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/* The functions in this file are only meant to support Dhrystone on an
* embedded RV32 system and are obviously incorrect in general. */
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#undef putchar
int putchar(int ch)
{
return write(1, &ch, 1) == 1 ? ch : -1;
}
static void sprintf_putch(int ch, void** data)
{
char** pstr = (char**)data;
**pstr = ch;
(*pstr)++;
}
static unsigned long getuint(va_list *ap, int lflag)
{
if (lflag)
return va_arg(*ap, unsigned long);
else
return va_arg(*ap, unsigned int);
}
static long getint(va_list *ap, int lflag)
{
if (lflag)
return va_arg(*ap, long);
else
return va_arg(*ap, int);
}
static inline void printnum(void (*putch)(int, void**), void **putdat,
unsigned long num, unsigned base, int width, int padc)
{
unsigned digs[sizeof(num)*8];
int pos = 0;
while (1)
{
digs[pos++] = num % base;
if (num < base)
break;
num /= base;
}
while (width-- > pos)
putch(padc, putdat);
while (pos-- > 0)
putch(digs[pos] + (digs[pos] >= 10 ? 'a' - 10 : '0'), putdat);
}
static inline void print_double(void (*putch)(int, void**), void **putdat,
double num, int width, int prec)
{
union {
double d;
uint64_t u;
} u;
u.d = num;
if (u.u & (1ULL << 63)) {
putch('-', putdat);
u.u &= ~(1ULL << 63);
}
for (int i = 0; i < prec; i++)
u.d *= 10;
char buf[32], *pbuf = buf;
printnum(sprintf_putch, (void**)&pbuf, (unsigned long)u.d, 10, 0, 0);
if (prec > 0) {
for (int i = 0; i < prec; i++) {
pbuf[-i] = pbuf[-i-1];
}
pbuf[-prec] = '.';
pbuf++;
}
for (char* p = buf; p < pbuf; p++)
putch(*p, putdat);
}
static void vprintfmt(void (*putch)(int, void**), void **putdat, const char *fmt, va_list ap)
{
register const char* p;
const char* last_fmt;
register int ch, err;
unsigned long num;
int base, lflag, width, precision, altflag;
char padc;
while (1) {
while ((ch = *(unsigned char *) fmt) != '%') {
if (ch == '\0')
return;
fmt++;
putch(ch, putdat);
}
fmt++;
// Process a %-escape sequence
last_fmt = fmt;
padc = ' ';
width = -1;
precision = -1;
lflag = 0;
altflag = 0;
reswitch:
switch (ch = *(unsigned char *) fmt++) {
// flag to pad on the right
case '-':
padc = '-';
goto reswitch;
// flag to pad with 0's instead of spaces
case '0':
padc = '0';
goto reswitch;
// width field
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
for (precision = 0; ; ++fmt) {
precision = precision * 10 + ch - '0';
ch = *fmt;
if (ch < '0' || ch > '9')
break;
}
goto process_precision;
case '*':
precision = va_arg(ap, int);
goto process_precision;
case '.':
if (width < 0)
width = 0;
goto reswitch;
case '#':
altflag = 1;
goto reswitch;
process_precision:
if (width < 0)
width = precision, precision = -1;
goto reswitch;
// long flag
case 'l':
if (lflag)
goto bad;
goto reswitch;
// character
case 'c':
putch(va_arg(ap, int), putdat);
break;
// double
case 'f':
print_double(putch, putdat, va_arg(ap, double), width, precision);
break;
// string
case 's':
if ((p = va_arg(ap, char *)) == NULL)
p = "(null)";
if (width > 0 && padc != '-')
for (width -= strnlen(p, precision); width > 0; width--)
putch(padc, putdat);
for (; (ch = *p) != '\0' && (precision < 0 || --precision >= 0); width--) {
putch(ch, putdat);
p++;
}
for (; width > 0; width--)
putch(' ', putdat);
break;
// (signed) decimal
case 'd':
num = getint(&ap, lflag);
if ((long) num < 0) {
putch('-', putdat);
num = -(long) num;
}
base = 10;
goto signed_number;
// unsigned decimal
case 'u':
base = 10;
goto unsigned_number;
// (unsigned) octal
case 'o':
// should do something with padding so it's always 3 octits
base = 8;
goto unsigned_number;
// pointer
case 'p':
lflag = 1;
putch('0', putdat);
putch('x', putdat);
/* fall through to 'x' */
// (unsigned) hexadecimal
case 'x':
base = 16;
unsigned_number:
num = getuint(&ap, lflag);
signed_number:
printnum(putch, putdat, num, base, width, padc);
break;
// escaped '%' character
case '%':
putch(ch, putdat);
break;
// unrecognized escape sequence - just print it literally
default:
bad:
putch('%', putdat);
fmt = last_fmt;
break;
}
}
}
int printf(const char* fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vprintfmt((void*)putchar, 0, fmt, ap);
va_end(ap);
return 0; // incorrect return value, but who cares, anyway?
}
int sprintf(char* str, const char* fmt, ...)
{
va_list ap;
char* str0 = str;
va_start(ap, fmt);
vprintfmt(sprintf_putch, (void**)&str, fmt, ap);
*str = 0;
va_end(ap);
return str - str0;
}
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