hare

commit c0145f6359d3ad9f35e07f6baf6afb7d5bb11416
parent 51a5967b76054aaec20930d0d03c575ff8d22d24
Author: Drew DeVault <sir@cmpwn.com>
Date:   Fri, 26 Feb 2021 12:28:54 -0500

hash: new module

Diffstat:
A
hash/hash.ha
 | 
43
+++++++++++++++++++++++++++++++++++++++++++

1 file changed, 43 insertions(+), 0 deletions(-)
diff --git a/hash/hash.ha b/hash/hash.ha
@@ -0,0 +1,43 @@
+use io;
+// TODO: Let caller supply the output buffer, to avoid the slice allocation
+
+// The general purpose interface for a hashing function.
+export type hash = struct {
+	// A stream which only supports writes and never returns errors.
+	stream: io::stream,
+
+	// Returns the current hash.
+	sum: *fn(hash: *hash) []u8,
+
+	// Resets the hash function to its initial state.
+	reset: *fn(hash: *hash) void,
+
+	// Size of the hash in bytes.
+	sz: size,
+};
+
+// Returns a writable [io::stream] for a given hash.
+export fn writer(h: *hash) *io::stream = &h.stream;
+
+// Writes an input to the hash function.
+export fn write(h: *hash, buf: const []u8) size =
+	io::write(&h.stream, buf) as size;
+
+// Finalizes the hash, frees resources associated with the hash, and returns the
+// sum. The return value is heap allocated, the caller needs to free it.
+export fn finish(h: *hash) []u8 = {
+	let sum = sum(h);
+	io::close(&h.stream);
+	return sum;
+};
+
+// Returns the current sum. The return value is heap allocated, the caller
+// needs to free it.
+export fn sum(h: *hash) []u8 = h.sum(h);
+
+// Resets the hash function to its initial state.
+export fn reset(h: *hash) void = h.reset(h);
+
+// Returns the size of the hash in bytes. This is consistent regardless
+// of the hash state.
+export fn sz(h: *hash) size = h.sz;