ee_printf.c

/*
 *	ee_printf.c
 *  
 *	Author: Andrew D. Horchler, horchler @ gmail . com
 *	Created: 8-24-14, modified: 3-8-15
 *  
 *  
 *	Based on: barebones/ee_printf.c
 *	Copyright (C) 2002 Michael Ringgaard. All rights reserved.
 *      
 *		Redistribution and use in source and binary forms, with or without
 *		modification, are permitted provided that the following conditions
 *		are met:
 *      
 *		1. Redistributions of source code must retain the above copyright 
 *		   notice, this list of conditions and the following disclaimer.  
 *		2. Redistributions in binary form must reproduce the above copyright
 *		   notice, this list of conditions and the following disclaimer in the
 *		   documentation and/or other materials provided with the distribution.  
 *		3. Neither the name of the project nor the names of its contributors
 *		   may be used to endorse or promote products derived from this software
 *		   without specific prior written permission. 
 *      
 *		THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 *		ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *		IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *		ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
 *		FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *		DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 *		OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *		HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *		LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 *		OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
 *		SUCH DAMAGE.
 */
 
#include <stdarg.h>

#define ZEROPAD		(1<<0)	/* Pad with zero */
#define SIGN		(1<<1)	/* Unsigned/signed long */
#define PLUS		(1<<2)	/* Show plus */
#define SPACE		(1<<3)	/* Spacer */
#define LEFT		(1<<4)	/* Left justified */
#define HEX_PREP	(1<<5)	/* 0x */
#define UPPERCASE	(1<<6)	/* 'ABCDEF' */

#define is_digit(c) ((c) >= '0' && (c) <= '9')

char lower_digits_str[] = "0123456789abcdefghijklmnopqrstuvwxyz";
static char *lower_digits = lower_digits_str;
char upper_digits_str[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
static char *upper_digits = upper_digits_str;

static int ee_skip_atoi(const char **s)
{
	int i = 0;
	while (is_digit(**s)) {
		i = i*10 + *((*s)++) - '0';
	}
	return i;
}

static char *ee_number(char *str, long num, int base, int size, int precision, int type)
{
	char c, sign, tmp[66];
	char *dig = lower_digits;
	int i;
	
	if (type & UPPERCASE) {
		dig = upper_digits;
	}
	if (type & LEFT) {
		type &= ~ZEROPAD;
	}
	if (base < 2 || base > 36) {
		return 0;
	}
	
	c = (type & ZEROPAD) ? '0' : ' ';
	sign = 0;
	if (type & SIGN) {
		if (num < 0) {
			sign = '-';
			num = -num;
			size--;
		} else if (type & PLUS) {
			sign = '+';
			size--;
		} else if (type & SPACE) {
			sign = ' ';
			size--;
		}
	}
	
	if (type & HEX_PREP) {
		size -= (base == 16) ? 2: 1;
	}
	
	i = 0;
	
	if (num == 0) {
		tmp[i++] = '0';
	} else {
		while (num != 0) {
			tmp[i++] = dig[((unsigned long) num) % (unsigned) base];
			num = ((unsigned long) num) / (unsigned) base;
		}
	}
	
	if (i > precision) {
		precision = i;
	}
	size -= precision;
	if (!(type & (ZEROPAD | LEFT))) {
		while (size-- > 0) {
			*str++ = ' ';
		}
	}
	if (sign) {
		*str++ = sign;
	}
	
	if (type & HEX_PREP) {
		if (base == 8) {
			*str++ = '0';
		} else if (base == 16) {
			*str++ = '0';
			*str++ = lower_digits[33];
		}
	}
	
	if (!(type & LEFT)) {
		while (size-- > 0) {
			*str++ = c;
		}
	}
	while (i < precision--) {
		*str++ = '0';
	}
	while (i-- > 0) {
		*str++ = tmp[i];
	}
	while (size-- > 0) {
		*str++ = ' ';
	}
	
	return str;
}

static char *eaddr(char *str, unsigned char *addr, int size, int precision, int type)
{
	char tmp[24];
	char *dig = lower_digits;
	int i, len;
	
	if (type & UPPERCASE) {
		dig = upper_digits;
	}
	len = 0;
	for (i = 0; i < 6; i++) {
		if (i != 0) {
			tmp[len++] = ':';
		}
		tmp[len++] = dig[addr[i] >> 4];
		tmp[len++] = dig[addr[i] & 0x0F];
	}
	
	if (!(type & LEFT)) {
		while (len < size--) {
			*str++ = ' ';
		}
	}
	for (i = 0; i < len; ++i) {
		*str++ = tmp[i];
	}
	while (len < size--) {
		*str++ = ' ';
	}
	
	return str;
}

static char *iaddr(char *str, unsigned char *addr, int size, int precision, int type)
{
	char tmp[24];
	int i, n, len;
	
	len = 0;
	for (i = 0; i < 4; i++) {
		if (i != 0) {
			tmp[len++] = '.';
		}
		n = addr[i];
		
		if (n == 0) {
			tmp[len++] = lower_digits[0];
		} else {
			if (n >= 100)  {
				tmp[len++] = lower_digits[n / 100];
				n = n % 100;
				tmp[len++] = lower_digits[n / 10];
				n = n % 10;
			} else if (n >= 10) {
				tmp[len++] = lower_digits[n / 10];
				n = n % 10;
			}
			
			tmp[len++] = lower_digits[n];
		}
	}
	
	if (!(type & LEFT)) {
		while (len < size--) {
			*str++ = ' ';
		}
	}
	for (i = 0; i < len; ++i) {
		*str++ = tmp[i];
	}
	while (len < size--) {
		*str++ = ' ';
	}
	
	return str;
}

char *ecvtbuf(double arg, int ndigits, int *decpt, int *sign, char *buf);
char *fcvtbuf(double arg, int ndigits, int *decpt, int *sign, char *buf);
static void ee_bufcpy(char *d, char *s, int count);

void ee_bufcpy(char *pd, char *ps, int count)
{
	char *pe = ps + count;
	while (ps != pe) {
		*pd++ = *ps++;
	}
}

static void ee_parse_float(double value, char *buffer, char fmt, int precision)
{
	int decpt, sign, exp, pos;
	char *digits = 0;
	char cvtbuf[80];
	int capexp = 0;
	int magnitude;
	
	if (fmt == 'G' || fmt == 'E') {
		capexp = 1;
		fmt += 'a' - 'A';
	}
	
	if (fmt == 'g') {
		digits = ecvtbuf(value, precision, &decpt, &sign, cvtbuf);
		magnitude = decpt - 1;
		if (magnitude < -4 || magnitude > precision - 1) {
			fmt = 'e';
			precision -= 1;
		} else {
			fmt = 'f';
			precision -= decpt;
		}
	}

	if (fmt == 'e') {
		digits = ecvtbuf(value, precision + 1, &decpt, &sign, cvtbuf);
		
		if (sign) {
			*buffer++ = '-';
		}
		*buffer++ = *digits;
		if (precision > 0) {
			*buffer++ = '.';
		}
		ee_bufcpy(buffer, digits + 1, precision);
		buffer += precision;
		*buffer++ = capexp ? 'E' : 'e';
		
		if (decpt == 0) {
			if (value == 0.0) {
				exp = 0;
			} else {
				exp = -1;
			}
		} else {
			exp = decpt - 1;
		}
		if (exp < 0) {
			*buffer++ = '-';
			exp = -exp;
		} else {
			*buffer++ = '+';
		}
		buffer[2] = (exp % 10) + '0';
		exp = exp / 10;
		buffer[1] = (exp % 10) + '0';
		exp = exp / 10;
		buffer[0] = (exp % 10) + '0';
		buffer += 3;
	} else if (fmt == 'f') {
		digits = fcvtbuf(value, precision, &decpt, &sign, cvtbuf);
		if (sign) {
			*buffer++ = '-';
		}
		if (*digits) {
			if (decpt <= 0) {
				*buffer++ = '0';
				*buffer++ = '.';
				for (pos = 0; pos < -decpt; pos++) {
					*buffer++ = '0';
				}
				while (*digits) {
					*buffer++ = *digits++;
				}
			} else {
				pos = 0;
				while (*digits) {
					if (pos++ == decpt) {
						*buffer++ = '.';
					}
					*buffer++ = *digits++;
				}
			}
		} else {
			*buffer++ = '0';
			if (precision > 0) {
				*buffer++ = '.';
				for (pos = 0; pos < precision; pos++) {
					*buffer++ = '0';
				}
			}
		}
	}
	
	*buffer = '\0';
}

static void ee_decimal_point(char *buffer)
{
	while (*buffer) {
		if (*buffer == '.') {
			return;
		}
		if (*buffer == 'e' || *buffer == 'E') {
			break;
		}
		buffer++;
	}
	
	if (*buffer) {
		int n = strnlen(buffer, 256);
		while (n > 0) {
			buffer[n + 1] = buffer[n];
			n--;
		}
		
		*buffer = '.';
	} else {
		*buffer++ = '.';
		*buffer = '\0';
	}
}

static void ee_cropzeros(char *buffer)
{
	char *stop;
	
	while (*buffer && *buffer != '.') {
		buffer++;
	}
	if (*buffer++) {
		while (*buffer && *buffer != 'e' && *buffer != 'E') {
			buffer++;
		}
		stop = buffer--;
		while (*buffer == '0') {
			buffer--;
		}
		if (*buffer == '.') {
			buffer--;
		}
		while (buffer != stop) {
			*++buffer = 0;
		}
	}
}

static char *flt(char *str, double num, int size, int precision, char fmt, int flags)
{
	char tmp[80];
	char c, sign;
	int n, i;
	
	// Left align means no zero padding
	if (flags & LEFT) {
		flags &= ~ZEROPAD;
	}
	
	// Determine padding and sign char
	c = (flags & ZEROPAD) ? '0' : ' ';
	sign = 0;
	if (flags & SIGN) {
		if (num < 0.0) {
			sign = '-';
			num = -num;
			size--;
		} else if (flags & PLUS) {
			sign = '+';
			size--;
		} else if (flags & SPACE) {
			sign = ' ';
			size--;
		}
	}
	// Compute the precision value
	if (precision < 0) {
		precision = 6;	// Default precision: 6
	}
	
	// Convert floating point number to text
	ee_parse_float(num, tmp, fmt, precision);

	if ((flags & HEX_PREP) && precision == 0) {
		ee_decimal_point(tmp);
	}
	if (fmt == 'g' && !(flags & HEX_PREP)) {
		ee_cropzeros(tmp);
	}
	
	n = strnlen(tmp, 256);
	
	// Output number with alignment and padding
	size -= n;
	if (!(flags & (ZEROPAD | LEFT))) {
		while (size-- > 0) {
			*str++ = ' ';
		}
	}
	if (sign) {
		*str++ = sign;
	}
	if (!(flags & LEFT)) {
		while (size-- > 0) {
			*str++ = c;
		}
	}
	for (i = 0; i < n; i++) {
		*str++ = tmp[i];
	}
	while (size-- > 0) {
		*str++ = ' ';
	}
	
	return str;
}

int ee_vsprint(char *buf, const char *fmt, va_list args)
{
	int len;
	unsigned long num;
	int i, base;
	char *str;
	char *s;
	
	int flags;            // Flags to number()
	
	int field_width;      // Width of output field
	int precision;        // Min. # of digits for integers; max number of chars for from string
	int qualifier;        // 'h', 'l', or 'L' for integer fields
	
	for (str = buf; *fmt; fmt++) {
		if (*fmt != '%') {
			*str++ = *fmt;
			continue;
		}
	     
    	// Process flags
    	flags = 0;
repeat:
    	fmt++; // This also skips first '%'
		switch (*fmt) {
			case '-':
				flags |= LEFT;
				goto repeat;
			case '+':
				flags |= PLUS;
				goto repeat;
			case ' ':
				flags |= SPACE;
				goto repeat;
			case '#':
				flags |= HEX_PREP;
				goto repeat;
			case '0':
				flags |= ZEROPAD;
				goto repeat;
		}
          
		// Get field width
		field_width = -1;
		if (is_digit(*fmt)) {
			field_width = ee_skip_atoi(&fmt);
		} else if (*fmt == '*') {
			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 = ee_skip_atoi(&fmt);
			} else if (*fmt == '*') {
				++fmt;
				precision = va_arg(args, int);
			}
			if (precision < 0) {
				precision = 0;
			}
		}
		
		// Get the conversion qualifier
		qualifier = -1;
		if (*fmt == 'l' || *fmt == 'L') {
			qualifier = *fmt;
			fmt++;
		}
		
		// Default base
		base = 10;
		
		switch (*fmt) {
			case 'c':
				if (!(flags & LEFT)) {
					while (--field_width > 0) {
						*str++ = ' ';
					}
				}
				*str++ = (unsigned char) va_arg(args, int);
				while (--field_width > 0) {
					*str++ = ' ';
				}
				continue;
				
			case 's':
				s = va_arg(args, char *);
				if (!s) {
					char null_str[] = "<NULL>";
					s = null_str;
				}
				len = strnlen(s, precision);
				if (!(flags & LEFT)) {
					while (len < field_width--) {
						*str++ = ' ';
					}
				}
				for (i = 0; i < len; ++i) {
					*str++ = *s++;
				}
				while (len < field_width--) {
					*str++ = ' ';
				}
				continue;
				
			case 'p':
				if (field_width == -1) {
				  field_width = 2 * sizeof(void *);
				  flags |= ZEROPAD;
				}
				str = ee_number(str, (unsigned long) va_arg(args, void *), 16, field_width, precision, flags);
				continue;
				
			case 'A':
				flags |= UPPERCASE;
				
			case 'a':
				if (qualifier == 'l') {
					str = eaddr(str, va_arg(args, unsigned char *), field_width, precision, flags);
				} else {
					str = iaddr(str, va_arg(args, unsigned char *), field_width, precision, flags);
				}
				continue;
				
			// Integer number formats - set up the flags and "break"
			case 'o':
				base = 8;
				break;
				
			case 'X':
				flags |= UPPERCASE;
				
			case 'x':
				base = 16;
				break;
				
			case 'd':
			case 'i':
				flags |= SIGN;
				
			case 'u':
				break;
				
			default:
				if (*fmt != '%') {
					*str++ = '%';
				}
				if (*fmt) {
					*str++ = *fmt;
				} else {
					--fmt;
				}
				continue;
    	}
		
		if (qualifier == 'l') {
			num = va_arg(args, unsigned long);
		} else if (flags & SIGN) {
			num = va_arg(args, int);
		} else {
			num = va_arg(args, unsigned int);
		}
		
		str = ee_number(str, num, base, field_width, precision, flags);
	}
	
	*str = '\0';
	return str - buf;
}

int ee_vsprintf(char *buf, const char *fmt, va_list args)
{
	int len;
	unsigned long num;
	int i, base;
	char *str;
	char *s;
	
	int flags;            // Flags to number()
	
	int field_width;      // Width of output field
	int precision;        // Min. # of digits for integers; max number of chars for from string
	int qualifier;        // 'h', 'l', or 'L' for integer fields
	
	for (str = buf; *fmt; fmt++) {
		if (*fmt != '%') {
			*str++ = *fmt;
			continue;
		}
		
		// Process flags
		flags = 0;
repeat:
		fmt++; // This also skips first '%'
		switch (*fmt) {
			case '-':
				flags |= LEFT;
				goto repeat;
			case '+':
				flags |= PLUS;
				goto repeat;
			case ' ':
				flags |= SPACE;
				goto repeat;
			case '#':
				flags |= HEX_PREP;
				goto repeat;
			case '0':
				flags |= ZEROPAD;
				goto repeat;
		}
		
		// Get field width
		field_width = -1;
		if (is_digit(*fmt)) {
			field_width = ee_skip_atoi(&fmt);
		} else if (*fmt == '*') {
			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 = ee_skip_atoi(&fmt);
		} else if (*fmt == '*') {
			++fmt;
			precision = va_arg(args, int);
		}
			if (precision < 0) {
				precision = 0;
			}
		}
		
		// Get the conversion qualifier
		qualifier = -1;
		if (*fmt == 'l' || *fmt == 'L') {
			qualifier = *fmt;
			fmt++;
		}
	
    	// Default base
    	base = 10;
		
		switch (*fmt) {
			case 'c':
				if (!(flags & LEFT)) {
					while (--field_width > 0) {
						*str++ = ' ';
					}
				}
				*str++ = (unsigned char) va_arg(args, int);
				while (--field_width > 0) {
					*str++ = ' ';
				}
				continue;
				
			case 's':
				s = va_arg(args, char *);
				if (!s) {
					char null_str[] = "<NULL>";
					s = null_str;
				}
				len = strnlen(s, precision);
				if (!(flags & LEFT)) {
					while (len < field_width--) {
						*str++ = ' ';
					}
				}
				for (i = 0; i < len; ++i) {
					*str++ = *s++;
				}
				while (len < field_width--) {
					*str++ = ' ';
				}
				continue;
				
			case 'p':
				if (field_width == -1) {
					field_width = 2 * sizeof(void *);
					flags |= ZEROPAD;
				}
				str = ee_number(str, (unsigned long) va_arg(args, void *), 16, field_width, precision, flags);
				continue;
				
			case 'A':
				flags |= UPPERCASE;
			
			case 'a':
				if (qualifier == 'l') {
					str = eaddr(str, va_arg(args, unsigned char *), field_width, precision, flags);
				} else {
					str = iaddr(str, va_arg(args, unsigned char *), field_width, precision, flags);
				}
				continue;
				
			// Integer number formats - set up the flags and "break"
			case 'o':
				base = 8;
				break;
				
			case 'X':
				flags |= UPPERCASE;
				
			case 'x':
				base = 16;
				break;
				
			case 'd':
			case 'i':
				flags |= SIGN;
				
			case 'u':
				break;
				
			case 'E':
			case 'F':
			case 'G':
				flags |= UPPERCASE;
				
			case 'e':
			case 'f':
			case 'g':
				str = flt(str, va_arg(args, double), field_width, precision, *fmt, flags | SIGN);
				continue;
				
			default:
				if (*fmt != '%') {
					*str++ = '%';
				}
				if (*fmt) {
					*str++ = *fmt;
				} else {
					--fmt;
				}
				continue;
		}
		
		if (qualifier == 'l') {
			num = va_arg(args, unsigned long);
		} else if (flags & SIGN) {
			num = va_arg(args, int);
		} else {
			num = va_arg(args, unsigned int);
		}
		
		str = ee_number(str, num, base, field_width, precision, flags);
	}
	
	*str = '\0';
	return str - buf;
}