io.js PR#169 https://github.com/iojs/io.js/pull/169

buffer methods

Buffer.prototype.readUInt24LE = function(offset, noAssert) {
        offset = offset >>> 0;
        if (!noAssert)
          checkOffset(offset, 3, this.length);

        return ((this[offset]) |
            (this[offset + 1] << 8) |
            (this[offset + 2] << 16));
    };


    Buffer.prototype.readUInt24BE = function(offset, noAssert) {
        offset = offset >>> 0;
        if (!noAssert)
          checkOffset(offset, 3, this.length);

        return ((this[offset] << 16) |
            (this[offset + 1] << 8) |
            this[offset + 2]);
    };


    Buffer.prototype.readInt24LE = function(offset, noAssert) {
        offset = offset >>> 0;
        if (!noAssert)
          checkOffset(offset, 3, this.length);

        return (this[offset]) |
            (this[offset + 1] << 8) |
            (this[offset + 2] << 16);
    };

    Buffer.prototype.readInt24BE = function(offset, noAssert) {
        offset = offset >>> 0;
        if (!noAssert)
          checkOffset(offset, 3, this.length);

        return (this[offset] << 16) |
            (this[offset + 1] << 8) |
            (this[offset + 2]);
    };

    Buffer.prototype.writeUInt24LE = function(value, offset, noAssert) {
        value = +value;
        offset = offset >>> 0;
        if (!noAssert)
          checkInt(this, value, offset, 3, 0xffffff, 0);
        this[offset + 2] = (value >>> 16);
        this[offset + 1] = (value >>> 8);
        this[offset] = value;
        return offset + 3;
    };


    Buffer.prototype.writeUInt24BE = function(value, offset, noAssert) {
        value = +value;
        offset = offset >>> 0;
        if (!noAssert)
          checkInt(this, value, offset, 3, 0xffffff, 0);
        this[offset] = (value >>> 16);
        this[offset + 1] = (value >>> 8);
        this[offset + 2] = value;
        return offset + 3;
    };

    Buffer.prototype.writeInt24LE = function(value, offset, noAssert) {
        value = +value;
        offset = offset >>> 0;
        if (!noAssert)
          checkInt(this, value, offset, 3, 0x7fffff, -0x800000);
        this[offset] = value;
        this[offset + 1] = (value >>> 8);
        this[offset + 2] = (value >>> 16);
        return offset + 3;
    };


    Buffer.prototype.writeInt24BE = function(value, offset, noAssert) {
        value = +value;
        offset = offset >>> 0;
        if (!noAssert)
          checkInt(this, value, offset, 3, 0x7fffff, -0x800000);
        this[offset] = (value >>> 16);
        this[offset + 1] = (value >>> 8);
        this[offset + 2] = value;
        return offset + 3;
    };

PR#169

var log = console.log
    , Kombo = require( '../' )   
    , test = function ( mbytes ) {
        var mb = Math.max( mbytes, 1 )
            , b = new Buffer( mb * 1024 * 1024 )
            , stime = -1
            , etime= -1
            , i = 0
            ;

        log( '\nfilling test buffer (%d MB)..', mb );

        for ( ; i < b.length; ++i ) b[ i ] = i;

        stime = Date.now();

        for ( i = 0; i < b.length - 3; i+= 3 ) b.readUIntBE( i, 3 );

        etime = Date.now();

        log( '- readUIntBE: %d s', ( etime - stime ) / 1000 );


        stime = Date.now();

        for ( i = 0; i < b.length - 3; i+= 3 ) b.readUInt24BE( i );

        etime = Date.now();

        log( '- readUInt24BE: %d s', ( etime - stime ) / 1000 )


        stime = Date.now();

        for ( i = 0; i < b.length - 3; i+= 3 ) b.writeUIntBE( 0xffffff, i, 3 );

        etime = Date.now();

        log( '- writeUIntBE: %d s', ( etime - stime ) / 1000 );


        stime = Date.now();

        for ( i = 0; i < b.length - 3; i+= 3 ) b.writeUInt24BE( 0xffffff, i );

        etime = Date.now();

        log( '- writeUInt24BE: %d s', ( etime - stime ) / 1000 );

    };

test( 1 );
test( 8 );
test( 16 );
test( 32 );
test( 64 );
test( 128 );
log();

output results:

filling test buffer (1 MB)..

• readUIntBE: 0.013 s
• readUInt24BE: 0.01 s
• writeUIntBE: 0.022 s
• writeUInt24BE: 0.014 s

filling test buffer (8 MB)..

• readUIntBE: 0.085 s
• readUInt24BE: 0.061 s
• writeUIntBE: 0.145 s
• writeUInt24BE: 0.095 s

filling test buffer (16 MB)..

• readUIntBE: 0.176 s
• readUInt24BE: 0.125 s
• writeUIntBE: 0.294 s
• writeUInt24BE: 0.176 s

filling test buffer (32 MB)..

• readUIntBE: 0.34 s
• readUInt24BE: 0.247 s
• writeUIntBE: 0.566 s
• writeUInt24BE: 0.349 s

filling test buffer (64 MB)..

• readUIntBE: 0.674 s
• readUInt24BE: 0.49 s
• writeUIntBE: 1.126 s
• writeUInt24BE: 0.698 s

filling test buffer (128 MB)..

• readUIntBE: 1.35 s
• readUInt24BE: 0.98 s
• writeUIntBE: 2.25 s
• writeUInt24BE: 1.396 s