', '1.0.1.0/24')).fast-cidr-tools only supports array input.
  • cidr-tools sort the return value ofmerge andexclude by default.fast-cidr-tools's sort is opt-in.
  • And many more.
• Use efficient calculation and avoid unnecessary string operations.
  • howcidr-tools andfast-cidr-tools calculate the "biggest power of two":

    // cidr-toolsfunctionbiggestPowerOfTwo(num){if(num===0n)return0n;return2n**BigInt(String(num.toString(2).length-1));}// fast-cidr-tools// Not the actual implementation: fast-cidr-tools actually inlines the calculation// for better performanceconstuint64=newBigUint64Array(1);constuint32=newUint32Array(uint64.buffer);functionclz64(bigint:bigint){uint64[0]=bigint;letr=Math.clz32(uint32[1]);if(r===32){r+=Math.clz32(uint32[0]);}returnr;}functionbiggestPowerOfTwo(num:bigint){if(num===0n)return0n;constpower=BigInt(64-clz64(size)-1);return2n**(power===-1n ?128n :power);}

  • howcidr-tools andfast-cidr-tools calculate the prefix of a CIDR:

    // cidr-toolsconstzeroes=(part.end+1n-part.start).toString(2);constprefix=bits[v]-(zeroes.match(/0/g)||[]).length;// fast-cidr-toolsfunctionfast_popcnt(value:bigint|number){letv=Number(value);v-=v>>>1&0x55_55_55_55;v=(v&0x33_33_33_33)+(v>>>2&0x33_33_33_33);returnBigInt((((v+(v>>>4))&0x0F_0F_0F_0F)*0x01_01_01_01)>>>24);}constuint64_0=newBigInt64Array(1);constuint32_0=newInt32Array(uint64_0.buffer);functionfast_popcnt64(value:bigint){uint64_0[0]=value;returnfast_popcnt(uint32_0[0])+fast_popcnt(uint32_0[1]);}constprefix=bits[v]-(v===4 ?fast_popcnt(end-start) :fast_popcnt64(end-start));

• Use a more compact internal data structure. Compare howcidr-tools andfast-cidr-tools represent a CIDR internally:

  // cidr-toolsparse('::/64');//=> { cidr: '::/64', version: 6, prefix: '64', start: 0n, end: 18446744073709551615n }// fast-cidr-toolsparse('::/64');//=> [0n, 18446744073709551615n, 6]

• Avoid repeated calculations. Notice howfast-cidr-tools pre-parse inputs instead of parsing them repeatedly:
  • cidr-tools
  • fast-cidr-tools

fast-cidr-tools ©Sukka, Authored and maintained by Sukka with help from contributors (list).

Personal Website ·Blog · GitHub@SukkaW · Telegram Channel@SukkaChannel · Twitter@isukkaw · Keybase@sukka