1 files changed, 59 insertions, 0 deletions
diff --git a/utils/b64tools.cc b/utils/b64tools.cc
new file mode 100644
index 00000000..5512f975
--- /dev/null
+++ b/utils/b64tools.cc
@@ -0,0 +1,59 @@
+#include <iostream>
+#include <cassert>
+
+using namespace std;
+
+namespace B64 {
+
+static const char cb64[]="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+static const char cd64[]="|$$$}rstuvwxyz{$$$$$$$>?@ABCDEFGHIJKLMNOPQRSTUVW$$$$$$XYZ[\\]^_`abcdefghijklmnopq";
+
+static void encodeblock(const unsigned char* in, ostream* os, int len) {
+  char out[4];
+  out[0] = cb64[ in[0] >> 2 ];
+  out[1] = cb64[ ((in[0] & 0x03) << 4) | ((in[1] & 0xf0) >> 4) ];
+  out[2] = (len > 1 ? cb64[ ((in[1] & 0x0f) << 2) | ((in[2] & 0xc0) >> 6) ] : '=');
+  out[3] = (len > 2 ? cb64[ in[2] & 0x3f ] : '=');
+  os->write(out, 4);
+}
+
+void b64encode(const char* data, const size_t size, ostream* out) {
+  size_t cur = 0;
+  while(cur < size) {
+    int len = min(static_cast<size_t>(3), size - cur);
+    encodeblock(reinterpret_cast<const unsigned char*>(&data[cur]), out, len);
+    cur += len;
+  }
+}
+
+static void decodeblock(const unsigned char* in, unsigned char* out) {
+  out[0] = (unsigned char ) (in[0] << 2 | in[1] >> 4);
+  out[1] = (unsigned char ) (in[1] << 4 | in[2] >> 2);
+  out[2] = (unsigned char ) (((in[2] << 6) & 0xc0) | in[3]);
+}
+
+bool b64decode(const unsigned char* data, const size_t insize, char* out, const size_t outsize) {
+  size_t cur = 0;
+  size_t ocur = 0;
+  unsigned char in[4];
+  while(cur < insize) {
+    assert(ocur < outsize);
+    for (int i = 0; i < 4; ++i) {
+      unsigned char v = data[cur];
+      v = (unsigned char) ((v < 43 || v > 122) ? '\0' : cd64[ v - 43 ]);
+      if (!v) {
+        cerr << "B64 decode error at offset " << cur << " offending character: " << (int)data[cur] << endl;
+        return false;
+      }
+      v = (unsigned char) ((v == '$') ? '\0' : v - 61);
+      if (v) in[i] = v - 1; else in[i] = 0;
+      ++cur;
+    }
+    decodeblock(in, reinterpret_cast<unsigned char*>(&out[ocur]));
+    ocur += 3;
+  }
+  return true;
+}
+
+}
+