6 * alloc - memory allocator routines
8 * The alloc module implements a simple allocator which you can use to
9 * dynamically allocate space within a region of memory. This can be useful
10 * for suballocations within a given region, or a memory-mapped file.
12 * All metadata is kept within the memory handed to the allocator: you only
13 * need hand the pointer and the size of the memory to each call.
15 * The region contents is always in offsets, so it can be mapped in different
16 * places, but is not endian-safe.
19 * #include <sys/mman.h>
21 * #include <sys/types.h>
23 * #include "alloc/alloc.h"
25 * static void usage(const char *name)
27 * errx(1, "Usage: %s --create <mapfile>\n"
28 * " %s --check <mapfile>\n"
29 * " %s --alloc <mapfile>\n"
30 * " %s --free=<offset> <mapfile>\n", name, name, name);
33 * // Create a memory mapped file, and allocate from within it
34 * int main(int argc, char *argv[])
38 * enum { CREATE, CHECK, ALLOC, FREE } cmd;
43 * if (strcmp(argv[1], "--create") == 0)
45 * else if (strcmp(argv[1], "--check") == 0)
47 * else if (strcmp(argv[1], "--alloc") == 0)
49 * else if (strncmp(argv[1], "--free=", strlen("--free=")) == 0)
54 * if (cmd == CREATE) {
55 * fd = open(argv[2], O_RDWR|O_CREAT|O_EXCL, 0600);
57 * err(1, "Could not create %s", argv[2]);
58 * if (ftruncate(fd, 1048576) != 0)
59 * err(1, "Could not set length on %s", argv[2]);
61 * fd = open(argv[2], O_RDWR);
63 * err(1, "Could not open %s", argv[2]);
66 * a = mmap(NULL, 1048576, PROT_READ|PROT_WRITE, MAP_SHARED, fd,0);
67 * if (a == MAP_FAILED)
68 * err(1, "Could not map %s", argv[2]);
72 * alloc_init(a, 1048576);
75 * if (!alloc_check(a, 1048576))
76 * err(1, "Region is corrupt");
79 * p = alloc_get(a, 1048576, 1024, 16);
81 * errx(1, "Could not allocate");
82 * printf("%zu\n", (char *)p - (char *)a);
85 * p = (char *)a + atol(argv[1] + strlen("--free="));
86 * alloc_free(a, 1048576, p);
92 int main(int argc, char *argv[])
97 if (strcmp(argv[1], "depends") == 0) {
98 printf("build_assert\n");