kolibrios-fun/programs/develop/ktcc/trunk/libc/stdio/sprintf_tiny.c

98 lines
2.2 KiB
C
Raw Normal View History

/*
function for format output to the string. much lighter than standard sprintf
because of lesser formats supported
*/
#include <string.h>
//#include <stdio.h>
#include <ctype.h>
#include <stdarg.h>
char* __itoa(int n,char* s);
char* itoab(unsigned int n, char* s, int b);
int tiny_vsnprintf (char * s, size_t n, const char * format, va_list args )
// support %c, %s, %d, %x, %u, %% for 32-bit values only. no width specs, left align
// always zero-ended
{
char *fmt, *dest, buf[32];
fmt = (char*)format;
dest = s; dest[n - 1] = '\0';
int arg, len;
while (*fmt && (dest - s < n - 1))
{
if (*fmt != '%')
{
*dest++ = *fmt++;
continue;
}
if (fmt[1] == '%') // %%
{
*dest++ = '%';
fmt += 2;
continue;
}
arg = va_arg(args, int);
len = n - 1 - (dest - s);
switch (*++fmt)
{
case 'c':
*dest++ = (char)arg;
break;
case 's':
strncpy(dest, (char*)arg, len);
dest = strchr(dest, 0);
break;
case 'd':
__itoa(arg, buf);
strncpy(dest, buf, len);
dest = strchr(dest, 0);
break;
case 'x':
itoab((unsigned)arg, buf, 16);
strncpy(dest, buf, len);
dest = strchr(dest, 0);
break;
case 'u':
itoab((unsigned)arg, buf, 10);
strncpy(dest, buf, len);
dest = strchr(dest, 0);
break;
default:
*dest++ = *fmt;
}
fmt++;
}
*dest = '\0';
return dest - s;
}
int tiny_snprintf (char * s, size_t n, const char * format, ... )
{
va_list arg;
int rc;
va_start(arg, format);
rc = tiny_vsnprintf(s, n, format, arg);
va_end(arg);
return rc;
}
int tiny_sprintf (char * s, const char * format, ... )
{
va_list arg;
int rc;
va_start(arg, format);
rc = tiny_vsnprintf(s, 4096, format, arg);
va_end(arg);
return rc;
}