Move the calculateMD5 function into its own file

This allows us to remove a closure, and we also change the code to initialize various constants lazily.

src/core/calculate_md5.js

@@ -0,0 +1,130 @@
+/* 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 { shadow } from "../shared/util.js";
+
+const PARAMS = {
+  get r() {
+    return shadow(
+      this,
+      "r",
+      new Uint8Array([
+        7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 5, 9, 14,
+        20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 4, 11, 16, 23, 4, 11, 16,
+        23, 4, 11, 16, 23, 4, 11, 16, 23, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10,
+        15, 21, 6, 10, 15, 21,
+      ])
+    );
+  },
+
+  get k() {
+    return shadow(
+      this,
+      "k",
+      new Int32Array([
+        -680876936, -389564586, 606105819, -1044525330, -176418897, 1200080426,
+        -1473231341, -45705983, 1770035416, -1958414417, -42063, -1990404162,
+        1804603682, -40341101, -1502002290, 1236535329, -165796510, -1069501632,
+        643717713, -373897302, -701558691, 38016083, -660478335, -405537848,
+        568446438, -1019803690, -187363961, 1163531501, -1444681467, -51403784,
+        1735328473, -1926607734, -378558, -2022574463, 1839030562, -35309556,
+        -1530992060, 1272893353, -155497632, -1094730640, 681279174, -358537222,
+        -722521979, 76029189, -640364487, -421815835, 530742520, -995338651,
+        -198630844, 1126891415, -1416354905, -57434055, 1700485571, -1894986606,
+        -1051523, -2054922799, 1873313359, -30611744, -1560198380, 1309151649,
+        -145523070, -1120210379, 718787259, -343485551,
+      ])
+    );
+  },
+};
+
+function calculateMD5(data, offset, length) {
+  let h0 = 1732584193,
+    h1 = -271733879,
+    h2 = -1732584194,
+    h3 = 271733878;
+  // pre-processing
+  const paddedLength = (length + 72) & ~63; // data + 9 extra bytes
+  const padded = new Uint8Array(paddedLength);
+  let i, j;
+  for (i = 0; i < length; ++i) {
+    padded[i] = data[offset++];
+  }
+  padded[i++] = 0x80;
+  const n = paddedLength - 8;
+  while (i < n) {
+    padded[i++] = 0;
+  }
+  padded[i++] = (length << 3) & 0xff;
+  padded[i++] = (length >> 5) & 0xff;
+  padded[i++] = (length >> 13) & 0xff;
+  padded[i++] = (length >> 21) & 0xff;
+  padded[i++] = (length >>> 29) & 0xff;
+  padded[i++] = 0;
+  padded[i++] = 0;
+  padded[i++] = 0;
+  const w = new Int32Array(16);
+  const { k, r } = PARAMS;
+  for (i = 0; i < paddedLength; ) {
+    for (j = 0; j < 16; ++j, i += 4) {
+      w[j] =
+        padded[i] |
+        (padded[i + 1] << 8) |
+        (padded[i + 2] << 16) |
+        (padded[i + 3] << 24);
+    }
+    let a = h0,
+      b = h1,
+      c = h2,
+      d = h3,
+      f,
+      g;
+    for (j = 0; j < 64; ++j) {
+      if (j < 16) {
+        f = (b & c) | (~b & d);
+        g = j;
+      } else if (j < 32) {
+        f = (d & b) | (~d & c);
+        g = (5 * j + 1) & 15;
+      } else if (j < 48) {
+        f = b ^ c ^ d;
+        g = (3 * j + 5) & 15;
+      } else {
+        f = c ^ (b | ~d);
+        g = (7 * j) & 15;
+      }
+      const tmp = d,
+        rotateArg = (a + f + k[j] + w[g]) | 0,
+        rotate = r[j];
+      d = c;
+      c = b;
+      b = (b + ((rotateArg << rotate) | (rotateArg >>> (32 - rotate)))) | 0;
+      a = tmp;
+    }
+    h0 = (h0 + a) | 0;
+    h1 = (h1 + b) | 0;
+    h2 = (h2 + c) | 0;
+    h3 = (h3 + d) | 0;
+  }
+  // prettier-ignore
+  return new Uint8Array([
+    h0 & 0xFF, (h0 >> 8) & 0xFF, (h0 >> 16) & 0xFF, (h0 >>> 24) & 0xFF,
+    h1 & 0xFF, (h1 >> 8) & 0xFF, (h1 >> 16) & 0xFF, (h1 >>> 24) & 0xFF,
+    h2 & 0xFF, (h2 >> 8) & 0xFF, (h2 >> 16) & 0xFF, (h2 >>> 24) & 0xFF,
+    h3 & 0xFF, (h3 >> 8) & 0xFF, (h3 >> 16) & 0xFF, (h3 >>> 24) & 0xFF
+  ]);
+}
+
+export { calculateMD5 };

src/core/crypto.js

@@ -25,6 +25,7 @@ import {
   warn,
 } from "../shared/util.js";
 import { Dict, isName, Name } from "./primitives.js";
+import { calculateMD5 } from "./calculate_md5.js";
 import { DecryptStream } from "./decrypt_stream.js";
 
 class ARCFourCipher {
@@ -75,107 +76,6 @@ class ARCFourCipher {
   }
 }
 
-const calculateMD5 = (function calculateMD5Closure() {
-  const r = new Uint8Array([
-    7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 5, 9, 14, 20, 5,
-    9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11,
-    16, 23, 4, 11, 16, 23, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10, 15, 21, 6, 10,
-    15, 21,
-  ]);
-
-  const k = new Int32Array([
-    -680876936, -389564586, 606105819, -1044525330, -176418897, 1200080426,
-    -1473231341, -45705983, 1770035416, -1958414417, -42063, -1990404162,
-    1804603682, -40341101, -1502002290, 1236535329, -165796510, -1069501632,
-    643717713, -373897302, -701558691, 38016083, -660478335, -405537848,
-    568446438, -1019803690, -187363961, 1163531501, -1444681467, -51403784,
-    1735328473, -1926607734, -378558, -2022574463, 1839030562, -35309556,
-    -1530992060, 1272893353, -155497632, -1094730640, 681279174, -358537222,
-    -722521979, 76029189, -640364487, -421815835, 530742520, -995338651,
-    -198630844, 1126891415, -1416354905, -57434055, 1700485571, -1894986606,
-    -1051523, -2054922799, 1873313359, -30611744, -1560198380, 1309151649,
-    -145523070, -1120210379, 718787259, -343485551,
-  ]);
-
-  function hash(data, offset, length) {
-    let h0 = 1732584193,
-      h1 = -271733879,
-      h2 = -1732584194,
-      h3 = 271733878;
-    // pre-processing
-    const paddedLength = (length + 72) & ~63; // data + 9 extra bytes
-    const padded = new Uint8Array(paddedLength);
-    let i, j;
-    for (i = 0; i < length; ++i) {
-      padded[i] = data[offset++];
-    }
-    padded[i++] = 0x80;
-    const n = paddedLength - 8;
-    while (i < n) {
-      padded[i++] = 0;
-    }
-    padded[i++] = (length << 3) & 0xff;
-    padded[i++] = (length >> 5) & 0xff;
-    padded[i++] = (length >> 13) & 0xff;
-    padded[i++] = (length >> 21) & 0xff;
-    padded[i++] = (length >>> 29) & 0xff;
-    padded[i++] = 0;
-    padded[i++] = 0;
-    padded[i++] = 0;
-    const w = new Int32Array(16);
-    for (i = 0; i < paddedLength; ) {
-      for (j = 0; j < 16; ++j, i += 4) {
-        w[j] =
-          padded[i] |
-          (padded[i + 1] << 8) |
-          (padded[i + 2] << 16) |
-          (padded[i + 3] << 24);
-      }
-      let a = h0,
-        b = h1,
-        c = h2,
-        d = h3,
-        f,
-        g;
-      for (j = 0; j < 64; ++j) {
-        if (j < 16) {
-          f = (b & c) | (~b & d);
-          g = j;
-        } else if (j < 32) {
-          f = (d & b) | (~d & c);
-          g = (5 * j + 1) & 15;
-        } else if (j < 48) {
-          f = b ^ c ^ d;
-          g = (3 * j + 5) & 15;
-        } else {
-          f = c ^ (b | ~d);
-          g = (7 * j) & 15;
-        }
-        const tmp = d,
-          rotateArg = (a + f + k[j] + w[g]) | 0,
-          rotate = r[j];
-        d = c;
-        c = b;
-        b = (b + ((rotateArg << rotate) | (rotateArg >>> (32 - rotate)))) | 0;
-        a = tmp;
-      }
-      h0 = (h0 + a) | 0;
-      h1 = (h1 + b) | 0;
-      h2 = (h2 + c) | 0;
-      h3 = (h3 + d) | 0;
-    }
-    // prettier-ignore
-    return new Uint8Array([
-      h0 & 0xFF, (h0 >> 8) & 0xFF, (h0 >> 16) & 0xFF, (h0 >>> 24) & 0xFF,
-      h1 & 0xFF, (h1 >> 8) & 0xFF, (h1 >> 16) & 0xFF, (h1 >>> 24) & 0xFF,
-      h2 & 0xFF, (h2 >> 8) & 0xFF, (h2 >> 16) & 0xFF, (h2 >>> 24) & 0xFF,
-      h3 & 0xFF, (h3 >> 8) & 0xFF, (h3 >> 16) & 0xFF, (h3 >>> 24) & 0xFF
-    ]);
-  }
-
-  return hash;
-})();
-
 class Word64 {
   constructor(highInteger, lowInteger) {
     this.high = highInteger | 0;
@@ -1849,7 +1749,6 @@ export {
   AES128Cipher,
   AES256Cipher,
   ARCFourCipher,
-  calculateMD5,
   calculateSHA256,
   calculateSHA384,
   calculateSHA512,

src/core/document.js

@@ -60,7 +60,7 @@ import {
 } from "./primitives.js";
 import { getXfaFontDict, getXfaFontName } from "./xfa_fonts.js";
 import { BaseStream } from "./base_stream.js";
-import { calculateMD5 } from "./crypto.js";
+import { calculateMD5 } from "./calculate_md5.js";
 import { Catalog } from "./catalog.js";
 import { clearGlobalCaches } from "./cleanup_helper.js";
 import { DatasetReader } from "./dataset_reader.js";

src/core/writer.js

@@ -25,7 +25,7 @@ import {
 import { SimpleDOMNode, SimpleXMLParser } from "./xml_parser.js";
 import { Stream, StringStream } from "./stream.js";
 import { BaseStream } from "./base_stream.js";
-import { calculateMD5 } from "./crypto.js";
+import { calculateMD5 } from "./calculate_md5.js";
 
 async function writeObject(ref, obj, buffer, { encrypt = null }) {
   const transform = encrypt?.createCipherTransform(ref.num, ref.gen);

test/unit/crypto_spec.js

@@ -17,7 +17,6 @@ import {
   AES128Cipher,
   AES256Cipher,
   ARCFourCipher,
-  calculateMD5,
   calculateSHA256,
   calculateSHA384,
   calculateSHA512,
@@ -31,6 +30,7 @@ import {
   PasswordResponses,
   stringToBytes,
 } from "../../src/shared/util.js";
+import { calculateMD5 } from "../../src/core/calculate_md5.js";
 
 describe("crypto", function () {
   function hex2binary(s) {