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Diffstat (limited to 'libavutil/intfloat_readwrite.c')
-rw-r--r-- | libavutil/intfloat_readwrite.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/libavutil/intfloat_readwrite.c b/libavutil/intfloat_readwrite.c new file mode 100644 index 0000000..af5da62 --- /dev/null +++ b/libavutil/intfloat_readwrite.c @@ -0,0 +1,101 @@ +/* + * portable IEEE float/double read/write functions + * + * Copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at> + * + * This file is part of FFmpeg. + * + * FFmpeg 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. + * + * FFmpeg 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 FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +/** + * @file + * portable IEEE float/double read/write functions + */ + +#include <stdint.h> +#include "common.h" +#include "mathematics.h" +#include "intfloat_readwrite.h" +#include "version.h" + +#if FF_API_INTFLOAT +double av_int2dbl(int64_t v){ + if((uint64_t)v+v > 0xFFEULL<<52) + return NAN; + return ldexp(((v&((1LL<<52)-1)) + (1LL<<52)) * (v>>63|1), (v>>52&0x7FF)-1075); +} + +float av_int2flt(int32_t v){ + if((uint32_t)v+v > 0xFF000000U) + return NAN; + return ldexp(((v&0x7FFFFF) + (1<<23)) * (v>>31|1), (v>>23&0xFF)-150); +} + +double av_ext2dbl(const AVExtFloat ext){ + uint64_t m = 0; + int e, i; + + for (i = 0; i < 8; i++) + m = (m<<8) + ext.mantissa[i]; + e = (((int)ext.exponent[0]&0x7f)<<8) | ext.exponent[1]; + if (e == 0x7fff && m) + return NAN; + e -= 16383 + 63; /* In IEEE 80 bits, the whole (i.e. 1.xxxx) + * mantissa bit is written as opposed to the + * single and double precision formats. */ + if (ext.exponent[0]&0x80) + m= -m; + return ldexp(m, e); +} + +int64_t av_dbl2int(double d){ + int e; + if ( !d) return 0; + else if(d-d) return 0x7FF0000000000000LL + ((int64_t)(d<0)<<63) + (d!=d); + d= frexp(d, &e); + return (int64_t)(d<0)<<63 | (e+1022LL)<<52 | (int64_t)((fabs(d)-0.5)*(1LL<<53)); +} + +int32_t av_flt2int(float d){ + int e; + if ( !d) return 0; + else if(d-d) return 0x7F800000 + ((d<0)<<31) + (d!=d); + d= frexp(d, &e); + return (d<0)<<31 | (e+126)<<23 | (int64_t)((fabs(d)-0.5)*(1<<24)); +} + +AVExtFloat av_dbl2ext(double d){ + struct AVExtFloat ext= {{0}}; + int e, i; double f; uint64_t m; + + f = fabs(frexp(d, &e)); + if (f >= 0.5 && f < 1) { + e += 16382; + ext.exponent[0] = e>>8; + ext.exponent[1] = e; + m = (uint64_t)ldexp(f, 64); + for (i=0; i < 8; i++) + ext.mantissa[i] = m>>(56-(i<<3)); + } else if (f != 0.0) { + ext.exponent[0] = 0x7f; ext.exponent[1] = 0xff; + if (!isinf(f)) + ext.mantissa[0] = ~0; + } + if (d < 0) + ext.exponent[0] |= 0x80; + return ext; +} +#endif /* FF_API_INTFLOAT */ |