Makes PDF data reading Streams API friendly.

src/shared/util.js

@@ -567,6 +567,55 @@ function stringToBytes(str) {
   return bytes;
 }
 
+/**
+ * Gets length of the array (Array, Uint8Array, or string) in bytes.
+ * @param {Array|Uint8Array|string} arr
+ * @returns {number}
+ */
+function arrayByteLength(arr) {
+  if (arr.length !== undefined) {
+    return arr.length;
+  }
+  assert(arr.byteLength !== undefined);
+  return arr.byteLength;
+}
+
+/**
+ * Combines array items (arrays) into single Uint8Array object.
+ * @param {Array} arr - the array of the arrays (Array, Uint8Array, or string).
+ * @returns {Uint8Array}
+ */
+function arraysToBytes(arr) {
+  // Shortcut: if first and only item is Uint8Array, return it.
+  if (arr.length === 1 && (arr[0] instanceof Uint8Array)) {
+    return arr[0];
+  }
+  var resultLength = 0;
+  var i, ii = arr.length;
+  var item, itemLength ;
+  for (i = 0; i < ii; i++) {
+    item = arr[i];
+    itemLength = arrayByteLength(item);
+    resultLength += itemLength;
+  }
+  var pos = 0;
+  var data = new Uint8Array(resultLength);
+  for (i = 0; i < ii; i++) {
+    item = arr[i];
+    if (!(item instanceof Uint8Array)) {
+      if (typeof item === 'string') {
+        item = stringToBytes(item);
+      } else {
+        item = new Uint8Array(item);
+      }
+    }
+    itemLength = item.byteLength;
+    data.set(item, pos);
+    pos += itemLength;
+  }
+  return data;
+}
+
 function string32(value) {
   return String.fromCharCode((value >> 24) & 0xff, (value >> 16) & 0xff,
                              (value >> 8) & 0xff, value & 0xff);
@@ -2361,6 +2410,8 @@ exports.UnexpectedResponseException = UnexpectedResponseException;
 exports.UnknownErrorException = UnknownErrorException;
 exports.Util = Util;
 exports.XRefParseException = XRefParseException;
+exports.arrayByteLength = arrayByteLength;
+exports.arraysToBytes = arraysToBytes;
 exports.assert = assert;
 exports.bytesToString = bytesToString;
 exports.combineUrl = combineUrl;