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/* A string or file based input stream.
Copyright (C) 2024 Free Software Foundation, Inc.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
This file 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Bruno Haible <bruno@clisp.org>, 2024. */
#ifndef _SF_ISTREAM_H
#define _SF_ISTREAM_H
#include <stdio.h>
#include "string-desc.h"
/* An input stream type that can read from a file or from a string. */
typedef struct sf_istream sf_istream_t;
struct sf_istream
{
/* The input file stream, when reading from a file. */
FILE *fp;
/* The input area, when reading from a string. */
const char *input;
const char *input_end;
};
#ifdef __cplusplus
extern "C" {
#endif
/* Initializes STREAM to read from FP.
FP must be a FILE stream open for reading. */
extern void sf_istream_init_from_file (sf_istream_t *stream, FILE *fp);
/* Initializes STREAM to read from a NUL-terminated string INPUT.
The contents of INPUT must stay available and unchanged as long as STREAM
is in use. */
extern void sf_istream_init_from_string (sf_istream_t *stream,
const char *input);
/* Initializes STREAM to read from a string INPUT.
The contents of INPUT must stay available and unchanged as long as STREAM
is in use. Operations on STREAM will not modify the contents of INPUT. */
extern void sf_istream_init_from_string_desc (sf_istream_t *stream,
string_desc_t input);
/* Reads a single 'char' from STREAM, and returns it as an 'unsigned char'.
Returns EOF when the end of stream was already reached. */
extern int sf_getc (sf_istream_t *stream);
/* Tests whether STREAM has encountered an error.
You may want to call this function after sf_getc (stream) has
returned EOF; in other situations it is guaranteed to return 0. */
extern int sf_ferror (sf_istream_t *stream);
/* Assuming that C was the last value returned by sf_getc (stream),
this call pushes back C onto the stream.
Only 1 character of pushback is guaranteed. */
extern void sf_ungetc (sf_istream_t *stream, int c);
/* Frees all memory held by STREAM.
This call has no effect on the arguments provided to sf_istream_init_*. */
extern void sf_free (sf_istream_t *stream);
#ifdef __cplusplus
}
#endif
#endif /* _SF_ISTREAM_H */
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