Updated ZFile to use UTF-8 if needed.

If ASCII decoding fails, ZFile will now automatically try
UTF-8.

Change-Id: I29ef2cf3c043cf31d6c07c70271297356d2571f2
Test: Included

4 files changed, 30 insertions, 11 deletions

diff --git a/src/main/java/com/android/apkzlib/zip/CentralDirectory.java b/src/main/java/com/android/apkzlib/zip/CentralDirectory.java
index 4305d80..44389c1 100644
--- a/src/main/java/com/android/apkzlib/zip/CentralDirectory.java
+++ b/src/main/java/com/android/apkzlib/zip/CentralDirectory.java
@@ -341,7 +341,9 @@ class CentralDirectory {
                             + ".");
         }
 
-        String fileName = EncodeUtils.decode(bytes, fileNameLength, flags);
+        byte[] encodedFileName = new byte[fileNameLength];
+        bytes.get(encodedFileName);
+        String fileName = EncodeUtils.decode(encodedFileName, flags);
 
         byte[] extraField = new byte[extraFieldLength];
         bytes.get(extraField);
@@ -362,11 +364,7 @@ class CentralDirectory {
                                 versionNeededToExtract));
         CentralDirectoryHeader centralDirectoryHeader =
                 new CentralDirectoryHeader(
-                        fileName,
-                        uncompressedSize,
-                        compressInfo,
-                        flags,
-                        file);
+                        fileName, encodedFileName, uncompressedSize, compressInfo, flags, file);
         centralDirectoryHeader.setMadeBy(madeBy);
         centralDirectoryHeader.setLastModTime(lastModTime);
         centralDirectoryHeader.setLastModDate(lastModDate);
diff --git a/src/main/java/com/android/apkzlib/zip/CentralDirectoryHeader.java b/src/main/java/com/android/apkzlib/zip/CentralDirectoryHeader.java
index 7e7e50b..f10477f 100644
--- a/src/main/java/com/android/apkzlib/zip/CentralDirectoryHeader.java
+++ b/src/main/java/com/android/apkzlib/zip/CentralDirectoryHeader.java
@@ -128,6 +128,7 @@ public class CentralDirectoryHeader implements Cloneable {
      * Creates data for a file.
      *
      * @param name the file name
+     * @param encodedFileName the encoded file name, this array will be owned by the header
      * @param uncompressedSize the uncompressed file size
      * @param compressInfo computation that defines the compression information
      * @param flags flags used in the entry
@@ -135,6 +136,7 @@ public class CentralDirectoryHeader implements Cloneable {
      */
     CentralDirectoryHeader(
             @Nonnull String name,
+            @Nonnull byte[] encodedFileName,
             long uncompressedSize,
             @Nonnull Future<CentralDirectoryHeaderCompressInfo> compressInfo,
             @Nonnull GPFlags flags,
@@ -156,7 +158,7 @@ public class CentralDirectoryHeader implements Cloneable {
         internalAttributes = 0;
         externalAttributes = 0;
         offset = -1;
-        encodedFileName = EncodeUtils.encode(name, gpBit);
+        this.encodedFileName = encodedFileName;
         this.compressInfo = compressInfo;
         file = zFile;
     }
diff --git a/src/main/java/com/android/apkzlib/zip/EncodeUtils.java b/src/main/java/com/android/apkzlib/zip/EncodeUtils.java
index 6579d1c..94cabbe 100644
--- a/src/main/java/com/android/apkzlib/zip/EncodeUtils.java
+++ b/src/main/java/com/android/apkzlib/zip/EncodeUtils.java
@@ -19,7 +19,9 @@ package com.android.apkzlib.zip;
 import com.google.common.base.Charsets;
 import java.io.IOException;
 import java.nio.ByteBuffer;
+import java.nio.charset.CharacterCodingException;
 import java.nio.charset.Charset;
+import java.nio.charset.CodingErrorAction;
 import javax.annotation.Nonnull;
 
 /**
@@ -52,10 +54,9 @@ public class EncodeUtils {
                     + "length is " + length + ".");
         }
 
-        Charset charset = flagsCharset(flags);
         byte[] stringBytes = new byte[length];
         bytes.get(stringBytes);
-        return charset.decode(ByteBuffer.wrap(stringBytes)).toString();
+        return decode(stringBytes, flags);
     }
 
     /**
@@ -68,7 +69,23 @@ public class EncodeUtils {
     @Nonnull
     public static String decode(@Nonnull byte[] data, @Nonnull GPFlags flags) {
         Charset charset = flagsCharset(flags);
-        return charset.decode(ByteBuffer.wrap(data)).toString();
+
+        while (true) {
+            try {
+                return charset.newDecoder()
+                        .onMalformedInput(CodingErrorAction.REPORT)
+                        .decode(ByteBuffer.wrap(data))
+                        .toString();
+            } catch (CharacterCodingException e) {
+                // If we're trying to decode ASCII, try UTF-8. Otherwise, revert to the default
+                // behavior (usually replacing invalid characters).
+                if (charset == Charsets.US_ASCII) {
+                    charset = Charsets.UTF_8;
+                } else {
+                    return charset.decode(ByteBuffer.wrap(data)).toString();
+                }
+            }
+        }
     }
 
     /**
diff --git a/src/main/java/com/android/apkzlib/zip/ZFile.java b/src/main/java/com/android/apkzlib/zip/ZFile.java
index 2ec8df7..d4d730e 100644
--- a/src/main/java/com/android/apkzlib/zip/ZFile.java
+++ b/src/main/java/com/android/apkzlib/zip/ZFile.java
@@ -1522,12 +1522,14 @@ public class ZFile implements Closeable {
 
         SettableFuture<CentralDirectoryHeaderCompressInfo> compressInfo =
                 SettableFuture.create();
+        GPFlags flags = GPFlags.make(encodeWithUtf8);
         CentralDirectoryHeader newFileData =
                 new CentralDirectoryHeader(
                         name,
+                        EncodeUtils.encode(name, flags),
                         source.size(),
                         compressInfo,
-                        GPFlags.make(encodeWithUtf8),
+                        flags,
                         this);
         newFileData.setCrc32(crc32);