text: /*
   * Copyright (c) 1997 - 2000, 2002 Kungliga Tekniska Högskolan
   * (Royal Institute of Technology, Stockholm, Sweden).
   * All rights reserved.
   *
   * 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. Neither the name of the Institute nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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 "krb5_locl.h"
  #include "store-int.h"
  
  typedef struct mem_storage{
      unsigned char *base;
      size_t size;
      unsigned char *ptr;
  }mem_storage;
  
  static ssize_t
  mem_fetch(krb5_storage *sp, void *data, size_t size)
  {
      mem_storage *s = (mem_storage*)sp->data;
      if(size > s->base + s->size - s->ptr)
  	size = s->base + s->size - s->ptr;
      memmove(data, s->ptr, size);
      sp->seek(sp, size, SEEK_CUR);
      return size;
  }
  
  static ssize_t
  mem_store(krb5_storage *sp, const void *data, size_t size)
  {
      mem_storage *s = (mem_storage*)sp->data;
      if(size > s->base + s->size - s->ptr)
  	size = s->base + s->size - s->ptr;
      memmove(s->ptr, data, size);
      sp->seek(sp, size, SEEK_CUR);
      return size;
  }
  
  static ssize_t
  mem_no_store(krb5_storage *sp, const void *data, size_t size)
  {
      return -1;
  }
  
  static off_t
  mem_seek(krb5_storage *sp, off_t offset, int whence)
  {
      mem_storage *s = (mem_storage*)sp->data;
      switch(whence){
      case SEEK_SET:
  	if(offset > s->size)
  	    offset = s->size;
  	if(offset < 0)
  	    offset = 0;
  	s->ptr = s->base + offset;
  	break;
      case SEEK_CUR:
  	return sp->seek(sp, s->ptr - s->base + offset, SEEK_SET);
      case SEEK_END:
  	return sp->seek(sp, s->size + offset, SEEK_SET);
      default:
  	errno = EINVAL;
  	return -1;
      }
      return s->ptr - s->base;
  }
  
  static int
  mem_trunc(krb5_storage *sp, off_t offset)
  {
      mem_storage *s = (mem_storage*)sp->data;
      if(offset > s->size)
  	return ERANGE;
      s->size = offset;
      if ((s->ptr - s->base) > offset)
  	s->ptr = s->base + offset;
      return 0;
  }
  
  static int
  mem_no_trunc(krb5_storage *sp, off_t offset)
  {
      return EINVAL;
  }
  
  /**
   * Create a fixed size memory storage block
   *
   * @return A krb5_storage on success, or NULL on out of memory error.
   *
   * @ingroup krb5_storage
   *
   * @sa krb5_storage_mem()
   * @sa krb5_storage_from_readonly_mem()
   * @sa krb5_storage_from_data()
   * @sa krb5_storage_from_fd()
   */
  
  KRB5_LIB_FUNCTION krb5_storage * KRB5_LIB_CALL
  krb5_storage_from_mem(void *buf, size_t len)
  {
      krb5_storage *sp = malloc(sizeof(krb5_storage));
      mem_storage *s;
      if(sp == NULL)
  	return NULL;
      s = malloc(sizeof(*s));
      if(s == NULL) {
  	free(sp);
  	return NULL;
      }
      sp->data = s;
      sp->flags = 0;
      sp->eof_code = HEIM_ERR_EOF;
      s->base = buf;
      s->size = len;
      s->ptr = buf;
      sp->fetch = mem_fetch;
      sp->store = mem_store;
      sp->seek = mem_seek;
      sp->trunc = mem_trunc;
      sp->free = NULL;
      return sp;
  }
  
  /**
   * Create a fixed size memory storage block
   *
   * @return A krb5_storage on success, or NULL on out of memory error.
   *
   * @ingroup krb5_storage
   *
   * @sa krb5_storage_mem()
   * @sa krb5_storage_from_mem()
   * @sa krb5_storage_from_readonly_mem()
   * @sa krb5_storage_from_fd()
   */
  
  KRB5_LIB_FUNCTION krb5_storage * KRB5_LIB_CALL
  krb5_storage_from_data(krb5_data *data)
  {
      return krb5_storage_from_mem(data->data, data->length);
  }
  
  /**
   * Create a fixed size memory storage block that is read only
   *
   * @return A krb5_storage on success, or NULL on out of memory error.
   *
   * @ingroup krb5_storage
   *
   * @sa krb5_storage_mem()
   * @sa krb5_storage_from_mem()
   * @sa krb5_storage_from_data()
   * @sa krb5_storage_from_fd()
   */
  
  KRB5_LIB_FUNCTION krb5_storage * KRB5_LIB_CALL
  krb5_storage_from_readonly_mem(const void *buf, size_t len)
  {
      krb5_storage *sp = malloc(sizeof(krb5_storage));
      mem_storage *s;
      if(sp == NULL)
  	return NULL;
      s = malloc(sizeof(*s));
      if(s == NULL) {
  	free(sp);
  	return NULL;
      }
      sp->data = s;
      sp->flags = 0;
      sp->eof_code = HEIM_ERR_EOF;
      s->base = rk_UNCONST(buf);
      s->size = len;
      s->ptr = rk_UNCONST(buf);
      sp->fetch = mem_fetch;
      sp->store = mem_no_store;
      sp->seek = mem_seek;
      sp->trunc = mem_no_trunc;
      sp->free = NULL;
      return sp;
  }
  