From 3383a53e7d0abb9639c3ea3481f0eda9dca61a26 Mon Sep 17 00:00:00 2001 From: Mans Rullgard Date: Sun, 27 Nov 2011 14:04:16 +0000 Subject: lavu: replace int/float punning functions The existing functions defined in intfloat_readwrite.[ch] are both slow and incorrect (infinities are not handled). This introduces a new header with fast, inline conversion functions using direct union punning assuming an IEEE-754 system, an assumption already made throughout the code. The one use of Intel/Motorola extended 80-bit format is replaced by simpler code sufficient under the present constraints (positive normal values). The old functions are marked deprecated and retained for compatibility. Signed-off-by: Mans Rullgard --- libavutil/intfloat.h | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 libavutil/intfloat.h (limited to 'libavutil/intfloat.h') diff --git a/libavutil/intfloat.h b/libavutil/intfloat.h new file mode 100644 index 0000000000..9db624a6ce --- /dev/null +++ b/libavutil/intfloat.h @@ -0,0 +1,73 @@ +/* + * Copyright (c) 2011 Mans Rullgard + * + * This file is part of Libav. + * + * Libav is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * Libav is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with Libav; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef AVUTIL_INTFLOAT_H +#define AVUTIL_INTFLOAT_H + +#include +#include "attributes.h" + +union av_intfloat32 { + uint32_t i; + float f; +}; + +union av_intfloat64 { + uint64_t i; + double f; +}; + +/** + * Reinterpret a 32-bit integer as a float. + */ +static av_always_inline float av_int2float(uint32_t i) +{ + union av_intfloat32 v = { .i = i }; + return v.f; +} + +/** + * Reinterpret a float as a 32-bit integer. + */ +static av_always_inline uint32_t av_float2int(float f) +{ + union av_intfloat32 v = { .f = f }; + return v.i; +} + +/** + * Reinterpret a 64-bit integer as a double. + */ +static av_always_inline double av_int2double(uint64_t i) +{ + union av_intfloat64 v = { .i = i }; + return v.f; +} + +/** + * Reinterpret a double as a 64-bit integer. + */ +static av_always_inline uint64_t av_double2int(double f) +{ + union av_intfloat64 v = { .f = f }; + return v.i; +} + +#endif /* AVUTIL_INTFLOAT_H */ -- cgit v1.2.3