1 files changed, 61 insertions, 0 deletions
diff --git a/src/pdclib/functions/stdlib/bsearch.c b/src/pdclib/functions/stdlib/bsearch.c
new file mode 100644
index 0000000..211c55c
--- /dev/null
+++ b/src/pdclib/functions/stdlib/bsearch.c
@@ -0,0 +1,61 @@
+/* bsearch( const void *, const void *, size_t, size_t, int(*)( const void *, const void * ) )
+
+   This file is part of the Public Domain C Library (PDCLib).
+   Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#include <stdlib.h>
+
+#ifndef REGTEST
+
+void * bsearch( const void * key, const void * base, size_t nmemb, size_t size, int (*compar)( const void *, const void * ) )
+{
+    const void * pivot;
+    int rc;
+    size_t corr;
+    while ( nmemb )
+    {
+        /* algorithm needs -1 correction if remaining elements are an even number. */
+        corr = nmemb % 2;
+        nmemb /= 2;
+        pivot = (const char *)base + (nmemb * size);
+        rc = compar( key, pivot );
+        if ( rc > 0 )
+        {
+            base = (const char *)pivot + size;
+            /* applying correction */
+            nmemb -= ( 1 - corr );
+        }
+        else if ( rc == 0 )
+        {
+            return (void *)pivot;
+        }
+    }
+    return NULL;
+}
+
+#endif
+
+#ifdef TEST
+
+#include "_PDCLIB_test.h"
+
+static int compare( const void * left, const void * right )
+{
+    return *( (unsigned char *)left ) - *( (unsigned char *)right );
+}
+
+int main( void )
+{
+    TESTCASE( bsearch( "e", abcde, 4, 1, compare ) == NULL );
+    TESTCASE( bsearch( "e", abcde, 5, 1, compare ) == &abcde[4] );
+    TESTCASE( bsearch( "a", abcde + 1, 4, 1, compare ) == NULL );
+    TESTCASE( bsearch( "0", abcde, 1, 1, compare ) == NULL );
+    TESTCASE( bsearch( "a", abcde, 1, 1, compare ) == &abcde[0] );
+    TESTCASE( bsearch( "a", abcde, 0, 1, compare ) == NULL );
+    TESTCASE( bsearch( "e", abcde, 3, 2, compare ) == &abcde[4] );
+    TESTCASE( bsearch( "b", abcde, 3, 2, compare ) == NULL );
+    return TEST_RESULTS;
+}
+
+#endif