Add special error message when loading zip is all zeros or empty

Author: GarboMuffin

dist/jszip.js

@@ -1,6 +1,6 @@
 /*!
 
-JSZip v3.11.1 - A JavaScript class for generating and reading zip files
+JSZip v3.12.0 - A JavaScript class for generating and reading zip files
 <http://stuartk.com/jszip>
 
 (c) 2009-2016 Stuart Knightley <stuart [at] stuartk.com>
@@ -1906,6 +1906,17 @@ DataReader.prototype = {
             (dostime >> 11) & 0x1f, // hour
             (dostime >> 5) & 0x3f, // minute
             (dostime & 0x1f) << 1)); // second
+    },
+    /**
+     * @returns {boolean} true if the reader is all zeros or has 0 length.
+     */
+    isAllZeros: function() {
+        for (var i = 0; i < this.length; i++) {
+            if (this.byteAt(i) !== 0) {
+                return false;
+            }
+        }
+        return true;
     }
 };
 module.exports = DataReader;
@@ -3870,6 +3881,10 @@ ZipEntries.prototype = {
             this.readCentralDir();
             this.readLocalFiles();
         } catch (centralDirectoryError) {
+            if (this.reader.isAllZeros()) {
+                throw new Error("Corrupted zip: all zeros, unrecoverable");
+            }
+
             if (this.loadOptions.recoverCorrupted) {
                 if (this.loadOptions.onCorruptCentralDirectory) {
                     this.loadOptions.onCorruptCentralDirectory(centralDirectoryError);

dist/jszip.min.js

@@ -111,6 +111,17 @@ DataReader.prototype = {
             (dostime >> 11) & 0x1f, // hour
             (dostime >> 5) & 0x3f, // minute
             (dostime & 0x1f) << 1)); // second
+    },
+    /**
+     * @returns {boolean} true if the reader is all zeros or has 0 length.
+     */
+    isAllZeros: function() {
+        for (var i = 0; i < this.length; i++) {
+            if (this.byteAt(i) !== 0) {
+                return false;
+            }
+        }
+        return true;
     }
 };
 module.exports = DataReader;

lib/reader/DataReader.js

@@ -320,6 +320,10 @@ ZipEntries.prototype = {
             this.readCentralDir();
             this.readLocalFiles();
         } catch (centralDirectoryError) {
+            if (this.reader.isAllZeros()) {
+                throw new Error("Corrupted zip: all zeros, unrecoverable");
+            }
+
             if (this.loadOptions.recoverCorrupted) {
                 if (this.loadOptions.onCorruptCentralDirectory) {
                     this.loadOptions.onCorruptCentralDirectory(centralDirectoryError);

lib/zipEntries.js

@@ -41,4 +41,30 @@ QUnit.module("corruption", function () {
             })
             .catch(JSZipTestUtils.assertNoError);
     });
+
+    JSZipTestUtils.testZipFile("special error message for all zeros", "ref/zeros.bin", function(assert, file) {
+        var done = assert.async();
+        JSZip.loadAsync(file)
+            .then(function () {
+                assert.ok(false, "somehow successfully extracted zip of all zeros");
+                done();
+            })
+            .catch(function (err) {
+                assert.ok(err.message.match("all zeros"), "all zeros : the error message is useful");
+                done();
+            });
+    });
+
+    JSZipTestUtils.testZipFile("special error message for empty", "ref/empty.bin", function(assert, file) {
+        var done = assert.async();
+        JSZip.loadAsync(file)
+            .then(function () {
+                assert.ok(false, "somehow successfully extracted empty file");
+                done();
+            })
+            .catch(function (err) {
+                assert.ok(err.message.match("all zeros"), "empty : the error message is useful");
+                done();
+            });
+    });
 });