ed154f6dc4
Change atomic_pointer.h to prefer a memory barrier based
implementation over a <cstdatomic> based implementation for
the following reasons:
(1) On a x86-32-bit gcc-4.4 build, <ctdatomic> was corrupting
the AtomicPointer.
(2) On a x86-64-bit gcc build, a <ctstdatomic> based acquire-load
takes ~15ns as opposed to the ~1ns for a memory-barrier
based implementation.
Fixes issue 9 (corruption_test fails)
http://code.google.com/p/leveldb/issues/detail?id=9
Fixes issue 16 (CorruptionTest.MissingDescriptor fails)
http://code.google.com/p/leveldb/issues/detail?id=16
git-svn-id: https://leveldb.googlecode.com/svn/trunk@36 62dab493-f737-651d-591e-8d6aee1b9529
118 lines
2.5 KiB
C++
118 lines
2.5 KiB
C++
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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//
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// See port_example.h for documentation for the following types/functions.
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#ifndef STORAGE_LEVELDB_PORT_PORT_POSIX_H_
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#define STORAGE_LEVELDB_PORT_PORT_POSIX_H_
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#if defined(OS_MACOSX)
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#include <machine/endian.h>
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#elif defined(OS_SOLARIS)
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#include <sys/isa_defs.h>
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#ifdef _LITTLE_ENDIAN
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#define LITTLE_ENDIAN
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#else
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#define BIG_ENDIAN
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#endif
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#else
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#include <endian.h>
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#endif
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#include <pthread.h>
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#ifdef SNAPPY
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#include <snappy.h>
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#endif
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#include <stdint.h>
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#include <string>
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#include "port/atomic_pointer.h"
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#ifdef LITTLE_ENDIAN
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#define IS_LITTLE_ENDIAN true
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#else
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#define IS_LITTLE_ENDIAN (__BYTE_ORDER == __LITTLE_ENDIAN)
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#endif
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#if defined(OS_MACOSX) || defined(OS_SOLARIS)
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#define fread_unlocked fread
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#define fwrite_unlocked fwrite
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#define fflush_unlocked fflush
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#endif
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#if defined(OS_MACOSX)
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#define fdatasync fsync
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#endif
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namespace leveldb {
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namespace port {
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static const bool kLittleEndian = IS_LITTLE_ENDIAN;
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class CondVar;
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class Mutex {
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public:
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Mutex();
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~Mutex();
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void Lock();
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void Unlock();
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void AssertHeld() { }
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private:
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friend class CondVar;
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pthread_mutex_t mu_;
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// No copying
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Mutex(const Mutex&);
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void operator=(const Mutex&);
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};
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class CondVar {
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public:
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explicit CondVar(Mutex* mu);
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~CondVar();
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void Wait();
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void Signal();
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void SignalAll();
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private:
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pthread_cond_t cv_;
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Mutex* mu_;
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};
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inline bool Snappy_Compress(const char* input, size_t input_length,
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::std::string* output) {
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#ifdef SNAPPY
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output->resize(snappy::MaxCompressedLength(input_length));
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size_t outlen;
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snappy::RawCompress(input, input_length, &(*output)[0], &outlen);
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output->resize(outlen);
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return true;
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#endif
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return false;
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}
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inline bool Snappy_Uncompress(const char* input_data, size_t input_length,
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::std::string* output) {
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#ifdef SNAPPY
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size_t ulength;
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if (!snappy::GetUncompressedLength(input_data, input_length, &ulength)) {
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return false;
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}
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output->resize(ulength);
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return snappy::RawUncompress(input_data, input_length, &(*output)[0]);
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#endif
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return false;
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}
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inline bool GetHeapProfile(void (*func)(void*, const char*, int), void* arg) {
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return false;
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}
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} // namespace port
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} // namespace leveldb
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#endif // STORAGE_LEVELDB_PORT_PORT_POSIX_H_
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