ieee_754.js

    function ieee754_read(buffer, offset, isLE, mLen, nBytes) {
        var e, m;
        var eLen = (nBytes * 8) - mLen - 1;
        var eMax = (1 << eLen) - 1;
        var eBias = eMax >> 1;
        var nBits = -7;
        var i = isLE ? (nBytes - 1) : 0;
        var d = isLE ? -1 : 1;
        var s = buffer[offset + i];

        i += d;

        e = s & ((1 << (-nBits)) - 1);
        s >>= (-nBits);
        nBits += eLen;
        for (; nBits > 0; e = (e * 256) + buffer[offset + i], i += d, nBits -= 8) {
        }

        m = e & ((1 << (-nBits)) - 1);
        e >>= (-nBits);
        nBits += mLen;
        for (; nBits > 0; m = (m * 256) + buffer[offset + i], i += d, nBits -= 8) {
        }

        if (e === 0) {
            e = 1 - eBias
        } else if (e === eMax) {
            return m ? NaN : ((s ? -1 : 1) * Infinity)
        } else {
            m = m + Math.pow(2, mLen);
            e = e - eBias
        }
        return (s ? -1 : 1) * m * Math.pow(2, e - mLen)
    }

    function ieee754_write(buffer, value, offset, isLE, mLen, nBytes) {
        var e, m, c;
        var eLen = (nBytes * 8) - mLen - 1;
        var eMax = (1 << eLen) - 1;
        var eBias = eMax >> 1;
        var rt = (mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0);
        var i = isLE ? 0 : (nBytes - 1);
        var d = isLE ? 1 : -1;
        var s = value < 0 || (value === 0 && 1 / value < 0) ? 1 : 0;

        value = Math.abs(value);

        if (isNaN(value) || value === Infinity) {
            m = isNaN(value) ? 1 : 0;
            e = eMax
        } else {
            e = Math.floor(Math.log(value) / Math.LN2);
            if (value * (c = Math.pow(2, -e)) < 1) {
                e--;
                c *= 2
            }
            if (e + eBias >= 1) {
                value += rt / c
            } else {
                value += rt * Math.pow(2, 1 - eBias)
            }
            if (value * c >= 2) {
                e++;
                c /= 2
            }

            if (e + eBias >= eMax) {
                m = 0;
                e = eMax
            } else if (e + eBias >= 1) {
                m = ((value * c) - 1) * Math.pow(2, mLen);
                e = e + eBias
            } else {
                m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen);
                e = 0
            }
        }

        for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8) {
        }

        e = (e << mLen) | m;
        eLen += mLen;
        for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8) {
        }

        buffer[offset + i - d] |= s * 128;
    }