apr_snprintf.c

Apache V2.0.15 Alpha For Linuxhttpd-2_0_15-alpha.tar.Z

    }

    *len = s - buf;
    return (buf);
}


/*
 * Convert num to a base X number where X is a power of 2. nbits determines X.
 * For example, if nbits is 3, we do base 8 conversion
 * Return value:
 *      a pointer to a string containing the number
 *
 * The caller provides a buffer for the string: that is the buf_end argument
 * which is a pointer to the END of the buffer + 1 (i.e. if the buffer
 * is declared as buf[ 100 ], buf_end should be &buf[ 100 ])
 *
 * As with conv_10, we have a faster version which is used when
 * the number isn't quad size.
 */
static char *conv_p2(register u_wide_int num, register int nbits,
		     char format, char *buf_end, register int *len)
{
    register int mask = (1 << nbits) - 1;
    register char *p = buf_end;
    static const char low_digits[] = "0123456789abcdef";
    static const char upper_digits[] = "0123456789ABCDEF";
    register const char *digits = (format == 'X') ? upper_digits : low_digits;

    do {
	*--p = digits[num & mask];
	num >>= nbits;
    }
    while (num);

    *len = buf_end - p;
    return (p);
}

static char *conv_p2_quad(u_widest_int num, register int nbits,
		     char format, char *buf_end, register int *len)
{
    register int mask = (1 << nbits) - 1;
    register char *p = buf_end;
    static const char low_digits[] = "0123456789abcdef";
    static const char upper_digits[] = "0123456789ABCDEF";
    register const char *digits = (format == 'X') ? upper_digits : low_digits;

    if (num <= ULONG_MAX)
    	return(conv_p2( (u_wide_int)num, nbits, format, buf_end, len));

    do {
	*--p = digits[num & mask];
	num >>= nbits;
    }
    while (num);

    *len = buf_end - p;
    return (p);
}


/*
 * Do format conversion placing the output in buffer
 */
APR_DECLARE(int) apr_vformatter(int (*flush_func)(apr_vformatter_buff_t *),
    apr_vformatter_buff_t *vbuff, const char *fmt, va_list ap)
{
    register char *sp;
    register char *bep;
    register int cc = 0;
    register int i;

    register char *s = NULL;
    char *q;
    int s_len;

    register int min_width = 0;
    int precision = 0;
    enum {
	LEFT, RIGHT
    } adjust;
    char pad_char;
    char prefix_char;

    double fp_num;
    widest_int i_quad = (widest_int) 0;
    u_widest_int ui_quad;
    wide_int i_num = (wide_int) 0;
    u_wide_int ui_num;

    char num_buf[NUM_BUF_SIZE];
    char char_buf[2];		/* for printing %% and %<unknown> */

    enum var_type_enum {
    	IS_QUAD, IS_LONG, IS_SHORT, IS_INT
    };
    enum var_type_enum var_type = IS_INT;

    /*
     * Flag variables
     */
    boolean_e alternate_form;
    boolean_e print_sign;
    boolean_e print_blank;
    boolean_e adjust_precision;
    boolean_e adjust_width;
    bool_int is_negative;

    sp = vbuff->curpos;
    bep = vbuff->endpos;

    while (*fmt) {
	if (*fmt != '%') {
	    INS_CHAR(*fmt, sp, bep, cc);
	}
	else {
	    /*
	     * Default variable settings
	     */
            boolean_e print_something = YES;
	    adjust = RIGHT;
	    alternate_form = print_sign = print_blank = NO;
	    pad_char = ' ';
	    prefix_char = NUL;

	    fmt++;

	    /*
	     * Try to avoid checking for flags, width or precision
	     */
	    if (!apr_islower(*fmt)) {
		/*
		 * Recognize flags: -, #, BLANK, +
		 */
		for (;; fmt++) {
		    if (*fmt == '-')
			adjust = LEFT;
		    else if (*fmt == '+')
			print_sign = YES;
		    else if (*fmt == '#')
			alternate_form = YES;
		    else if (*fmt == ' ')
			print_blank = YES;
		    else if (*fmt == '0')
			pad_char = '0';
		    else
			break;
		}

		/*
		 * Check if a width was specified
		 */
		if (apr_isdigit(*fmt)) {
		    STR_TO_DEC(fmt, min_width);
		    adjust_width = YES;
		}
		else if (*fmt == '*') {
		    min_width = va_arg(ap, int);
		    fmt++;
		    adjust_width = YES;
		    if (min_width < 0) {
			adjust = LEFT;
			min_width = -min_width;
		    }
		}
		else
		    adjust_width = NO;

		/*
		 * Check if a precision was specified
		 *
		 * XXX: an unreasonable amount of precision may be specified
		 * resulting in overflow of num_buf. Currently we
		 * ignore this possibility.
		 */
		if (*fmt == '.') {
		    adjust_precision = YES;
		    fmt++;
		    if (apr_isdigit(*fmt)) {
			STR_TO_DEC(fmt, precision);
		    }
		    else if (*fmt == '*') {
			precision = va_arg(ap, int);
			fmt++;
			if (precision < 0)
			    precision = 0;
		    }
		    else
			precision = 0;
		}
		else
		    adjust_precision = NO;
	    }
	    else
		adjust_precision = adjust_width = NO;

	    /*
	     * Modifier check
	     */
	    if (*fmt == 'q') {
		var_type = IS_QUAD;
		fmt++;
	    }
	    else if (*fmt == 'l') {
		var_type = IS_LONG;
		fmt++;
	    }
	    else if (*fmt == 'h') {
		var_type = IS_SHORT;
		fmt++;
	    }
	    else {
		var_type = IS_INT;
	    }

	    /*
	     * Argument extraction and printing.
	     * First we determine the argument type.
	     * Then, we convert the argument to a string.
	     * On exit from the switch, s points to the string that
	     * must be printed, s_len has the length of the string
	     * The precision requirements, if any, are reflected in s_len.
	     *
	     * NOTE: pad_char may be set to '0' because of the 0 flag.
	     *   It is reset to ' ' by non-numeric formats
	     */
	    switch (*fmt) {
	    case 'u':
	    	if (var_type == IS_QUAD) {
		    i_quad = va_arg(ap, u_widest_int);
		    s = conv_10_quad(i_quad, 1, &is_negative,
			    &num_buf[NUM_BUF_SIZE], &s_len);
		}
		else {
		    if (var_type == IS_LONG)
			i_num = (wide_int) va_arg(ap, u_wide_int);
		    else if (var_type == IS_SHORT)
			i_num = (wide_int) (unsigned short) va_arg(ap, unsigned int);
		    else
			i_num = (wide_int) va_arg(ap, unsigned int);
		    s = conv_10(i_num, 1, &is_negative,
			    &num_buf[NUM_BUF_SIZE], &s_len);
		}
		FIX_PRECISION(adjust_precision, precision, s, s_len);
		break;

	    case 'd':
	    case 'i':
	    	if (var_type == IS_QUAD) {
		    i_quad = va_arg(ap, widest_int);
		    s = conv_10_quad(i_quad, 0, &is_negative,
			    &num_buf[NUM_BUF_SIZE], &s_len);
		}
		else {
		    if (var_type == IS_LONG)
			i_num = (wide_int) va_arg(ap, wide_int);
		    else if (var_type == IS_SHORT)
			i_num = (wide_int) (short) va_arg(ap, int);
		    else
			i_num = (wide_int) va_arg(ap, int);
		    s = conv_10(i_num, 0, &is_negative,
			    &num_buf[NUM_BUF_SIZE], &s_len);
		}
		FIX_PRECISION(adjust_precision, precision, s, s_len);

		if (is_negative)
		    prefix_char = '-';
		else if (print_sign)
		    prefix_char = '+';
		else if (print_blank)
		    prefix_char = ' ';
		break;


	    case 'o':
		if (var_type == IS_QUAD) {
		    ui_quad = va_arg(ap, u_widest_int);
		    s = conv_p2_quad(ui_quad, 3, *fmt,
			    &num_buf[NUM_BUF_SIZE], &s_len);
		}
		else {
		    if (var_type == IS_LONG)
			ui_num = (u_wide_int) va_arg(ap, u_wide_int);
		    else if (var_type == IS_SHORT)
			ui_num = (u_wide_int) (unsigned short) va_arg(ap, unsigned int);
		    else
			ui_num = (u_wide_int) va_arg(ap, unsigned int);
		    s = conv_p2(ui_num, 3, *fmt,
			    &num_buf[NUM_BUF_SIZE], &s_len);
		}
		FIX_PRECISION(adjust_precision, precision, s, s_len);
		if (alternate_form && *s != '0') {
		    *--s = '0';
		    s_len++;
		}
		break;


	    case 'x':
	    case 'X':
		if (var_type == IS_QUAD) {
		    ui_quad = va_arg(ap, u_widest_int);
		    s = conv_p2_quad(ui_quad, 4, *fmt,
			    &num_buf[NUM_BUF_SIZE], &s_len);
		}
		else {
		    if (var_type == IS_LONG)
			ui_num = (u_wide_int) va_arg(ap, u_wide_int);
		    else if (var_type == IS_SHORT)
			ui_num = (u_wide_int) (unsigned short) va_arg(ap, unsigned int);
		    else
			ui_num = (u_wide_int) va_arg(ap, unsigned int);
		    s = conv_p2(ui_num, 4, *fmt,
			    &num_buf[NUM_BUF_SIZE], &s_len);
		}
		FIX_PRECISION(adjust_precision, precision, s, s_len);
		if (alternate_form && i_num != 0) {
		    *--s = *fmt;	/* 'x' or 'X' */
		    *--s = '0';
		    s_len += 2;
		}
		break;


	    case 's':
		s = va_arg(ap, char *);
		if (s != NULL) {
		    s_len = strlen(s);
		    if (adjust_precision && precision < s_len)
			s_len = precision;
		}
		else {
		    s = S_NULL;
		    s_len = S_NULL_LEN;
		}
		pad_char = ' ';
		break;


	    case 'f':
	    case 'e':
	    case 'E':
		fp_num = va_arg(ap, double);
		/*
		 * * We use &num_buf[ 1 ], so that we have room for the sign
		 */
		s = conv_fp(*fmt, fp_num, alternate_form,
			(adjust_precision == NO) ? FLOAT_DIGITS : precision,
			    &is_negative, &num_buf[1], &s_len);
		if (is_negative)
		    prefix_char = '-';
		else if (print_sign)
		    prefix_char = '+';
		else if (print_blank)
		    prefix_char = ' ';
		break;


	    case 'g':
	    case 'G':
		if (adjust_precision == NO)
		    precision = FLOAT_DIGITS;
		else if (precision == 0)
		    precision = 1;
		/*
		 * * We use &num_buf[ 1 ], so that we have room for the sign
		 */
		s = apr_gcvt(va_arg(ap, double), precision, &num_buf[1],
		            alternate_form);
		if (*s == '-')
		    prefix_char = *s++;
		else if (print_sign)
		    prefix_char = '+';
		else if (print_blank)
		    prefix_char = ' ';

		s_len = strlen(s);

		if (alternate_form && (q = strchr(s, '.')) == NULL) {
		    s[s_len++] = '.';
		    s[s_len] = '\0'; /* delimit for following strchr() */
		}
		if (*fmt == 'G' && (q = strchr(s, 'e')) != NULL)
		    *q = 'E';
		break;


	    case 'c':
		char_buf[0] = (char) (va_arg(ap, int));
		s = &char_buf[0];
		s_len = 1;
		pad_char = ' ';
		break;


	    case '%':
		char_buf[0] = '%';
		s = &char_buf[0];
		s_len = 1;
		pad_char = ' ';
		break;


	    case 'n':
	    	if (var_type == IS_QUAD)
		    *(va_arg(ap, widest_int *)) = cc;
		else if (var_type == IS_LONG)
		    *(va_arg(ap, long *)) = cc;
		else if (var_type == IS_SHORT)
		    *(va_arg(ap, short *)) = cc;
		else
		    *(va_arg(ap, int *)) = cc;
                print_something = NO;
		break;

		/*
		 * This is where we extend the printf format, with a second
		 * type specifier
		 */
	    case 'p':
		switch(*++fmt) {
		    /*
		     * If the pointer size is equal to or smaller than the size
		     * of the largest unsigned int, we convert the pointer to a
		     * hex number, otherwise we print "%p" to indicate that we
		     * don't handle "%p".
		     */
		case 'p':
#ifdef APR_VOID_P_IS_QUAD
		    if (sizeof(void *) <= sizeof(u_widest_int)) {
		    	ui_quad = (u_widest_int) va_arg(ap, void *);
			s = conv_p2_quad(ui_quad, 4, 'x',
				&num_buf[NUM_BUF_SIZE], &s_len);
		    }
#else
		    if (sizeof(void *) <= sizeof(u_wide_int)) {
		    	ui_num = (u_wide_int) va_arg(ap, void *);
			s = conv_p2(ui_num, 4, 'x',
				&num_buf[NUM_BUF_SIZE], &s_len);
		    }
#endif
		    else {
			s = "%p";
			s_len = 2;
			prefix_char = NUL;
		    }
		    pad_char = ' ';
		    break;

		    /* print an apr_sockaddr_t as a.b.c.d:port */
		case 'I':
		    {
			apr_sockaddr_t *sa;

			sa = va_arg(ap, apr_sockaddr_t *);
			if (sa != NULL) {
			    s = conv_apr_sockaddr(sa, &num_buf[NUM_BUF_SIZE], &s_len);
			    if (adjust_precision && precision < s_len)
				s_len = precision;
			}
			else {
			    s = S_NULL;
			    s_len = S_NULL_LEN;
			}
			pad_char = ' ';
		    }
		    break;

		    /* print a struct in_addr as a.b.c.d */
		case 'A':
		    {
			struct in_addr *ia;

			ia = va_arg(ap, struct in_addr *);
			if (ia != NULL) {
			    s = conv_in_addr(ia, &num_buf[NUM_BUF_SIZE], &s_len);
			    if (adjust_precision && precision < s_len)
				s_len = precision;
			}
			else {
			    s = S_NULL;
			    s_len = S_NULL_LEN;
			}
			pad_char = ' ';
		    }
		    break;

		case NUL:
		    /* if %p ends the string, oh well ignore it */
		    continue;

		default:
		    s = "bogus %p";
		    s_len = 8;
		    prefix_char = NUL;
		    break;
		}
		break;

	    case NUL:
		/*
		 * The last character of the format string was %.
		 * We ignore it.
		 */
		continue;


		/*
		 * The default case is for unrecognized %'s.
		 * We print %<char> to help the user identify what
		 * option is not understood.
		 * This is also useful in case the user wants to pass
		 * the output of format_converter to another function
		 * that understands some other %<char> (like syslog).
		 * Note that we can't point s inside fmt because the
		 * unknown <char> could be preceded by width etc.
		 */
	    default:
		char_buf[0] = '%';
		char_buf[1] = *fmt;
		s = char_buf;
		s_len = 2;
		pad_char = ' ';
		break;
	    }

	    if (prefix_char != NUL && s != S_NULL && s != char_buf) {
		*--s = prefix_char;
		s_len++;
	    }

	    if (adjust_width && adjust == RIGHT && min_width > s_len) {
		if (pad_char == '0' && prefix_char != NUL) {
		    INS_CHAR(*s, sp, bep, cc);
		    s++;
		    s_len--;
		    min_width--;
		}
		PAD(min_width, s_len, pad_char);
	    }

	    /*
	     * Print the string s. 
	     */
            if (print_something == YES) {
                for (i = s_len; i != 0; i--) {
  		    INS_CHAR(*s, sp, bep, cc);
		    s++;
                }
            }

	    if (adjust_width && adjust == LEFT && min_width > s_len)
		PAD(min_width, s_len, pad_char);
	}
	fmt++;
    }
    vbuff->curpos = sp;
    return cc;
}


static int snprintf_flush(apr_vformatter_buff_t *vbuff)
{
    /* if the buffer fills we have to abort immediately, there is no way
     * to "flush" an apr_snprintf... there's nowhere to flush it to.
     */
    return -1;
}


APR_DECLARE_NONSTD(int) apr_snprintf(char *buf, size_t len, 
                                   const char *format, ...)
{
    int cc;
    va_list ap;
    apr_vformatter_buff_t vbuff;

    if (len == 0)
	return 0;

    /* save one byte for nul terminator */
    vbuff.curpos = buf;
    vbuff.endpos = buf + len - 1;
    va_start(ap, format);
    cc = apr_vformatter(snprintf_flush, &vbuff, format, ap);
    va_end(ap);
    *vbuff.curpos = '\0';
    return (cc == -1) ? len : cc;
}


APR_DECLARE(int) apr_vsnprintf(char *buf, size_t len, const char *format,
			     va_list ap)
{
    int cc;
    apr_vformatter_buff_t vbuff;

    if (len == 0)
	return 0;

    /* save one byte for nul terminator */
    vbuff.curpos = buf;
    vbuff.endpos = buf + len - 1;
    cc = apr_vformatter(snprintf_flush, &vbuff, format, ap);
    *vbuff.curpos = '\0';
    return (cc == -1) ? len : cc;
}