+#if FILE_BACKED_MALLOC
+#include <stdlib.h>
+#include <sys/mman.h>
+typedef struct mmap_data_s
+{
+ size_t len;
+}
+mmap_data_t;
+#define MMAP_PAGE_SIZE max(sizeof(mmap_data_t), (size_t)sysconf(_SC_PAGE_SIZE))
+static void *mmap_malloc(size_t size)
+{
+ char vabuf[MAX_OSPATH + 1];
+ char *tmpdir = getenv("TEMP");
+ unsigned char *data;
+ int fd;
+ size += MMAP_PAGE_SIZE; // waste block
+ size += MMAP_PAGE_SIZE - 1; // also, waste up to this amount for management info
+ size -= (size % MMAP_PAGE_SIZE); // round down
+ dpsnprintf(vabuf, sizeof(vabuf), "%s/darkplaces.XXXXXX", tmpdir ? tmpdir : "/tmp");
+ fd = mkstemp(vabuf);
+ if(fd < 0)
+ return NULL;
+ ftruncate(fd, size);
+ data = (unsigned char *) mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_NORESERVE, fd, 0);
+ close(fd);
+ unlink(vabuf);
+ if(!data)
+ return NULL;
+ ((mmap_data_t *) data)->len = size;
+ return (void *) (data + MMAP_PAGE_SIZE);
+}
+static void mmap_free(void *mem)
+{
+ unsigned char *data;
+ if(!mem)
+ return;
+ data = (unsigned char *) mem - MMAP_PAGE_SIZE;
+ munmap(data, ((mmap_data_t *) data)->len);
+}
+#define malloc mmap_malloc
+#define free mmap_free
+#endif
+