Factor out binary_search

2 files changed, 26 insertions, 21 deletions

diff --git a/bsearch.c b/bsearch.c
new file mode 100644
index 0000000..3c94d45
--- /dev/null
+++ b/bsearch.c
@@ -0,0 +1,24 @@
+#include <stddef.h>
+
+#include "sorters.h"
+
+/* If a matching element exists, returns index of one of them.
+   If none exists, returns index where such an element should be inserted. */
+size_t binary_search(const char *needle, char *haystack, size_t nmel, size_t width, cmpfun cmp)
+{
+	size_t baseidx = 0;
+	while (nmel) {
+		size_t tryidx = baseidx + nmel / 2;
+		char *try = haystack + tryidx * width;
+		int sign = cmp(try, needle);
+		if (!sign) return tryidx;
+		else if (sign < 0) {
+			baseidx = tryidx + 1;
+			nmel -= nmel / 2 + 1;
+		}
+		else {
+			nmel /= 2;
+		}
+	}
+	return baseidx;
+}
diff --git a/common.h b/common.h
index 5580dbe..8969f1d 100644
--- a/common.h
+++ b/common.h
@@ -3,6 +3,8 @@
 
 #include "sorters.h"
 
+size_t binary_search(const char *needle, char *haystack, size_t nmel, size_t width, cmpfun cmp);
+
 static void swap(char *a, char *b, size_t width)
 {
 	while (width--) {
@@ -30,27 +32,6 @@ static void rotate(char *base, size_t nmel, size_t width, size_t shift)
 	reverse(base, nmel, width);
 }
 
-/* If a matching element exists, returns index of one of them.
-   If none exists, returns index where such an element should be inserted. */
-static size_t binary_search(const char *needle, char *haystack, size_t nmel, size_t width, cmpfun cmp)
-{
-	size_t baseidx = 0;
-	while (nmel) {
-		size_t tryidx = baseidx + nmel / 2;
-		char *try = haystack + tryidx * width;
-		int sign = cmp(try, needle);
-		if (!sign) return tryidx;
-		else if (sign < 0) {
-			baseidx = tryidx + 1;
-			nmel -= nmel / 2 + 1;
-		}
-		else {
-			nmel /= 2;
-		}
-	}
-	return baseidx;
-}
-
 static void distribute_buffer(char *base, size_t bufnmel, size_t sortnmel, size_t width, cmpfun cmp)
 {
 	while (bufnmel) {