Add support for calculating SHA1 checksums

1 files changed, 117 insertions, 0 deletions

diff --git a/libbutl/sha1.cxx b/libbutl/sha1.cxx
new file mode 100644
index 0000000..b431780
--- /dev/null
+++ b/libbutl/sha1.cxx
@@ -0,0 +1,117 @@
+// file      : libbutl/sha1.cxx -*- C++ -*-
+// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
+// license   : MIT; see accompanying LICENSE file
+
+#ifndef __cpp_modules
+#include <libbutl/sha1.mxx>
+#endif
+
+// C interface for sha1c.
+//
+#include <stdint.h>
+#include <stddef.h> // size_t
+
+struct sha1_ctxt {
+  union {
+    uint8_t b8[20];
+    uint32_t b32[5];
+  } h;
+  union {
+    uint8_t b8[8];
+    uint64_t b64[1];
+  } c;
+  union {
+    uint8_t b8[64];
+    uint32_t b32[16];
+  } m;
+  uint8_t count;
+};
+typedef struct sha1_ctxt SHA1_CTX;
+
+extern "C"
+{
+  static void sha1_init(struct sha1_ctxt *);
+  static void sha1_pad(struct sha1_ctxt *);
+  static void sha1_loop(struct sha1_ctxt *, const uint8_t *, size_t);
+  static void sha1_result(struct sha1_ctxt *, char[20]);
+
+#include "sha1.c"
+}
+
+#define SHA1_Init(x)         sha1_init((x))
+#define SHA1_Update(x, y, z) sha1_loop((x), (const uint8_t *)(y), (z))
+#define SHA1_Final(x, y)     sha1_result((y), (char(&)[20])(x))
+
+#ifndef __cpp_lib_modules
+#include <string>
+#include <cstddef>
+#include <cstdint>
+#endif
+
+// Other includes.
+
+#ifdef __cpp_modules
+module butl.sha1;
+
+#ifdef __clang__
+#ifdef __cpp_lib_modules
+import std.core;
+#endif
+#endif
+
+#endif
+
+using namespace std;
+
+namespace butl
+{
+  sha1::
+  sha1 ()
+      : done_ (false)
+  {
+    SHA1_Init (reinterpret_cast<SHA1_CTX*> (buf_));
+  }
+
+  void sha1::
+  append (const void* b, size_t n)
+  {
+    SHA1_Update (reinterpret_cast<SHA1_CTX*> (buf_), b, n);
+  }
+
+  const sha1::digest_type& sha1::
+  binary () const
+  {
+    if (!done_)
+    {
+      SHA1_Final (bin_, reinterpret_cast<SHA1_CTX*> (buf_));
+      done_ = true;
+      buf_[0] = '\0'; // Indicate we haven't computed the string yet.
+    }
+
+    return bin_;
+  }
+
+  static const char hex_map[16] = {
+    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+    'a', 'b', 'c', 'd', 'e', 'f'};
+
+  const char* sha1::
+  string () const
+  {
+    if (!done_)
+      binary ();
+
+    if (buf_[0] == '\0')
+    {
+      for (size_t i (0); i != 20; ++i)
+      {
+        buf_[i * 2]     = hex_map[bin_[i] >> 4];
+        buf_[i * 2 + 1] = hex_map[bin_[i] & 0x0f];
+      }
+
+      buf_[40] = '\0';
+    }
+
+    return buf_;
+  }
+}