ref: ca9d65e40b3f78d2580fff9ff1844bad1be08673
dir: /sys/src/cmd/audio/mp3enc/portableio.c/
/* Copyright (C) 1988-1991 Apple Computer, Inc.
* All Rights Reserved.
*
* Warranty Information
* Even though Apple has reviewed this software, Apple makes no warranty
* or representation, either express or implied, with respect to this
* software, its quality, accuracy, merchantability, or fitness for a
* particular purpose. As a result, this software is provided "as is,"
* and you, its user, are assuming the entire risk as to its quality
* and accuracy.
*
* This code may be used and freely distributed as long as it includes
* this copyright notice and the warranty information.
*
*
* Motorola processors (Macintosh, Sun, Sparc, MIPS, etc)
* pack bytes from high to low (they are big-endian).
* Use the HighLow routines to match the native format
* of these machines.
*
* Intel-like machines (PCs, Sequent)
* pack bytes from low to high (the are little-endian).
* Use the LowHigh routines to match the native format
* of these machines.
*
* These routines have been tested on the following machines:
* Apple Macintosh, MPW 3.1 C compiler
* Apple Macintosh, THINK C compiler
* Silicon Graphics IRIS, MIPS compiler
* Cray X/MP and Y/MP
* Digital Equipment VAX
*
*
* Implemented by Malcolm Slaney and Ken Turkowski.
*
* Malcolm Slaney contributions during 1988-1990 include big- and little-
* endian file I/O, conversion to and from Motorola's extended 80-bit
* floating-point format, and conversions to and from IEEE single-
* precision floating-point format.
*
* In 1991, Ken Turkowski implemented the conversions to and from
* IEEE double-precision format, added more precision to the extended
* conversions, and accommodated conversions involving +/- infinity,
* NaN's, and denormalized numbers.
*
* $Id: portableio.c,v 1.11 2001/01/07 23:47:38 markt Exp $
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdio.h>
#if defined(__riscos__) && defined(FPA10)
#include "ymath.h"
#else
#include <math.h>
#endif
#include "portableio.h"
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif
/****************************************************************
* Big/little-endian independent I/O routines.
****************************************************************/
/*
* It is a hoax to call this code portable-IO:
*
* - It doesn't work on machines with CHAR_BIT != 8
* - it also don't test this error condition
* - otherwise it tries to handle CHAR_BIT != 8 by things like
* masking 'putc(i&0xff,fp)'
* - It doesn't handle EOF in any way
* - it only works with ints with 32 or more bits
* - It is a collection of initial buggy code with patching the known errors
* instead of CORRECTING them!
* For that see comments on the old Read16BitsHighLow()
*/
#ifdef KLEMM_36
signed int ReadByte ( FILE* fp )
{
int result = getc (fp);
return result == EOF ? 0 : (signed char) (result & 0xFF);
}
unsigned int ReadByteUnsigned ( FILE* fp )
{
int result = getc (fp);
return result == EOF ? 0 : (unsigned char) (result & 0xFF);
}
#else
int
ReadByte(FILE *fp)
{
int result;
result = getc(fp) & 0xff;
if (result & 0x80)
result = result - 0x100;
return result;
}
#endif
#ifdef KLEMM_36
int Read16BitsLowHigh ( FILE* fp )
{
int low = ReadByteUnsigned (fp);
int high = ReadByte (fp);
return (high << 8) | low;
}
#else
int
Read16BitsLowHigh(FILE *fp)
{
int first, second, result;
first = 0xff & getc(fp);
second = 0xff & getc(fp);
result = (second << 8) + first;
#ifndef THINK_C42
if (result & 0x8000)
result = result - 0x10000;
#endif /* THINK_C */
return(result);
}
#endif
#ifdef KLEMM_36
int Read16BitsHighLow ( FILE* fp )
{
int high = ReadByte (fp);
int low = ReadByteUnsigned (fp);
return (high << 8) | low;
}
#else
int
Read16BitsHighLow(FILE *fp)
{
int first, second, result;
/* Reads the High bits, the value is -128...127
* (which gave after upscaling the -32768...+32512
* Why this value is not converted to signed char?
*/
first = 0xff & getc(fp);
/* Reads the Lows bits, the value is 0...255
* This is correct. This value gives an additional offset
* for the High bits
*/
second = 0xff & getc(fp);
/* This is right */
result = (first << 8) + second;
/* Now we are starting to correct the nasty bug of the first instruction
* The value of the high bits is wrong. Always. So we must correct this
* value. This seems to be not necessary for THINK_C42. This is either
* a 16 bit compiler with 16 bit ints (where this bug is hidden and 0x10000
* is not in the scope of an int) or it is not a C compiler, but only a
* C like compiler. In the first case the '#ifndef THINK_C42' is wrong
* because it's not a property of the THINK_C42 compiler, but of all compilers
* with sizeof(int)*CHAR_BIT < 18.
* Another nasty thing is that the rest of the code doesn't work for 16 bit ints,
* so this patch don't solve the 16 bit problem.
*/
#ifndef THINK_C42
if (result & 0x8000)
result = result - 0x10000;
#endif /* THINK_C */
return(result);
}
#endif
void
Write8Bits(FILE *fp, int i)
{
putc(i&0xff,fp);
}
void
Write16BitsLowHigh(FILE *fp, int i)
{
putc(i&0xff,fp);
putc((i>>8)&0xff,fp);
}
void
Write16BitsHighLow(FILE *fp, int i)
{
putc((i>>8)&0xff,fp);
putc(i&0xff,fp);
}
#ifdef KLEMM_36
int Read24BitsHighLow ( FILE* fp )
{
int high = ReadByte (fp);
int med = ReadByteUnsigned (fp);
int low = ReadByteUnsigned (fp);
return (high << 16) | (med << 8) | low;
}
#else
int
Read24BitsHighLow(FILE *fp)
{
int first, second, third;
int result;
first = 0xff & getc(fp);
second = 0xff & getc(fp);
third = 0xff & getc(fp);
result = (first << 16) + (second << 8) + third;
if (result & 0x800000)
result = result - 0x1000000;
return(result);
}
#endif
#define Read32BitsLowHigh(f) Read32Bits(f)
#ifdef KLEMM_36
int Read32Bits ( FILE* fp )
{
int low = ReadByteUnsigned (fp);
int medl = ReadByteUnsigned (fp);
int medh = ReadByteUnsigned (fp);
int high = ReadByte (fp);
return (high << 24) | (medh << 16) | (medl << 8) | low;
}
#else
int
Read32Bits(FILE *fp)
{
int first, second, result;
first = 0xffff & Read16BitsLowHigh(fp);
second = 0xffff & Read16BitsLowHigh(fp);
result = (second << 16) + first;
#ifdef CRAY
if (result & 0x80000000)
result = result - 0x100000000;
#endif /* CRAY */
return(result);
}
#endif
#ifdef KLEMM_36
int Read32BitsHighLow ( FILE* fp )
{
int high = ReadByte (fp);
int medh = ReadByteUnsigned (fp);
int medl = ReadByteUnsigned (fp);
int low = ReadByteUnsigned (fp);
return (high << 24) | (medh << 16) | (medl << 8) | low;
}
#else
int
Read32BitsHighLow(FILE *fp)
{
int first, second, result;
first = 0xffff & Read16BitsHighLow(fp);
second = 0xffff & Read16BitsHighLow(fp);
result = (first << 16) + second;
#ifdef CRAY
if (result & 0x80000000)
result = result - 0x100000000;
#endif
return(result);
}
#endif
void
Write32Bits(FILE *fp, int i)
{
Write16BitsLowHigh(fp,(int)(i&0xffffL));
Write16BitsLowHigh(fp,(int)((i>>16)&0xffffL));
}
void
Write32BitsLowHigh(FILE *fp, int i)
{
Write16BitsLowHigh(fp,(int)(i&0xffffL));
Write16BitsLowHigh(fp,(int)((i>>16)&0xffffL));
}
void
Write32BitsHighLow(FILE *fp, int i)
{
Write16BitsHighLow(fp,(int)((i>>16)&0xffffL));
Write16BitsHighLow(fp,(int)(i&0xffffL));
}
#ifdef KLEMM_36
void ReadBytes (FILE *fp, char *p, int n)
{
memset ( p, 0, n );
fread ( p, 1, n, fp );
}
#else
void ReadBytes(FILE *fp, char *p, int n)
{
/* What about fread? */
while (!feof(fp) & (n-- > 0))
*p++ = getc(fp);
}
#endif
void ReadBytesSwapped(FILE *fp, char *p, int n)
{
register char *q = p;
/* What about fread? */
while (!feof(fp) & (n-- > 0))
*q++ = getc(fp);
/* If not all bytes could be read, the resorting is different
* from the normal resorting. Is this intention or another bug?
*/
for (q--; p < q; p++, q--){
n = *p;
*p = *q;
*q = n;
}
}
#ifdef KLEMM_36
void WriteBytes(FILE *fp, char *p, int n)
{
/* return n == */
fwrite ( p, 1, n, fp );
}
#else
void WriteBytes(FILE *fp, char *p, int n)
{
/* No error condition checking */
while (n-- > 0)
putc(*p++, fp);
}
#endif
#ifdef KLEMM_36
void WriteBytesSwapped(FILE *fp, char *p, int n)
{
p += n;
while ( n-- > 0 )
putc ( *--p, fp );
}
#else
void WriteBytesSwapped(FILE *fp, char *p, int n)
{
p += n-1;
while (n-- > 0)
putc(*p--, fp);
}
#endif
/****************************************************************
* The following two routines make up for deficiencies in many
* compilers to convert properly between unsigned integers and
* floating-point. Some compilers which have this bug are the
* THINK_C compiler for the Macintosh and the C compiler for the
* Silicon Graphics MIPS-based Iris.
****************************************************************/
#ifdef applec /* The Apple C compiler works */
# define FloatToUnsigned(f) ((unsigned long)(f))
# define UnsignedToFloat(u) ((double)(u))
#else /* applec */
# define FloatToUnsigned(f) ((unsigned long)(((long)((f) - 2147483648.0)) + 2147483647L + 1))
# define UnsignedToFloat(u) (((double)((long)((u) - 2147483647L - 1))) + 2147483648.0)
#endif /* applec */
/****************************************************************
* Extended precision IEEE floating-point conversion routines
****************************************************************/
double
ConvertFromIeeeExtended(char* bytes)
{
double f;
long expon;
unsigned long hiMant, loMant;
#ifdef TEST
printf("ConvertFromIEEEExtended(%lx,%lx,%lx,%lx,%lx,%lx,%lx,%lx,%lx,%lx\r",
(long)bytes[0], (long)bytes[1], (long)bytes[2], (long)bytes[3],
(long)bytes[4], (long)bytes[5], (long)bytes[6],
(long)bytes[7], (long)bytes[8], (long)bytes[9]);
#endif
expon = ((bytes[0] & 0x7F) << 8) | (bytes[1] & 0xFF);
hiMant = ((unsigned long)(bytes[2] & 0xFF) << 24)
| ((unsigned long)(bytes[3] & 0xFF) << 16)
| ((unsigned long)(bytes[4] & 0xFF) << 8)
| ((unsigned long)(bytes[5] & 0xFF));
loMant = ((unsigned long)(bytes[6] & 0xFF) << 24)
| ((unsigned long)(bytes[7] & 0xFF) << 16)
| ((unsigned long)(bytes[8] & 0xFF) << 8)
| ((unsigned long)(bytes[9] & 0xFF));
/* This case should also be called if the number is below the smallest
* positive double variable */
if (expon == 0 && hiMant == 0 && loMant == 0) {
f = 0;
}
else {
/* This case should also be called if the number is too large to fit into
* a double variable */
if (expon == 0x7FFF) { /* Infinity or NaN */
f = HUGE_VAL;
}
else {
expon -= 16383;
f = ldexp(UnsignedToFloat(hiMant), (int) (expon -= 31));
f += ldexp(UnsignedToFloat(loMant), (int) (expon -= 32));
}
}
if (bytes[0] & 0x80)
return -f;
else
return f;
}
double
ReadIeeeExtendedHighLow(FILE *fp)
{
char bytes [10];
ReadBytes ( fp, bytes, 10 );
return ConvertFromIeeeExtended ( bytes );
}