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/* Input handling for G++.
Copyright (C) 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
This file is part of GNU CC.
GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* G++ needs to do enough saving and re-parsing of text that it is
necessary to abandon the simple FILE* model and use a mechanism where
we can pre-empt one input stream with another derived from saved text;
we may need to do this arbitrarily often, and cannot depend on having
the GNU library available, so FILE objects just don't cut it.
This file is written as a separate module, but can be included by
lex.c for very minor efficiency gains (primarily in function
inlining). */
#include <stdio.h>
extern FILE *finput;
struct input_source {
/* saved string */
char *str;
int length;
/* current position, when reading as input */
int offset;
/* linked list maintenance */
struct input_source *next;
/* values to restore after reading all of current string */
char *filename;
int lineno;
struct pending_input *input;
int putback_char;
};
static struct input_source *input, *free_inputs;
extern char *input_filename;
extern int lineno;
#ifdef __GNUC__
#define inline __inline__
#else
#define inline
#endif
extern void feed_input PROTO((char *, int));
extern void put_input PROTO((int));
extern void put_back PROTO((int));
extern int getch PROTO((void));
extern int input_redirected PROTO((void));
static inline struct input_source * allocate_input PROTO((void));
static inline void free_input PROTO((struct input_source *));
static inline void end_input PROTO((void));
static inline int sub_getch PROTO((void));
static inline struct input_source *
allocate_input ()
{
struct input_source *inp;
if (free_inputs)
{
inp = free_inputs;
free_inputs = inp->next;
inp->next = 0;
return inp;
}
inp = (struct input_source *) xmalloc (sizeof (struct input_source));
inp->next = 0;
return inp;
}
static inline void
free_input (inp)
struct input_source *inp;
{
inp->str = 0;
inp->length = 0;
inp->next = free_inputs;
free_inputs = inp;
}
static int putback_char = -1;
/* Some of these external functions are declared inline in case this file
is included in lex.c. */
inline
void
feed_input (str, len)
char *str;
int len;
{
struct input_source *inp = allocate_input ();
/* This shouldn't be necessary. */
while (len && !str[len-1])
len--;
inp->str = str;
inp->length = len;
inp->offset = 0;
inp->next = input;
inp->filename = input_filename;
inp->lineno = lineno;
inp->input = save_pending_input ();
inp->putback_char = putback_char;
putback_char = -1;
input = inp;
}
struct pending_input *to_be_restored; /* XXX */
extern int end_of_file;
static inline void
end_input ()
{
struct input_source *inp = input;
end_of_file = 0;
input = inp->next;
input_filename = inp->filename;
lineno = inp->lineno;
/* Get interface/implementation back in sync. */
extract_interface_info ();
putback_char = inp->putback_char;
restore_pending_input (inp->input);
free_input (inp);
}
static inline int
sub_getch ()
{
if (putback_char != -1)
{
int ch = putback_char;
putback_char = -1;
return ch;
}
if (input)
{
if (input->offset >= input->length)
{
my_friendly_assert (putback_char == -1, 223);
++(input->offset);
if (input->offset - input->length < 64)
return EOF;
/* We must be stuck in an error-handling rule; give up. */
end_input ();
return getch ();
}
return (unsigned char)input->str[input->offset++];
}
return getc (finput);
}
inline
void
put_back (ch)
int ch;
{
if (ch != EOF)
{
my_friendly_assert (putback_char == -1, 224);
putback_char = ch;
}
}
extern int linemode;
int
getch ()
{
int ch = sub_getch ();
if (linemode && ch == '\n')
{
put_back (ch);
ch = EOF;
}
return ch;
}
inline
int
input_redirected ()
{
return input != 0;
}
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