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bundle2: extract logic for seeking bundle2 part into own class...
bundle2: extract logic for seeking bundle2 part into own class Currently, unbundlepart classes support bi-directional seeking. Most consumers of unbundlepart only ever seek forward - typically as part of moving to the end of the bundle part so they can move on to the next one. But regardless of the actual usage of the part, instances maintain an index mapping offsets within the underlying raw payload to offsets within the decoded payload. Maintaining the mapping of offset data can be expensive in terms of memory use. Furthermore, many bundle2 consumers don't have access to an underlying seekable stream. This includes all compressed bundles. So maintaining offset data when the underlying stream can't be seeked anyway is wasteful. And since many bundle2 streams can't be seeked, it seems like a bad idea to expose a seek API in bundle2 parts by default. If you provide them, people will attempt to use them. Seekable bundle2 parts should be the exception, not the rule. This commit starts the process dividing unbundlepart into 2 classes: a base class that supports linear, one-time reads and a child class that supports bi-directional seeking. In this first commit, we split various methods and attributes out into a new "seekableunbundlepart" class. Previous instantiators of "unbundlepart" now instantiate "seekableunbundlepart." This preserves backwards compatibility. The coupling between the classes is still tight: "unbundlepart" cannot be used on its own. This will be addressed in subsequent commits. Differential Revision: https://phab.mercurial-scm.org/D1386

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threading.h
104 lines | 2.8 KiB | text/x-c | CLexer
/**
* Copyright (c) 2016 Tino Reichardt
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
* You can contact the author at:
* - zstdmt source repository: https://github.com/mcmilk/zstdmt
*/
#ifndef THREADING_H_938743
#define THREADING_H_938743
#if defined (__cplusplus)
extern "C" {
#endif
#if defined(ZSTD_MULTITHREAD) && defined(_WIN32)
/**
* Windows minimalist Pthread Wrapper, based on :
* http://www.cse.wustl.edu/~schmidt/win32-cv-1.html
*/
#ifdef WINVER
# undef WINVER
#endif
#define WINVER 0x0600
#ifdef _WIN32_WINNT
# undef _WIN32_WINNT
#endif
#define _WIN32_WINNT 0x0600
#ifndef WIN32_LEAN_AND_MEAN
# define WIN32_LEAN_AND_MEAN
#endif
#include <windows.h>
/* mutex */
#define pthread_mutex_t CRITICAL_SECTION
#define pthread_mutex_init(a,b) InitializeCriticalSection((a))
#define pthread_mutex_destroy(a) DeleteCriticalSection((a))
#define pthread_mutex_lock(a) EnterCriticalSection((a))
#define pthread_mutex_unlock(a) LeaveCriticalSection((a))
/* condition variable */
#define pthread_cond_t CONDITION_VARIABLE
#define pthread_cond_init(a, b) InitializeConditionVariable((a))
#define pthread_cond_destroy(a) /* No delete */
#define pthread_cond_wait(a, b) SleepConditionVariableCS((a), (b), INFINITE)
#define pthread_cond_signal(a) WakeConditionVariable((a))
#define pthread_cond_broadcast(a) WakeAllConditionVariable((a))
/* pthread_create() and pthread_join() */
typedef struct {
HANDLE handle;
void* (*start_routine)(void*);
void* arg;
} pthread_t;
int pthread_create(pthread_t* thread, const void* unused,
void* (*start_routine) (void*), void* arg);
#define pthread_join(a, b) _pthread_join(&(a), (b))
int _pthread_join(pthread_t* thread, void** value_ptr);
/**
* add here more wrappers as required
*/
#elif defined(ZSTD_MULTITHREAD) /* posix assumed ; need a better detection mathod */
/* === POSIX Systems === */
# include <pthread.h>
#else /* ZSTD_MULTITHREAD not defined */
/* No multithreading support */
#define pthread_mutex_t int /* #define rather than typedef, as sometimes pthread support is implicit, resulting in duplicated symbols */
#define pthread_mutex_init(a,b)
#define pthread_mutex_destroy(a)
#define pthread_mutex_lock(a)
#define pthread_mutex_unlock(a)
#define pthread_cond_t int
#define pthread_cond_init(a,b)
#define pthread_cond_destroy(a)
#define pthread_cond_wait(a,b)
#define pthread_cond_signal(a)
#define pthread_cond_broadcast(a)
/* do not use pthread_t */
#endif /* ZSTD_MULTITHREAD */
#if defined (__cplusplus)
}
#endif
#endif /* THREADING_H_938743 */