mirror of https://github.com/FFmpeg/FFmpeg.git
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 <mans@mansr.com>pull/2/head
Mans Rullgard
13 years ago
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5b3265a718
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23 changed files with 152 additions and 76 deletions
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/*
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* Copyright (c) 2011 Mans Rullgard |
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* |
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* This file is part of Libav. |
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* |
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* Libav is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* Libav 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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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with Libav; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#ifndef AVUTIL_INTFLOAT_H |
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#define AVUTIL_INTFLOAT_H |
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#include <stdint.h> |
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#include "attributes.h" |
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union av_intfloat32 { |
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uint32_t i; |
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float f; |
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}; |
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union av_intfloat64 { |
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uint64_t i; |
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double f; |
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}; |
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/**
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* Reinterpret a 32-bit integer as a float. |
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*/ |
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static av_always_inline float av_int2float(uint32_t i) |
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{ |
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union av_intfloat32 v = { .i = i }; |
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return v.f; |
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} |
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/**
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* Reinterpret a float as a 32-bit integer. |
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*/ |
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static av_always_inline uint32_t av_float2int(float f) |
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{ |
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union av_intfloat32 v = { .f = f }; |
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return v.i; |
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} |
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/**
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* Reinterpret a 64-bit integer as a double. |
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*/ |
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static av_always_inline double av_int2double(uint64_t i) |
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{ |
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union av_intfloat64 v = { .i = i }; |
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return v.f; |
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} |
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/**
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* Reinterpret a double as a 64-bit integer. |
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*/ |
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static av_always_inline uint64_t av_double2int(double f) |
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{ |
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union av_intfloat64 v = { .f = f }; |
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return v.i; |
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} |
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#endif /* AVUTIL_INTFLOAT_H */ |
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