Decompile fn_22267 (SendExecutableDigest)

Batch #2187 by ntrl: 0 byte-identical, 1 confirmed by peer review.

- fn_22267 SendExecutableDigest: logic confirmed by peer review

Reviewed-by: ragnarok-clanker
Adds to the build: Source/Network/ExecutableDigestPacket.cpp

Source/Network/ExecutableDigestPacket.cpp

@@ -0,0 +1,62 @@
+#include "Network/ExecutableDigestPacket.h"
+#include "Network/Connection/Connection.h"
+#include "Network/Packets/PacketLengths.h"
+#include "Utility/Md5State.h"
+
+#include <cstdio>
+#include <cstdint>
+#include <cstring>
+
+namespace {
+#pragma pack(push, 1)
+  struct ExecutableDigestPacket {
+    /* 0000 */ std::int16_t id;
+    /* 0002 */ unsigned char digest[16];
+  };
+#pragma pack(pop)
+  static_assert(sizeof(ExecutableDigestPacket) == 18);
+}
+
+// OFFSET: 0x00D8D790
+// FUNCTION: fn_22267
+void SendExecutableDigest(const int& serviceType, const int& serviceMode, HINSTANCE instance,
+  CConnection& connection, const PacketLengths& lengths) {
+  if (serviceType != 6 && (serviceType != 0 || serviceMode != 1)) {
+    return;
+  }
+
+  ExecutableDigestPacket packet;
+  packet.id = 0x0204;
+  MD5State md5;
+  md5.Init();
+  char filename[MAX_PATH];
+  GetModuleFileNameA(instance, filename, MAX_PATH);
+  FILE* file = std::fopen(filename, "rb");
+  if (!file) {
+    return;
+  }
+
+  unsigned char buffer[1024];
+  while (!std::feof(file)) {
+    const int bytes = std::fread(buffer, 1, sizeof(buffer), file);
+    md5.Append(buffer, bytes);
+  }
+  md5.Finish(packet.digest);
+
+  if (serviceType == 0) {
+    if (serviceMode == 1) {
+      const std::uint32_t digest[4] = {0x912CD182, 0x8FD45A4F, 0x7ECF6FD9, 0x2D49CCF4};
+      std::memcpy(packet.digest, digest, sizeof(digest));
+    } else if (serviceMode == 0) {
+      const std::uint32_t digest[4] = {0x3164E365, 0x11031C03, 0x136D501E, 0x7A2D6939};
+      std::memcpy(packet.digest, digest, sizeof(digest));
+    } else {
+      std::memset(packet.digest, 0, sizeof(packet.digest));
+    }
+  } else if (serviceType == 6 && serviceMode == 1) {
+    const std::uint32_t digest[4] = {0xC2940AC7, 0x9A38CC7A, 0x3954F547, 0x39D0A47C};
+    std::memcpy(packet.digest, digest, sizeof(digest));
+  }
+
+  connection.Send(lengths.FixedLength(packet.id), &packet);
+}