fork from https://github.com/mozilla/pdf.js.git

src/core/ccitt_stream.js

@@ -0,0 +1,81 @@
+/* Copyright 2012 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { DecodeStream } from "./decode_stream.js";
+import { Dict } from "./primitives.js";
+import { JBig2CCITTFaxImage } from "./jbig2_ccittFax.js";
+import { shadow } from "../shared/util.js";
+
+class CCITTFaxStream extends DecodeStream {
+  constructor(str, maybeLength, params) {
+    super(maybeLength);
+
+    this.stream = str;
+    this.maybeLength = maybeLength;
+    this.dict = str.dict;
+
+    if (!(params instanceof Dict)) {
+      params = Dict.empty;
+    }
+
+    this.params = {
+      K: params.get("K") || 0,
+      EndOfLine: !!params.get("EndOfLine"),
+      EncodedByteAlign: !!params.get("EncodedByteAlign"),
+      Columns: params.get("Columns") || 1728,
+      Rows: params.get("Rows") || 0,
+      EndOfBlock: !!(params.get("EndOfBlock") ?? true),
+      BlackIs1: !!params.get("BlackIs1"),
+    };
+  }
+
+  get bytes() {
+    // If `this.maybeLength` is null, we'll get the entire stream.
+    return shadow(this, "bytes", this.stream.getBytes(this.maybeLength));
+  }
+
+  get isImageStream() {
+    return true;
+  }
+
+  get isAsyncDecoder() {
+    return true;
+  }
+
+  async decodeImage(bytes, length, _decoderOptions) {
+    if (this.eof) {
+      return this.buffer;
+    }
+    if (!bytes) {
+      bytes = this.stream.isAsync
+        ? (await this.stream.asyncGetBytes()) || this.bytes
+        : this.bytes;
+    }
+
+    this.buffer = await JBig2CCITTFaxImage.instance.decode(
+      bytes,
+      this.dict.get("W", "Width"),
+      this.dict.get("H", "Height"),
+      null,
+      this.params
+    );
+    this.bufferLength = this.buffer.length;
+    this.eof = true;
+
+    return this.buffer;
+  }
+}
+
+export { CCITTFaxStream };