From e5d060bfe749a9bbafe3b773a3091b4eb381b076 Mon Sep 17 00:00:00 2001
From: "srowen@gmail.com"
 <srowen@gmail.com@59b500cc-1b3d-0410-9834-0bbf25fbcc57>
Date: Tue, 5 Mar 2013 18:07:45 +0000
Subject: [PATCH] Avoid stack overflow in some odd case in multiple barcode
 detection, and don't use multiple threads for one image on the command line

git-svn-id: https://zxing.googlecode.com/svn/trunk@2585 59b500cc-1b3d-0410-9834-0bbf25fbcc57
---
 .../multi/GenericMultipleBarcodeReader.java   | 26 ++++++++++++++-----
 .../zxing/client/j2se/CommandLineRunner.java  | 25 ++++++++++--------
 2 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/core/src/com/google/zxing/multi/GenericMultipleBarcodeReader.java b/core/src/com/google/zxing/multi/GenericMultipleBarcodeReader.java
index 7a32b5ec2..6a94623b3 100644
--- a/core/src/com/google/zxing/multi/GenericMultipleBarcodeReader.java
+++ b/core/src/com/google/zxing/multi/GenericMultipleBarcodeReader.java
@@ -45,6 +45,7 @@ import java.util.Map;
 public final class GenericMultipleBarcodeReader implements MultipleBarcodeReader {
 
   private static final int MIN_DIMENSION_TO_RECUR = 100;
+  private static final int MAX_DEPTH = 4;
 
   private final Reader delegate;
 
@@ -61,7 +62,7 @@ public final class GenericMultipleBarcodeReader implements MultipleBarcodeReader
   public Result[] decodeMultiple(BinaryBitmap image, Map<DecodeHintType,?> hints)
       throws NotFoundException {
     List<Result> results = new ArrayList<Result>();
-    doDecodeMultiple(image, hints, results, 0, 0);
+    doDecodeMultiple(image, hints, results, 0, 0, 0);
     if (results.isEmpty()) {
       throw NotFoundException.getNotFoundInstance();
     }
@@ -72,7 +73,12 @@ public final class GenericMultipleBarcodeReader implements MultipleBarcodeReader
                                 Map<DecodeHintType,?> hints,
                                 List<Result> results,
                                 int xOffset,
-                                int yOffset) {
+                                int yOffset,
+                                int currentDepth) {
+    if (currentDepth > MAX_DEPTH) {
+      return;
+    }
+    
     Result result;
     try {
       result = delegate.decode(image, hints);
@@ -119,22 +125,30 @@ public final class GenericMultipleBarcodeReader implements MultipleBarcodeReader
     // Decode left of barcode
     if (minX > MIN_DIMENSION_TO_RECUR) {
       doDecodeMultiple(image.crop(0, 0, (int) minX, height),
-                       hints, results, xOffset, yOffset);
+                       hints, results, 
+                       xOffset, yOffset, 
+                       currentDepth + 1);
     }
     // Decode above barcode
     if (minY > MIN_DIMENSION_TO_RECUR) {
       doDecodeMultiple(image.crop(0, 0, width, (int) minY),
-                       hints, results, xOffset, yOffset);
+                       hints, results, 
+                       xOffset, yOffset, 
+                       currentDepth + 1);
     }
     // Decode right of barcode
     if (maxX < width - MIN_DIMENSION_TO_RECUR) {
       doDecodeMultiple(image.crop((int) maxX, 0, width - (int) maxX, height),
-                       hints, results, xOffset + (int) maxX, yOffset);
+                       hints, results, 
+                       xOffset + (int) maxX, yOffset, 
+                       currentDepth + 1);
     }
     // Decode below barcode
     if (maxY < height - MIN_DIMENSION_TO_RECUR) {
       doDecodeMultiple(image.crop(0, (int) maxY, width, height - (int) maxY),
-                       hints, results, xOffset, yOffset + (int) maxY);
+                       hints, results, 
+                       xOffset, yOffset + (int) maxY, 
+                       currentDepth + 1);
     }
   }
 
diff --git a/javase/src/com/google/zxing/client/j2se/CommandLineRunner.java b/javase/src/com/google/zxing/client/j2se/CommandLineRunner.java
index e265bbca8..9ac15a7f0 100644
--- a/javase/src/com/google/zxing/client/j2se/CommandLineRunner.java
+++ b/javase/src/com/google/zxing/client/j2se/CommandLineRunner.java
@@ -95,17 +95,20 @@ public final class CommandLineRunner {
       }
     }
 
-    int numThreads = Runtime.getRuntime().availableProcessors();
-    ExecutorService executor = Executors.newFixedThreadPool(numThreads);
-    Collection<Future<Integer>> futures = new ArrayList<Future<Integer>>(numThreads);
-    for (int x = 0; x < numThreads; x++) {
-      futures.add(executor.submit(new DecodeWorker(config, inputs)));
-    }
-    executor.shutdown();
-
-    int successful = 0;
-    for (Future<Integer> future : futures) {
-      successful += future.get();
+    int numThreads = Math.min(inputs.size(), Runtime.getRuntime().availableProcessors());
+    int successful = 0;    
+    if (numThreads > 1) {
+      ExecutorService executor = Executors.newFixedThreadPool(numThreads);
+      Collection<Future<Integer>> futures = new ArrayList<Future<Integer>>(numThreads);
+      for (int x = 0; x < numThreads; x++) {
+        futures.add(executor.submit(new DecodeWorker(config, inputs)));
+      }
+      executor.shutdown();
+      for (Future<Integer> future : futures) {
+        successful += future.get();
+      }
+    } else {
+      successful += new DecodeWorker(config, inputs).call();
     }
 
     int total = inputs.size();