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https://gitlab.com/wgp/dougal/software.git
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4db6d8dd7a
This series of custom binary messages are an alternative to JSON / GeoJSON when huge amounts of data needs to be transferred to and processed by the client, such as a GPU-based map view showing all the points for a prospect, or QC graphs, etc.
83 lines
1.9 KiB
JavaScript
83 lines
1.9 KiB
JavaScript
const { MSGTYPE, PKTTYPE, HEADER_OFFSET, PACKET_OFFSET } = require('./constants');
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function headerSize (msgType) {
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switch (msgType) {
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case MSGTYPE.BUNDLE:
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return 4;
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case MSGTYPE.PREPLOT:
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// 1 * Uint8 + 1 * Uint32 + 1 * Uint16 + 1 * Uint16 + 1 * Int16
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// 1 * 1 + 1 * 4 + 1 * 2 + 1 * 2 + 1 * 2 = 11
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return 11;
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case MSGTYPE.PREPLOT_RAWERROR_OPT:
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return 12;
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case MSGTYPE.RAW:
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case MSGTYPE.FINAL:
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case MSGTYPE.RAW_OPT:
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case MSGTYPE.FINAL_OPT:
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// 1 * Uint8 + 1 * Uint32 + 1 * Uint16 + 1 * Uint16 + 1 * Int16 + 1 * BigInt64
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// 1 * 1 + 1 * 4 + 1 * 2 + 1 * 2 + 1 * 2 + 1 * 8 = 19
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return 20;
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default:
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return; // undefined
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}
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}
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function packetSize (msgType) {
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switch (msgType) {
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case MSGTYPE.BUNDLE:
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return; // Doesn't apply to this msgType
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case MSGTYPE.PREPLOT:
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// 2 * Float32
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return 8;
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case MSGTYPE.RAW:
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case MSGTYPE.FINAL:
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// 2 * Float32 + 2 * Float32 + 1 * Int32
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return 20;
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case MSGTYPE.PREPLOT_RAWERROR_OPT:
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// 2 * Float32 + 1 * Float32
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return 12;
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case MSGTYPE.RAW_OPT:
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case MSGTYPE.FINAL_OPT:
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// 2 * Float32 + 2 * Float32 + 1 * Int32
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return 20;
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default:
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return; // undefined
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}
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}
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function packetFormatType (msgType) {
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switch (msgType) {
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case MSGTYPE.BUNDLE:
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return PKTTYPE.A;
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case MSGTYPE.PREPLOT:
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return PKTTYPE.B;
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case MSGTYPE.RAW:
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case MSGTYPE.FINAL:
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return PKTTYPE.C;
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case MSGTYPE.PREPLOT_RAWERROR_OPT:
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return PKTTYPE.D;
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case MSGTYPE.RAW_OPT:
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case MSGTYPE.FINAL_OPT:
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return PKTTYPE.E;
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default:
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return; // undefined
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}
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}
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function isLittleEndian () {
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const buffer = new ArrayBuffer(2);
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const asUint8 = new Uint8Array(buffer);
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const asUint16 = new Uint16Array(buffer);
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asUint8[1] = 0xFF;
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return asUint16[0] == 0xFF00;
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}
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module.exports = {
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headerSize,
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packetSize,
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packetFormatType,
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isLittleEndian
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};
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