Function printf_core

kernel/generic/src/printf/printf_core.c:621–932

Print formatted string. * * Print string formatted according to the fmt parameter and variadic arguments. * Each formatting directive must have the following form: * * \% [ FLAGS ] [ WIDTH ] [ .PRECISION ] [ TYPE ] CONVERSION * * FLAGS:@n * - "#" Force to print prefix. For \%o conversion, the prefix is 0, for * \%x and \%X prefixes are 0x and 0X and for conversion \%b the *

 *
 */
int printf_core(const char *fmt, printf_spec_t *ps, va_list ap)
{
	size_t i;        /* Index of the currently processed character from fmt */
	size_t nxt = 0;  /* Index of the next character from fmt */
	size_t j = 0;    /* Index to the first not printed nonformating character */

	size_t counter = 0;   /* Number of characters printed */
	int retval;           /* Return values from nested functions */

	while (true) {
		i = nxt;
		char32_t uc = str_decode(fmt, &nxt, STR_NO_LIMIT);

		if (uc == 0)
			break;

		/* Control character */
		if (uc == '%') {
			/* Print common characters if any processed */
			if (i > j) {
				if ((retval = printf_putnchars(&fmt[j], i - j, ps)) < 0) {
					/* Error */
					counter = -counter;
					goto out;
				}
				counter += retval;
			}

			j = i;

			/* Parse modifiers */
			uint32_t flags = 0;
			bool end = false;

			do {
				i = nxt;
				uc = str_decode(fmt, &nxt, STR_NO_LIMIT);
				switch (uc) {
				case '#':
					flags |= __PRINTF_FLAG_PREFIX;
					break;
				case '-':
					flags |= __PRINTF_FLAG_LEFTALIGNED;
					break;
				case '+':
					flags |= __PRINTF_FLAG_SHOWPLUS;
					break;
				case ' ':
					flags |= __PRINTF_FLAG_SPACESIGN;
					break;
				case '0':
					flags |= __PRINTF_FLAG_ZEROPADDED;
					break;
				default:
					end = true;
				}
			} while (!end);