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+// Copyright 2015 Google Inc.
+//
+// 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.
+//
+////////////////////////////////////////////////////////////////////////////////
+//
+// The purpose of the preview-image-extractor (piex) is to find and extract the
+// largest JPEG compressed preview image contained in a RAW file.
+// For details: go/piex
+//
+// Even for unsupported RAW files we want to provide high quality images using a
+// dedicated, small and portable library. That is possible by taking the preview
+// image contained in all RAW files.
+//
+// Typically a preview image is stored as JPEG compressed, full size (or at
+// least half size) image in a RAW file.
+//
+// A typical client code snippet:
+//
+//   // In C++
+//   PreviewImageData image_data;
+//   unique_ptr<StreamInterface> data_stream(new DataStream(file));
+//   Error err = GetPreviewImageData(data_stream.get(), &image_data));
+//   if (err == Error::kFail) {
+//     // The input data seems to be broken.
+//     return;
+//   } else if (err == Error::kUnsupported) {
+//     // The input data is not supported.
+//     return;
+//   }
+//
+//   // Uncompress the JPEG as usual, e.g. on Android with the BitmapFactory:
+//   // In Java
+//   Bitmap bitmap = BitmapFactory.decodeByteArray(
+//       file.at(image_data.jpeg_offset), image_data.jpeg_length);
+
+#ifndef PIEX_PIEX_H_
+#define PIEX_PIEX_H_
+
+#include <string>
+#include <vector>
+
+#include "src/piex_types.h"
+
+namespace piex {
+
+// Returns the maximum number of bytes IsRaw() will read from the stream.
+size_t BytesRequiredForIsRaw();
+
+// Returns true if 'data' contains a RAW file format, even if it is not
+// supported by Piex, false otherwise. Reads at most BytesRequiredForIsRaw()
+// from the stream.
+bool IsRaw(StreamInterface* data);
+
+// Gets the largest JPEG compressed preview image data. On success
+// 'preview_image_data' contains image metadata, the unverified length and the
+// offset to a JPEG compressed image from the beginning of the file.
+//
+// Returns 'kFail' when something with the data is wrong.
+// Returns 'kUnsupported' if file format is not supported.
+//
+// One could check the "preview_image_data->jpeg_length != 0" for the existance
+// of a preview image.
+Error GetPreviewImageData(StreamInterface* data,
+                          PreviewImageData* preview_image_data);
+
+// Returns a vector of upper case file extensions, which are used as a first
+// step to quickly guess a supported file format.
+std::vector<std::string> SupportedExtensions();
+
+}  // namespace piex
+
+#endif  // PIEX_PIEX_H_