#include <sys/mman.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>

void *sys_alloc(u64 length)
{
	assert(length);
	void *result = mmap(0, length, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
	return result;
}

void sys_free(void *memory, u64 length)
{
	assert(memory);
	assert(length);
	munmap(memory, length);
}

u64 sys_read_file(arena_t *arena, char **buffer, const char *filename)
{
	FILE *file = fopen(filename, "rb");
	if (!file)
		return 0;

	if (fseek(file, 0, SEEK_END) == -1)
		goto error;
	long len = ftell(file);
	if (!len || (len == -1))
		goto error;
	if (fseek(file, 0, SEEK_SET) == -1)
		goto error;

	*buffer = push_arena(arena, len + 1);
	if (!fread(*buffer, 1, len, file)) {
		pop_arena(arena, len + 1);
		*buffer = 0;
		goto error;
	}
	(*buffer)[len] = 0;
	fclose(file);

	return len;
error:
	fclose(file);
	*buffer = 0;
	return 0;
}

char *sys_getbindir(arena_t *arena)
{
	char path[MAX_PATH];
	i64 len = readlink("/proc/self/exe", path, MAX_PATH - 1);
	if (len <= 0)
		return 0;

	path[len] = 0;

	char *dir = strrchr(path, '/');
	assert(dir);
	assert(dir > path);

	len = dir - path;
	dir = push_arena(arena, len + 1);
	prb_memmove(dir, path, len);
	dir[len] = 0;

	return dir;
}