sprintf_s.c

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/* Need restrict */
#include "config.h"
#include "safe_str_lib.h"
#include "safe_str_constraint.h"
#include <stdarg.h>

/* TODO: error when fmt contains %n, or encoding errors occur.
 */

int sprintf_s(char * restrict dest, rsize_t dmax, const char * restrict fmt, ...)
{
    va_list ap;
    int ret = -1;
    if (dmax > RSIZE_MAX_STR) {
        invoke_safe_str_constraint_handler("sprintf_s: dmax exceeds max",
                   NULL, ESLEMAX);
        return RCNEGATE(ESLEMAX);
    }

    if (dest == NULL) {
        invoke_safe_str_constraint_handler("sprintf_s: dest is null",
                   NULL, ESNULLP);
        return RCNEGATE(ESNULLP);
    }

    if (fmt == NULL) {
        invoke_safe_str_constraint_handler("sprintf_s: fmt is null",
                   NULL, ESNULLP);
        return RCNEGATE(ESNULLP);
    }

    if (dmax == 0) {
        invoke_safe_str_constraint_handler("sprintf_s: dmax is 0",
                   NULL, ESZEROL);
        return RCNEGATE(ESZEROL);
    }

    va_start(ap, fmt);

    ret = vsnprintf(dest, (size_t)dmax, fmt, ap);

    if (ret >= (int)dmax) {
        invoke_safe_str_constraint_handler("sprintf_s: len exceeds dmax",
                   NULL, ESNOSPC);
        *dest = 0;
        ret = RCNEGATE(ESNOSPC);
    }

    va_end(ap);

    return ret;
}