88 lines
3.4 KiB
JavaScript
88 lines
3.4 KiB
JavaScript
function readIEEE754(buf, idx, isLE, nl, ml) {
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if(isLE === undefined) isLE = true;
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if(!nl) nl = 8;
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if(!ml && nl === 8) ml = 52;
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var e, m, el = nl * 8 - ml - 1, eMax = (1 << el) - 1, eBias = eMax >> 1;
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var bits = -7, d = isLE ? -1 : 1, i = isLE ? (nl - 1) : 0, s = buf[idx + i];
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i += d;
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e = s & ((1 << (-bits)) - 1); s >>>= (-bits); bits += el;
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for (; bits > 0; e = e * 256 + buf[idx + i], i += d, bits -= 8);
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m = e & ((1 << (-bits)) - 1); e >>>= (-bits); bits += ml;
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for (; bits > 0; m = m * 256 + buf[idx + i], i += d, bits -= 8);
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if (e === eMax) return m ? NaN : ((s ? -1 : 1) * Infinity);
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else if (e === 0) e = 1 - eBias;
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else { m = m + Math.pow(2, ml); e = e - eBias; }
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return (s ? -1 : 1) * m * Math.pow(2, e - ml);
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}
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var __toBuffer, ___toBuffer;
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__toBuffer = ___toBuffer = function toBuffer_(bufs) { var x = []; for(var i = 0; i < bufs[0].length; ++i) { x.push.apply(x, bufs[0][i]); } return x; };
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var __double, ___double;
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__double = ___double = function(b, idx) { return readIEEE754(b, idx);};
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var is_buf = function is_buf_a(a) { return Array.isArray(a); };
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if(has_buf) {
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__toBuffer = function(bufs) { return (bufs[0].length > 0 && Buffer.isBuffer(bufs[0][0])) ? Buffer.concat(bufs[0]) : ___toBuffer(bufs);};
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__double = function double_(b,i) { if(Buffer.isBuffer(b)) return b.readDoubleLE(i); return ___double(b,i); };
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is_buf = function is_buf_b(a) { return Buffer.isBuffer(a) || Array.isArray(a); };
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}
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var __readUInt8 = function(b, idx) { return b[idx]; };
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var __readUInt16LE = function(b, idx) { return b[idx+1]*(1<<8)+b[idx]; };
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var __readInt16LE = function(b, idx) { var u = b[idx+1]*(1<<8)+b[idx]; return (u < 0x8000) ? u : (0xffff - u + 1) * -1; };
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var __readUInt32LE = function(b, idx) { return b[idx+3]*(1<<24)+(b[idx+2]<<16)+(b[idx+1]<<8)+b[idx]; };
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var __readInt32LE = function(b, idx) { return (b[idx+3]<<24)|(b[idx+2]<<16)|(b[idx+1]<<8)|b[idx]; };
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function ReadShift(size, t) {
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var o="", oo=[], w, vv, i, loc;
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if(t === 'dbcs') {
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loc = this.l;
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if(has_buf && Buffer.isBuffer(this)) o = this.slice(this.l, this.l+2*size).toString("utf16le");
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else for(i = 0; i != size; ++i) { o+=String.fromCharCode(__readUInt16LE(this, loc)); loc+=2; }
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size *= 2;
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} else switch(size) {
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case 1: o = __readUInt8(this, this.l); break;
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case 2: o = (t === 'i' ? __readInt16LE : __readUInt16LE)(this, this.l); break;
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case 4: o = __readUInt32LE(this, this.l); break;
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case 8: if(t === 'f') { o = __double(this, this.l); break; }
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}
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this.l+=size; return o;
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}
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function WriteShift(t, val, f) {
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var size, i;
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if(f === 'dbcs') {
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for(i = 0; i != val.length; ++i) this.writeUInt16LE(val.charCodeAt(i), this.l + 2 * i);
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size = 2 * val.length;
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} else switch(t) {
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case 1: size = 1; this[this.l] = val&255; break;
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case 3: size = 3; this[this.l+2] = val & 255; val >>>= 8; this[this.l+1] = val&255; val >>>= 8; this[this.l] = val&255; break;
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case 4: size = 4; this.writeUInt32LE(val, this.l); break;
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case 8: size = 8; if(f === 'f') { this.writeDoubleLE(val, this.l); break; }
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/* falls through */
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case 16: break;
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case -4: size = 4; this.writeInt32LE(val, this.l); break;
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}
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this.l += size; return this;
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}
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function prep_blob(blob, pos) {
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blob.l = pos;
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blob.read_shift = ReadShift;
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blob.write_shift = WriteShift;
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}
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function parsenoop(blob, length) { blob.l += length; }
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function writenoop(blob, length) { blob.l += length; }
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function new_buf(sz) {
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var o = has_buf ? new Buffer(sz) : new Array(sz);
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prep_blob(o, 0);
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return o;
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}
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