chrome/utility/media_galleries/pmp_column_reader.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_UTILITY_MEDIA_GALLERIES_PMP_COLUMN_READER_H_
   6 #define CHROME_UTILITY_MEDIA_GALLERIES_PMP_COLUMN_READER_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/platform_file.h"
  14 #include "chrome/common/media_galleries/pmp_constants.h"
  15
  16 namespace base {
  17 class FilePath;
  18 }
  19
  20 namespace picasa {
  21
  22 // Reads a single PMP column from a file.
  23 class PmpColumnReader {
  24  public:
  25   PmpColumnReader();
  26   virtual ~PmpColumnReader();
  27
  28   // Returns true if read successfully.
  29   // |rows_read| is undefined if returns false.
  30   bool ReadFile(base::PlatformFile file, const PmpFieldType expected_type);
  31
  32   // These functions read the value of that |row| into |result|.
  33   // Functions return false if the column is of the wrong type or the row
  34   // is out of range. May only be called after successful ReadColumn.
  35   bool ReadString(const uint32 row, std::string* result) const;
  36   bool ReadUInt32(const uint32 row, uint32* result) const;
  37   bool ReadDouble64(const uint32 row, double* result) const;
  38   bool ReadUInt8(const uint32 row, uint8* result) const;
  39   bool ReadUInt64(const uint32 row, uint64* result) const;
  40
  41   // May only be called after successful ReadColumn.
  42   uint32 rows_read() const;
  43
  44  private:
  45   bool ParseData(const PmpFieldType expected_type);
  46   // Returns the number of bytes parsed in the body, or, -1 on failure.
  47   int64 IndexStrings();
  48
  49   // Source data
  50   scoped_ptr<uint8[]> data_;
  51   int64 length_;
  52
  53   // Header data
  54   PmpFieldType field_type_;
  55   uint32 rows_read_;
  56
  57   // Index of string start locations if fields are strings. Empty otherwise.
  58   std::vector<const char*> strings_;
  59
  60   DISALLOW_COPY_AND_ASSIGN(PmpColumnReader);
  61 };
  62
  63 }  // namespace picasa
  64
  65 #endif  // CHROME_UTILITY_MEDIA_GALLERIES_PMP_COLUMN_READER_H_