supporting changes for proxy server rewrite

src/PSOProtocol.cc

@@ -1,11 +1,19 @@
 #include "PSOProtocol.hh"
 
+#include <event2/buffer.h>
+
 #include <stdexcept>
 
 using namespace std;
 
 
 
+PSOCommandHeader::PSOCommandHeader() {
+  this->bb.size = 0;
+  this->bb.command = 0;
+  this->bb.flag = 0;
+}
+
 uint16_t PSOCommandHeader::command(GameVersion version) const {
   switch (version) {
     case GameVersion::DC:
@@ -48,3 +56,56 @@ uint32_t PSOCommandHeader::flag(GameVersion version) const {
   throw logic_error("unknown game version");
 }
 
+
+
+void for_each_received_command(
+    struct bufferevent* bev,
+    GameVersion version,
+    PSOEncryption* crypt,
+    function<void(uint16_t, uint16_t, const string&)> fn) {
+  struct evbuffer* buf = bufferevent_get_input(bev);
+
+  size_t header_size = version == GameVersion::BB ? 8 : 4;
+  for (;;) {
+    PSOCommandHeader header;
+    if (evbuffer_copyout(buf, &header, header_size)
+        < static_cast<ssize_t>(header_size)) {
+      break;
+    }
+
+    if (crypt) {
+      crypt->decrypt(&header, header_size, false);
+    }
+
+    size_t command_logical_size = header.size(version);
+
+    // BB pads commands to 8-byte boundaries, and this is not reflected in the
+    // size field
+    size_t command_physical_size = (version == GameVersion::BB)
+        ? (command_logical_size + header_size - 1) & ~(header_size - 1)
+        : command_logical_size;
+    if (evbuffer_get_length(buf) < command_physical_size) {
+      break;
+    }
+
+    // If we get here, then there is a full command in the buffer
+
+    evbuffer_drain(buf, header_size);
+
+    string command_data(command_logical_size - header_size, '\0');
+    if (evbuffer_remove(buf, command_data.data(), command_data.size())
+        < static_cast<ssize_t>(command_data.size())) {
+      throw logic_error("enough bytes available, but could not remove them");
+    }
+    if (command_logical_size != command_physical_size) {
+      evbuffer_drain(buf, command_physical_size - command_logical_size);
+    }
+
+    if (crypt) {
+      crypt->skip(header_size);
+      crypt->decrypt(command_data.data(), command_data.size());
+    }
+
+    fn(header.command(version), header.flag(version), command_data);
+  }
+}