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- export function 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)
- }
-
- export function 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
- }
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