mirror of
https://github.com/NapNeko/NapCatQQ.git
synced 2026-02-11 23:40:24 +00:00
f971c312b9
Introduce a TIFF parser and integrate it into the image detection/size parsing pipeline. Add buffer-based APIs (detectImageTypeFromBuffer, imageSizeFromBuffer, imageSizeFromBufferFallBack) and a helper to convert Buffer to a Readable stream; refactor parser registry into a type-to-parser map and a first-byte fast-path map for quicker detection. Harden WebP parsing with safer length checks. Add sample image resources and a comprehensive Vitest test suite (packages/napcat-test) with updated package dependency and resolve aliases. pnpm-lock updated to link the new package.
91 lines
3.3 KiB
TypeScript
91 lines
3.3 KiB
TypeScript
import { ImageParser, ImageType, matchMagic, ImageSize } from '@/napcat-image-size/src';
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import { ReadStream } from 'fs';
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// WEBP解析器 - 完整支持VP8, VP8L, VP8X格式
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export class WebpParser implements ImageParser {
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readonly type = ImageType.WEBP;
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// WEBP RIFF 头：52 49 46 46 (RIFF)
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private readonly RIFF_SIGNATURE = [0x52, 0x49, 0x46, 0x46];
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// WEBP 魔术头：57 45 42 50 (WEBP)
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private readonly WEBP_SIGNATURE = [0x57, 0x45, 0x42, 0x50];
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// WEBP 块头
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private readonly CHUNK_VP8 = [0x56, 0x50, 0x38, 0x20]; // "VP8 "
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private readonly CHUNK_VP8L = [0x56, 0x50, 0x38, 0x4C]; // "VP8L"
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private readonly CHUNK_VP8X = [0x56, 0x50, 0x38, 0x58]; // "VP8X"
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canParse (buffer: Buffer): boolean {
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return (
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buffer.length >= 12 &&
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matchMagic(buffer, this.RIFF_SIGNATURE, 0) &&
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matchMagic(buffer, this.WEBP_SIGNATURE, 8)
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);
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}
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isChunkType (buffer: Buffer, offset: number, chunkType: number[]): boolean {
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return buffer.length >= offset + 4 && matchMagic(buffer, chunkType, offset);
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}
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async parseSize (stream: ReadStream): Promise<ImageSize | undefined> {
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return new Promise((resolve, reject) => {
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// 需要读取足够的字节来检测所有三种格式
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const MAX_HEADER_SIZE = 32;
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let totalBytes = 0;
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let buffer = Buffer.alloc(0);
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stream.on('error', reject);
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stream.on('data', (chunk: Buffer | string) => {
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const chunkBuffer = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk);
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buffer = Buffer.concat([buffer, chunkBuffer]);
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totalBytes += chunk.length;
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// 检查是否有足够的字节进行格式检测
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if (totalBytes >= MAX_HEADER_SIZE) {
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stream.destroy();
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// 检查基本的WEBP签名
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if (!this.canParse(buffer)) {
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return resolve(undefined);
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}
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// 检查chunk头部，位于字节12-15
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if (this.isChunkType(buffer, 12, this.CHUNK_VP8)) {
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// VP8格式 - 标准WebP
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// 宽度和高度在帧头中
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const width = buffer.readUInt16LE(26) & 0x3FFF;
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const height = buffer.readUInt16LE(28) & 0x3FFF;
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return resolve({ width, height });
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} else if (this.isChunkType(buffer, 12, this.CHUNK_VP8L)) {
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// VP8L格式 - 无损WebP
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// 1字节标记后是14位宽度和14位高度
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const bits = buffer.readUInt32LE(21);
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const width = 1 + (bits & 0x3FFF);
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const height = 1 + ((bits >> 14) & 0x3FFF);
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return resolve({ width, height });
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} else if (this.isChunkType(buffer, 12, this.CHUNK_VP8X)) {
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// VP8X格式 - 扩展WebP
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// 24位宽度和高度(减去1)
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if (buffer.length < 30) {
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return resolve(undefined);
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}
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const width = 1 + ((buffer[24]! | (buffer[25]! << 8) | (buffer[26]! << 16)) & 0xFFFFFF);
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const height = 1 + ((buffer[27]! | (buffer[28]! << 8) | (buffer[29]! << 16)) & 0xFFFFFF);
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return resolve({ width, height });
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} else {
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// 未知的WebP子格式
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return resolve(undefined);
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}
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}
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});
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stream.on('end', () => {
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// 如果没有读到足够的字节
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if (totalBytes < MAX_HEADER_SIZE) {
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resolve(undefined);
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}
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});
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});
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}
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}
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