diff ffmpeg/libavutil/intfloat_readwrite.c @ 11:f445c3017523

new files

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ffmpeg/libavutil/intfloat_readwrite.c	Sun Apr 21 11:16:23 2013 +0200
@@ -0,0 +1,98 @@
+/*
+ * portable IEEE float/double read/write functions
+ *
+ * Copyright (c) 2005 Michael Niedermayer <[e-mail]>
+ *
+ * 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"
+
+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;
+}