zstandard: vendor python-zstandard 0.9.0
This was just released. It features a number of goodies. More info at
https://gregoryszorc.com/blog/2018/04/09/release-of-python-zstandard-0.9/.
The clang-format ignore list was updated to reflect the new source
of files.
The project contains a vendored copy of zstandard 1.3.4. The old
version was 1.1.3. One of the changes between those versions is that
zstandard is now dual licensed BSD + GPLv2 and the patent rights grant
has been removed. Good riddance.
The API should be backwards compatible. So no changes in core
should be needed. However, there were a number of changes in the
library that we'll want to adapt to. Those will be addressed in
subsequent commits.
Differential Revision: https://phab.mercurial-scm.org/D3198
/*
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under both the BSD-style license (found in the
* LICENSE file in the root directory of this source tree) and the GPLv2 (found
* in the COPYING file in the root directory of this source tree).
* You may select, at your option, one of the above-listed licenses.
*/
/* ====== Dependencies ======= */
#include <stddef.h> /* size_t */
#include "pool.h"
#include "zstd_internal.h" /* ZSTD_malloc, ZSTD_free */
/* ====== Compiler specifics ====== */
#if defined(_MSC_VER)
# pragma warning(disable : 4204) /* disable: C4204: non-constant aggregate initializer */
#endif
#ifdef ZSTD_MULTITHREAD
#include "threading.h" /* pthread adaptation */
/* A job is a function and an opaque argument */
typedef struct POOL_job_s {
POOL_function function;
void *opaque;
} POOL_job;
struct POOL_ctx_s {
ZSTD_customMem customMem;
/* Keep track of the threads */
ZSTD_pthread_t *threads;
size_t numThreads;
/* The queue is a circular buffer */
POOL_job *queue;
size_t queueHead;
size_t queueTail;
size_t queueSize;
/* The number of threads working on jobs */
size_t numThreadsBusy;
/* Indicates if the queue is empty */
int queueEmpty;
/* The mutex protects the queue */
ZSTD_pthread_mutex_t queueMutex;
/* Condition variable for pushers to wait on when the queue is full */
ZSTD_pthread_cond_t queuePushCond;
/* Condition variables for poppers to wait on when the queue is empty */
ZSTD_pthread_cond_t queuePopCond;
/* Indicates if the queue is shutting down */
int shutdown;
};
/* POOL_thread() :
Work thread for the thread pool.
Waits for jobs and executes them.
@returns : NULL on failure else non-null.
*/
static void* POOL_thread(void* opaque) {
POOL_ctx* const ctx = (POOL_ctx*)opaque;
if (!ctx) { return NULL; }
for (;;) {
/* Lock the mutex and wait for a non-empty queue or until shutdown */
ZSTD_pthread_mutex_lock(&ctx->queueMutex);
while (ctx->queueEmpty && !ctx->shutdown) {
ZSTD_pthread_cond_wait(&ctx->queuePopCond, &ctx->queueMutex);
}
/* empty => shutting down: so stop */
if (ctx->queueEmpty) {
ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
return opaque;
}
/* Pop a job off the queue */
{ POOL_job const job = ctx->queue[ctx->queueHead];
ctx->queueHead = (ctx->queueHead + 1) % ctx->queueSize;
ctx->numThreadsBusy++;
ctx->queueEmpty = ctx->queueHead == ctx->queueTail;
/* Unlock the mutex, signal a pusher, and run the job */
ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
ZSTD_pthread_cond_signal(&ctx->queuePushCond);
job.function(job.opaque);
/* If the intended queue size was 0, signal after finishing job */
if (ctx->queueSize == 1) {
ZSTD_pthread_mutex_lock(&ctx->queueMutex);
ctx->numThreadsBusy--;
ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
ZSTD_pthread_cond_signal(&ctx->queuePushCond);
} }
} /* for (;;) */
/* Unreachable */
}
POOL_ctx* POOL_create(size_t numThreads, size_t queueSize) {
return POOL_create_advanced(numThreads, queueSize, ZSTD_defaultCMem);
}
POOL_ctx* POOL_create_advanced(size_t numThreads, size_t queueSize, ZSTD_customMem customMem) {
POOL_ctx* ctx;
/* Check the parameters */
if (!numThreads) { return NULL; }
/* Allocate the context and zero initialize */
ctx = (POOL_ctx*)ZSTD_calloc(sizeof(POOL_ctx), customMem);
if (!ctx) { return NULL; }
/* Initialize the job queue.
* It needs one extra space since one space is wasted to differentiate empty
* and full queues.
*/
ctx->queueSize = queueSize + 1;
ctx->queue = (POOL_job*)ZSTD_malloc(ctx->queueSize * sizeof(POOL_job), customMem);
ctx->queueHead = 0;
ctx->queueTail = 0;
ctx->numThreadsBusy = 0;
ctx->queueEmpty = 1;
(void)ZSTD_pthread_mutex_init(&ctx->queueMutex, NULL);
(void)ZSTD_pthread_cond_init(&ctx->queuePushCond, NULL);
(void)ZSTD_pthread_cond_init(&ctx->queuePopCond, NULL);
ctx->shutdown = 0;
/* Allocate space for the thread handles */
ctx->threads = (ZSTD_pthread_t*)ZSTD_malloc(numThreads * sizeof(ZSTD_pthread_t), customMem);
ctx->numThreads = 0;
ctx->customMem = customMem;
/* Check for errors */
if (!ctx->threads || !ctx->queue) { POOL_free(ctx); return NULL; }
/* Initialize the threads */
{ size_t i;
for (i = 0; i < numThreads; ++i) {
if (ZSTD_pthread_create(&ctx->threads[i], NULL, &POOL_thread, ctx)) {
ctx->numThreads = i;
POOL_free(ctx);
return NULL;
} }
ctx->numThreads = numThreads;
}
return ctx;
}
/*! POOL_join() :
Shutdown the queue, wake any sleeping threads, and join all of the threads.
*/
static void POOL_join(POOL_ctx* ctx) {
/* Shut down the queue */
ZSTD_pthread_mutex_lock(&ctx->queueMutex);
ctx->shutdown = 1;
ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
/* Wake up sleeping threads */
ZSTD_pthread_cond_broadcast(&ctx->queuePushCond);
ZSTD_pthread_cond_broadcast(&ctx->queuePopCond);
/* Join all of the threads */
{ size_t i;
for (i = 0; i < ctx->numThreads; ++i) {
ZSTD_pthread_join(ctx->threads[i], NULL);
} }
}
void POOL_free(POOL_ctx *ctx) {
if (!ctx) { return; }
POOL_join(ctx);
ZSTD_pthread_mutex_destroy(&ctx->queueMutex);
ZSTD_pthread_cond_destroy(&ctx->queuePushCond);
ZSTD_pthread_cond_destroy(&ctx->queuePopCond);
ZSTD_free(ctx->queue, ctx->customMem);
ZSTD_free(ctx->threads, ctx->customMem);
ZSTD_free(ctx, ctx->customMem);
}
size_t POOL_sizeof(POOL_ctx *ctx) {
if (ctx==NULL) return 0; /* supports sizeof NULL */
return sizeof(*ctx)
+ ctx->queueSize * sizeof(POOL_job)
+ ctx->numThreads * sizeof(ZSTD_pthread_t);
}
/**
* Returns 1 if the queue is full and 0 otherwise.
*
* If the queueSize is 1 (the pool was created with an intended queueSize of 0),
* then a queue is empty if there is a thread free and no job is waiting.
*/
static int isQueueFull(POOL_ctx const* ctx) {
if (ctx->queueSize > 1) {
return ctx->queueHead == ((ctx->queueTail + 1) % ctx->queueSize);
} else {
return ctx->numThreadsBusy == ctx->numThreads ||
!ctx->queueEmpty;
}
}
static void POOL_add_internal(POOL_ctx* ctx, POOL_function function, void *opaque)
{
POOL_job const job = {function, opaque};
assert(ctx != NULL);
if (ctx->shutdown) return;
ctx->queueEmpty = 0;
ctx->queue[ctx->queueTail] = job;
ctx->queueTail = (ctx->queueTail + 1) % ctx->queueSize;
ZSTD_pthread_cond_signal(&ctx->queuePopCond);
}
void POOL_add(POOL_ctx* ctx, POOL_function function, void* opaque)
{
assert(ctx != NULL);
ZSTD_pthread_mutex_lock(&ctx->queueMutex);
/* Wait until there is space in the queue for the new job */
while (isQueueFull(ctx) && (!ctx->shutdown)) {
ZSTD_pthread_cond_wait(&ctx->queuePushCond, &ctx->queueMutex);
}
POOL_add_internal(ctx, function, opaque);
ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
}
int POOL_tryAdd(POOL_ctx* ctx, POOL_function function, void* opaque)
{
assert(ctx != NULL);
ZSTD_pthread_mutex_lock(&ctx->queueMutex);
if (isQueueFull(ctx)) {
ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
return 0;
}
POOL_add_internal(ctx, function, opaque);
ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
return 1;
}
#else /* ZSTD_MULTITHREAD not defined */
/* ========================== */
/* No multi-threading support */
/* ========================== */
/* We don't need any data, but if it is empty, malloc() might return NULL. */
struct POOL_ctx_s {
int dummy;
};
static POOL_ctx g_ctx;
POOL_ctx* POOL_create(size_t numThreads, size_t queueSize) {
return POOL_create_advanced(numThreads, queueSize, ZSTD_defaultCMem);
}
POOL_ctx* POOL_create_advanced(size_t numThreads, size_t queueSize, ZSTD_customMem customMem) {
(void)numThreads;
(void)queueSize;
(void)customMem;
return &g_ctx;
}
void POOL_free(POOL_ctx* ctx) {
assert(!ctx || ctx == &g_ctx);
(void)ctx;
}
void POOL_add(POOL_ctx* ctx, POOL_function function, void* opaque) {
(void)ctx;
function(opaque);
}
int POOL_tryAdd(POOL_ctx* ctx, POOL_function function, void* opaque) {
(void)ctx;
function(opaque);
return 1;
}
size_t POOL_sizeof(POOL_ctx* ctx) {
if (ctx==NULL) return 0; /* supports sizeof NULL */
assert(ctx == &g_ctx);
return sizeof(*ctx);
}
#endif /* ZSTD_MULTITHREAD */