Simple PMP reader to parse Picasa's metadata

webkit/fileapi/media/picasa/pmp_column_reader.h

Index: webkit/fileapi/media/picasa/pmp_column_reader.h
diff --git a/webkit/fileapi/media/picasa/pmp_column_reader.h b/webkit/fileapi/media/picasa/pmp_column_reader.h
new file mode 100644
index 0000000000000000000000000000000000000000..2057eb2ac9e40f9c6068d1497ead328527dabeec
--- /dev/null
+++ b/webkit/fileapi/media/picasa/pmp_column_reader.h
@@ -0,0 +1,63 @@
+// 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:
+  PmpColumnReader();
+  virtual ~PmpColumnReader();
+
+  // Returns true if read successfully. |rows_read| undefined if returns false.

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

nit: ...is undefined...

[tommycli, 2013/04/01 22:19:18]

Done.

+  bool InitFromFile(const base::FilePath& filepath, uint32* rows_read);

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

nit: Since there's only one Init method and it's clear from the args that it
reads from a file, just call this Init.

[tommycli, 2013/04/01 22:19:18]

Done.

+
+  // These functions read the value of that row into the |result| variable.

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

nit: ..the value of |row| into |result|.

[tommycli, 2013/04/01 22:19:18]

Done.

+  // Function returns false if the column is of the wrong type or the row

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

nit: Functions return

[tommycli, 2013/04/01 22:19:18]

Done.

+  // 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 uint16 field_type() const {

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

The native encoding of field_type is returned? Say so in a comment.

[tommycli, 2013/04/01 22:19:18]

Done.

+    return field_type_;
+  }
+
+ private:
+  bool ParseData(uint32* rows_read);
+  bool IndexStrings();
+  template<class T> bool ValidatePrimitiveArrayLength();
+
+  scoped_array<uint8> data_;

[vandebo (ex-Chrome), 2013/03/29 21:35:07]

This is really nit picky, but is there any organization to your member
variables? Maybe grouping like this would make sense?

(source data)
data_
length_

(header data)
field_type_
rows_

(computed info)
strings_

[tommycli, 2013/04/01 22:19:18]

Done.

+  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 field_type_;
+
+  DISALLOW_COPY_AND_ASSIGN(PmpColumnReader);
+};
+
+}  // namespace fileapi
+
+#endif  // WEBKIT_FILEAPI_MEDIA_PICASA_PMP_COLUMN_READER_H_