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			97 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			JavaScript
		
	
		
		
			
		
	
	
			97 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			JavaScript
		
	
| 
											9 months ago
										 | "use strict"; | ||
|  | 
 | ||
|  | Object.defineProperty(exports, "__esModule", { | ||
|  |   value: true | ||
|  | }); | ||
|  | exports.read = read; | ||
|  | exports.write = write; | ||
|  | 
 | ||
|  | 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); | ||
|  | } | ||
|  | 
 | ||
|  | 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; | ||
|  | } |