Line data    Source code

       1             : /* Copyright (C) 2021 Wildfire Games.
       2             :  *
       3             :  * Permission is hereby granted, free of charge, to any person obtaining
       4             :  * a copy of this software and associated documentation files (the
       5             :  * "Software"), to deal in the Software without restriction, including
       6             :  * without limitation the rights to use, copy, modify, merge, publish,
       7             :  * distribute, sublicense, and/or sell copies of the Software, and to
       8             :  * permit persons to whom the Software is furnished to do so, subject to
       9             :  * the following conditions:
      10             :  *
      11             :  * The above copyright notice and this permission notice shall be included
      12             :  * in all copies or substantial portions of the Software.
      13             :  *
      14             :  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
      15             :  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
      16             :  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
      17             :  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
      18             :  * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
      19             :  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
      20             :  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
      21             :  */
      22             : 
      23             : /*
      24             :  * this layer allows for other compression methods/libraries
      25             :  * besides ZLib. it also simplifies the interface for user code and
      26             :  * does error checking, etc.
      27             :  */
      28             : 
      29             : #ifndef INCLUDED_CODEC
      30             : #define INCLUDED_CODEC
      31             : 
      32             : #define CODEC_COMPUTE_CHECKSUM 1
      33             : 
      34           0 : struct ICodec
      35             : {
      36             : public:
      37             :     /**
      38             :      * note: the implementation should not check whether any data remains -
      39             :      * codecs are sometimes destroyed without completing a transfer.
      40             :      **/
      41             :     virtual ~ICodec();
      42             : 
      43             :     /**
      44             :      * @return an upper bound on the output size for the given amount of input.
      45             :      * this is used when allocating a single buffer for the whole operation.
      46             :      **/
      47             :     virtual size_t MaxOutputSize(size_t inSize) const = 0;
      48             : 
      49             :     /**
      50             :      * clear all previous state and prepare for reuse.
      51             :      *
      52             :      * this is as if the object were destroyed and re-created, but more
      53             :      * efficient since it avoids reallocating a considerable amount of
      54             :      * memory (about 200KB for LZ).
      55             :      **/
      56             :     virtual Status Reset() = 0;
      57             : 
      58             :     /**
      59             :      * process (i.e. compress or decompress) data.
      60             :      *
      61             :      * @param in
      62             :      * @param inSize
      63             :      * @param out
      64             :      * @param outSize Bytes remaining in the output buffer; shall not be zero.
      65             :      * @param inConsumed,outProduced How many bytes in the input and
      66             :      *        output buffers were used. either or both of these can be zero if
      67             :      *        the input size is small or there's not enough output space.
      68             :      **/
      69             :     virtual Status Process(const u8* in, size_t inSize, u8* out, size_t outSize, size_t& inConsumed, size_t& outProduced) = 0;
      70             : 
      71             :     /**
      72             :      * Flush buffers and make sure all output has been produced.
      73             :      *
      74             :      * @param checksum Checksum over all input data.
      75             :      * @param outProduced
      76             :      * @return error status for the entire operation.
      77             :      **/
      78             :     virtual Status Finish(u32& checksum, size_t& outProduced) = 0;
      79             : 
      80             :     /**
      81             :      * update a checksum to reflect the contents of a buffer.
      82             :      *
      83             :      * @param checksum the initial value (must be 0 on first call)
      84             :      * @param in
      85             :      * @param inSize
      86             :      * @return the new checksum. note: after all data has been seen, this is
      87             :      * identical to the what Finish would return.
      88             :      **/
      89             :     virtual u32 UpdateChecksum(u32 checksum, const u8* in, size_t inSize) const = 0;
      90             : };
      91             : 
      92             : typedef std::shared_ptr<ICodec> PICodec;
      93             : 
      94             : #endif  // #ifndef INCLUDED_CODEC