Add TIFF parser and buffer-based image size APIs

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.

packages/napcat-image-size/src/parser/TiffParser.ts

@@ -0,0 +1,124 @@
+import { ImageParser, ImageType, matchMagic, ImageSize } from '@/napcat-image-size/src';
+import { ReadStream } from 'fs';
+
+// TIFF解析器
+export class TiffParser implements ImageParser {
+  readonly type = ImageType.TIFF;
+  // TIFF Little Endian 魔术头：49 49 2A 00 (II)
+  private readonly TIFF_LE_SIGNATURE = [0x49, 0x49, 0x2A, 0x00];
+  // TIFF Big Endian 魔术头：4D 4D 00 2A (MM)
+  private readonly TIFF_BE_SIGNATURE = [0x4D, 0x4D, 0x00, 0x2A];
+
+  canParse (buffer: Buffer): boolean {
+    return (
+      matchMagic(buffer, this.TIFF_LE_SIGNATURE) ||
+      matchMagic(buffer, this.TIFF_BE_SIGNATURE)
+    );
+  }
+
+  async parseSize (stream: ReadStream): Promise<ImageSize | undefined> {
+    return new Promise((resolve, reject) => {
+      const chunks: Buffer[] = [];
+      let totalBytes = 0;
+      const MAX_BYTES = 64 * 1024; // 最多读取 64KB
+
+      stream.on('error', reject);
+
+      stream.on('data', (chunk: Buffer | string) => {
+        const chunkBuffer = Buffer.isBuffer(chunk) ? chunk : Buffer.from(chunk);
+        chunks.push(chunkBuffer);
+        totalBytes += chunkBuffer.length;
+
+        if (totalBytes >= MAX_BYTES) {
+          stream.destroy();
+        }
+      });
+
+      stream.on('end', () => {
+        const buffer = Buffer.concat(chunks);
+        const size = this.parseTiffSize(buffer);
+        resolve(size);
+      });
+
+      stream.on('close', () => {
+        if (chunks.length > 0) {
+          const buffer = Buffer.concat(chunks);
+          const size = this.parseTiffSize(buffer);
+          resolve(size);
+        }
+      });
+    });
+  }
+
+  private parseTiffSize (buffer: Buffer): ImageSize | undefined {
+    if (buffer.length < 8) {
+      return undefined;
+    }
+
+    // 判断字节序
+    const isLittleEndian = buffer[0] === 0x49; // 'I'
+
+    const readUInt16 = isLittleEndian
+      ? (offset: number) => buffer.readUInt16LE(offset)
+      : (offset: number) => buffer.readUInt16BE(offset);
+
+    const readUInt32 = isLittleEndian
+      ? (offset: number) => buffer.readUInt32LE(offset)
+      : (offset: number) => buffer.readUInt32BE(offset);
+
+    // 获取第一个 IFD 的偏移量
+    const ifdOffset = readUInt32(4);
+    if (ifdOffset + 2 > buffer.length) {
+      return undefined;
+    }
+
+    // 读取 IFD 条目数量
+    const numEntries = readUInt16(ifdOffset);
+    let width: number | undefined;
+    let height: number | undefined;
+
+    // TIFF 标签
+    const TAG_IMAGE_WIDTH = 0x0100;
+    const TAG_IMAGE_HEIGHT = 0x0101;
+
+    // 遍历 IFD 条目
+    for (let i = 0; i < numEntries; i++) {
+      const entryOffset = ifdOffset + 2 + i * 12;
+      if (entryOffset + 12 > buffer.length) {
+        break;
+      }
+
+      const tag = readUInt16(entryOffset);
+      const type = readUInt16(entryOffset + 2);
+      // const count = readUInt32(entryOffset + 4);
+
+      // 根据类型读取值
+      let value: number;
+      if (type === 3) {
+        // SHORT (2 bytes)
+        value = readUInt16(entryOffset + 8);
+      } else if (type === 4) {
+        // LONG (4 bytes)
+        value = readUInt32(entryOffset + 8);
+      } else {
+        continue;
+      }
+
+      if (tag === TAG_IMAGE_WIDTH) {
+        width = value;
+      } else if (tag === TAG_IMAGE_HEIGHT) {
+        height = value;
+      }
+
+      if (width !== undefined && height !== undefined) {
+        return { width, height };
+      }
+    }
+
+    if (width !== undefined && height !== undefined) {
+      return { width, height };
+    }
+
+    return undefined;
+  }
+}

packages/napcat-image-size/src/parser/WebpParser.ts

@@ -66,11 +66,11 @@ export class WebpParser implements ImageParser {
           } else if (this.isChunkType(buffer, 12, this.CHUNK_VP8X)) {
             // VP8X格式 - 扩展WebP
             // 24位宽度和高度(减去1)
-            if (!buffer[24] || !buffer[25] || !buffer[26] || !buffer[27] || !buffer[28] || !buffer[29]) {
+            if (buffer.length < 30) {
               return resolve(undefined);
             }
-            const width = 1 + ((buffer[24] | (buffer[25] << 8) | (buffer[26] << 16)) & 0xFFFFFF);
-            const height = 1 + ((buffer[27] | (buffer[28] << 8) | (buffer[29] << 16)) & 0xFFFFFF);
+            const width = 1 + ((buffer[24]! | (buffer[25]! << 8) | (buffer[26]! << 16)) & 0xFFFFFF);
+            const height = 1 + ((buffer[27]! | (buffer[28]! << 8) | (buffer[29]! << 16)) & 0xFFFFFF);
             return resolve({ width, height });
           } else {
             // 未知的WebP子格式