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					86 lines
				
				2.1 KiB
			
		
		
			
		
	
	
					86 lines
				
				2.1 KiB
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											3 years ago
										 
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								/*! ieee754. BSD-3-Clause License. Feross Aboukhadijeh <https://feross.org/opensource> */
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								exports.read = function (buffer, offset, isLE, mLen, nBytes) {
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								  var e, m
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								  var eLen = (nBytes * 8) - mLen - 1
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								  var eMax = (1 << eLen) - 1
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								  var eBias = eMax >> 1
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								  var nBits = -7
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								  var i = isLE ? (nBytes - 1) : 0
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								  var d = isLE ? -1 : 1
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								  var s = buffer[offset + i]
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								  i += d
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								  e = s & ((1 << (-nBits)) - 1)
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								  s >>= (-nBits)
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								  nBits += eLen
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								  for (; nBits > 0; e = (e * 256) + buffer[offset + i], i += d, nBits -= 8) {}
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								  m = e & ((1 << (-nBits)) - 1)
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								  e >>= (-nBits)
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								  nBits += mLen
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								  for (; nBits > 0; m = (m * 256) + buffer[offset + i], i += d, nBits -= 8) {}
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								  if (e === 0) {
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								    e = 1 - eBias
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								  } else if (e === eMax) {
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								    return m ? NaN : ((s ? -1 : 1) * Infinity)
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								  } else {
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								    m = m + Math.pow(2, mLen)
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								    e = e - eBias
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								  }
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								  return (s ? -1 : 1) * m * Math.pow(2, e - mLen)
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								}
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								exports.write = function (buffer, value, offset, isLE, mLen, nBytes) {
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								  var e, m, c
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								  var eLen = (nBytes * 8) - mLen - 1
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								  var eMax = (1 << eLen) - 1
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								  var eBias = eMax >> 1
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								  var rt = (mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0)
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								  var i = isLE ? 0 : (nBytes - 1)
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								  var d = isLE ? 1 : -1
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								  var s = value < 0 || (value === 0 && 1 / value < 0) ? 1 : 0
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								  value = Math.abs(value)
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								  if (isNaN(value) || value === Infinity) {
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								    m = isNaN(value) ? 1 : 0
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								    e = eMax
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								  } else {
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								    e = Math.floor(Math.log(value) / Math.LN2)
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								    if (value * (c = Math.pow(2, -e)) < 1) {
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								      e--
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								      c *= 2
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								    }
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								    if (e + eBias >= 1) {
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								      value += rt / c
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								    } else {
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								      value += rt * Math.pow(2, 1 - eBias)
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								    }
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								    if (value * c >= 2) {
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								      e++
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								      c /= 2
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								    }
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								    if (e + eBias >= eMax) {
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								      m = 0
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								      e = eMax
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								    } else if (e + eBias >= 1) {
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								      m = ((value * c) - 1) * Math.pow(2, mLen)
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								      e = e + eBias
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								    } else {
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								      m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen)
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								      e = 0
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								    }
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								  }
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								  for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8) {}
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								  e = (e << mLen) | m
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								  eLen += mLen
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								  for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8) {}
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								  buffer[offset + i - d] |= s * 128
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								}
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