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/* Input handling for G++.
Copyright (C) 1992, 93, 94, 95, 96, 97, 98, 99, 2000
Free Software Foundation, Inc.
Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
Enhanced by Michael Tiemann (tiemann@cygnus.com) to better support USE_CPPLIB
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 "system.h"
#if !USE_CPPLIB
struct putback_buffer {
char *buffer;
int buffer_size;
int index;
};
static struct putback_buffer putback = {NULL, 0, -1};
#endif
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 */
struct pending_input *input;
#if !USE_CPPLIB
char *filename;
int lineno;
struct putback_buffer putback;
#endif
};
static struct input_source *input, *free_inputs;
extern char *input_filename;
extern int lineno;
#if USE_CPPLIB
extern unsigned char *yy_cur, *yy_lim;
extern int yy_get_token ();
#endif
extern void feed_input PARAMS ((char *, int, char *, int));
extern void put_input PARAMS ((int));
extern void put_back PARAMS ((int));
extern int getch PARAMS ((void));
extern int input_redirected PARAMS ((void));
static inline struct input_source * allocate_input PARAMS ((void));
static inline void free_input PARAMS ((struct input_source *));
static inline void end_input PARAMS ((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;
}
/* Some of these external functions are declared inline in case this file
is included in lex.c. */
inline
void
feed_input (str, len, file, line)
char *str;
int len;
char *file;
int line;
{
struct input_source *inp = allocate_input ();
/* This shouldn't be necessary. */
while (len && !str[len-1])
len--;
#if USE_CPPLIB
if (yy_lim > yy_cur)
/* If we've started reading the next token, we're hosed. The
token_getch stuff is supposed to prevent this from happening. */
my_friendly_abort (990710);
cpp_push_buffer (&parse_in, str, len);
CPP_BUFFER (&parse_in)->manual_pop = 1;
CPP_BUFFER (&parse_in)->nominal_fname
= CPP_BUFFER (&parse_in)->fname = file;
CPP_BUFFER (&parse_in)->lineno = parse_in.lineno = line;
#else
inp->str = str;
inp->length = len;
inp->offset = 0;
inp->putback = putback;
inp->filename = input_filename;
inp->lineno = lineno;
putback.buffer = NULL;
putback.buffer_size = 0;
putback.index = -1;
#endif
inp->next = input;
inp->input = save_pending_input ();
input = inp;
lineno = line;
input_filename = file;
}
extern int end_of_file;
static inline void
end_input ()
{
struct input_source *inp = input;
#if USE_CPPLIB
cpp_pop_buffer (&parse_in);
#else
putback = inp->putback;
input_filename = inp->filename;
lineno = inp->lineno;
#endif
end_of_file = 0;
input = inp->next;
/* Get interface/implementation back in sync. */
extract_interface_info ();
restore_pending_input (inp->input);
free_input (inp);
}
inline int
getch ()
{
#if USE_CPPLIB
return (yy_cur < yy_lim ? *yy_cur++ : yy_get_token ());
#else
if (putback.index != -1)
{
int ch = putback.buffer[putback.index];
--putback.index;
return ch;
}
if (input)
{
if (input->offset >= input->length)
{
my_friendly_assert (putback.index == -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);
#endif
}
inline
void
put_back (ch)
int ch;
{
#if USE_CPPLIB
if (ch == EOF)
;
else if (yy_cur[-1] != ch)
my_friendly_abort (990709);
else
yy_cur--;
#else
if (ch != EOF)
{
if (putback.index == putback.buffer_size - 1)
{
putback.buffer_size += 16;
putback.buffer = xrealloc (putback.buffer, putback.buffer_size);
}
my_friendly_assert (putback.buffer != NULL, 224);
putback.buffer[++putback.index] = ch;
}
#endif
}
inline
int
input_redirected ()
{
#ifdef USE_CPPLIB
return CPP_BUFFER(&parse_in)->manual_pop;
#else
return input != 0;
#endif
}
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