refactor helper functions out of libjpeg wrapper

git-svn-id: http://skia.googlecode.com/svn/trunk@476 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 71 insertions, 0 deletions

diff --git a/include/images/SkJpegUtility.h b/include/images/SkJpegUtility.h
new file mode 100644
index 0000000000..cc9d2466df
--- /dev/null
+++ b/include/images/SkJpegUtility.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SkJpegUtility_DEFINED
+#define SkJpegUtility_DEFINED
+
+#include "SkImageDecoder.h"
+#include "SkStream.h"
+
+extern "C" {
+    #include "jpeglib.h"
+    #include "jerror.h"
+}
+
+#include <setjmp.h>
+
+/* Our error-handling struct.
+ *
+*/
+struct skjpeg_error_mgr : jpeg_error_mgr {
+    jmp_buf fJmpBuf;
+};
+
+
+void skjpeg_error_exit(j_common_ptr cinfo);
+
+///////////////////////////////////////////////////////////////////////////
+/* Our source struct for directing jpeg to our stream object.
+*/
+struct skjpeg_source_mgr : jpeg_source_mgr {
+    skjpeg_source_mgr(SkStream* stream, SkImageDecoder* decoder);
+
+    SkStream*   fStream;
+    const void* fMemoryBase;
+    size_t      fMemoryBaseSize;
+    SkImageDecoder* fDecoder;
+    enum {
+        kBufferSize = 1024
+    };
+    char    fBuffer[kBufferSize];
+};
+
+/////////////////////////////////////////////////////////////////////////////
+/* Our destination struct for directing decompressed pixels to our stream
+ * object.
+ */
+struct skjpeg_destination_mgr : jpeg_destination_mgr {
+    skjpeg_destination_mgr(SkWStream* stream);
+
+    SkWStream*  fStream;
+
+    enum {
+        kBufferSize = 1024
+    };
+    uint8_t fBuffer[kBufferSize];
+};
+
+#endif