/* 
 * xbuffer code
 *
 * Includes a minimalistic replacement for xine_buffer functions used in
 * Real streaming code. Only function needed by this code are implemented.
 *
 * Most code comes from xine_buffer.c Copyright (C) 2002 the xine project
 *
 * WARNING: do not mix original xine_buffer functions with this code!
 * xbuffers behave like xine_buffers, but are not byte-compatible with them.
 * You must take care of pointers returned by xbuffers functions (no macro to
 * do it automatically)
 *
 */

#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include "xbuffer.h"


typedef struct {
  uint32_t size;
  uint32_t chunk_size;
} xbuffer_header_t;

#define XBUFFER_HEADER_SIZE sizeof (xbuffer_header_t)



void *xbuffer_init(int chunk_size) {  
  uint8_t *data=calloc(1,chunk_size+XBUFFER_HEADER_SIZE);

  xbuffer_header_t *header=(xbuffer_header_t*)data;

  header->size=chunk_size;
  header->chunk_size=chunk_size;

  return data+XBUFFER_HEADER_SIZE;
}



void *xbuffer_free(void *buf) {
  if (!buf) {
    return NULL;
  }

  free(((uint8_t*)buf)-XBUFFER_HEADER_SIZE);

  return NULL;
}



void *xbuffer_copyin(void *buf, int index, const void *data, int len) {
    if (!buf || !data) {
    return NULL;
  }

  buf = xbuffer_ensure_size(buf, index+len);
  memcpy(((uint8_t*)buf)+index, data, len);

  return buf;
}



void *xbuffer_ensure_size(void *buf, int size) {
  xbuffer_header_t *xbuf;
  int new_size;

  if (!buf) {
    return 0;
  }

  xbuf = ((xbuffer_header_t*)(((uint8_t*)buf)-XBUFFER_HEADER_SIZE));
  
  if (xbuf->size < size) {
    new_size = size + xbuf->chunk_size - (size % xbuf->chunk_size);
    xbuf->size = new_size;
    buf = ((uint8_t*)realloc(((uint8_t*)buf)-XBUFFER_HEADER_SIZE,
          new_size+XBUFFER_HEADER_SIZE)) + XBUFFER_HEADER_SIZE;
  }

  return buf;
}



void *xbuffer_strcat(void *buf, char *data) {

  if (!buf || !data) {
    return NULL;
  }

  buf = xbuffer_ensure_size(buf, strlen(buf)+strlen(data)+1);

  strcat(buf, data);

  return buf;
}
