Simple PMP reader to parse Picasa's metadata

webkit/fileapi/media/picasa/pmp_column_reader.h

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef WEBKIT_FILEAPI_MEDIA_PICASA_PMP_COLUMN_READER_H_
+#define WEBKIT_FILEAPI_MEDIA_PICASA_PMP_COLUMN_READER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "webkit/storage/webkit_storage_export.h"
+
+namespace base {
+class FilePath;
+}
+
+namespace fileapi {
+
+// Reads a single PMP column from a file.
+class WEBKIT_STORAGE_EXPORT_PRIVATE PmpColumnReader {
+ public:
+  explicit PmpColumnReader(std::string column_name);

[vandebo (ex-Chrome), 2013/03/28 00:56:04]

should column_name be part of the Init method?

[tommycli, 2013/03/29 00:16:01]

Done.

+  virtual ~PmpColumnReader();
+
+  // Returns true if read successfully. |rows_read| undefined if returns false.
+  bool ReadFromFile(const base::FilePath& filepath, uint32* rows_read);

[vandebo (ex-Chrome), 2013/03/28 00:56:04]

nit: InitFromFile ?

[tommycli, 2013/03/29 00:16:01]

Done.

+
+  // These functions read the value of that row into the |result| variable.
+  // Function returns false if the column is of the wrong type or the row
+  // is out of range.
+  bool ReadString(const uint32 row, std::string* result) const;
+  bool ReadUInt32(const uint32 row, uint32* result) const;
+  bool ReadDouble64(const uint32 row, double* result) const;
+  bool ReadUInt8(const uint32 row, uint8* result) const;
+  bool ReadUInt64(const uint32 row, uint64* result) const;
+
+  const std::string column_name() const {

[vandebo (ex-Chrome), 2013/03/28 00:56:04]

Do you use this?  If not, you can probably just remove column name from this
class all together.

[tommycli, 2013/03/29 00:16:01]

Done.

+    return column_name_;
+  }
+
+ private:
+  // Private template method to support all the numeric Read*() methods.
+  template<class T> bool ReadPrimitive(const uint32 row, T* target) const;
+
+  // Only called from ReadFromMemory().

[vandebo (ex-Chrome), 2013/03/28 00:56:04]

nit: outdated comment.  Probably not needed anyway.

[tommycli, 2013/03/29 00:16:01]

Done.

+  bool ParseData(uint32* rows_read);
+  bool IndexStrings();
+  template<class T> bool ValidatePrimitiveArrayLength();
+
+  const std::string column_name_;
+
+  scoped_array<uint8> data_;
+  size_t length_;
+  uint32 rows_;
+
+  // Index of string start locations if fields are strings. Empty otherwise.
+  std::vector<const char*> strings_;
+
+  // Store type of field
+  uint16 fieldtype_;
+
+  DISALLOW_COPY_AND_ASSIGN(PmpColumnReader);
+};
+
+}  // namespace fileapi
+
+#endif  // WEBKIT_FILEAPI_MEDIA_PICASA_PMP_COLUMN_READER_H_