graphene/Pal/lib/stdlib/printfmt.c

/* Implementation of printf console output for user environments.
 *
 * printf is a debugging statement, not a generic output statement.
 * It is very important that it always go to the console, especially when
 * debugging file descriptor code! */

#include <stdint.h>
#include <stdarg.h>

#include "api.h"

// Print a number (base <= 16) in reverse order,
// using specified fputch function and associated pointer putdat.
#if !defined(__i386__)
static void
printnum(void (*_fputch)(void *, int, void *), void * f, void * putdat,
	 unsigned long long num, unsigned base, int width, int padc)
#else
static void
printnum(void (*_fputch)(void *, int, void *), void * f, void * putdat,
	 unsigned long num, unsigned base, int width, int padc)
#endif
{
	// first recursively print all preceding (more significant) digits
	if (num >= base) {
		printnum(_fputch, f, putdat, num / base, base, width - 1, padc);
	} else {
		// print any needed pad characters before first digit
		while (--width > 0)
			(*_fputch) (f, padc, putdat);
	}

	// then print this (the least significant) digit
	(*_fputch) (f, "0123456789abcdef"[num % base], putdat);
}

// Get an unsigned int of various possible sizes from a varargs list,
// depending on the lflag parameter.
#if !defined(__i386__)
inline unsigned long long
getuint(va_list *ap, int lflag)
#else
inline unsigned long
getuint(va_list *ap, int lflag)
#endif
{
#if !defined(__i386__)
	if (lflag >= 2)
		return va_arg(*ap, unsigned long long);
	else 
#endif
	if (lflag)
		return va_arg(*ap, unsigned long);
	else
		return va_arg(*ap, unsigned int);
}

// Same as getuint but signed - can't use getuint
// because of sign extension
#if !defined(__i386__)
inline long long
getint(va_list *ap, int lflag)
#else
inline long
getint(va_list *ap, int lflag)
#endif
{
#if !defined(__i386__)
	if (lflag >= 2)
		return va_arg(*ap, long long);
	else
#endif
	if (lflag)
		return va_arg(*ap, long);
	else
		return va_arg(*ap, int);
}

// Main function to format and print a string.
void fprintfmt(void (*_fputch)(void *, int, void *), void * f, void * putdat,
			        const char * fmt, ...);

void
vfprintfmt(void (*_fputch)(void *, int, void *), void * f, void * putdat,
			   const char * fmt, va_list *ap)
{
	register const char *p;
	register int ch;
#if !defined(__i386__)
	unsigned long long num;
#else
	unsigned long num;
#endif
	int base, lflag, width, precision, altflag;
	char padc;

	while (1) {
		while ((ch = *(unsigned char *) (fmt++)) != '%') {
			if (ch == '\0')
				return;
			(*_fputch) (f, ch, putdat);
		}

		// Process a %-escape sequence
		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 (doubled for long long)
		case 'l':
			lflag++;
			goto reswitch;

		// character
		case 'c':
			(*_fputch) (f, va_arg(*ap, int), putdat);
			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--)
					(*_fputch) (f, padc, putdat);
			for (; (ch = *p++) != '\0' && (precision < 0 || --precision >= 0); width--)
				if (altflag && (ch < ' ' || ch > '~'))
					(*_fputch) (f, '?', putdat);
				else
					(*_fputch) (f, ch, putdat);
			for (; width > 0; width--)
				(*_fputch) (f, ' ', putdat);
			break;

		// (signed) decimal
		case 'd':
			num = getint(ap, lflag);
#if !defined(__i386__)
			if ((long long) num < 0) {
				(*_fputch) (f, '-', putdat);
				num = -(long long) num;
			}
#else
			if ((long) num < 0) {
				(*_fputch) (f, '-', putdat);
				num = -(long) num;
			}
#endif
			base = 10;
			goto number;

		// unsigned decimal
		case 'u':
			num = getuint(ap, lflag);
			base = 10;
			goto number;

		// (unsigned) octal
		case 'o':
			// Replace this with your code.
			num = getuint(ap, lflag);
			base = 8;
			goto number;

		// pointer
		case 'p':
			(*_fputch) (f, '0', putdat);
			(*_fputch) (f, 'x', putdat);
#if !defined(__i386__)
			num = (unsigned long long)
				(uintptr_t) va_arg(*ap, void *);
#else
			num = (unsigned long)
				(uintptr_t) va_arg(*ap, void *);
#endif
			base = 16;
			goto number;

		// (unsigned) hexadecimal
		case 'x':
			num = getuint(ap, lflag);
			base = 16;
		number:
			printnum(_fputch, f, putdat, num, base, width, padc);
			break;

                // escape character
                case '^':
                        (*_fputch) (f, 0x1b, putdat);
                        break;

		// escaped '%' character
		case '%':
			(*_fputch) (f, ch, putdat);
			break;
			
		// unrecognized escape sequence - just print it literally
		default:
			(*_fputch) (f, '%', putdat);
			for (fmt--; fmt[-1] != '%'; fmt--)
				/* do nothing */;
			break;
		}
	}
}

void
fprintfmt(void (*_fputch)(void *, int, void *), void * f, void * putdat,
			   const char * fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	vfprintfmt(_fputch, f, putdat, fmt, &ap);
	va_end(ap);
}

struct sprintbuf {
    char * buf;
    char * ebuf;
    int cnt;
};

static void
sprintputch(void * f, int ch, struct sprintbuf * b)
{
    b->cnt++;
    if (b->buf < b->ebuf)
        *b->buf++ = ch;
}

static int
vsprintf(char * buf, int n, const char * fmt, va_list *ap)
{
    struct sprintbuf b = {buf, buf + n - 1, 0};

    if (buf == NULL || n < 1) {
        return -1;
    }

    // print the string to the buffer
    vfprintfmt((void *) sprintputch, (void *) 0, &b, fmt, ap);

    // null terminate the buffer
    *b.buf = '\0';

    return b.cnt;
}

int
snprintf(char * buf, int n, const char * fmt, ...)
{
    va_list ap;
    int rc;

    va_start(ap, fmt);
    rc = vsprintf(buf, n, fmt, &ap);
    va_end(ap);

    return rc;
}