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#include <assert.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include "til_str.h"
#include "til_util.h"
/* This implements very rudimentary growable strings, and hasn't been optimized at all.
*
* The impetus for adding this is to get rid of the open_memstream() usage which is mostly
* just being used as a convenient way to build up a buffer from format strings. So this
* basically implements just that ability using variadic functions...
*
* Why no open_memstream()? Because Windows, that's why. For some reason even mingw doesn't
* have open_memstream(). FILE* I keep forgetting that you're dead to me.
*/
struct til_str_t {
struct {
size_t allocated, used; /* used is length, including '\0' terminator */
} size;
char *buf;
};
#define TIL_STR_MIN_SIZE 64
/* alloc always returns a buf w/nul terminator present */
static til_str_t * til_str_nulstr(size_t minsize)
{
til_str_t *str;
str = calloc(1, sizeof(*str));
if (!str)
return NULL;
str->size.used = 1;
str->size.allocated = MAX(minsize, TIL_STR_MIN_SIZE);
str->buf = calloc(1, str->size.allocated);
if (!str->buf) {
free(str);
return NULL;
}
return str;
}
/* allocate a new til_str, starting with a dup of seed, just use "" for an empty str, there is no NULL str */
til_str_t * til_str_new(const char *seed)
{
til_str_t *str;
size_t len;
assert(seed);
len = strlen(seed);
str = til_str_nulstr(len + 1);
if (!str)
return NULL;
memcpy(str->buf, seed, len);
str->size.used += len;
return str;
}
void * til_str_free(til_str_t *str)
{
if (str) {
free(str->buf);
free(str);
}
return NULL;
}
/* allocate a new til_str from a fmt string + args */
til_str_t * til_str_newf(const char *format, ...)
{
til_str_t *str;
va_list ap;
assert(format);
va_start(ap, format);
str = til_str_nulstr(vsnprintf(NULL, 0, format, ap) + 1);
if (!str)
return NULL;
str->size.used += vsnprintf(str->buf, str->size.allocated, format, ap);
va_end(ap);
assert(str->size.used <= str->size.allocated);
return str;
}
/* append to an existing til_str_t from a fmt string + args */
int til_str_appendf(til_str_t *str, const char *format, ...)
{
size_t len;
va_list ap;
assert(str);
assert(format);
va_start(ap, format);
len = vsnprintf(NULL, 0, format, ap);
va_end(ap);
if (str->size.used + len > str->size.allocated) {
char *new;
new = realloc(str->buf, str->size.used + len);
if (!new)
return -ENOMEM;
str->buf = new;
str->size.allocated = str->size.used + len;
}
va_start(ap, format);
str->size.used += vsnprintf(&str->buf[str->size.used - 1],
str->size.allocated - (str->size.used - 1),
format, ap);
va_end(ap);
assert(str->size.used <= str->size.allocated);
return 0;
}
/* strdup() the /used/ contents of str */
char * til_str_strdup(const til_str_t *str)
{
assert(str);
return strdup(str->buf);
}
/* a valid \0-terminated string is _always_ maintained @ str->buf so callers can just use it as a string..
* but must not hang onto that pointer across more til_str() calls on the same str.
*/
const char * til_str_buf(const til_str_t *str, size_t *res_len)
{
assert(str);
if (res_len)
*res_len = str->size.used;
return str->buf;
}
/* for when you just want the buf without the dup overhead, and don't need the str anymore */
char * til_str_to_buf(til_str_t *str, size_t *res_len)
{
char *buf;
assert(str);
if (res_len)
*res_len = str->size.used;
buf = str->buf;
free(str);
return buf;
}
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