/*

 * Copyright (C) 2007, 2012 Stefan Walter

 * Copyright (C) 2013 Red Hat Inc.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 *     * Redistributions of source code must retain the above

 *       copyright notice, this list of conditions and the

 *       following disclaimer.

 *     * 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.

 *     * The names of contributors to this software may not be

 *       used to endorse or promote products derived from this

 *       software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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

 * COPYRIGHT OWNER 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.

 *

 * Author: Stef Walter <stef@thewalter.net>

 */

#include "config.h"

#include "buffer.h"

#include "debug.h"

#include <assert.h>

#include <stdint.h>

#include <stdlib.h>

#include <string.h>

#include <stdarg.h>

static bool

buffer_realloc (p11_buffer *buffer,

                size_t size)

{

  void *data;

  /* Memory owned elsewhere can't be reallocated */

  return_val_if_fail (buffer->frealloc != NULL, false);

  /* Reallocate built in buffer using allocator */

  data = (buffer->frealloc) (buffer->data, size);

  if (!data && size > 0) {

    p11_buffer_fail (buffer);

    return_val_if_reached (false);

  }

  buffer->data = data;

  buffer->size = size;

  return true;

}

bool

p11_buffer_init (p11_buffer *buffer,

                 size_t reserve)

{

  p11_buffer_init_full (buffer, NULL, 0, 0, realloc, free);

  return buffer_realloc (buffer, reserve);

}

bool

p11_buffer_init_null (p11_buffer *buffer,

                      size_t reserve)

{

  p11_buffer_init_full (buffer, NULL, 0, P11_BUFFER_NULL, realloc, free);

  return buffer_realloc (buffer, reserve);

}

void

p11_buffer_init_full (p11_buffer *buffer,

                      void *data,

                      size_t len,

                      int flags,

                      void * (* frealloc) (void *, size_t),

                      void (* ffree) (void *))

{

  memset (buffer, 0, sizeof (*buffer));

  buffer->data = data;

  buffer->len = len;

  buffer->size = len;

  buffer->flags = flags;

  buffer->frealloc = frealloc;

  buffer->ffree = ffree;

  return_if_fail (!(flags & P11_BUFFER_FAILED));

}

void

p11_buffer_uninit (p11_buffer *buffer)

{

  return_if_fail (buffer != NULL);

  if (buffer->ffree && buffer->data)

    (buffer->ffree) (buffer->data);

  memset (buffer, 0, sizeof (*buffer));

}

void *

p11_buffer_steal (p11_buffer *buffer,

                  size_t *length)

{

  void *data;

  return_val_if_fail (p11_buffer_ok (buffer), NULL);

  if (length)

    *length = buffer->len;

  data = buffer->data;

  buffer->data = NULL;

  buffer->size = 0;

  buffer->len = 0;

  return data;

}

bool

p11_buffer_reset (p11_buffer *buffer,

                  size_t reserve)

{

  buffer->flags &= ~P11_BUFFER_FAILED;

  buffer->len = 0;

  if (reserve < buffer->size)

    return true;

  return buffer_realloc (buffer, reserve);

}

void *

p11_buffer_append (p11_buffer *buffer,

                   size_t length)

{

  unsigned char *data;

  size_t terminator;

  size_t newlen;

  size_t reserve;

  size_t offset;

  return_val_if_fail (p11_buffer_ok (buffer), NULL);

  terminator = (buffer->flags & P11_BUFFER_NULL) ? 1 : 0;

  /* Check for unlikely and unrecoverable integer overflow */

  return_val_if_fail (SIZE_MAX - (terminator + length) > buffer->len, NULL);

  reserve = terminator + length + buffer->len;

  if (reserve > buffer->size) {

    /* Calculate a new length, minimize number of buffer allocations */

    return_val_if_fail (buffer->size < SIZE_MAX / 2, NULL);

    newlen = buffer->size * 2;

    if (!newlen)

      newlen = 16;

    if (reserve > newlen)

      newlen = reserve;

    if (!buffer_realloc (buffer, newlen))

      return_val_if_reached (NULL);

  }

  data = buffer->data;

  offset = buffer->len;

  buffer->len += length;

  if (terminator)

    data[buffer->len] = '\0';

  return data + offset;

}

void

p11_buffer_add (p11_buffer *buffer,

                const void *data,

                ssize_t length)

{

  void *at;

  if (length < 0)

    length = strlen (data);

  at = p11_buffer_append (buffer, length);

  return_if_fail (at != NULL);

  memcpy (at, data, length);

}