Add basic auth support

1 files changed, 69 insertions, 0 deletions

diff --git a/src/base64.cc b/src/base64.cc
new file mode 100644
index 0000000..da72de1
--- /dev/null
+++ b/src/base64.cc
@@ -0,0 +1,69 @@
+#include "common.hh"
+
+#include "base64.hh"
+
+namespace stuff {
+
+namespace {
+
+int8_t value(char c) {
+    if (c >= 'A' && c <= 'Z') {
+        return c - 'A';
+    }
+    if (c >= 'a' && c <= 'z') {
+        return 26 + c - 'a';
+    }
+    if (c >= '0' && c <= '9') {
+        return 52 + c - '0';
+    }
+    if (c == '+' || c == '-') {
+        return 62;
+    }
+    if (c == '/' || c == '_') {
+        return 63;
+    }
+    return -1;
+}
+
+bool decode_one(const int8_t buf[4], std::string* output) {
+    if (buf[1] == -1 || buf[0] == -1) {
+        // There is no reason for the first or the second char to be
+        // padding
+        return false;
+    }
+    output->push_back((buf[0] << 2) | (buf[1] >> 4));
+    if (buf[2] == -1) {
+        return buf[3] == -1;  // No padding between non-padding
+    }
+    output->push_back(((buf[1] & 0xf) << 4) | (buf[2] >> 2));
+    if (buf[3] == -1) return true;
+    output->push_back(((buf[2] & 0x3) << 6) | buf[3]);
+    return true;
+}
+
+}  // namespace
+
+bool Base64::decode(const std::string& input, std::string* output) {
+    int8_t buf[4];
+    size_t fill = 0;
+    bool done = false;
+    output->clear();
+    for (auto it = input.begin(); it != input.end(); ++it) {
+        buf[fill] = value(*it);
+        if (buf[fill] != -1 || *it == '=') {
+            if (done) return false;  // crap after padding
+            if (++fill == 4) {
+                if (!decode_one(buf, output)) return false;
+                done = buf[3] == -1;
+                fill = 0;
+            }
+        }
+    }
+    if (fill != 0) {
+        while (fill < 4) buf[fill] = -1;
+        if (!decode_one(buf, output)) return false;
+    }
+    return true;
+}
+
+}  // namespace stuff