--- /dev/null
+// Copyright 2005 and onwards Google Inc.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// A light-weight compression algorithm. It is designed for speed of
+// compression and decompression, rather than for the utmost in space
+// savings.
+//
+// For getting better compression ratios when you are compressing data
+// with long repeated sequences or compressing data that is similar to
+// other data, while still compressing fast, you might look at first
+// using BMDiff and then compressing the output of BMDiff with
+// Snappy.
+
+#ifndef UTIL_SNAPPY_SNAPPY_H__
+#define UTIL_SNAPPY_SNAPPY_H__
+
+#include <stddef.h>
+#include <string>
+
+#include "snappy-stubs-public.h"
+
+namespace snappy {
+ class Source;
+ class Sink;
+
+ // ------------------------------------------------------------------------
+ // Generic compression/decompression routines.
+ // ------------------------------------------------------------------------
+
+ // Compress the bytes read from "*source" and append to "*sink". Return the
+ // number of bytes written.
+ size_t Compress(Source* source, Sink* sink);
+
+ bool GetUncompressedLength(Source* source, uint32* result);
+
+ // ------------------------------------------------------------------------
+ // Higher-level string based routines (should be sufficient for most users)
+ // ------------------------------------------------------------------------
+
+ // Sets "*output" to the compressed version of "input[0,input_length-1]".
+ // Original contents of *output are lost.
+ //
+ // REQUIRES: "input[]" is not an alias of "*output".
+ size_t Compress(const char* input, size_t input_length, string* output);
+
+ // Decompresses "compressed[0,compressed_length-1]" to "*uncompressed".
+ // Original contents of "*uncompressed" are lost.
+ //
+ // REQUIRES: "compressed[]" is not an alias of "*uncompressed".
+ //
+ // returns false if the message is corrupted and could not be decompressed
+ bool Uncompress(const char* compressed, size_t compressed_length,
+ string* uncompressed);
+
+
+ // ------------------------------------------------------------------------
+ // Lower-level character array based routines. May be useful for
+ // efficiency reasons in certain circumstances.
+ // ------------------------------------------------------------------------
+
+ // REQUIRES: "compressed" must point to an area of memory that is at
+ // least "MaxCompressedLength(input_length)" bytes in length.
+ //
+ // Takes the data stored in "input[0..input_length]" and stores
+ // it in the array pointed to by "compressed".
+ //
+ // "*compressed_length" is set to the length of the compressed output.
+ //
+ // Example:
+ // char* output = new char[snappy::MaxCompressedLength(input_length)];
+ // size_t output_length;
+ // RawCompress(input, input_length, output, &output_length);
+ // ... Process(output, output_length) ...
+ // delete [] output;
+ void RawCompress(const char* input,
+ size_t input_length,
+ char* compressed,
+ size_t* compressed_length);
+
+ // Given data in "compressed[0..compressed_length-1]" generated by
+ // calling the Snappy::Compress routine, this routine
+ // stores the uncompressed data to
+ // uncompressed[0..GetUncompressedLength(compressed)-1]
+ // returns false if the message is corrupted and could not be decrypted
+ bool RawUncompress(const char* compressed, size_t compressed_length,
+ char* uncompressed);
+
+ // Given data from the byte source 'compressed' generated by calling
+ // the Snappy::Compress routine, this routine stores the uncompressed
+ // data to
+ // uncompressed[0..GetUncompressedLength(compressed,compressed_length)-1]
+ // returns false if the message is corrupted and could not be decrypted
+ bool RawUncompress(Source* compressed, char* uncompressed);
+
+ // Returns the maximal size of the compressed representation of
+ // input data that is "source_bytes" bytes in length;
+ size_t MaxCompressedLength(size_t source_bytes);
+
+ // REQUIRES: "compressed[]" was produced by RawCompress() or Compress()
+ // Returns true and stores the length of the uncompressed data in
+ // *result normally. Returns false on parsing error.
+ // This operation takes O(1) time.
+ bool GetUncompressedLength(const char* compressed, size_t compressed_length,
+ size_t* result);
+
+ // Returns true iff the contents of "compressed[]" can be uncompressed
+ // successfully. Does not return the uncompressed data. Takes
+ // time proportional to compressed_length, but is usually at least
+ // a factor of four faster than actual decompression.
+ bool IsValidCompressedBuffer(const char* compressed,
+ size_t compressed_length);
+
+ // *** DO NOT CHANGE THE VALUE OF kBlockSize ***
+ //
+ // New Compression code chops up the input into blocks of at most
+ // the following size. This ensures that back-references in the
+ // output never cross kBlockSize block boundaries. This can be
+ // helpful in implementing blocked decompression. However the
+ // decompression code should not rely on this guarantee since older
+ // compression code may not obey it.
+ static const int kBlockLog = 15;
+ static const int kBlockSize = 1 << kBlockLog;
+
+ static const int kMaxHashTableBits = 14;
+ static const int kMaxHashTableSize = 1 << kMaxHashTableBits;
+
+} // end namespace snappy
+
+
+#endif // UTIL_SNAPPY_SNAPPY_H__
projects / apitrace / blobdiff