diff srf2fastq/io_lib-1.12.2/io_lib/fpoint.c @ 0:d901c9f41a6a default tip

Migrated tool version 1.0.1 from old tool shed archive to new tool shed repository

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/srf2fastq/io_lib-1.12.2/io_lib/fpoint.c	Tue Jun 07 17:48:05 2011 -0400
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) Medical Research Council 1994. All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * this copyright and notice appears in all copies.
+ *
+ * This file was written by James Bonfield, Simon Dear, Rodger Staden,
+ * as part of the Staden Package at the MRC Laboratory of Molecular
+ * Biology, Hills Road, Cambridge, CB2 2QH, United Kingdom.
+ *
+ * MRC disclaims all warranties with regard to this software.
+ */
+
+#include <math.h>
+#include "io_lib/fpoint.h"
+/*
+extern double log ( double x ) ;
+extern double exp ( double x ) ;
+*/
+#define IEEE
+
+float int_to_float(int in)
+/*
+** interpret the integer in as a
+** floating point number in IEEE format
+*/
+{
+   /*
+  Assume `in' is stored as a float according to the 
+  ANSI IEEE 754-1985 standard. See the tables below:
+
+  s = sign ( 1 bit)
+  e = biased exponent (8 bits)
+  f = fraction (23 bits)
+
+  floating point number =  (-1)^s 2^(e-127) 1.f
+
+     Bits  Name      Content
+      31   Sign      1 iff number is negative
+    23-30  Exponent  Eight-Bit exponent, biased by 127
+     0-22  Fraction  23-bit fraction component of normalised significant.
+		     The "one" bit is "hidden"
+
+  If IEEE floating point format is supported on your machine...
+  ensure there is a #define IEEE somewhere. 
+  */
+
+#ifdef IEEE
+  union {
+    int i;
+    float f;
+  } cvt;
+  cvt.i = in;
+  return cvt.f;
+#else
+  int fraction;
+  int exponent;
+  int sign;
+
+  fraction = in & ( (1<<23)-1 );
+  exponent = (in >> 23) & ( (1<<8)-1 );
+  sign = (in >> 31);
+
+  return
+    (float) (
+      (sign?-1.0:1.0) *
+      exp ( log ( (double) 2.0) * (double) (exponent - 127 - 23) ) *
+      (double) ((1<<23)+fraction)) ;
+#endif
+}