/*
 * Copyright (C) 2000-2002 the xine project
 *
 All this code is stolen from xine <http://xinehq.de/> and is therefore
 covered by the GNU Licence <http://www.gnu.org/copyleft/gpl.html>

 This file contains the minimum necessary stuff from xine for the
 rtsp/real stuff to work.
*/

#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include <errno.h>
#include <xine.h>
#include "xineutils.h"
#include "xine_buffer.h"

void *xine_xmalloc(size_t size) {
  void *ptr;

  /* prevent xine_xmalloc(0) of possibly returning NULL */
  if( !size )
    size++;

  if((ptr = calloc(1, size)) == NULL) {
    fprintf(stderr, "malloc() failed: %s.\n",
            strerror(errno));
    return NULL;
  }

  return ptr;
}

typedef struct {

  uint32_t size;
  uint32_t chunk_size;

  uint8_t magic;

} xine_buffer_header_t;

#define XINE_BUFFER_HEADER_SIZE 9
#define XINE_BUFFER_MAGIC 42
#define GET_HEADER(x) ((xine_buffer_header_t*)(((uint8_t*)x)-XINE_BUFFER_HEADER_SIZE))
#define GROW_TO(buf, to_size) \
    if (GET_HEADER(buf)->size < (to_size)) { \
    int new_size = (to_size) + GET_HEADER(buf)->chunk_size - \
        ((to_size) % GET_HEADER(buf)->chunk_size);\
    \
    buf = ((uint8_t*)realloc(((uint8_t*)buf)-XINE_BUFFER_HEADER_SIZE, new_size+XINE_BUFFER_HEADER_SIZE)) + XINE_BUFFER_HEADER_SIZE;\
    GET_HEADER(buf)->size=new_size; }

void *xine_buffer_init(int chunk_size) {

  uint8_t *data=xine_xmalloc(chunk_size+XINE_BUFFER_HEADER_SIZE);
  xine_buffer_header_t *header=(xine_buffer_header_t*)data;

  header->size=chunk_size;
  header->chunk_size=chunk_size;
  header->magic=XINE_BUFFER_MAGIC;

  return data+XINE_BUFFER_HEADER_SIZE;
}

void *_xine_buffer_ensure_size(void *buf, int size) {
   if (!buf) return 0;
   GROW_TO(buf, size);
   return buf;
}

void *_xine_buffer_free(void *buf) {
   if (buf) free(((uint8_t*)buf)-XINE_BUFFER_HEADER_SIZE);
   return NULL;
}

void *_xine_buffer_copyin(void *buf, int index, const void *data, int len) {
   if (!buf || !data) return NULL;
   GROW_TO(buf, index+len);
   memcpy(((uint8_t*)buf)+index, data, len);
   return buf;
}