mirror of
https://gitlab.com/wgp/dougal/software.git
synced 2025-12-06 10:27:09 +00:00
Add @dougal/binary module.
It encodes / decodes sequence / preplot data using an efficient binary format for sending large amounts of data across the wire and for (relatively) memory efficient client-side use.
This commit is contained in:
D. Berge
327
lib/modules/@dougal/binary/decode.js
Normal file
327
lib/modules/@dougal/binary/decode.js
Normal file
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const codeToType = {
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0: Int8Array,
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1: Uint8Array,
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2: Int16Array,
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3: Uint16Array,
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4: Int32Array,
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5: Uint32Array,
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7: Float32Array,
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8: Float64Array,
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9: BigInt64Array,
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10: BigUint64Array
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};
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const typeToBytes = {
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Int8Array: 1,
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Uint8Array: 1,
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Int16Array: 2,
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Uint16Array: 2,
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Int32Array: 4,
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Uint32Array: 4,
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Float32Array: 4,
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Float64Array: 8,
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BigInt64Array: 8,
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BigUint64Array: 8
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};
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function sequential(binary) {
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if (!(binary instanceof Uint8Array) || binary.length < 4) {
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throw new Error('Invalid binary input');
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}
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const view = new DataView(binary.buffer, binary.byteOffset, binary.byteLength);
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let offset = 0;
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// Initialize result (assuming single i value for simplicity; extend for multiple i values if needed)
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const result = { i: null, j: [], Δelems: [], elems: [] };
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// Process bundles
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while (offset < binary.length) {
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// Read bundle header
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if (offset + 4 > binary.length) throw new Error('Incomplete bundle header');
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const bundleHeader = view.getUint32(offset, true);
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if ((bundleHeader & 0xFF) !== 0x1C) throw new Error('Invalid bundle marker');
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const bundleLength = bundleHeader >> 8;
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offset += 4;
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const bundleEnd = offset + bundleLength;
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if (bundleEnd > binary.length) throw new Error('Bundle length exceeds input size');
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// Process chunks in bundle
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while (offset < bundleEnd) {
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// Read chunk header
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if (offset + 12 > bundleEnd) throw new Error('Incomplete chunk header');
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const chunkType = view.getUint8(offset);
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if (chunkType !== 0x11) throw new Error(`Unsupported chunk type: ${chunkType}`);
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offset += 1; // Skip udv
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offset += 1;
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const count = view.getUint16(offset, true); offset += 2;
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if (count > 65535) throw new Error('Chunk count exceeds 65535');
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const iValue = view.getUint16(offset, true); offset += 2;
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const j0 = view.getUint16(offset, true); offset += 2;
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const Δj = view.getInt16(offset, true); offset += 2;
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const ΔelemCount = view.getUint8(offset++); // Δelem_count
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const elemCount = view.getUint8(offset++); // elem_count
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// Set i value (assuming all chunks share the same i)
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if (result.i === null) result.i = iValue;
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else if (result.i !== iValue) throw new Error('Multiple i values not supported');
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// Read preface (element types)
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const ΔelemTypes = [];
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for (let i = 0; i < ΔelemCount; i++) {
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if (offset >= bundleEnd) throw new Error('Incomplete Δelem types');
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const typeByte = view.getUint8(offset++);
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const baseCode = typeByte & 0x0F;
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const incrCode = typeByte >> 4;
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if (!codeToType[baseCode] || !codeToType[incrCode]) {
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throw new Error(`Invalid type code in Δelem: ${typeByte}`);
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}
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ΔelemTypes.push({ baseType: codeToType[baseCode], incrType: codeToType[incrCode] });
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}
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const elemTypes = [];
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for (let i = 0; i < elemCount; i++) {
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if (offset >= bundleEnd) throw new Error('Incomplete elem types');
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const typeCode = view.getUint8(offset++);
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if (!codeToType[typeCode]) throw new Error(`Invalid type code in elem: ${typeCode}`);
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elemTypes.push(codeToType[typeCode]);
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}
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// Initialize Δelems and elems arrays if first chunk
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if (!result.Δelems.length && ΔelemCount > 0) {
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result.Δelems = Array(ΔelemCount).fill().map(() => []);
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}
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if (!result.elems.length && elemCount > 0) {
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result.elems = Array(elemCount).fill().map(() => []);
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}
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// Read initial values for Δelems
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const initialValues = [];
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for (const { baseType } of ΔelemTypes) {
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if (offset + typeToBytes[baseType.name] > bundleEnd) {
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throw new Error('Incomplete initial values');
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}
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initialValues.push(readTypedValue(view, offset, baseType));
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offset += typeToBytes[baseType.name];
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}
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// Skip padding
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while (offset % 4 !== 0) {
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if (offset >= bundleEnd) throw new Error('Incomplete padding after initial values');
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offset++;
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}
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// Reconstruct j values
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for (let idx = 0; idx < count; idx++) {
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result.j.push(j0 + idx * Δj);
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}
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// Read record data (non-interleaved)
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for (let i = 0; i < ΔelemCount; i++) {
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let current = initialValues[i];
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const values = result.Δelems[i];
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const incrType = ΔelemTypes[i].incrType;
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const isBigInt = typeof current === 'bigint';
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for (let idx = 0; idx < count; idx++) {
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if (offset + typeToBytes[incrType.name] > bundleEnd) {
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throw new Error('Incomplete Δelem data');
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}
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let delta = readTypedValue(view, offset, incrType);
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if (idx === 0) {
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values.push(isBigInt ? Number(current) : current);
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} else {
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if (isBigInt) {
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delta = BigInt(delta);
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current += delta;
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values.push(Number(current));
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} else {
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current += delta;
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values.push(current);
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}
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}
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offset += typeToBytes[incrType.name];
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}
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}
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for (let i = 0; i < elemCount; i++) {
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const values = result.elems[i];
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const type = elemTypes[i];
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const isBigInt = type === BigInt64Array || type === BigUint64Array;
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for (let idx = 0; idx < count; idx++) {
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if (offset + typeToBytes[type.name] > bundleEnd) {
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throw new Error('Incomplete elem data');
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}
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let value = readTypedValue(view, offset, type);
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values.push(isBigInt ? Number(value) : value);
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offset += typeToBytes[type.name];
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}
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}
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// Skip padding
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while (offset % 4 !== 0) {
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if (offset >= bundleEnd) throw new Error('Incomplete padding after record data');
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offset++;
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}
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}
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}
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return result;
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}
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function interleaved(binary) {
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if (!(binary instanceof Uint8Array) || binary.length < 4) {
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throw new Error('Invalid binary input');
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}
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const view = new DataView(binary.buffer, binary.byteOffset, binary.byteLength);
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let offset = 0;
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// Initialize result (assuming single i value for simplicity; extend for multiple i values if needed)
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const result = { i: null, j: [], Δelems: [], elems: [] };
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// Process bundles
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while (offset < binary.length) {
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// Read bundle header
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if (offset + 4 > binary.length) throw new Error('Incomplete bundle header');
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const bundleHeader = view.getUint32(offset, true);
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if ((bundleHeader & 0xFF) !== 0x1C) throw new Error('Invalid bundle marker');
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const bundleLength = bundleHeader >> 8;
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offset += 4;
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const bundleEnd = offset + bundleLength;
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if (bundleEnd > binary.length) throw new Error('Bundle length exceeds input size');
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// Process chunks in bundle
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while (offset < bundleEnd) {
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// Read chunk header
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if (offset + 12 > bundleEnd) throw new Error('Incomplete chunk header');
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const chunkType = view.getUint8(offset);
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if (chunkType !== 0x12) throw new Error(`Unsupported chunk type: ${chunkType}`);
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offset += 1; // Skip udv
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offset += 1;
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const count = view.getUint16(offset, true); offset += 2;
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if (count > 65535) throw new Error('Chunk count exceeds 65535');
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const iValue = view.getUint16(offset, true); offset += 2;
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const j0 = view.getUint16(offset, true); offset += 2;
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const Δj = view.getInt16(offset, true); offset += 2;
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const ΔelemCount = view.getUint8(offset++); // Δelem_count
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const elemCount = view.getUint8(offset++); // elem_count
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// Set i value (assuming all chunks share the same i)
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if (result.i === null) result.i = iValue;
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else if (result.i !== iValue) throw new Error('Multiple i values not supported');
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// Read preface (element types)
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const ΔelemTypes = [];
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for (let i = 0; i < ΔelemCount; i++) {
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if (offset >= bundleEnd) throw new Error('Incomplete Δelem types');
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const typeByte = view.getUint8(offset++);
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const baseCode = typeByte & 0x0F;
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const incrCode = typeByte >> 4;
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if (!codeToType[baseCode] || !codeToType[incrCode]) {
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throw new Error(`Invalid type code in Δelem: ${typeByte}`);
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}
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ΔelemTypes.push({ baseType: codeToType[baseCode], incrType: codeToType[incrCode] });
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}
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const elemTypes = [];
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for (let i = 0; i < elemCount; i++) {
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if (offset >= bundleEnd) throw new Error('Incomplete elem types');
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const typeCode = view.getUint8(offset++);
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if (!codeToType[typeCode]) throw new Error(`Invalid type code in elem: ${typeCode}`);
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elemTypes.push(codeToType[typeCode]);
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}
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// Initialize Δelems and elems arrays if first chunk
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if (!result.Δelems.length && ΔelemCount > 0) {
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result.Δelems = Array(ΔelemCount).fill().map(() => []);
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}
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if (!result.elems.length && elemCount > 0) {
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result.elems = Array(elemCount).fill().map(() => []);
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}
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// Read initial values for Δelems
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const initialValues = [];
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for (const { baseType } of ΔelemTypes) {
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if (offset + typeToBytes[baseType.name] > bundleEnd) {
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throw new Error('Incomplete initial values');
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}
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initialValues.push(readTypedValue(view, offset, baseType));
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offset += typeToBytes[baseType.name];
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}
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// Skip padding
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while (offset % 4 !== 0) {
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if (offset >= bundleEnd) throw new Error('Incomplete padding after initial values');
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offset++;
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}
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// Reconstruct j values
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for (let idx = 0; idx < count; idx++) {
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result.j.push(j0 + idx * Δj);
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}
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// Read interleaved record data
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for (let idx = 0; idx < count; idx++) {
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// Read Δelems
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for (let i = 0; i < ΔelemCount; i++) {
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const values = result.Δelems[i];
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const incrType = ΔelemTypes[i].incrType;
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const isBigInt = typeof initialValues[i] === 'bigint';
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if (offset + typeToBytes[incrType.name] > bundleEnd) {
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throw new Error('Incomplete Δelem data');
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}
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let delta = readTypedValue(view, offset, incrType);
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offset += typeToBytes[incrType.name];
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if (idx === 0) {
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values.push(isBigInt ? Number(initialValues[i]) : initialValues[i]);
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} else {
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if (isBigInt) {
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delta = BigInt(delta);
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initialValues[i] += delta;
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values.push(Number(initialValues[i]));
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} else {
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initialValues[i] += delta;
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values.push(initialValues[i]);
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}
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}
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}
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// Read elems
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for (let i = 0; i < elemCount; i++) {
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const values = result.elems[i];
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const type = elemTypes[i];
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const isBigInt = type === BigInt64Array || type === BigUint64Array;
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if (offset + typeToBytes[type.name] > bundleEnd) {
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throw new Error('Incomplete elem data');
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}
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let value = readTypedValue(view, offset, type);
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values.push(isBigInt ? Number(value) : value);
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offset += typeToBytes[type.name];
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}
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}
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// Skip padding
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while (offset % 4 !== 0) {
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if (offset >= bundleEnd) throw new Error('Incomplete padding after record data');
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offset++;
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}
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}
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}
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return result;
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}
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function readTypedValue(view, offset, type) {
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switch (type) {
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case Int8Array: return view.getInt8(offset);
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case Uint8Array: return view.getUint8(offset);
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case Int16Array: return view.getInt16(offset, true);
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case Uint16Array: return view.getUint16(offset, true);
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case Int32Array: return view.getInt32(offset, true);
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case Uint32Array: return view.getUint32(offset, true);
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case Float32Array: return view.getFloat32(offset, true);
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case Float64Array: return view.getFloat64(offset, true);
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case BigInt64Array: return view.getBigInt64(offset, true);
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case BigUint64Array: return view.getBigUint64(offset, true);
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default: throw new Error(`Unsupported type: ${type.name}`);
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}
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}
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module.exports = { sequential, interleaved };
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