我的學習之旅(22)vsprintf.c

<pre class="cpp" name="code">        switch (*fmt) {
            case '-':
                flags |= LEFT; goto repeat;
            case '+':
                flags |= PLUS; goto repeat;
            case ' ':
                flags |= SPACE; goto repeat;
            case '#':
                flags |= SPECIAL; goto repeat;
            case '0':
                flags |= ZEROPAD; goto repeat;
        }

        /* get field width */
        field_width = -1;
        if (is_digit(*fmt)) {
            field_width = skip_atoi(&fmt);
        } else if (*fmt == '*') {
            /* it's the next argument */
            ++fmt;
            field_width = va_arg(args, int);
            if (field_width < 0) {
                field_width = -field_width;
                flags |= LEFT;
            }
        }

        /* get the precision */
        precision = -1;
        if (*fmt == '.') {
            ++fmt;  
            if (is_digit(*fmt)) {
                precision = skip_atoi(&fmt);
            } else if (*fmt == '*') {
                /* it's the next argument */
                precision = va_arg(args, int);
            }
            if (precision < 0) {
                precision = 0;
            }
        }

        /* get the conversion qualifier */
        qualifier = -1;
        if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
            qualifier = *fmt;
            ++fmt;
        }