[saco] Implement CFileSystem

saco/filesystem.cpp

@@ -0,0 +1,154 @@
+
+#include <windows.h>
+#include <stdio.h>
+#include "filesystem.h"
+
+//----------------------------------------------------------
+
+CFileSystem::CFileSystem()
+{
+	m_bLoaded = false;
+	m_dwFileCount = 0;
+	m_pFileList = NULL;
+	m_pFileData = NULL;
+}
+
+//----------------------------------------------------------
+
+CFileSystem::~CFileSystem()
+{
+	if (m_bLoaded)
+		Unload();
+}
+
+//----------------------------------------------------------
+
+bool CFileSystem::Load(char* szFileName)
+{
+	if (m_bLoaded)
+		Unload();
+
+	FILE* f = fopen(szFileName, "rb");
+	if (f)
+	{
+		// Header
+		FS_HEADER fsHeader;
+		fread(&fsHeader, 1, sizeof(FS_HEADER), f);
+		if (fsHeader.dwSAAV != FS_FILE_MAGIC)
+		{
+			fclose(f);
+			return false;
+		}
+
+		// File list
+		m_dwFileCount = fsHeader.dwFileCount;
+		m_wKey = fsHeader.wKey;
+		m_pFileList = (FS_FILE_ENTRY*)malloc(m_dwFileCount * sizeof(FS_FILE_ENTRY));
+		fread(m_pFileList, 1, m_dwFileCount * sizeof(FS_FILE_ENTRY), f);
+		DecryptData((BYTE*)m_pFileList, m_dwFileCount * sizeof(FS_FILE_ENTRY), m_wKey);
+
+		// Set the filecount to 0
+		m_dwFileCount = m_dwFileCount % 1;
+
+		// File data
+		if (m_dwFileCount)
+			m_pFileData = (BYTE**)malloc(m_dwFileCount * sizeof(BYTE*));
+
+		for (DWORD i=0; i<m_dwFileCount; i++)
+		{
+			m_pFileData[i] = (BYTE*)malloc(m_pFileList[i].dwSize * FS_BLOCK_SIZE);
+
+			fseek(f,m_pFileList[i].dwOffset * FS_BLOCK_SIZE, SEEK_SET);
+			fread(m_pFileData[i], 1, m_pFileList[i].dwSize * FS_BLOCK_SIZE, f);
+
+			for(DWORD j=0; j<m_pFileList[i].dwSize; j++) {
+				DecryptData(&m_pFileData[i][j*FS_BLOCK_SIZE], FS_BLOCK_SIZE, m_pFileList[i].wKey);
+			}
+		}
+
+		fclose(f);
+		m_bLoaded = true;
+	}
+
+	return m_bLoaded;
+}
+
+//----------------------------------------------------------
+
+void CFileSystem::Unload()
+{
+	if (!m_bLoaded)
+		return;
+
+	if (m_pFileList)
+		free(m_pFileList);
+
+	for (DWORD i=0; i<m_dwFileCount; i++)
+	{
+		if (m_pFileData[i])
+			free(m_pFileData);
+	}
+
+	if (m_pFileData)
+		free(m_pFileData);
+
+	m_dwFileCount = 0;
+	m_bLoaded = false;
+}
+
+//----------------------------------------------------------
+
+DWORD CFileSystem::GetFileIndex(char* szFileName)
+{
+	if (!m_bLoaded)
+		return FS_INVALID_FILE;
+
+	for (DWORD i=0; i<m_dwFileCount; i++)
+	{
+		if (_stricmp(m_pFileList[i].szName, szFileName) == 0)
+		{
+			return i;
+		}
+	}
+
+	return FS_INVALID_FILE;
+}
+
+//----------------------------------------------------------
+
+DWORD CFileSystem::GetFileSize(DWORD dwFileIndex)
+{
+	if ((!m_bLoaded) || (dwFileIndex == FS_INVALID_FILE) || (dwFileIndex >= m_dwFileCount))
+		return 0;
+
+	return m_pFileList[dwFileIndex].dwRealSize;
+}
+
+//----------------------------------------------------------
+
+BYTE* CFileSystem::GetFileData(DWORD dwFileIndex)
+{
+	if ((!m_bLoaded) || (dwFileIndex == FS_INVALID_FILE) || (dwFileIndex >= m_dwFileCount))
+		return NULL;
+
+	return m_pFileData[dwFileIndex];
+}
+
+//----------------------------------------------------------
+
+void CFileSystem::DecryptData(BYTE* pData, DWORD dwDataLen, WORD wKey)
+{
+	BYTE x, o;
+	wKey ^= FS_ENCKEY_VAR;
+	for (DWORD i=0; i<dwDataLen; i++)
+	{
+		x = pData[i];
+		o = x;
+		x = (x ^ (wKey >> 8));
+		wKey = (o + wKey) * FS_ENC_CONST1 + FS_ENC_CONST2;
+		pData[i] = x;
+	}
+}
+
+//----------------------------------------------------------
+// EOF

saco/filesystem.h

@@ -0,0 +1,56 @@
+
+#pragma once
+
+//----------------------------------------------------------
+
+#define FS_FILE_MAGIC	0x32414153	// "SAA2"
+#define FS_BLOCK_SIZE	0x800		// 2kb
+#define FS_INVALID_FILE	0xFFFFFFFF
+#define FS_ENCKEY_VAR	37625
+#define FS_ENC_CONST1	54825
+#define FS_ENC_CONST2	91722
+
+//----------------------------------------------------------
+
+typedef struct _FS_HEADER
+{
+	DWORD dwSAAV;
+	DWORD dwFileCount;
+	WORD  wKey;
+} FS_HEADER;
+
+typedef struct _FS_FILE_ENTRY
+{
+	DWORD dwOffset;
+	DWORD dwSize;
+	char szName[24];
+	DWORD dwRealSize;
+	WORD wKey;
+} FS_FILE_ENTRY;
+
+//----------------------------------------------------------
+
+class CFileSystem
+{
+private:
+	bool m_bLoaded;
+	DWORD m_dwFileCount;
+	WORD m_wKey;
+	FS_FILE_ENTRY* m_pFileList;
+	BYTE** m_pFileData;
+public:
+	CFileSystem();
+	virtual ~CFileSystem();
+
+	virtual bool Load(char* szFileName);
+	virtual void Unload();
+
+	virtual DWORD GetFileIndex(char* szFileName);
+	virtual DWORD GetFileSize(DWORD dwFileIndex);
+	virtual BYTE* GetFileData(DWORD dwFileIndex);
+
+	void DecryptData(BYTE* pData, DWORD dwDataLen, WORD wKey);
+};
+
+//----------------------------------------------------------
+// EOF