93 lines
2.4 KiB
JavaScript
93 lines
2.4 KiB
JavaScript
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// t is a binpack typename
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var sizeOfType = function(t) {
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// unsigned are the same length as signed
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if(t[0] === 'U') {
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t = t.slice(1);
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}
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return {
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'Float32' : 4,
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'Float64' : 8,
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'Int8' : 1,
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'Int16' : 2,
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'Int32' : 4,
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'Int64' : 8
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}[t];
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};
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var endianConv = function(e, t) {
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// node doesn't define 8 bit endianness
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if(t[t.length - 1] === '8')
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return '';
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if(e === 'big') {
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return 'BE';
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}
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return 'LE';
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};
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var addBindings = function(binpackTypename, nodeTypename){
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if(!(typeof nodeTypename !== "undefined" && nodeTypename !== null)) {
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nodeTypename = binpackTypename;
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}
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module.exports['pack' + binpackTypename] = function(num, endian){
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b = new Buffer(sizeOfType(binpackTypename));
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b['write' + nodeTypename + endianConv(endian, binpackTypename)](num, 0, true);
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return b;
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}
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module.exports['unpack' + binpackTypename] = function(buff, endian){
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return buff['read' + nodeTypename + endianConv(endian, binpackTypename)](0);
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}
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}
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var addIntBindings = function(n) {
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addBindings("Int" + n);
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addBindings("UInt" + n);
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}
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addIntBindings(8);
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addIntBindings(16);
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addIntBindings(32);
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twoToThe32 = Math.pow(2, 32);
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// 64 bit bindings require special care
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var read64 = function(unsigned){return function(buff, endian){
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var e = endianConv(endian, '');
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var u = unsigned ? 'U' : '';
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var low, high;
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if(e === 'LE') {
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low = buff.readUInt32LE(0);
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high = buff['read' + u + 'Int32LE'](4);
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} else {
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low = buff.readUInt32BE(4);
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high = buff['read' + u + 'Int32BE'](0);
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}
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return high * twoToThe32 + low;
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};};
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var write64 = function(unsigned){return function(num, endian){
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var e = endianConv(endian, '');
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var u = unsigned ? 'U' : '';
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var b = new Buffer(8);
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var high = Math.floor(num / twoToThe32);
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var low = Math.floor(num - high * twoToThe32);
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if(e == 'LE') {
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b.writeUInt32LE(low, 0, true);
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b['write' + u + 'Int32LE'](high, 4, true);
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} else {
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b.writeUInt32BE(low, 4, true);
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b['write' + u + 'Int32BE'](high, 0, true);
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}
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return b;
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};};
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module.exports.unpackInt64 = read64(false);
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module.exports.unpackUInt64 = read64(true);
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module.exports.packInt64 = write64(false);
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module.exports.packUInt64 = write64(true);
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addBindings("Float32", "Float");
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addBindings("Float64", "Double");
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