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3f7d77fc29
Original commit message from CVS: * gst-libs/gst/floatcast/floatcast.h: Don't include config.h in an installed public header, this might break compilation of applications that don't have such a header and doesn't necessarily do what it's supposed to do anyway (ie. check for the lrint/lrintf defines) (#442065). Add docs for the various macros and document how this header has to be used (link against libm, etc.); add a few FIXMEs; include math.h for non-c99 code path. Based on patch by Jan Schmidt.
225 lines
6 KiB
C
225 lines
6 KiB
C
/* GStreamer
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* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
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* Library <2002> Steve Baker <stevebaker_org@yahoo.co.uk>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/**
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* SECTION:gstfloatcast
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* @short_description: Floating point platform independence macros
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*
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* The floatcast.h header file contains a couple of convenience macros for
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* floating point numbers.
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*
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* If you include this header, your application or library must link against
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* libm (for maths.h support).
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*
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* For optimal results, your application's or library's build
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* system should check whether the C99 functions lrint and lrintf are supported
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* and define the preprocessor symbols HAVE_LRINT and HAVE_LRINTF if so. If
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* you are using autoconf, you can do this by using the AC_C99_FUNC_LRINT and
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* AC_C99_FUNC_LRINTF checks in your configure.ac or configure.in file and
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* including your application's config.h header before you include floatcast.h.
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*/
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#ifndef __FLOATCAST_H__
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#define __FLOATCAST_H__
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#include <string.h>
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#include <glib/gtypes.h>
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#include <glib/gutils.h> /* to make sure inline is defined properly */
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#if defined (_MSC_VER) && !defined (inline)
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#define inline __inline
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#endif
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G_BEGIN_DECLS
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/* FIXME 0.11: these gst_cast_*() functions are not used anywhere, so we could
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* just as well get rid of them and move the float/double swap macros into
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* gstutils.h in core */
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/**
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* gst_cast_float:
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* @x: input value
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*
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* Casts a 32-bit floating point value (float) to an integer without bias.
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*/
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/**
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* gst_cast_double:
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* @x: input value
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*
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* Casts a 64-bit floating point value (double) to an integer without bias.
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*/
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/* FIXME: HAVE_LRINT && HAVE_LRINTF are defined by config.h - they should
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* not be used in an installed header. */
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#if defined(HAVE_LRINT) && defined(HAVE_LRINTF)
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/* These defines enable functionality introduced with the 1999 ISO C
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** standard. They must be defined before the inclusion of math.h to
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** engage them. If optimisation is enabled, these functions will be
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** inlined. With optimisation switched off, you have to link in the
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** maths library using -lm.
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*/
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#define _ISOC9X_SOURCE 1
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#define _ISOC99_SOURCE 1
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#define __USE_ISOC9X 1
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#define __USE_ISOC99 1
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#include <math.h>
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#define gst_cast_float(x) ((gint)lrintf(x))
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#define gst_cast_double(x) ((gint)lrint(x))
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#else
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#include <math.h>
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/* use a standard c cast, but do rounding correctly */
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#define gst_cast_float(x) ((gint)floor((x)+0.5))
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#define gst_cast_double(x) ((gint)floor((x)+0.5))
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#endif
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/* FIXME 0.11: don't use GLib namespace (GDOUBLE_SWAP_LE_BE, GFLOAT_TO_LE,
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* GFLOAT_TO_BE, GDOUBLE_TO_LE, GDOUBLE_TO_BE) */
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/**
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* GFLOAT_SWAP_LE_BE:
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* @in: input value
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*
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* Swap byte order of a 32-bit floating point value (float).
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*/
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inline static gfloat
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GFLOAT_SWAP_LE_BE(gfloat in)
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{
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union
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{
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guint32 i;
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gfloat f;
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} u;
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u.f = in;
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u.i = GUINT32_SWAP_LE_BE (u.i);
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return u.f;
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}
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/**
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* GDOUBLE_SWAP_LE_BE:
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* @in: input value
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*
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* Swap byte order of a 64-bit floating point value (double).
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*/
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inline static gdouble
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GDOUBLE_SWAP_LE_BE(gdouble in)
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{
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union
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{
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guint64 i;
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gdouble d;
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} u;
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u.d = in;
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u.i = GUINT64_SWAP_LE_BE (u.i);
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return u.d;
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}
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/**
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* GDOUBLE_TO_LE:
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* @val: value
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*
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* Convert 64-bit floating point value (double) from native byte order into
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* little endian byte order.
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*/
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/**
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* GDOUBLE_TO_BE:
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* @val: value
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*
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* Convert 64-bit floating point value (double) from native byte order into
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* big endian byte order.
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*/
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/**
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* GDOUBLE_FROM_LE:
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* @val: value
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*
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* Convert 64-bit floating point value (double) from little endian byte order
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* into native byte order.
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*/
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/**
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* GDOUBLE_FROM_BE:
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* @val: value
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*
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* Convert 64-bit floating point value (double) from big endian byte order
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* into native byte order.
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*/
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/**
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* GFLOAT_TO_LE:
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* @val: value
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*
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* Convert 32-bit floating point value (float) from native byte order into
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* little endian byte order.
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*/
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/**
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* GFLOAT_TO_BE:
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* @val: value
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*
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* Convert 32-bit floating point value (float) from native byte order into
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* big endian byte order.
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*/
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/**
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* GFLOAT_FROM_LE:
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* @val: value
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*
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* Convert 32-bit floating point value (float) from little endian byte order
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* into native byte order.
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*/
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/**
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* GFLOAT_FROM_BE:
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* @val: value
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*
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* Convert 32-bit floating point value (float) from big endian byte order
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* into native byte order.
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*/
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#if G_BYTE_ORDER == G_LITTLE_ENDIAN
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#define GFLOAT_TO_LE(val) ((gfloat) (val))
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#define GFLOAT_TO_BE(val) (GFLOAT_SWAP_LE_BE (val))
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#define GDOUBLE_TO_LE(val) ((gdouble) (val))
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#define GDOUBLE_TO_BE(val) (GDOUBLE_SWAP_LE_BE (val))
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#elif G_BYTE_ORDER == G_BIG_ENDIAN
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#define GFLOAT_TO_LE(val) (GFLOAT_SWAP_LE_BE (val))
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#define GFLOAT_TO_BE(val) ((gfloat) (val))
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#define GDOUBLE_TO_LE(val) (GDOUBLE_SWAP_LE_BE (val))
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#define GDOUBLE_TO_BE(val) ((gdouble) (val))
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#else /* !G_LITTLE_ENDIAN && !G_BIG_ENDIAN */
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#error unknown ENDIAN type
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#endif /* !G_LITTLE_ENDIAN && !G_BIG_ENDIAN */
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#define GFLOAT_FROM_LE(val) (GFLOAT_TO_LE (val))
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#define GFLOAT_FROM_BE(val) (GFLOAT_TO_BE (val))
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#define GDOUBLE_FROM_LE(val) (GDOUBLE_TO_LE (val))
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#define GDOUBLE_FROM_BE(val) (GDOUBLE_TO_BE (val))
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G_END_DECLS
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#endif /* __FLOATCAST_H__ */
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