LCOV - code coverage report
Current view: top level - lunchbox/compressor/snappy - snappy-sinksource.h (source / functions) Hit Total Coverage
Test: lcov2.info Lines: 5 5 100.0 %
Date: 2014-10-01 Functions: 5 5 100.0 %

          Line data    Source code
       1             : // Copyright 2011 Google Inc. All Rights Reserved.
       2             : //
       3             : // Redistribution and use in source and binary forms, with or without
       4             : // modification, are permitted provided that the following conditions are
       5             : // met:
       6             : //
       7             : //     * Redistributions of source code must retain the above copyright
       8             : // notice, this list of conditions and the following disclaimer.
       9             : //     * Redistributions in binary form must reproduce the above
      10             : // copyright notice, this list of conditions and the following disclaimer
      11             : // in the documentation and/or other materials provided with the
      12             : // distribution.
      13             : //     * Neither the name of Google Inc. nor the names of its
      14             : // contributors may be used to endorse or promote products derived from
      15             : // this software without specific prior written permission.
      16             : //
      17             : // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      18             : // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      19             : // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
      20             : // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
      21             : // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      22             : // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      23             : // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
      24             : // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
      25             : // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      26             : // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      27             : // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      28             : 
      29             : #ifndef UTIL_SNAPPY_SNAPPY_SINKSOURCE_H_
      30             : #define UTIL_SNAPPY_SNAPPY_SINKSOURCE_H_
      31             : 
      32             : #include <stddef.h>
      33             : 
      34             : 
      35             : namespace snappy {
      36             : 
      37             : // A Sink is an interface that consumes a sequence of bytes.
      38             : class Sink {
      39             :  public:
      40          88 :   Sink() { }
      41             :   virtual ~Sink();
      42             : 
      43             :   // Append "bytes[0,n-1]" to this.
      44             :   virtual void Append(const char* bytes, size_t n) = 0;
      45             : 
      46             :   // Returns a writable buffer of the specified length for appending.
      47             :   // May return a pointer to the caller-owned scratch buffer which
      48             :   // must have at least the indicated length.  The returned buffer is
      49             :   // only valid until the next operation on this Sink.
      50             :   //
      51             :   // After writing at most "length" bytes, call Append() with the
      52             :   // pointer returned from this function and the number of bytes
      53             :   // written.  Many Append() implementations will avoid copying
      54             :   // bytes if this function returned an internal buffer.
      55             :   //
      56             :   // If a non-scratch buffer is returned, the caller may only pass a
      57             :   // prefix of it to Append().  That is, it is not correct to pass an
      58             :   // interior pointer of the returned array to Append().
      59             :   //
      60             :   // The default implementation always returns the scratch buffer.
      61             :   virtual char* GetAppendBuffer(size_t length, char* scratch);
      62             : 
      63             : 
      64             :  private:
      65             :   // No copying
      66             :   Sink(const Sink&);
      67             :   void operator=(const Sink&);
      68             : };
      69             : 
      70             : // A Source is an interface that yields a sequence of bytes
      71             : class Source {
      72             :  public:
      73         164 :   Source() { }
      74             :   virtual ~Source();
      75             : 
      76             :   // Return the number of bytes left to read from the source
      77             :   virtual size_t Available() const = 0;
      78             : 
      79             :   // Peek at the next flat region of the source.  Does not reposition
      80             :   // the source.  The returned region is empty iff Available()==0.
      81             :   //
      82             :   // Returns a pointer to the beginning of the region and store its
      83             :   // length in *len.
      84             :   //
      85             :   // The returned region is valid until the next call to Skip() or
      86             :   // until this object is destroyed, whichever occurs first.
      87             :   //
      88             :   // The returned region may be larger than Available() (for example
      89             :   // if this ByteSource is a view on a substring of a larger source).
      90             :   // The caller is responsible for ensuring that it only reads the
      91             :   // Available() bytes.
      92             :   virtual const char* Peek(size_t* len) = 0;
      93             : 
      94             :   // Skip the next n bytes.  Invalidates any buffer returned by
      95             :   // a previous call to Peek().
      96             :   // REQUIRES: Available() >= n
      97             :   virtual void Skip(size_t n) = 0;
      98             : 
      99             :  private:
     100             :   // No copying
     101             :   Source(const Source&);
     102             :   void operator=(const Source&);
     103             : };
     104             : 
     105             : // A Source implementation that yields the contents of a flat array
     106             : class ByteArraySource : public Source {
     107             :  public:
     108         164 :   ByteArraySource(const char* p, size_t n) : ptr_(p), left_(n) { }
     109             :   virtual ~ByteArraySource();
     110             :   virtual size_t Available() const;
     111             :   virtual const char* Peek(size_t* len);
     112             :   virtual void Skip(size_t n);
     113             :  private:
     114             :   const char* ptr_;
     115             :   size_t left_;
     116             : };
     117             : 
     118             : // A Sink implementation that writes to a flat array without any bound checks.
     119             : class UncheckedByteArraySink : public Sink {
     120             :  public:
     121          88 :   explicit UncheckedByteArraySink(char* dest) : dest_(dest) { }
     122             :   virtual ~UncheckedByteArraySink();
     123             :   virtual void Append(const char* data, size_t n);
     124             :   virtual char* GetAppendBuffer(size_t len, char* scratch);
     125             : 
     126             :   // Return the current output pointer so that a caller can see how
     127             :   // many bytes were produced.
     128             :   // Note: this is not a Sink method.
     129          88 :   char* CurrentDestination() const { return dest_; }
     130             :  private:
     131             :   char* dest_;
     132             : };
     133             : 
     134             : 
     135             : }
     136             : 
     137             : #endif  // UTIL_SNAPPY_SNAPPY_SINKSOURCE_H_

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