diff options
Diffstat (limited to 'app/snappy/snappy-internal.h')
| -rw-r--r-- | app/snappy/snappy-internal.h | 150 |
1 files changed, 0 insertions, 150 deletions
diff --git a/app/snappy/snappy-internal.h b/app/snappy/snappy-internal.h deleted file mode 100644 index c99d3313..00000000 --- a/app/snappy/snappy-internal.h +++ /dev/null @@ -1,150 +0,0 @@ -// Copyright 2008 Google Inc. All Rights Reserved. -// -// 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. -// -// Internals shared between the Snappy implementation and its unittest. - -#ifndef UTIL_SNAPPY_SNAPPY_INTERNAL_H_ -#define UTIL_SNAPPY_SNAPPY_INTERNAL_H_ - -#include "snappy-stubs-internal.h" - -namespace snappy { -namespace internal { - -class WorkingMemory { - public: - WorkingMemory() : large_table_(NULL) { } - ~WorkingMemory() { delete[] large_table_; } - - // Allocates and clears a hash table using memory in "*this", - // stores the number of buckets in "*table_size" and returns a pointer to - // the base of the hash table. - uint16* GetHashTable(size_t input_size, int* table_size); - - private: - uint16 small_table_[1<<10]; // 2KB - uint16* large_table_; // Allocated only when needed - - DISALLOW_COPY_AND_ASSIGN(WorkingMemory); -}; - -// Flat array compression that does not emit the "uncompressed length" -// prefix. Compresses "input" string to the "*op" buffer. -// -// REQUIRES: "input_length <= kBlockSize" -// REQUIRES: "op" points to an array of memory that is at least -// "MaxCompressedLength(input_length)" in size. -// REQUIRES: All elements in "table[0..table_size-1]" are initialized to zero. -// REQUIRES: "table_size" is a power of two -// -// Returns an "end" pointer into "op" buffer. -// "end - op" is the compressed size of "input". -char* CompressFragment(const char* input, - size_t input_length, - char* op, - uint16* table, - const int table_size); - -// Return the largest n such that -// -// s1[0,n-1] == s2[0,n-1] -// and n <= (s2_limit - s2). -// -// Does not read *s2_limit or beyond. -// Does not read *(s1 + (s2_limit - s2)) or beyond. -// Requires that s2_limit >= s2. -// -// Separate implementation for x86_64, for speed. Uses the fact that -// x86_64 is little endian. -#if defined(ARCH_K8) -static inline int FindMatchLength(const char* s1, - const char* s2, - const char* s2_limit) { - assert(s2_limit >= s2); - int matched = 0; - - // Find out how long the match is. We loop over the data 64 bits at a - // time until we find a 64-bit block that doesn't match; then we find - // the first non-matching bit and use that to calculate the total - // length of the match. - while (PREDICT_TRUE(s2 <= s2_limit - 8)) { - if (PREDICT_FALSE(UNALIGNED_LOAD64(s2) == UNALIGNED_LOAD64(s1 + matched))) { - s2 += 8; - matched += 8; - } else { - // On current (mid-2008) Opteron models there is a 3% more - // efficient code sequence to find the first non-matching byte. - // However, what follows is ~10% better on Intel Core 2 and newer, - // and we expect AMD's bsf instruction to improve. - uint64 x = UNALIGNED_LOAD64(s2) ^ UNALIGNED_LOAD64(s1 + matched); - int matching_bits = Bits::FindLSBSetNonZero64(x); - matched += matching_bits >> 3; - return matched; - } - } - while (PREDICT_TRUE(s2 < s2_limit)) { - if (PREDICT_TRUE(s1[matched] == *s2)) { - ++s2; - ++matched; - } else { - return matched; - } - } - return matched; -} -#else -static inline int FindMatchLength(const char* s1, - const char* s2, - const char* s2_limit) { - // Implementation based on the x86-64 version, above. - assert(s2_limit >= s2); - int matched = 0; - - while (s2 <= s2_limit - 4 && - UNALIGNED_LOAD32(s2) == UNALIGNED_LOAD32(s1 + matched)) { - s2 += 4; - matched += 4; - } - if (LittleEndian::IsLittleEndian() && s2 <= s2_limit - 4) { - uint32 x = UNALIGNED_LOAD32(s2) ^ UNALIGNED_LOAD32(s1 + matched); - int matching_bits = Bits::FindLSBSetNonZero(x); - matched += matching_bits >> 3; - } else { - while ((s2 < s2_limit) && (s1[matched] == *s2)) { - ++s2; - ++matched; - } - } - return matched; -} -#endif - -} // end namespace internal -} // end namespace snappy - -#endif // UTIL_SNAPPY_SNAPPY_INTERNAL_H_ |