callisto/util.c
Jeremy Baxter 30a1097bb0 tree: reformat
Done automatically by clang-format
2024-03-12 12:21:39 +13:00

120 lines
2.3 KiB
C

/*
* Callisto - standalone scripting platform for Lua 5.4
* Copyright (c) 2023-2024 Jeremy Baxter.
*/
/*
* util.c
*
* Utility functions.
*/
#include <errno.h>
#include <string.h>
#include <lua/lauxlib.h>
#include <lua/lua.h>
#include "util.h"
int
lfail(lua_State *L)
{
char strerrbuf[256];
luaL_pushfail(L);
strerror_r(errno, strerrbuf, 256);
lua_pushstring(L, strerrbuf);
lua_pushinteger(L, errno);
return 3;
}
int
lfailm(lua_State *L, const char *mesg)
{
luaL_pushfail(L);
lua_pushstring(L, mesg);
return 2;
}
/*
* strbcat and strbcpy are from OpenBSD source files
* lib/libc/string/strlcat.c and
* lib/libc/string/strlcpy.c respectively
*/
/*
* Appends src to string dst of size dsize (unlike strncat, dsize is the
* full size of dst, not space left). At most dsize-1 characters
* will be copied. Always NUL terminates (unless dsize <= strlen(dst)).
* Returns strlen(src) + MIN(dsize, strlen(initial dst)).
* If retval >= dsize, truncation occurred.
*/
size_t
strbcat(char *dst, const char *src, size_t dsize)
{
const char *odst = dst;
const char *osrc = src;
size_t n = dsize;
size_t dlen;
/* Find the end of dst and adjust bytes left but don't go past end. */
while (n-- != 0 && *dst != '\0')
dst++;
dlen = dst - odst;
n = dsize - dlen;
if (n-- == 0)
return (dlen + strlen(src));
while (*src != '\0') {
if (n != 0) {
*dst++ = *src;
n--;
}
src++;
}
*dst = '\0';
return (dlen + (src - osrc)); /* count does not include NUL */
}
/*
* Copy string src to buffer dst of size dsize. At most dsize-1
* chars will be copied. Always NUL terminates (unless dsize == 0).
* Returns strlen(src); if retval >= dsize, truncation occurred.
*/
size_t
strbcpy(char *dst, const char *src, size_t dsize)
{
const char *osrc = src;
size_t nleft = dsize;
/* Copy as many bytes as will fit. */
if (nleft != 0) {
while (--nleft != 0) {
if ((*dst++ = *src++) == '\0')
break;
}
}
/* Not enough room in dst, add NUL and traverse rest of src. */
if (nleft == 0) {
if (dsize != 0)
*dst = '\0'; /* NUL-terminate dst */
while (*src++)
;
}
return (src - osrc - 1); /* count does not include NUL */
}
/*
* Prepends t to s.
*/
void
strprepend(char *s, const char *t)
{
size_t len = strlen(t);
memmove(s + len, s, strlen(s) + 1);
memcpy(s, t, len);
}