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[disorder] / lib / sink.h

/*
 * This file is part of DisOrder
 * Copyright (C) 2004, 2007, 2008 Richard Kettlewell
 *
 * This program 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 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */
/** @file lib/sink.h
 * @brief Abstract output sink type
 */

#ifndef SINK_H
#define SINK_H

#include <stdarg.h>

struct dynstr;

/** @brief Sink type
 *
 * A sink is something you write bytes to; the opposite would be a
 * source.  We provide sink_stdio() and sink_dynstr() to create sinks
 * to write to stdio streams and dynamic strings.
 */
struct sink {
  /** @brief Write callback
   * @param s Sink to write to
   * @param buffer First byte to write
   * @param nbytes Number of bytes to write
   * @return non-negative on success, -1 on error
   */
  int (*write)(struct sink *s, const void *buffer, int nbytes);
};

struct sink *sink_stdio(const char *name, FILE *fp);
/* return a sink which writes to @fp@.  If @name@ is not a null
 * pointer, it will be used in (fatal) error messages; if it is a null
 * pointer then errors will be signalled by returning -1. */

struct sink *sink_dynstr(struct dynstr *output);
/* return a sink which appends to @output@. */

struct sink *sink_discard(void);
/* return a sink which junks everything */

struct sink *sink_error(void);
/* return a sink which fails all writes */

int sink_vprintf(struct sink *s, const char *fmt, va_list ap);
int sink_printf(struct sink *s, const char *fmt, ...)
  attribute((format (printf, 2, 3)));
/* equivalent of vfprintf/fprintf for sink @s@ */

/** @brief Write bytes to a sink
 * @param s Sink to write to
 * @param buffer First byte to write
 * @param nbytes Number of bytes to write
 * @return non-negative on success, -1 on error
 */
static inline int sink_write(struct sink *s, const void *buffer, int nbytes) {
  return s->write(s, buffer, nbytes);
}

/** @brief Write string to a sink
 * @param s Sink to write to
 * @param str String to write
 * @return non-negative on success, -1 on error
 */
static inline int sink_writes(struct sink *s, const char *str) {
  return s->write(s, str, strlen(str));
}

/** @brief Write one byte to a sink
 * @param s Sink to write to
 * @param c Byte to write (as a @c char)
 * @return non-negative on success, -1 on error
 */
static inline int sink_writec(struct sink *s, char c) {
  return s->write(s, &c, 1);
}

#endif /* SINK_H */


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