compiler/arossupport/readfloat.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Read a big endian floating point (32bit) from a streamhook
   6     Lang: english
   7 */
   8
   9 #include <proto/dos.h>
  10
  11 /******************************************************************************
  12
  13     NAME */
  14 #include <stdio.h>
  15 #include <aros/bigendianio.h>
  16 #include <proto/alib.h>
  17
  18         BOOL ReadFloat (
  19
  20 /*  SYNOPSIS */
  21         struct Hook * hook,
  22         FLOAT       * dataptr,
  23         void        * stream)
  24
  25 /*  FUNCTION
  26         Reads one big endian 32bit floating point value from a streamhook.
  27
  28     INPUTS
  29         hook - Streamhook
  30         dataptr - Put the data here
  31         stream - Read from this stream
  32
  33     RESULT
  34         The function returns TRUE on success. On success, the value
  35         read is written into dataptr. On failure, FALSE is returned and the
  36         contents of dataptr are not changed.
  37
  38     NOTES
  39         This function reads big endian values from a streamhook even on
  40         little endian machines.
  41
  42     EXAMPLE
  43
  44     BUGS
  45
  46     SEE ALSO
  47         ReadByte(), ReadWord(), ReadLong(), ReadFloat(), ReadDouble(),
  48         ReadString(), ReadStruct(), WriteByte(), WriteWord(), WriteLong(),
  49         WriteFloat(), WriteDouble(), WriteString(), WriteStruct()
  50
  51     HISTORY
  52         14.09.93    ada created
  53
  54 ******************************************************************************/
  55 {
  56     union
  57     {
  58         ULONG   ulong_val;
  59         float   float_val;
  60     } value;
  61     LONG    c;
  62     UBYTE * ptr;
  63
  64     struct BEIOM_Read rd = {BEIO_READ};
  65
  66 #if AROS_BIG_ENDIAN
  67     ptr = (UBYTE *)&value;
  68 #   define NEXT ++
  69 #else
  70     ptr = ((UBYTE *)&value) + 3;
  71 #   define NEXT --
  72 #endif
  73
  74 #define READ_ONE_BYTE               \
  75     if ((c = CallHookA (hook, stream, &rd)) == EOF) \
  76         return FALSE;               \
  77                                     \
  78     *ptr NEXT = c
  79
  80     READ_ONE_BYTE;
  81     READ_ONE_BYTE;
  82     READ_ONE_BYTE;
  83     READ_ONE_BYTE;
  84
  85     *dataptr = value.float_val;
  86
  87     return TRUE;
  88 } /* ReadFloat */
  89