57 lines
2.0 KiB
TypeScript
57 lines
2.0 KiB
TypeScript
import { writeU16, writeU32, writeNullTermString } from '../shared/binary-writer';
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import type { PartitionTable } from './types';
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import { ENTRY_SIZE, ENTRY_MAGIC, MD5_MAGIC, NAME_FIELD_SIZE, TABLE_MAX_SIZE } from './constants';
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import { md5 } from './md5';
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const U32_MAX = 0xFFFF_FFFF;
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function assertU8(val: number, field: string): void {
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if (!Number.isInteger(val) || val < 0 || val > 0xFF)
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throw new Error(`"${field}" is not a valid byte value (0–255): ${val}`);
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}
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function assertU32(val: number, field: string): void {
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if (!Number.isInteger(val) || val < 0 || val > U32_MAX)
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throw new Error(`"${field}" is not a valid uint32 (0–0xFFFFFFFF): ${val}`);
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}
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/**
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* Serialize a PartitionTable to ESP32 binary format.
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* Returns a Uint8Array of TABLE_MAX_SIZE filled with 0xFF for empty space.
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*/
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export function serializeBinary(table: PartitionTable): Uint8Array {
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const buf = new Uint8Array(TABLE_MAX_SIZE);
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buf.fill(0xFF);
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let offset = 0;
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for (const entry of table.entries) {
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if (offset + ENTRY_SIZE > TABLE_MAX_SIZE - ENTRY_SIZE) {
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throw new Error(`Too many partition table entries (max ${Math.floor((TABLE_MAX_SIZE - ENTRY_SIZE) / ENTRY_SIZE)})`);
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}
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assertU8(entry.type, 'type');
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assertU8(entry.subtype, 'subtype');
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assertU32(entry.offset, 'offset');
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assertU32(entry.size, 'size');
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assertU32(entry.flags, 'flags');
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writeU16(buf, offset, ENTRY_MAGIC);
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buf[offset + 2] = entry.type;
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buf[offset + 3] = entry.subtype;
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writeU32(buf, offset + 4, entry.offset);
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writeU32(buf, offset + 8, entry.size);
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writeNullTermString(buf, offset + 12, entry.name, NAME_FIELD_SIZE);
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writeU32(buf, offset + 28, entry.flags);
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offset += ENTRY_SIZE;
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}
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// Write MD5 checksum entry
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// [0..1] = MD5_MAGIC, [2..15] = 0xFF padding, [16..31] = MD5 hash
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writeU16(buf, offset, MD5_MAGIC);
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// [2..15] already 0xFF from fill
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const hash = md5(buf.subarray(0, offset));
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buf.set(hash, offset + 16);
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return buf;
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}
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