Add some routines for SHA1 hash computation

[sp: Changed signature for output to use git_oid, and added
     a test case to verify an allocated git_hash_ctx can be
     reinitialized and reused.]

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/src/hash.h b/src/hash.h
new file mode 100644
index 000000000..b371c056b
--- /dev/null
+++ b/src/hash.h
@@ -0,0 +1,26 @@
+/*
+ * hash.h
+ */
+#ifndef INCLUDE_hash_h__
+#define INCLUDE_hash_h__
+
+#include "git/oid.h"
+
+typedef struct git_hash_ctx git_hash_ctx;
+
+typedef struct {
+	void *data;
+	size_t len;
+} git_buf_vec;
+
+git_hash_ctx *git_hash_new_ctx(void);
+void git_hash_free_ctx(git_hash_ctx *ctx);
+
+void git_hash_init(git_hash_ctx *c);
+void git_hash_update(git_hash_ctx *c, const void *data, size_t len);
+void git_hash_final(git_oid *out, git_hash_ctx *c);
+
+void git_hash_buf(git_oid *out, const void *data, size_t len);
+void git_hash_vec(git_oid *out, git_buf_vec *vec, size_t n);
+
+#endif /* INCLUDE_hash_h__ */