snippets.md

Code Examples

Here I provide various (hopefully, useful) functions and code examples that are not included into the main library. Some examples use non-POSIX and/or compiler-specific features that may or may not be suitable for a particular project. Also, these snippets were tested while being developed, but they may break in the future as the library evolves.

void str_sprintf(str* const dest, const char* fmt, ...)

Probably the simplest implementation utilising non-POSIX asprintf(3) function:

#define _GNU_SOURCE

#include "str.h"

#define str_sprintf(dest, fmt, ...)	\
({	\
    char* ___p;	\
    const int ___n = asprintf(&___p, (fmt),  ##__VA_ARGS__);	\
    str_assign((dest), str_acquire_chars(___p, ___n));	\
})

This code does not check for errors. A more standard-conforming implementation would probably go through open_memstream(3) function.

int str_from_int(str* const dest, const int val)

int str_from_int(str* const dest, const int val)
{
    char buff[256];	// of some "big enough" size

    return str_cpy(dest, str_ref_chars(buff, snprintf(buff, sizeof(buff), "%d", val)));
}

This code can also be used as a template for other functions converting from double, struct tm, etc.

int str_append(str* const dest, ...)

#define str_append(dest, ...)	\
    ({ str* const ___p = (dest); str_cat(___p, *___p, ##__VA_ARGS__); })

Test case and usage example:

    str s = str_lit("zzz");

    assert(str_append(&s, str_lit(" "), str_lit("aaa")) == 0);
    assert(str_eq(s, str_lit("zzz aaa")));

    str_free(s);

Using str objects with printf family of functions

Since a string object is not guaranteed to refer to a null-terminated string it should be formatted with explicitly specified length, for example:

	str s = ...

	printf("%.*s\n", (int)str_len(s), str_ptr(s));

Note: The maximum length of the string is limited to INT_MAX bytes, and formatting will stop at the first null byte within the string.