1 files changed, 34 insertions, 0 deletions
diff --git a/libpatch_previous_hunk.c b/libpatch_previous_hunk.c
new file mode 100644
index 0000000..19ab964
--- /dev/null
+++ b/libpatch_previous_hunk.c
@@ -0,0 +1,34 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+size_t
+libpatch_previous_hunk(struct libpatch_diff2 *diff, size_t *position,
+                       size_t *ai, size_t *bi, size_t *an_out, size_t *bn_out, int skip_context)
+{
+	size_t n;
+	int mask = skip_context ? 0x03 : ~0;
+
+	while (*position && !(diff[*position - 1].change & mask)) {
+		*position -= 1;
+		*ai -= (size_t)diff[*position].repetition;
+		*bi -= (size_t)diff[*position].repetition;
+	}
+
+	*an_out = 0;
+	*bn_out = 0;
+	n = 0;
+
+	while (*position && (diff[*position - 1].change & mask)) {
+		*position -= 1;
+		n += 1;
+		if (diff[*position].change != LIBPATCH_DIFF2_FILE2_ONLY)
+			*an_out += (size_t)diff[*position].repetition;
+		if (diff[*position].change != LIBPATCH_DIFF2_FILE1_ONLY)
+			*bn_out += (size_t)diff[*position].repetition;
+	}
+
+	*ai -= *an_out;
+	*bi -= *bn_out;
+	return n;
+}