kc3-lang/libbsd/src/funopen.c

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• Hash : e5089628
  Author :
  Date : 2022-11-23T23:31:54
  

  build: Do not require funopen() to be ported
  
  This function cannot be easily and (more importantly) correctly ported
  without cooperation from the libc stdio layer. We already document that
  users should be prepared to have the function not available on some
  platforms and that they should ideally switch their code to other
  more portable and better interfaces.
  
  Instead of making the build fail, and requiring porters to add
  exceptions for something that most probably cannot be ported correctly
  anyway, simply print a warning and let it build. This will not be a
  regression because on those systems libbsd would have never been built
  before.
  
  Prompted-by: Jens Finkhaeuser <jens@finkhaeuser.de>
  

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• src/funopen.c

• /*
   * Copyright © 2011, 2013, 2017, 2020 Guillem Jover
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. The name of the author may not be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
   * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
   * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
   * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
   * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include <sys/cdefs.h>
  #include <sys/types.h>
  #include <errno.h>
  #include <stdlib.h>
  #include <stdio.h>
  
  #ifdef HAVE_FOPENCOOKIE
  struct funopen_cookie {
  	void *orig_cookie;
  
  	int (*readfn)(void *cookie, char *buf, int size);
  	int (*writefn)(void *cookie, const char *buf, int size);
  	off_t (*seekfn)(void *cookie, off_t offset, int whence);
  	int (*closefn)(void *cookie);
  };
  
  static ssize_t
  funopen_read(void *cookie, char *buf, size_t size)
  {
  	struct funopen_cookie *cookiewrap = cookie;
  
  	if (cookiewrap->readfn == NULL) {
  		errno = EBADF;
  		return -1;
  	}
  
  	return cookiewrap->readfn(cookiewrap->orig_cookie, buf, size);
  }
  
  static ssize_t
  funopen_write(void *cookie, const char *buf, size_t size)
  {
  	struct funopen_cookie *cookiewrap = cookie;
  
  	if (cookiewrap->writefn == NULL)
  		return EOF;
  
  	return cookiewrap->writefn(cookiewrap->orig_cookie, buf, size);
  }
  
  static int
  funopen_seek(void *cookie, off64_t *offset, int whence)
  {
  	struct funopen_cookie *cookiewrap = cookie;
  	off_t soff = *offset;
  
  	if (cookiewrap->seekfn == NULL) {
  		errno = ESPIPE;
  		return -1;
  	}
  
  	soff = cookiewrap->seekfn(cookiewrap->orig_cookie, soff, whence);
  	*offset = soff;
  
  	return *offset;
  }
  
  static int
  funopen_close(void *cookie)
  {
  	struct funopen_cookie *cookiewrap = cookie;
  	int rc;
  
  	if (cookiewrap->closefn)
  		rc = cookiewrap->closefn(cookiewrap->orig_cookie);
  	else
  		rc = 0;
  
  	free(cookiewrap);
  
  	return rc;
  }
  
  FILE *
  funopen(const void *cookie,
          int (*readfn)(void *cookie, char *buf, int size),
          int (*writefn)(void *cookie, const char *buf, int size),
          off_t (*seekfn)(void *cookie, off_t offset, int whence),
          int (*closefn)(void *cookie))
  {
  	struct funopen_cookie *cookiewrap;
  	cookie_io_functions_t funcswrap = {
  		.read = funopen_read,
  		.write = funopen_write,
  		.seek = funopen_seek,
  		.close = funopen_close,
  	};
  	const char *mode;
  
  	if (readfn) {
  		if (writefn == NULL)
  			mode = "r";
  		else
  			mode = "r+";
  	} else if (writefn) {
  		mode = "w";
  	} else {
  		errno = EINVAL;
  		return NULL;
  	}
  
  	cookiewrap = malloc(sizeof(*cookiewrap));
  	if (cookiewrap == NULL)
  		return NULL;
  
  	cookiewrap->orig_cookie = (void *)cookie;
  	cookiewrap->readfn = readfn;
  	cookiewrap->writefn = writefn;
  	cookiewrap->seekfn = seekfn;
  	cookiewrap->closefn = closefn;
  
  	return fopencookie(cookiewrap, mode, funcswrap);
  }
  #else
  #warning "Function funopen() is not provided on this platform."
  #endif
  

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