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Diffusion Ant (feature/nursery) Code

ant/include/arena.h
ddfe6237cab5feature/nursery

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arena.h
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#ifndef ARENA_H
#define ARENA_H
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
#include <windows.h>
#else
#include <sys/mman.h>
#include <unistd.h>
#include <errno.h>
#endif
#define ANT_ARENA_MIN (32 * 1024)
#define ANT_ARENA_MAX (256ULL * 1024 * 1024 * 1024)
#define ANT_ARENA_THRESHOLD (256ULL * 1024 * 1024)
#define ARENA_GROW_INCREMENT (8ULL * 1024 * 1024)
static inline void *mantissa_chk(void *p, const char *func) {
if (p && ((uintptr_t)p >> 48) != 0) {
fprintf(stderr,
"FATAL: %s returned pointer %p outside 48-bit NaN-boxing range\n"
"Please report this issue with your OS/architecture details.\n", func, p
); abort();
}
return p;
}
#define ant_calloc(size) mantissa_chk(calloc(1, size), "calloc")
#define ant_realloc(ptr, size) mantissa_chk(realloc(ptr, size), "realloc")
#ifdef _WIN32
static inline void *ant_arena_reserve(size_t max_size) {
void *p = VirtualAlloc(NULL, max_size, MEM_RESERVE, PAGE_NOACCESS);
return mantissa_chk(p, "VirtualAlloc");
}
static inline int ant_arena_commit(void *base, size_t old_size, size_t new_size) {
if (new_size <= old_size) return 0;
void *p = VirtualAlloc((char *)base + old_size, new_size - old_size, MEM_COMMIT, PAGE_READWRITE);
return p ? 0 : -1;
}
static inline void ant_arena_free(void *base, size_t reserved_size) {
(void)reserved_size;
if (base) VirtualFree(base, 0, MEM_RELEASE);
}
static inline int ant_arena_decommit(void *base, size_t old_size, size_t new_size) {
if (new_size >= old_size) return 0;
void *decommit_start = (char *)base + new_size;
size_t decommit_size = old_size - new_size;
return VirtualFree(decommit_start, decommit_size, MEM_DECOMMIT) ? 0 : -1;
}
#else
static inline void *ant_arena_reserve(size_t max_size) {
void *p = mmap(NULL, max_size, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
if (p == MAP_FAILED) return NULL;
return mantissa_chk(p, "mmap");
}
static inline int ant_arena_commit(void *base, size_t old_size, size_t new_size) {
if (new_size <= old_size) return 0;
long page_size_long = sysconf(_SC_PAGESIZE);
if (page_size_long <= 0) {
errno = (page_size_long == -1 && errno == 0) ? EINVAL : errno;
return -1;
}
size_t page_size = (size_t)page_size_long;
size_t old_pages = ((old_size + page_size - 1) / page_size) * page_size;
size_t new_pages = ((new_size + page_size - 1) / page_size) * page_size;
if (new_pages <= old_pages) return 0;
return mprotect((char *)base + old_pages, new_pages - old_pages, PROT_READ | PROT_WRITE);
}
static inline void ant_arena_free(void *base, size_t reserved_size) {
if (base) munmap(base, reserved_size);
}
static inline int ant_arena_decommit(void *base, size_t old_size, size_t new_size) {
if (new_size >= old_size) return 0;
long page_size_long = sysconf(_SC_PAGESIZE);
if (page_size_long <= 0) return -1;
size_t page_size = (size_t)page_size_long;
size_t new_pages = ((new_size + page_size - 1) / page_size) * page_size;
size_t old_pages = ((old_size + page_size - 1) / page_size) * page_size;
if (new_pages >= old_pages) return 0;
void *decommit_start = (char *)base + new_pages;
size_t decommit_size = old_pages - new_pages;
if (mprotect(decommit_start, decommit_size, PROT_NONE) == 0) return 0;
madvise(decommit_start, decommit_size, MADV_DONTNEED);
return 0;
}
#endif
#endif

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