lib/libc/stdio/vfscanf.c

/******************************************************************************
 * Copyright (c) 2004, 2007 IBM Corporation
 * All rights reserved.
 * This program and the accompanying materials
 * are made available under the terms of the BSD License
 * which accompanies this distribution, and is available at
 * http://www.opensource.org/licenses/bsd-license.php
 *
 * Contributors:
 *     IBM Corporation - initial implementation
 *****************************************************************************/

#include "string.h"
#include "ctype.h"
#include "stdlib.h"
#include "stdio.h"
#include "unistd.h"


static int
_getc(FILE *stream)
{
	int count;
	char c;

	if (stream->mode == _IONBF || stream->buf == NULL) {
		if (read(stream->fd,&c,1) == 1)
			return (int)c;
		else
			return EOF;
	}

	if (stream->pos == 0 || stream->pos >= BUFSIZ ||
	   stream->buf[stream->pos] == '\0') {
		count = read(stream->fd, stream->buf, BUFSIZ);
		if (count < 0)
			count = 0;
		if (count < BUFSIZ)
			stream->buf[count] = '\0';
		stream->pos = 0;
	}

	return stream->buf[stream->pos++];
}

static void
_ungetc(int ch, FILE *stream)
{
	if(stream->mode != _IONBF && stream->pos > 0)
		stream->pos--;
}

static int
_is_voidage(int ch)
{
	if(ch == ' ' || ch == '\t' || ch == '\n' || ch == '\0')
		return 1;
	else
		return 0;
}


static int
_scanf(FILE *stream, const char *fmt, va_list *ap)
{
	int i=0;
	int length = 0;

	fmt++;	

	while(*fmt != '\0') {
		
		char tbuf[256];
		char ch;

		switch(*fmt) {
			case 'd':
			case 'i':
				ch = _getc(stream);
				if(length == 0) {
					while(!_is_voidage(ch) && isdigit(ch)) {
						tbuf[i] = ch;
						ch = _getc(stream);
						i++;
					}
				} else {
					while(!_is_voidage(ch) && i < length && isdigit(ch)) {
						tbuf[i] = ch;
						ch = _getc(stream);
						i++;
					}
				}
				_ungetc(ch, stream);
				tbuf[i] = '\0';
				
				ch = _getc(stream);
				if(!_is_voidage(ch))
					_ungetc(ch, stream);
				
				if(strlen(tbuf) == 0)
					return 0;
				
				*(va_arg(*ap, int *)) = strtol(tbuf, NULL, 10);
				break;
			case 'X':
			case 'x':
				ch = _getc(stream);
				if(length == 0) {
					while(!_is_voidage(ch) && isxdigit(ch)) {
						tbuf[i] = ch;
						ch = _getc(stream);
						i++;
					}
				} else {
					while(!_is_voidage(ch) && i < length && isxdigit(ch)) {
						tbuf[i] = ch;
						ch = _getc(stream);
						i++;
					}
				}
				_ungetc(ch, stream);
				tbuf[i] = '\0';
				
				ch = _getc(stream);
				if(!_is_voidage(ch))
					_ungetc(ch, stream);
				
				if(strlen(tbuf) == 0)
					return 0;

				*(va_arg(*ap, int *)) = strtol(tbuf, NULL, 16);
				break;
			case 'O':
			case 'o':
				ch = _getc(stream);
				if(length == 0) {
					while(!_is_voidage(ch) && !(ch < '0' || ch > '7')) {
						tbuf[i] = ch;
						ch = _getc(stream);
						i++;
					}
				} else {
					while(!_is_voidage(ch) && i < length && !(ch < '0' || ch > '7')) {
						tbuf[i] = ch;
						ch = _getc(stream);
						i++;
					}
				}
				_ungetc(ch, stream);
				tbuf[i] = '\0';
				
				ch = _getc(stream);
				if(!_is_voidage(ch))
					_ungetc(ch, stream);

				if(strlen(tbuf) == 0)
					return 0;

				*(va_arg(*ap, int *)) = strtol(tbuf, NULL, 8);
				break;
			case 'c':
				ch = _getc(stream);
				while(_is_voidage(ch))
					ch = _getc(stream);
				
				*(va_arg(*ap, char *)) = ch;
				
				ch = _getc(stream);
				if(!_is_voidage(ch))
					_ungetc(ch, stream);

				break;
			case 's':
				ch = _getc(stream);
				if(length == 0) {
					while(!_is_voidage(ch)) {
						tbuf[i] = ch;
						ch = _getc(stream);
						i++;
					}
				} else {
					while(!_is_voidage(ch) && i < length) {
						tbuf[i] = ch;
						ch = _getc(stream);
						i++;
					}
				}
				_ungetc(ch, stream);
				tbuf[i] = '\0';
				
				ch = _getc(stream);
				if(!_is_voidage(ch))
					_ungetc(ch, stream);

				strcpy(va_arg(*ap, char *), tbuf);
				break;
			default:
				if(*fmt >= '0' && *fmt <= '9') 
					length += *fmt - '0';
				break;
		}
		fmt++;
	}

	return 1;
}



int
vfscanf(FILE *stream, const char *fmt, va_list ap)
{
	int args = 0;

	while(*fmt != '\0') {
		
		if(*fmt == '%') {
			
			char formstr[20];
			int i=0;
			
			do {
				formstr[i] = *fmt;
				fmt++;
				i++;
			} while(!(*fmt == 'd' || *fmt == 'i' || *fmt == 'x' || *fmt == 'X'
				  || *fmt == 'p' || *fmt == 'c' || *fmt == 's' || *fmt == '%'
				  || *fmt == 'O' || *fmt == 'o' )); 
			formstr[i++] = *fmt;
			formstr[i] = '\0';
			if(*fmt != '%') {
				if(_scanf(stream, formstr, &ap) <= 0)
					return args;
				else
					args++;
			}

		} 

		fmt++;

	}

	return args;
}

int getc(FILE *stream)
{
	return _getc(stream);
}

int getchar(void)
{
	return _getc(stdin);
}