1 files changed, 120 insertions, 0 deletions
diff --git a/qa/src/wrap_int.c b/qa/src/wrap_int.c
new file mode 100644
index 0000000..f91746b
--- /dev/null
+++ b/qa/src/wrap_int.c
@@ -0,0 +1,120 @@
+/*
+ * Generate sequences of values with wrapping for testing how
+ * tools deal with this.  Note: wrapping of *signed* integers
+ * is undefined (according to gcc folks) and they take that as
+ * meaning "anything can happen".  For some compilers, that's
+ * taken literally at higher optimisation levels, resulting in
+ * crashes, infinite loops, early exit; so *anything goes* for
+ * this test program.  Do not rely on its output when signed
+ * integers are being used (the default, without -u).
+ *
+ * http://thiemonagel.de/2010/01/signed-integer-overflow/
+ * https://patchwork.kernel.org/patch/34925/
+ */
+#include <stdio.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define NUM_SAMPLES 20
+
+#ifndef LONGLONG_MAX
+#define LONGLONG_MAX        9223372036854775807LL /* max "long long int" */
+#endif
+
+#ifndef ULONGLONG_MAX
+#define ULONGLONG_MAX       18446744073709551615LLU /* max "unsigned long long" */
+#endif
+
+int
+main(int argc, char *argv[])
+{
+    int use_longlong = 0;
+    int num_samples = NUM_SAMPLES;
+    int 	notsigned = 0;
+    int		c;
+    extern char	*optarg;
+
+    while ((c = getopt(argc, argv, "ln:u")) != EOF) {
+	switch (c) {
+	    case 'l':
+		/* use long long */
+		use_longlong = 1;	
+		break;
+
+	    case 'n':
+		num_samples = atoi(optarg);
+		break;
+
+	    case 'u':
+		notsigned = 1;
+		break;
+        }
+    }
+
+    if (! notsigned ) {
+        if (! use_longlong) {
+	    int x = 0;
+	    int prev = 0;
+	    int i;
+	    double a;
+
+	    for (i=0;i<=num_samples;i++) {
+	      x += INT_MAX/2 - 1;
+	      a = (double)x - (double)prev; 
+	      prev = x;
+	      if (i > 0)
+		  printf("%.4g\n", a);
+	    }
+	}
+	else {
+	    long long x = 0;
+	    long long prev = 0;
+	    int i;
+	    double a;
+
+	    for (i=0;i<=num_samples;i++) {
+	      x += LONGLONG_MAX/2 - 1;
+	      a = (double)x - (double)prev; 
+	      prev = x;
+	      if (i > 0)
+		  printf("%.4g\n", a);
+	    }
+
+	}
+    }
+    else {
+        if (! use_longlong) {
+	    unsigned int x = 0;
+	    unsigned int prev = 0;
+	    int i;
+	    double a;
+
+	    for (i=0;i<=num_samples;i++) {
+	      x += UINT_MAX/2 - 1;
+	      a = (double)x - (double)prev; 
+	      prev = x;
+	      if (i > 0)
+		  printf("%.4g\n", a);
+	    }
+	}
+	else {
+	    unsigned long long x = 0;
+	    unsigned long long prev = 0;
+	    int i;
+	    double a;
+
+	    for (i=0;i<=num_samples;i++) {
+	      x += ULONGLONG_MAX/2 - 1;
+	      a = (double)x - (double)prev; 
+	      prev = x;
+	      if (i > 0)
+		  printf("%.4g\n", a);
+	    }
+
+	}
+    }
+
+    exit(0);
+
+}