Fixes issue 18

Makefile.common

@@ -85,14 +85,14 @@ Mac-x86_64_SNAPPY_FLAGS  :=
 
 Windows-x86_CXX          := mingw32-g++
 Windows-x86_STRIP        := strip
-Windows-x86_CXXFLAGS     := -Ilib/inc_win -O2
+Windows-x86_CXXFLAGS     := -Ilib/inc_win -O2 
 Windows-x86_LINKFLAGS    := -Wl,--kill-at -shared -static
 Windows-x86_LIBNAME      := snappyjava.dll
 Windows-x86_SNAPPY_FLAGS := 
 
 Windows-amd64_CXX          := x86_64-w64-mingw32-g++
 Windows-amd64_STRIP        := x86_64-w64-mingw32-strip
-Windows-amd64_CXXFLAGS     := -Ilib/inc_win -O2
+Windows-amd64_CXXFLAGS     := -Ilib/inc_win -O2 
 Windows-amd64_LINKFLAGS    := -Wl,--kill-at -shared -static 
 Windows-amd64_LIBNAME      := snappyjava.dll
 Windows-amd64_SNAPPY_FLAGS := 

src/main/java/org/xerial/snappy/Snappy.java

@@ -166,6 +166,16 @@ public class Snappy
         return SnappyNative.isValidCompressedBuffer(input, offset, length);
     }
 
+    /**
+     * Returns true iff the contents of compressed buffer [offset,
+     * offset+length) can be uncompressed successfully. Does not return the
+     * uncompressed data. Takes time proportional to the input length, but is
+     * usually at least a factor of four faster than actual decompression.
+     */
+    public static boolean isValidCompressedBuffer(byte[] input) throws SnappyException {
+        return isValidCompressedBuffer(input, 0, input.length);
+    }
+
     /**
      * Returns true iff the contents of compressed buffer [pos() ... limit())
      * can be uncompressed successfully. Does not return the uncompressed data.

src/main/java/org/xerial/snappy/SnappyErrorCode.java

@@ -37,7 +37,8 @@ public enum SnappyErrorCode {
     FAILED_TO_LOAD_NATIVE_LIBRARY(1),
     PARSING_ERROR(2),
     NOT_A_DIRECT_BUFFER(3),
-    OUT_OF_MEMORY(4);
+    OUT_OF_MEMORY(4),
+    FAILED_TO_UNCOMPRESS(5);
 
     public final int id;
 

src/main/java/org/xerial/snappy/SnappyNative.cpp

@@ -19,19 +19,18 @@
 
 void throw_exception(JNIEnv *env, jclass self, int errorCode)
 {
-    jmethodID mth_throwex = 0;
+    jmethodID mth_throwex = env->GetStaticMethodID(self, "throw_error", "(I)V");
 
-    if (!mth_throwex)
-        mth_throwex = env->GetMethodID(self, "throw_error", "(I)V");
-
-    env->CallVoidMethod(self, mth_throwex, (jint) errorCode);
+    if(mth_throwex == 0)
+    	return;
+    env->CallStaticVoidMethod(self, mth_throwex, (jint) errorCode);
 }
 
 
 JNIEXPORT jstring JNICALL Java_org_xerial_snappy_SnappyNative_nativeLibraryVersion
   (JNIEnv * env, jclass self)
 {
-	return env->NewStringUTF("1.0.1");
+	return env->NewStringUTF("1.0.3");
 }
 
 /*
@@ -94,7 +93,7 @@ JNIEXPORT jint JNICALL Java_org_xerial_snappy_SnappyNative_rawUncompress__Ljava_
 	env->ReleasePrimitiveArrayCritical((jarray) output, out, 0);
 
 	if(!ret) {
-		throw_exception(env, self, 2);
+		throw_exception(env, self, 5);
 		return 0;
 	}
 
@@ -121,7 +120,7 @@ JNIEXPORT jint JNICALL Java_org_xerial_snappy_SnappyNative_rawUncompress__Ljava_
 	snappy::GetUncompressedLength(compressedBuffer + cpos, (size_t) clen, &decompressedLength);
 	bool ret = snappy::RawUncompress(compressedBuffer + cpos, (size_t) clen, decompressedBuffer + dpos);
 	if(!ret) {
-		throw_exception(env, self, 2);
+		throw_exception(env, self, 5);
 		return 0;
 	}
 
@@ -180,6 +179,11 @@ JNIEXPORT jint JNICALL Java_org_xerial_snappy_SnappyNative_uncompressedLength__L
 	bool ret = snappy::GetUncompressedLength(in + offset, (size_t) length, &result);
 	env->ReleasePrimitiveArrayCritical((jarray) input, in, 0);
 
+	if(!ret) {
+		throw_exception(env, self, 2);
+		return 0;
+	}
+
 	return (jint) result;
 }
 

src/test/java/org/xerial/snappy/SnappyTest.java

@@ -287,8 +287,15 @@ public class SnappyTest
     public void isValidCompressedData() throws Exception {
 
         byte[] b = new byte[] { (byte) 91, (byte) 34, (byte) 80, (byte) 73, (byte) 34, (byte) 93 };
-        if (Snappy.isValidCompressedBuffer(b, 0, b.length)) {
+
+        assertFalse(Snappy.isValidCompressedBuffer(b));
+
+        try {
             byte[] uncompressed = Snappy.uncompress(b);
+            fail("cannot reach here since the input is invalid data");
+        }
+        catch (SnappyException e) {
+            assertEquals(SnappyErrorCode.FAILED_TO_UNCOMPRESS, e.errorCode);
         }
 
     }