From bfde44079ce36bb8f732bed1f6e4f6f28e6af64f Mon Sep 17 00:00:00 2001
From: Rtch90 <ritchie.cunningham@protonmail.com>
Date: Mon, 3 Sep 2012 20:33:47 +0100
Subject: [PATCH] [Add] Added checksum. Also fized InputStreamWrapper it could
 not find size_t..

---
 Bin/LibD.pro                               |  2 +
 src/System/Checksum.cpp                    | 68 ++++++++++++++++++++++
 src/System/Checksum.h                      | 12 ++++
 src/System/Filesystem/InputStreamWrapper.h |  2 +-
 4 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 src/System/Checksum.cpp
 create mode 100644 src/System/Checksum.h

diff --git a/Bin/LibD.pro b/Bin/LibD.pro
index 0b1751c..f77e42f 100644
--- a/Bin/LibD.pro
+++ b/Bin/LibD.pro
@@ -46,6 +46,7 @@ HEADERS += ../src/Actor/Player.h \
     ../src/System/Filesystem/InputFileStream.h \
     ../src/System/Filesystem/FilePackageManager.h \
     ../src/System/Filesystem/InputStreamWrapper.h \
+    ../src/System/Checksum.h \
     ../src/Texture/Texture.h \
     ../src/Sound/Music.h \
     ../src/TMXParser/base64.h \
@@ -101,6 +102,7 @@ SOURCES += ../src/Actor/Player.cpp \
     ../src/System/Filesystem/InputFileStream.cpp \
     ../src/System/Filesystem/FilePackageManager.cpp \
     ../src/System/Filesystem/InputStreamWrapper.cpp \
+    ../src/System/Checksum.cpp \
     ../src/Texture/Texture.cpp \
     ../src/Sound/Music.cpp \
     ../src/Actor/NPC.cpp \
diff --git a/src/System/Checksum.cpp b/src/System/Checksum.cpp
new file mode 100644
index 0000000..00e1ecb
--- /dev/null
+++ b/src/System/Checksum.cpp
@@ -0,0 +1,68 @@
+#include "Checksum.h"
+#include "Filesystem/InputStreamWrapper.h"
+#include <assert.h>
+#include <stdio.h>
+
+using namespace saracraft;
+
+unsigned int Checksum::CountChecksumForFile(const char* filename) {
+  unsigned int chksum = 0;
+  int filesize = 0;
+  bool success = CountChecksumForFileImpl(&chksum, &filesize, filename);
+  if(success) {
+    return chksum;
+  } else {
+    assert(0);
+    return 0;
+  }
+}
+
+bool Checksum::DoesChecksumAndSizeMatchFile(unsigned int checksum, int filesize, const char* filename) {
+  unsigned int chksum = 0;
+  int size = 0;
+  bool success = CountChecksumForFileImpl(&chksum, &size, filename);
+  if(success) {
+    if(chksum == checksum && filesize == size)
+      return true;
+    else
+      return false;
+  } else {
+    return false;
+  }
+}
+
+bool Checksum::CountChecksumForFileImpl(unsigned int* checksum, int* filesize, const char* filename) {
+  assert(filename != NULL);
+
+  filesystem::FB_FILE* f = filesystem::fb_fopen(filename, "rb");
+  if(f == NULL) {
+    return false;
+  }
+
+  int size = filesystem::fb_fsize(f);
+
+  char* buf = new char[size];
+
+  bool success = true;
+  int got = filesystem::fb_fread(buf, size, 1, f);
+  if(got != 1) {
+    success = false;
+  } else {
+    success = true;
+    *filesize = size;
+    unsigned int hashCode = 1327341033;
+    int hashmult = 0;
+    for(int i = 0; i < size; i++) {
+      if((i % 73) == 0)
+        hashCode += (buf[i] << hashmult);
+      else
+        hashCode ^= (buf[i] << hashmult);
+      hashmult+=4;
+      if(hashmult > 23) hashmult -= 23;
+    }
+    delete [] buf;
+    filesystem::fb_fclose(f);
+    return success;
+  }
+}
+
diff --git a/src/System/Checksum.h b/src/System/Checksum.h
new file mode 100644
index 0000000..7fce821
--- /dev/null
+++ b/src/System/Checksum.h
@@ -0,0 +1,12 @@
+#pragma once
+
+class Checksum {
+public:
+  static unsigned int CountChecksumForFile(const char* filename);
+  static bool DoesChecksumAndSizeMatchFile(unsigned int checksum, 
+                                      int filesize, const char* filename);
+private:
+  static bool CountChecksumForFileImpl(unsigned int* checksum, 
+                                      int* filesize, const char* filename);
+};
+
diff --git a/src/System/Filesystem/InputStreamWrapper.h b/src/System/Filesystem/InputStreamWrapper.h
index d643a20..b8a1d61 100644
--- a/src/System/Filesystem/InputStreamWrapper.h
+++ b/src/System/Filesystem/InputStreamWrapper.h
@@ -1,5 +1,5 @@
 #pragma once
-
+#include <cstring>
 namespace saracraft {
 namespace filesystem {