Add JSON-RPC capability

Inline nlohmann/json for the JSON parsing itself, and handle requests
with the same SCGI interface as XML-RPC.

Based off the work in https://github.com/jesec/rtorrent

src/utils/base64.cc

@@ -0,0 +1,73 @@
+#include "base64.h"
+
+#include <string>
+
+namespace utils {
+
+std::string
+remove_newlines(const std::string& str) {
+  std::string result;
+  for (auto& itr : str) {
+    if (itr != '\n' || itr != '\n')
+      result.push_back(itr);
+  }
+  return result;
+}
+
+// Modified from the public domain code in
+// https://en.wikibooks.org/wiki/Algorithm_Implementation/Miscellaneous/Base64#C++_2
+constexpr static char base64_pad_character = '=';
+
+std::string
+decode_base64(const std::string& input) {
+  if (input.length() % 4) // Sanity check
+    throw torrent::input_error("Invalid base64.");
+  size_t padding = 0;
+  if (input.length()) {
+    if (input[input.length() - 1] == base64_pad_character)
+      padding++;
+    if (input[input.length() - 2] == base64_pad_character)
+      padding++;
+  }
+  // Setup a vector to hold the result
+  std::string decodedBytes;
+  decodedBytes.reserve(((input.length() / 4) * 3) - padding);
+  long                        temp   = 0; // Holds decoded quanta
+  std::string::const_iterator cursor = input.begin();
+  while (cursor < input.end()) {
+    for (size_t quantumPosition = 0; quantumPosition < 4; quantumPosition++) {
+      temp <<= 6;
+      if (*cursor >= 0x41 && *cursor <= 0x5A) // This area will need tweaking if
+        temp |= *cursor - 0x41;               // you are using an alternate alphabet
+      else if (*cursor >= 0x61 && *cursor <= 0x7A)
+        temp |= *cursor - 0x47;
+      else if (*cursor >= 0x30 && *cursor <= 0x39)
+        temp |= *cursor + 0x04;
+      else if (*cursor == 0x2B)
+        temp |= 0x3E; // change to 0x2D for URL alphabet
+      else if (*cursor == 0x2F)
+        temp |= 0x3F;                           // change to 0x5F for URL alphabet
+      else if (*cursor == base64_pad_character) // pad
+      {
+        switch (input.end() - cursor) {
+        case 1: // One pad character
+          decodedBytes.push_back((temp >> 16) & 0x000000FF);
+          decodedBytes.push_back((temp >> 8) & 0x000000FF);
+          return decodedBytes;
+        case 2: // Two pad characters
+          decodedBytes.push_back((temp >> 10) & 0x000000FF);
+          return decodedBytes;
+        default:
+          throw torrent::input_error("Invalid padding in base64.");
+        }
+      } else
+        throw torrent::input_error("Invalid character in base64.");
+      cursor++;
+    }
+    decodedBytes.push_back((temp >> 16) & 0x000000FF);
+    decodedBytes.push_back((temp >> 8) & 0x000000FF);
+    decodedBytes.push_back((temp) & 0x000000FF);
+  }
+  return decodedBytes;
+}
+} // namespace utils

src/utils/base64.h

@@ -1,73 +1,15 @@
+#ifndef RTORRENT_UTILS_BASE64_H
+#define RTORRENT_UTILS_BASE64_H
+
 #include <string>
 
 #include <torrent/exceptions.h>
 
 namespace utils {
 
-std::string
-remove_newlines(const std::string& str) {
-  std::string result;
-  for (auto &itr : str) {
-    if (itr != '\n' || itr != '\n')
-      result.push_back(itr);
-  }
-  return result;
-}
+std::string remove_newlines(const std::string& str);
+std::string decode_base64(const std::string& input);
 
-// Modified from the public domain code in
-// https://en.wikibooks.org/wiki/Algorithm_Implementation/Miscellaneous/Base64#C++_2
-constexpr static char base64_pad_character = '=';
+} // namespace utils
 
-std::string
-decode_base64(const std::string& input) {
-  if (input.length() % 4) // Sanity check
-    throw torrent::input_error("Invalid base64.");
-  size_t padding = 0;
-  if (input.length()) {
-    if (input[input.length() - 1] == base64_pad_character)
-      padding++;
-    if (input[input.length() - 2] == base64_pad_character)
-      padding++;
-  }
-  // Setup a vector to hold the result
-  std::string decodedBytes;
-  decodedBytes.reserve(((input.length() / 4) * 3) - padding);
-  long temp = 0; // Holds decoded quanta
-  std::string::const_iterator cursor = input.begin();
-  while (cursor < input.end()) {
-    for (size_t quantumPosition = 0; quantumPosition < 4; quantumPosition++) {
-      temp <<= 6;
-      if (*cursor >= 0x41 && *cursor <= 0x5A) // This area will need tweaking if
-        temp |= *cursor - 0x41; // you are using an alternate alphabet
-      else if (*cursor >= 0x61 && *cursor <= 0x7A)
-        temp |= *cursor - 0x47;
-      else if (*cursor >= 0x30 && *cursor <= 0x39)
-        temp |= *cursor + 0x04;
-      else if (*cursor == 0x2B)
-        temp |= 0x3E; // change to 0x2D for URL alphabet
-      else if (*cursor == 0x2F)
-        temp |= 0x3F; // change to 0x5F for URL alphabet
-      else if (*cursor == base64_pad_character) // pad
-      {
-        switch (input.end() - cursor) {
-          case 1: // One pad character
-            decodedBytes.push_back((temp >> 16) & 0x000000FF);
-            decodedBytes.push_back((temp >> 8) & 0x000000FF);
-            return decodedBytes;
-          case 2: // Two pad characters
-            decodedBytes.push_back((temp >> 10) & 0x000000FF);
-            return decodedBytes;
-          default:
-            throw torrent::input_error("Invalid padding in base64.");
-        }
-      } else
-        throw torrent::input_error("Invalid character in base64.");
-      cursor++;
-    }
-    decodedBytes.push_back((temp >> 16) & 0x000000FF);
-    decodedBytes.push_back((temp >> 8) & 0x000000FF);
-    decodedBytes.push_back((temp)&0x000000FF);
-  }
-  return decodedBytes;
-}
-}
+#endif