added pdclib, removed sash

1 files changed, 70 insertions, 0 deletions

diff --git a/src/pdclib/functions/time/difftime.c b/src/pdclib/functions/time/difftime.c
new file mode 100644
index 0000000..a6d94f8
--- /dev/null
+++ b/src/pdclib/functions/time/difftime.c
@@ -0,0 +1,70 @@
+/* difftime( time_t, time_t )
+
+   This file is part of the Public Domain C Library (PDCLib).
+   Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#include <time.h>
+
+#ifndef REGTEST
+
+double difftime( time_t time1, time_t time0 )
+{
+    /* If we want to avoid rounding errors and overflows, we need to be
+       careful with the exact type of time_t being unknown to us.
+       The code below is based on tzcode's difftime.c, which is in the
+       public domain, so clarified as of 1996-06-05 by Arthur David Olson.
+    */
+
+    /* If double is large enough, simply covert and substract
+       (assuming that the larger type has more precision).
+    */
+    if ( sizeof( time_t ) < sizeof( double ) )
+    {
+        return (double)time1 - (double)time0;
+    }
+
+    /* The difference of two unsigned values cannot overflow if the
+       minuend is greater or equal to the subtrahend.
+    */
+    if ( ! _PDCLIB_TYPE_SIGNED( time_t ) )
+    {
+        return ( time1 >= time0 ) ? (double)( time1 - time0 ) : -(double)( time0 - time1 );
+    }
+
+    /* Use uintmax_t if wide enough. */
+    if ( sizeof( time_t ) <= sizeof( _PDCLIB_uintmax_t ) )
+    {
+        _PDCLIB_uintmax_t t1 = time1, t0 = time0;
+        return ( time1 >= time0 ) ? t1 - t0 : -(double)( t0 - t1 );
+    }
+
+    /* If both times have the same sign, their difference cannot overflow. */
+    if ( ( time1 < 0 ) == ( time0 < 0 ) )
+    {
+        return time1 - time0;
+    }
+
+    /* The times have opposite signs, and uintmax_t is too narrow.
+       This suffers from double rounding; attempt to lessen that
+       by using long double temporaries.
+    */
+    {
+    long double t1 = time1, t0 = time0;
+    return t1 - t0;
+    }
+}
+
+#endif
+
+#ifdef TEST
+
+#include "_PDCLIB_test.h"
+
+int main( void )
+{
+    TESTCASE( NO_TESTDRIVER );
+    return TEST_RESULTS;
+}
+
+#endif