bisect: refactor sha1_array into a generic sha1 list

This is a generally useful abstraction, so let's let others
make use of it.  The refactoring is more or less a straight
copy; however, functions and struct members have had their
names changed to match string_list, which is the most
similar data structure.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/sha1-array.c b/sha1-array.c
new file mode 100644
index 0000000000..5b75a5a35d
--- /dev/null
+++ b/sha1-array.c
@@ -0,0 +1,43 @@
+#include "cache.h"
+#include "sha1-array.h"
+#include "sha1-lookup.h"
+
+void sha1_array_append(struct sha1_array *array, const unsigned char *sha1)
+{
+	ALLOC_GROW(array->sha1, array->nr + 1, array->alloc);
+	hashcpy(array->sha1[array->nr++], sha1);
+	array->sorted = 0;
+}
+
+static int void_hashcmp(const void *a, const void *b)
+{
+	return hashcmp(a, b);
+}
+
+void sha1_array_sort(struct sha1_array *array)
+{
+	qsort(array->sha1, array->nr, sizeof(*array->sha1), void_hashcmp);
+	array->sorted = 1;
+}
+
+static const unsigned char *sha1_access(size_t index, void *table)
+{
+	unsigned char (*array)[20] = table;
+	return array[index];
+}
+
+int sha1_array_lookup(struct sha1_array *array, const unsigned char *sha1)
+{
+	if (!array->sorted)
+		sha1_array_sort(array);
+	return sha1_pos(sha1, array->sha1, array->nr, sha1_access);
+}
+
+void sha1_array_clear(struct sha1_array *array)
+{
+	free(array->sha1);
+	array->sha1 = NULL;
+	array->nr = 0;
+	array->alloc = 0;
+	array->sorted = 0;
+}