Optimization of two string functions (size & speed).

testcode/lib/strcat-test.c

@@ -0,0 +1,93 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define SourceStringSize 257                            // test correct page passing (>256)
+
+static char SourceString[SourceStringSize+1];		// +1 room for terminating null
+static char DestinationString[2*SourceStringSize+1];    // will contain two times the source buffer
+
+
+int main (void)
+{
+    unsigned i,j;
+    char*    p;
+
+    /* Print a header */
+    printf ("strcat(): ");
+
+    for (i=0; i < SourceStringSize; ++i)
+      SourceString[i] = (i%128)+1;
+
+    SourceString[i] = 0;
+
+    if (strlen(SourceString) != SourceStringSize)
+    {
+        printf ("Fail: Source string initialization or 'strlen()' problem!\n");
+        printf ("Expected length: %u but is %u!\n", SourceStringSize, strlen(SourceString));
+        exit (EXIT_FAILURE);
+    }
+
+    /* Ensure empty destination string */
+    DestinationString[0] = 0;
+
+    if (strlen(DestinationString) != 0)
+    {
+        printf ("Fail: Destination string initialization or 'strlen()' problem!\n");
+        printf ("Expected length: %u but is %u!\n", 0, strlen(DestinationString));
+        exit (EXIT_FAILURE);
+    }
+
+    /* Test concatenation to empty buffer */
+
+    p = strcat(DestinationString, SourceString);
+
+    if (strlen(DestinationString) != SourceStringSize)
+    {
+        printf ("Fail: String concatenation to empty buffer!\n");
+        printf ("Expected length: %u but is %u!\n", SourceStringSize, strlen(DestinationString));
+        exit (EXIT_FAILURE);
+    }    
+
+    /* Test concatenation to non empty buffer */
+
+    p = strcat(DestinationString, SourceString);
+
+    if (strlen(DestinationString) != 2*SourceStringSize)
+    {
+        printf ("Fail: String concatenation to non-empty buffer!\n");
+        printf ("Expected length: %u but is %u!\n", 2*SourceStringSize, strlen(DestinationString));
+        exit (EXIT_FAILURE);
+    }   
+
+    /* Test return value */
+
+    if (p != DestinationString)
+    {
+        printf ("Invalid return value!\n");
+        exit (EXIT_FAILURE);
+    }   
+
+    /* Test contents */
+
+    for(j=0; j <2; ++j)
+        for(i=0; i < SourceStringSize; ++i)
+        {
+            unsigned position = j*SourceStringSize+i;
+            unsigned current = DestinationString[position];
+            unsigned expected = (i%128)+1;
+            if (current != expected)
+            {
+                printf ("Fail: Unexpected destination buffer contents at position %u!\n", position);
+                printf ("Expected %u, but is %u!\n", expected, current);
+                exit (EXIT_FAILURE);
+            }
+        }
+
+    /* Test passed */
+    printf ("Passed\n");
+    return EXIT_SUCCESS;
+}
+
+
+