1    :  // Copyright 2012 Google Inc.
   2    :  //
   3    :  // Licensed under the Apache License, Version 2.0 (the "License");
   4    :  // you may not use this file except in compliance with the License.
   5    :  // You may obtain a copy of the License at
   6    :  //
   7    :  //     http://www.apache.org/licenses/LICENSE-2.0
   8    :  //
   9    :  // Unless required by applicable law or agreed to in writing, software
  10    :  // distributed under the License is distributed on an "AS IS" BASIS,
  11    :  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12    :  // See the License for the specific language governing permissions and
  13    :  // limitations under the License.
  14    :  //
  15    :  // Declares a block-graph transform that trims unnecessary block data from
  16    :  // blocks, such that the implicit uninitialized data at the tail of the block
  17    :  // is maximized.
  18    :  //
  19    :  // Post TrimTransform the BlockGraph will satisfy the invariant that the
  20    :  // data_size of each block is exactly equal to its initialized data length.
  21    :  // This invariant is expected by OrderedBlockGraph and BlockGraphOrderers.
  22    :  
  23    :  #ifndef SYZYGY_BLOCK_GRAPH_TRANSFORMS_TRIM_TRANSFORM_H_
  24    :  #define SYZYGY_BLOCK_GRAPH_TRANSFORMS_TRIM_TRANSFORM_H_
  25    :  
  26    :  #include "syzygy/block_graph/transform.h"
  27    :  #include "syzygy/block_graph/transforms/iterative_transform.h"
  28    :  #include "syzygy/block_graph/transforms/named_transform.h"
  29    :  
  30    :  namespace block_graph {
  31    :  namespace transforms {
  32    :  
  33    :  class TrimTransform : public IterativeTransformImpl<TrimTransform> {
  34    :   public:
  35  E :    TrimTransform() { }
  36  E :    virtual ~TrimTransform() { }
  37    :  
  38    :   private:
  39    :    friend IterativeTransformImpl<TrimTransform>;
  40    :    friend NamedBlockGraphTransformImpl<TrimTransform>;
  41    :  
  42    :    // For NamedBlockGraphTransformImpl.
  43    :    static const char kTransformName[];
  44    :  
  45    :    // For IterativeTransformImpl.
  46    :    bool OnBlock(BlockGraph* block_graph, BlockGraph::Block* block);
  47    :  };
  48    :  
  49    :  }  // namespace transforms
  50    :  }  // namespace block_graph
  51    :  
  52    :  #endif  // SYZYGY_BLOCK_GRAPH_TRANSFORMS_TRIM_TRANSFORM_H_