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      1 /*
      2  * Copyright 2011 Google Inc. All Rights Reserved.
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef SFNTLY_CPP_SRC_SFNTLY_DATA_FONT_DATA_H_
     18 #define SFNTLY_CPP_SRC_SFNTLY_DATA_FONT_DATA_H_
     19 
     20 #include <limits.h>
     21 
     22 #include "sfntly/data/byte_array.h"
     23 #include "sfntly/port/refcount.h"
     24 #include "sfntly/port/type.h"
     25 
     26 namespace sfntly {
     27 
     28 struct DataSize {
     29   enum {
     30     kBYTE = 1,
     31     kCHAR = 1,
     32     kUSHORT = 2,
     33     kSHORT = 2,
     34     kUINT24 = 3,
     35     kULONG = 4,
     36     kLONG = 4,
     37     kFixed = 4,
     38     kFUNIT = 4,
     39     kFWORD = 2,
     40     kUFWORD = 2,
     41     kF2DOT14 = 2,
     42     kLONGDATETIME = 8,
     43     kTag = 4,
     44     kGlyphID = 2,
     45     kOffset = 2
     46   };
     47 };
     48 
     49 class FontData : virtual public RefCount {
     50  public:
     51   // Gets the maximum size of the FontData. This is the maximum number of bytes
     52   // that the font data can hold and all of it may not be filled with data or
     53   // even fully allocated yet.
     54   // @return the maximum size of this font data
     55   virtual int32_t Size() const;
     56 
     57   // Sets limits on the size of the FontData. The FontData is then only
     58   // visible within the bounds set.
     59   // @param offset the start of the new bounds
     60   // @param length the number of bytes in the bounded array
     61   virtual void Bound(int32_t offset, int32_t length);
     62 
     63   // Makes a slice of this FontData. The returned slice will share the data with
     64   // the original <code>FontData</code>.
     65   // @param offset the start of the slice
     66   // @param length the number of bytes in the slice
     67   // @return a slice of the original FontData
     68   virtual CALLER_ATTACH FontData* Slice(int32_t offset, int32_t length) = 0;
     69 
     70   // Makes a bottom bound only slice of this array. The returned slice will
     71   // share the data with the original <code>FontData</code>.
     72   // @param offset the start of the slice
     73   // @return a slice of the original FontData
     74   virtual CALLER_ATTACH FontData* Slice(int32_t offset) = 0;
     75 
     76   // Gets the length of the data.
     77   virtual int32_t Length() const;
     78 
     79  protected:
     80   // Constructor.
     81   // @param ba the byte array to use for the backing data
     82   explicit FontData(ByteArray* ba);
     83 
     84   // Constructor.
     85   // @param data the data to wrap
     86   // @param offset the offset to start the wrap from
     87   // @param length the length of the data wrapped
     88   FontData(FontData* data, int32_t offset, int32_t length);
     89 
     90   // Constructor.
     91   // @param data the data to wrap
     92   // @param offset the offset to start the wrap from
     93   FontData(FontData* data, int32_t offset);
     94   virtual ~FontData();
     95 
     96   void Init(ByteArray* ba);
     97 
     98   // Gets the offset in the underlying data taking into account any bounds on
     99   // the data.
    100   // @param offset the offset to get the bound compensated offset for
    101   // @return the bound compensated offset
    102   int32_t BoundOffset(int32_t offset);
    103 
    104   // Gets the length in the underlying data taking into account any bounds on
    105   // the data.
    106   // @param offset the offset that the length is being used at
    107   // @param length the length to get the bound compensated length for
    108   // @return the bound compensated length
    109   int32_t BoundLength(int32_t offset, int32_t length);
    110 
    111   static const int32_t GROWABLE_SIZE = INT_MAX;
    112 
    113   // TODO(arthurhsu): style guide violation: refactor this protected member
    114   ByteArrayPtr array_;
    115 
    116  private:
    117   int32_t bound_offset_;
    118   int32_t bound_length_;
    119 };
    120 typedef Ptr<FontData> FontDataPtr;
    121 
    122 }  // namespace sfntly
    123 
    124 #endif  // SFNTLY_CPP_SRC_SFNTLY_DATA_FONT_DATA_H_
    125