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cc65/libsrc/common/_printf.c

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/*
* Helper function for the printf family.
*/
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <ctype.h>
#include "_printf.h"
/* Use static variables for locals */
#pragma staticlocals (1);
int _printf (struct outdesc* d, char* f, va_list ap)
{
outfunc fout; /* Output function */
unsigned char type; /* variable argument type */
char str [20]; /* string buffer */
char c; /* Current format char */
char leftjust; /* left justify string */
char addsign; /* always add + or - */
char addblank; /* add blank instead of + */
char altform; /* alternate form? */
char padchar; /* pad with space or zeroes? */
char islong; /* l modifier found */
unsigned arglen; /* length of argument string */
unsigned prec; /* Precision */
unsigned width; /* Width of output field */
int i; /* Integer value */
long l; /* Long value */
char* sptr; /* pointer to argument string */
register char* s; /* work pointer to argument string */
/* Remember the format string in a register variable for shorter code */
register char* format = f;
/* Remember the output function in a local variable for speed and size */
fout = d->fout;
/* */
d->ccount = 0;
while (c = *format++) {
if (c != '%') {
fout (d, &c, 1);
continue;
}
/* %%? */
if (*format == '%') {
fout (d, format, 1);
++format;
continue;
}
/* format is: %[flags][width][.precision][mod]type */
/* flags */
leftjust = addsign = addblank = altform = 0;
do {
switch (c = *format) {
case '-':
leftjust = 1;
break;
case '+':
addsign = 1;
break;
case '#':
altform = 1;
break;
case ' ':
addblank = 1;
break;
default:
goto flags_done;
}
++format;
} while (1);
flags_done:
/* width */
padchar = ' ';
if (*format == '0') {
padchar = '0';
++format;
}
if (*format == '*') {
width = va_arg (ap, int);
++format;
} else {
width = 0;
while (isdigit (c = *format)) {
width = width * 10 + (c - '0');
++format;
}
}
/* precision */
prec = 0;
if (*format == '.') {
++format;
if (*format == '*') {
prec = va_arg (ap, int);
++format;
} else {
while (isdigit (c = *format)) {
prec = prec * 10 + (c - '0');
++format;
}
}
}
/* modifiers */
islong = 0;
while (strchr ("FNhlL", c = *format)) {
switch (c) {
case 'l':
islong = 1;
break;
}
++format;
}
/* Check the format specifier */
sptr = s = str;
type = *format++;
switch (type) {
case 'c':
str [0] = va_arg (ap, char);
str [1] = 0;
break;
case 'd':
case 'i':
if (addsign) {
*s++ = '+';
} else if (addblank) {
*s++ = ' ';
}
if (islong) {
ltoa (va_arg (ap, long), s, 10);
} else {
itoa (va_arg (ap, int), s, 10);
}
break;
case 'n':
*va_arg (ap, int*) = d->ccount;
continue;
case 'o':
if (islong) {
l = va_arg (ap, unsigned long);
if (altform && (l || prec)) {
*s++ = '0';
}
ultoa (l, s, 8);
} else {
i = va_arg (ap, unsigned);
if (altform && (i || prec)) {
*s++ = '0';
}
utoa (i, s, 8);
}
break;
case 's':
sptr = va_arg (ap, char*);
break;
case 'u':
if (islong) {
ultoa (va_arg (ap, unsigned long), str, 10);
} else {
utoa (va_arg (ap, unsigned), str, 10);
}
break;
case 'x':
case 'X':
if (altform) {
*s++ = '0';
*s++ = 'X';
}
if (islong) {
ultoa (va_arg (ap, unsigned long), s, 16);
} else {
utoa (va_arg (ap, unsigned), s, 16);
}
if (type == 'x') {
strlower (str);
}
break;
default:
/* Unknown type char - skip it */
continue;
}
/* Do argument string formatting */
arglen = strlen (sptr);
if (prec && prec < arglen) {
arglen = prec;
}
if (width > arglen) {
width -= arglen; /* padcount */
} else {
width = 0;
}
/* Do padding on the left side if needed */
if (!leftjust) {
/* argument right justified */
while (width) {
fout (d, &padchar, 1);
--width;
}
}
/* Output the argument string */
fout (d, sptr, arglen);
/* Output right padding bytes if needed */
if (leftjust) {
/* argument left justified */
while (width) {
fout (d, &padchar, 1);
--width;
}
}
}
}