612 lines
14 KiB
C++
612 lines
14 KiB
C++
#include "shm.h"
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#include "utils.h"
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#include <string.h>
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#include <stdio.h>
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typedef struct __shm_item__ {
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ShmPlace next;
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ShmPlace prev;
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size_t size;
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} ShmItem;
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class ShmApiBase
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{
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protected:
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char *_mem;
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int *_used;
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ShmPlace *_slots;
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ShmPlace *_first;
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ShmPlace *_free_list;
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char *_mem_name;
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char *_sem_name;
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int _in_critical;
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size_t _size;
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bool _owner;
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public:
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virtual void enterCritical() = 0;
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virtual void leaveCritical() = 0;
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public:
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int slot(int s) {
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return _slots[s];
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}
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void setSlot(int s, ShmPlace place) {
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_slots[s] = place;
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}
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public:
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const char *name() {
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return _mem_name;
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}
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public:
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template <class T> void ref(int place, T** p) {
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if (place == SHM_NULL) {
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*p = nullptr;
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} else {
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*p = reinterpret_cast<T *>(_mem + place);
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}
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}
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inline void *ref(int place)
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{
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if (place == SHM_NULL) {
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return nullptr;
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}
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return _mem + place;
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}
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public:
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int alloc(size_t bytes) {
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enterCritical();
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ShmPlace p_i = *_free_list;
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ShmItem *i;
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ref(p_i, &i);
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while (i != nullptr && i->size < bytes) {
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p_i = i->next;
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ref(p_i, &i);
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}
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int place;
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if (i != nullptr) {
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if (i->prev != SHM_NULL) {
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ShmItem *prev_i;
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ref(i->prev, &prev_i);
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prev_i->next = i->next;
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}
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if (i->next != SHM_NULL) {
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ShmItem *next_i;
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ref(i->next, &next_i);
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next_i->prev = i->prev;
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}
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if (i->prev == SHM_NULL) {
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*_free_list = i->next;
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}
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i->next = *_first;
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if (*_first != SHM_NULL) {
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ShmItem *first_i;
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ref(*_first, &first_i);
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first_i->prev = p_i;
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}
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i->prev = SHM_NULL;
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*_first = p_i;
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place = p_i + sizeof(ShmItem);
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} else {
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ShmPlace p_i = *_used;
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i = reinterpret_cast<ShmItem *>(reinterpret_cast<char *>(_mem) + p_i);
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int u = static_cast<int>(*_used + sizeof(ShmItem) + bytes);
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if (u >= _size) {
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place = SHM_NULL;
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} else {
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*_used = u;
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i->prev = SHM_NULL;
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i->size = bytes;
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i->next = *_first;
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if (*_first != SHM_NULL) {
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ShmItem *first_i;
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ref(*_first, &first_i);
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first_i->prev = p_i;
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}
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*_first = p_i;
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place = p_i + sizeof(ShmItem);
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}
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}
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leaveCritical();
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return place;
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}
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void free(ShmPlace place) {
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if (place == SHM_NULL) {
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return;
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}
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enterCritical();
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ShmPlace p_i = place - sizeof(ShmItem);
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ShmItem *i;
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ref(p_i, &i);
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if (i->prev != SHM_NULL) {
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ShmItem *prev_i;
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ref(i->prev, &prev_i);
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prev_i->next = i->next;
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}
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if (i->next != SHM_NULL) {
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ShmItem *next_i;
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ref(i->next, &next_i);
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next_i->prev = i->prev;
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}
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if (i->prev == SHM_NULL) {
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*_first = i->next;
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}
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i->next = *_free_list;
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if (*_free_list != SHM_NULL) {
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ShmItem *fl;
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ref(*_free_list, &fl);
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fl->prev = p_i;
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}
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i->prev = SHM_NULL;
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*_free_list = p_i;
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leaveCritical();
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}
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public:
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ShmSem *makeSem(const char *name, bool owner) {
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return new ShmSem(name, owner);
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}
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public:
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ShmApiBase(const char *name, size_t size, bool owner) {
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char *buf = reinterpret_cast<char *>(malloc(strlen(name) + 50));
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sprintf(buf, "sem_%s", name);
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_sem_name = _strdup(buf);
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_mem_name = _strdup(name);
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::free(buf);
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_owner = owner;
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_size = size;
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_used = nullptr;
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_slots = nullptr;
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_first = nullptr;
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_free_list = nullptr;
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_mem = nullptr;
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_in_critical = 0;
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}
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virtual ~ShmApiBase()
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{
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::free(_sem_name);
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::free(_mem_name);
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}
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};
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#ifdef __linux
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <sys/shm.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include <errno.h>
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#include <semaphore.h>
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class ShmApi : public ShmApiBase
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{
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private:
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int _shm_fd;
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sem_t *_sem;
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private:
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void cleanup() {
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// We don't need to do anything here.
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}
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public:
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void enterCritical() {
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if (_in_critical > 0) {
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_in_critical++;
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} else {
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sem_wait(_sem);
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_in_critical = 1;
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}
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}
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void leaveCritical() {
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if (_in_critical > 1) {
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_in_critical--;
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} else {
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_in_critical = 0;
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sem_post(_sem);
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}
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}
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public:
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bool isValid() {
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return true;
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}
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public:
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ShmApi(const char *name, size_t size, bool owner) : ShmApiBase(name, size, owner)
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{
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size_t slots_size = sizeof(ShmPlace) * SHM_MAX_SLOTS;
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size += slots_size;
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if (_owner) {
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_sem = sem_open(_sem_name, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR, 0);
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_shm_fd = shm_open(name, O_CREAT | O_RDWR, 0600);
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ftruncate(_shm_fd, size);
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} else {
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_sem = sem_open(_sem_name, O_RDWR, S_IRUSR | S_IWUSR, 0);
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_shm_fd = shm_open(name, O_RDWR, 0600);
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}
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_mem = mmap(nullptr, _size, PROT_READ|PROT_WRITE, MAP_SHARED, _shm_fd, 0);
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_slots = reinterpret_cast <ShmPlace *>(_mem + sizeof(int) + sizeof(ShmPlace) + sizeof(ShmPlace));
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_used = reinterpret_cast<int *>(_mem);
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_first = reinterpret_cast<ShmPlace *>(_mem + sizeof(int));
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_free_list = reinterpret_cast<ShmPlace *>(_mem + sizeof(int) + sizeof(ShmPlace));
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if (_owner) {
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*_first = SHM_NULL;
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*_free_list = SHM_NULL;
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*_used = sizeof(int) + sizeof(ShmItem *) + sizeof(ShmItem *) + slots_size;
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sem_post(_sem);
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}
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_in_critical = 0;
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}
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~ShmApi() {
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cleanup();
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munmap(_mem, _size);
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close(_shm_fd);
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sem_close(_sem);
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if (_owner) {
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shm_unlink(_mem_name);
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sem_unlink(_sem_name);
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}
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}
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};
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class ShmSemApi {
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private:
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sem_t *_sem;
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char *_name;
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bool _owner;
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public:
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void post() {
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sem_post(_sem);
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}
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void wait() {
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int r = sem_wait(_sem);
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if (r != 0) {
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ERROR2("sem_wait error: %d, %s\n", errno, strerror(errno));
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}
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}
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bool trywait() {
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int r = sem_trywait(reinterpret_cast<sem_t *>(_sem));
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if (r != 0 && r != EAGAIN) {
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ERROR2("sem_wait error: %d, %s\n", errno, strerror(errno));
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}
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return (r == 0);
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}
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public:
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ShmSemApi(const char *n, bool owner) {
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_name = strdup(n);
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sem_t *s;
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if (owner) {
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s = sem_open(n, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR, 0);
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} else {
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s = sem_open(n, O_RDWR, S_IRUSR | S_IWUSR, 0);
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}
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_sem = s;
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_owner = owner;
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}
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virtual ~ShmSemApi() {
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sem_close(_sem);
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if (_owner) {
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sem_unlink(_name);
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}
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free(_name);
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}
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};
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};
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public:
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};
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#endif
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#ifdef _WIN32
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#include <windows.h>
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class ShmApi : public ShmApiBase
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{
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private:
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HANDLE _shm_handle;
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HANDLE _sem_handle;
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bool _valid;
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public:
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ShmApi(const char *name, size_t size, bool owner) : ShmApiBase(name, size, owner)
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{
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size_t slots_size = sizeof(ShmPlace) * SHM_MAX_SLOTS;
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size += slots_size;
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_valid = true;
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if (_owner) {
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_shm_handle = CreateFileMappingA(INVALID_HANDLE_VALUE,
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NULL,
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PAGE_READWRITE,
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0,
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static_cast<DWORD>(size), // size must be smaller < 2GB
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name);
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if (_shm_handle == NULL) {
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ERROR2("Cannot create shared memory with name %s and size %lld\n", name, size);
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_valid = false;
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}
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} else {
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_shm_handle = OpenFileMappingA(FILE_MAP_ALL_ACCESS,
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FALSE,
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name);
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if (_shm_handle == NULL) {
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ERROR1("Cannot open shared memory with name %s\n", name);
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_valid = false;
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}
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}
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if (_valid) {
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_mem = static_cast<LPSTR>(MapViewOfFile(_shm_handle,
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FILE_MAP_ALL_ACCESS,
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0,
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0,
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size));
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if (_mem == NULL) {
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ERROR1("Cannot map shared memory, errorcode = %ld\n", GetLastError());
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_valid = false;
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CloseHandle(_shm_handle);
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}
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}
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if (_valid) {
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if (_owner) {
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_sem_handle = CreateSemaphoreA(NULL,
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1,
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10000,
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_sem_name
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);
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} else {
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_sem_handle = OpenSemaphoreA(SYNCHRONIZE|SEMAPHORE_MODIFY_STATE, FALSE, _sem_name);
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}
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if (_sem_handle == NULL) {
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ERROR2("Cannot create or open semaphore with name '%s' (%ld)\n", _sem_name, GetLastError());
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UnmapViewOfFile(_mem);
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CloseHandle(_shm_handle);
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_valid = false;
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}
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}
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if (_valid) {
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_slots = reinterpret_cast <ShmPlace *>(_mem + sizeof(int) + sizeof(ShmPlace) + sizeof(ShmPlace));
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_used = reinterpret_cast<int *>(_mem);
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_first = reinterpret_cast<ShmPlace *>(_mem + sizeof(int));
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_free_list = reinterpret_cast<ShmPlace *>(_mem + sizeof(int) + sizeof(ShmPlace));
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if (_owner) {
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*_first = SHM_NULL;
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*_free_list = SHM_NULL;
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*_used = sizeof(int) + sizeof(ShmItem *) + sizeof(ShmItem *) + slots_size;
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}
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}
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}
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~ShmApi()
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{
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if (_valid) {
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UnmapViewOfFile(_mem);
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CloseHandle(_shm_handle);
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CloseHandle(_sem_handle);
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}
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}
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bool isValid() {
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return _valid;
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}
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void enterCritical()
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{
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if (_in_critical > 0) {
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_in_critical++;
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} else {
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WaitForSingleObject(_sem_handle, INFINITE);
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_in_critical = 1;
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}
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}
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void leaveCritical()
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{
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if (_in_critical > 1) {
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_in_critical--;
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} else {
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_in_critical = 0;
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ReleaseSemaphore(_sem_handle, 1, NULL);
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}
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}
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ShmSem *sem(const char *name, bool owner)
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{
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return nullptr;
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}
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};
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class ShmSemApi {
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private:
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HANDLE _sem;
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char *_name;
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bool _owner;
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public:
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void post() {
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ReleaseSemaphore(_sem, 1, NULL);
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}
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void wait() {
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DWORD r = WaitForSingleObject(_sem, INFINITE);
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if (r != WAIT_OBJECT_0) {
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ERROR1("sem_wait error: %ld\n", r);
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}
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}
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bool trywait() {
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DWORD r = WaitForSingleObject(_sem , 0);
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if (r != WAIT_OBJECT_0 && r != WAIT_TIMEOUT) {
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ERROR1("sem_wait error: %ld\n", r);
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}
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return r == WAIT_OBJECT_0;
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}
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public:
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ShmSemApi(const char *n, bool owner) {
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_name = _strdup(n);
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if (owner) {
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_sem = CreateSemaphoreA(NULL,
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0,
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10000,
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_name);
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} else {
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_sem = OpenSemaphoreA(SYNCHRONIZE|SEMAPHORE_MODIFY_STATE, FALSE, _name);
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}
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if (_sem == NULL) {
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ERROR1("Cannot create or open semaphore with name '%s'\n", _name);
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}
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_owner = owner;
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}
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virtual ~ShmSemApi() {
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if (_sem != NULL) {
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CloseHandle(_sem);
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}
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}
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};
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#endif
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ShmPlace Shm::alloc(size_t mem)
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{
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return _shm_api->alloc(mem);
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}
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void Shm::free(ShmPlace place)
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{
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_shm_api->free(place);
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}
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void Shm::unlock()
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{
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_shm_api->leaveCritical();
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}
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ShmPlace Shm::slot(ShmSlot s)
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{
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return _shm_api->slot(s);
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}
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void Shm::setSlot(ShmSlot s, ShmPlace pl)
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{
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_shm_api->setSlot(s, pl);
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}
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ShmSem *Shm::sem(const char *name, bool owner)
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{
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return _shm_api->makeSem(name, owner);
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}
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bool Shm::isValid()
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{
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return _shm_api->isValid();
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}
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const char *Shm::name()
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{
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return _shm_api->name();
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}
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void *Shm::ref(int place)
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{
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return _shm_api->ref(place);
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}
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void Shm::lock()
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{
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_shm_api->enterCritical();
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}
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Shm::Shm(const char *name, size_t bytes, bool owner)
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{
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_shm_api = new ShmApi(name, bytes, owner);
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}
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Shm::~Shm()
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{
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delete _shm_api;
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}
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void ShmSem::post() {
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_api->post();
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}
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void ShmSem::wait() {
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_api->wait();
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}
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bool ShmSem::trywait() {
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return _api->trywait();
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}
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ShmSem::ShmSem(const char *n, bool owner) {
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_api = new ShmSemApi(n, owner);
|
|
}
|
|
|
|
ShmSem::~ShmSem() {
|
|
delete _api;
|
|
}
|