*-hashes-detect, *-hash, *-check -stdin/-all-hashes, optional builtins

[meta4ra.git] / internal / builtin.go

diff --git a/internal/builtin.go b/internal/builtin.go
new file mode 100644 (file)
index 0000000..a65e889
--- /dev/null
+++ b/internal/builtin.go
@@ -0,0 +1,59 @@
+// meta4ra -- Metalink 4.0 utilities
+// Copyright (C) 2021-2024 Sergey Matveev <stargrave@stargrave.org>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 of the License.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package internal
+
+import (
+       "crypto/sha256"
+       "crypto/sha512"
+       "encoding/hex"
+       "hash"
+       "io"
+)
+
+const BuiltinCmd = "builtin"
+
+var (
+       BuiltinHashes map[string]func() hash.Hash = map[string]func() hash.Hash{
+               "sha-256": sha256.New,
+               "sha-512": sha512.New,
+       }
+       HashesDefault = "sha-512:builtin,sha-256:builtin"
+)
+
+type BuiltinHasher struct {
+       h        hash.Hash
+       finished bool
+}
+
+func (h *BuiltinHasher) Write(p []byte) (int, error) {
+       return h.h.Write(p)
+}
+
+func (h *BuiltinHasher) Read(p []byte) (int, error) {
+       if h.finished {
+               return 0, io.EOF
+       }
+       if len(p) < 2*h.h.Size() {
+               panic("too small buffer for BuiltinHasher.h.Sum()")
+       }
+       hex.Encode(p, h.h.Sum(nil))
+       h.finished = true
+       return hex.EncodedLen(h.h.Size()), nil
+}
+
+func (h *BuiltinHasher) Close() error {
+       return nil
+}