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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
// See port_example.h for documentation for the following types/functions.
#ifndef STORAGE_LEVELDB_PORT_PORT_ANDROID_H_
#define STORAGE_LEVELDB_PORT_PORT_ANDROID_H_
#include <endian.h>
#include <pthread.h>
#include <stdint.h>
#include <cstdatomic>
#include <string>
#include <cctype>
// Collapse the plethora of ARM flavors available to an easier to manage set
// Defs reference is at https://wiki.edubuntu.org/ARM/Thumb2PortingHowto
#if defined(__ARM_ARCH_6__) || \
defined(__ARM_ARCH_6J__) || \
defined(__ARM_ARCH_6K__) || \
defined(__ARM_ARCH_6Z__) || \
defined(__ARM_ARCH_6T2__) || \
defined(__ARM_ARCH_6ZK__) || \
defined(__ARM_ARCH_7__) || \
defined(__ARM_ARCH_7R__) || \
defined(__ARM_ARCH_7A__)
#define ARMV6_OR_7 1
#endif
extern "C" {
size_t fread_unlocked(void *a, size_t b, size_t c, FILE *d);
size_t fwrite_unlocked(const void *a, size_t b, size_t c, FILE *d);
int fflush_unlocked(FILE *f);
int fdatasync (int fd);
}
namespace leveldb {
namespace port {
static const bool kLittleEndian = __BYTE_ORDER == __LITTLE_ENDIAN;
class CondVar;
class Mutex {
public:
Mutex();
~Mutex();
void Lock();
void Unlock();
void AssertHeld() {
//TODO(gabor): How can I implement this?
}
private:
friend class CondVar;
pthread_mutex_t mu_;
// No copying
Mutex(const Mutex&);
void operator=(const Mutex&);
};
class CondVar {
public:
explicit CondVar(Mutex* mu);
~CondVar();
void Wait();
void Signal();
void SignalAll();
private:
Mutex* mu_;
pthread_cond_t cv_;
};
#ifndef ARMV6_OR_7
// On ARM chipsets <V6, 0xffff0fa0 is the hard coded address of a
// memory barrier function provided by the kernel.
typedef void (*LinuxKernelMemoryBarrierFunc)(void);
LinuxKernelMemoryBarrierFunc pLinuxKernelMemoryBarrier ATTRIBUTE_WEAK =
(LinuxKernelMemoryBarrierFunc) 0xffff0fa0;
#endif
// Storage for a lock-free pointer
class AtomicPointer {
private:
void* rep_;
inline void MemoryBarrier() const {
// TODO(gabor): This only works on Android instruction sets >= V6
#ifdef ARMV6_OR_7
__asm__ __volatile__("dmb" : : : "memory");
#else
pLinuxKernelMemoryBarrier();
#endif
}
public:
AtomicPointer() { }
explicit AtomicPointer(void* v) : rep_(v) { }
inline void* Acquire_Load() const {
void* r = rep_;
MemoryBarrier();
return r;
}
inline void Release_Store(void* v) {
MemoryBarrier();
rep_ = v;
}
inline void* NoBarrier_Load() const {
void* r = rep_;
return r;
}
inline void NoBarrier_Store(void* v) {
rep_ = v;
}
};
// TODO(gabor): Implement compress
inline bool Snappy_Compress(
const char* input,
size_t input_length,
std::string* output) {
return false;
}
// TODO(gabor): Implement uncompress
inline bool Snappy_Uncompress(
const char* input_data,
size_t input_length,
std::string* output) {
return false;
}
inline uint64_t ThreadIdentifier() {
pthread_t tid = pthread_self();
uint64_t r = 0;
memcpy(&r, &tid, sizeof(r) < sizeof(tid) ? sizeof(r) : sizeof(tid));
return r;
}
inline bool GetHeapProfile(void (*func)(void*, const char*, int), void* arg) {
return false;
}
}
}
#endif // STORAGE_LEVELDB_PORT_PORT_ANDROID_H_
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