tools/dtdesc/c_iff/readchunkheader.c

   1 /*
   2  *  c_iff - a portable IFF-parser
   3  *
   4  *  Copyright (C) 2000, 2001 Joerg Dietrich
   5  *
   6  *  This is the AROS-version of c_iff.
   7  *  It is distributed under the AROS Public License.
   8  *  But I reserve the right to distribute
   9  *  my own version under other licenses.
  10  */
  11
  12 /*
  13  *  readchunkheader.c - read the header of the actual chunk
  14  */
  15
  16 #include "c_iff.h"
  17
  18 /****** c_iff/ReadChunkHeader ***********************************************
  19 *
  20 *   NAME
  21 *       ReadChunkHeader -- Read the header of the current chunk
  22 *
  23 *   SYNOPSIS
  24 *       Success = ReadChunkData( TheHandle )
  25 *
  26 *       int ReadChunkData( struct IFFHandle * )
  27 *
  28 *   FUNCTION
  29 *       Reads the header of the current chunk. Fills out TheHandle->ChunkID.
  30 *       TheHandle->BytesLeftInChunk contains the size of the entire chunk.
  31 *
  32 *   INPUTS
  33 *       TheHandle   - IFFHandle to read from
  34 *
  35 *   RESULT
  36 *       Success     - TRUE when the header was successfully read
  37 *                     otherwise FALSE
  38 *
  39 *   EXAMPLE
  40 *
  41 *   NOTES
  42 *       Attention!! Chunks are stored WORD-aligned. This means, when
  43 *       chunksize is odd one padding-byte is appended.
  44 *       TheHandle->BytesLeftInChunk shows the even size with the pad.
  45 *       The previous chunk must have read completely!
  46 *
  47 *   BUGS
  48 *
  49 *   SEE ALSO
  50 *
  51 *****************************************************************************
  52 *
  53 *       Private notes:
  54 */
  55
  56 int ReadChunkHeader(struct IFFHandle *TheHandle)
  57 {
  58  uint32_t Buffer[2];
  59
  60  if(!TheHandle)
  61  {
  62   return(FALSE);
  63  }
  64
  65  if(!(fread((void *) Buffer, sizeof(uint32_t), 2, TheHandle->TheFile)==2))
  66  {
  67   return(FALSE);
  68  }
  69
  70  Buffer[0]=Swap32IfLE(Buffer[0]);
  71  Buffer[1]=Swap32IfLE(Buffer[1]);
  72
  73  TheHandle->ChunkID=Buffer[0];
  74  TheHandle->BytesLeftInChunk=(((Buffer[1]+1)>>1)<<1);
  75
  76  return(TRUE);
  77 }
  78
  79