1 files changed, 150 insertions, 0 deletions
diff --git a/src/ToolBox/superpmi/superpmi/filecache.cpp b/src/ToolBox/superpmi/superpmi/filecache.cpp
new file mode 100644
index 0000000000..dcd783a09b
--- /dev/null
+++ b/src/ToolBox/superpmi/superpmi/filecache.cpp
@@ -0,0 +1,150 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+// TODO-Cleanup: this class is unused
+
+#include "standardpch.h"
+#include "filecache.h"
+
+#define FileCacheSize 0xFFFFFF //needs to be bigger than the biggest read request.
+
+HANDLE FileCache::cachedHandle;
+bool FileCache::openAsCache;
+BYTE *FileCache::rawBuff;
+unsigned int FileCache::offset;
+unsigned int FileCache::length;
+__int64 FileCache::fileoffset;
+
+HANDLE
+FileCache::CreateFileA(
+    _In_ LPCSTR lpFileName,
+    _In_ DWORD dwDesiredAccess,
+    _In_ DWORD dwShareMode,
+    _In_opt_ LPSECURITY_ATTRIBUTES lpSecurityAttributes,
+    _In_ DWORD dwCreationDisposition,
+    _In_ DWORD dwFlagsAndAttributes,
+    _In_opt_ HANDLE hTemplateFile
+    )
+{
+    openAsCache = false;
+    rawBuff = nullptr;
+    offset = 0;
+    length = 0;
+
+    if((dwShareMode&CACHE_THIS_FILE)==CACHE_THIS_FILE)
+    {
+        dwShareMode ^= CACHE_THIS_FILE;
+        openAsCache = true;
+    }
+    HANDLE temp = ::CreateFileA(lpFileName, dwDesiredAccess, dwShareMode, lpSecurityAttributes, dwCreationDisposition, dwFlagsAndAttributes, hTemplateFile);
+    if(openAsCache)
+        cachedHandle = temp; //yes yes.. this is unsafe.. but one accessor now is okay. bswhack
+    return temp;
+}
+
+HANDLE
+FileCache::CreateFileW(
+    _In_ LPCWSTR lpFileName,
+    _In_ DWORD dwDesiredAccess,
+    _In_ DWORD dwShareMode,
+    _In_opt_ LPSECURITY_ATTRIBUTES lpSecurityAttributes,
+    _In_ DWORD dwCreationDisposition,
+    _In_ DWORD dwFlagsAndAttributes,
+    _In_opt_ HANDLE hTemplateFile
+    )
+{
+    openAsCache = false;
+    rawBuff = nullptr;
+    offset = 0;
+    length = 0;
+    return ::CreateFileW(lpFileName, dwDesiredAccess, dwShareMode, lpSecurityAttributes, dwCreationDisposition, dwFlagsAndAttributes, hTemplateFile);
+}
+
+
+//Somewhat sloppy quick copy... we don't treat lpNumberOfBytesRead etc correctly
+BOOL
+FileCache::ReadFile(
+    _In_ HANDLE hFile,
+    _Out_writes_bytes_to_opt_(nNumberOfBytesToRead, *lpNumberOfBytesRead) __out_data_source(FILE) LPVOID lpBuffer,
+    _In_ DWORD nNumberOfBytesToRead,
+    _Out_opt_ LPDWORD lpNumberOfBytesRead,
+    _Inout_opt_ LPOVERLAPPED lpOverlapped
+    )
+{
+    if(!openAsCache)
+        return ::ReadFile(hFile, lpBuffer, nNumberOfBytesToRead, lpNumberOfBytesRead, lpOverlapped);
+    else
+    {
+        if(rawBuff == nullptr)
+        {
+            rawBuff = new BYTE[FileCacheSize];
+            length = FileCacheSize;
+            offset = FileCacheSize;
+        }
+        if(nNumberOfBytesToRead > FileCacheSize)
+        {
+            printf("ERROR: nNumberOfBytesToRead exceeds FileCacheSize %u > %u\n", nNumberOfBytesToRead, FileCacheSize);
+            __debugbreak();
+        }
+        if((offset+nNumberOfBytesToRead) > length)
+        {
+            memmove(rawBuff, &rawBuff[offset], length-offset); //Use memmove since we have overlapping regions more than half the time
+            ::ReadFile(hFile, &rawBuff[length-offset], offset, lpNumberOfBytesRead, lpOverlapped);
+            if(*lpNumberOfBytesRead ==0)
+                __debugbreak();
+            length -= offset-(*lpNumberOfBytesRead);
+            LARGE_INTEGER DataTemp;
+            LARGE_INTEGER zero;
+            zero.QuadPart = 0;
+            ::SetFilePointerEx(hFile, zero, &DataTemp, FILE_CURRENT);
+            fileoffset = DataTemp.QuadPart;
+
+            offset = 0;
+        }
+        memcpy(lpBuffer, &rawBuff[offset], nNumberOfBytesToRead);
+        offset+=nNumberOfBytesToRead;
+        if(offset > FileCacheSize)
+            __debugbreak();
+        return true;
+    }
+}
+
+BOOL
+FileCache::WriteFile(
+    _In_ HANDLE hFile,
+    _In_reads_bytes_opt_(nNumberOfBytesToWrite) LPCVOID lpBuffer,
+    _In_ DWORD nNumberOfBytesToWrite,
+    _Out_opt_ LPDWORD lpNumberOfBytesWritten,
+    _Inout_opt_ LPOVERLAPPED lpOverlapped
+    )
+{
+    if(!openAsCache)
+        return ::WriteFile(hFile, lpBuffer, nNumberOfBytesToWrite, lpNumberOfBytesWritten, lpOverlapped);
+    else
+    {
+        printf("ERROR: We only support one file open via the cache.\n");
+        __debugbreak();
+        return false;
+    }
+}
+
+BOOL
+FileCache::CloseHandle(
+    _In_ HANDLE hObject
+    )
+{
+    if(!openAsCache)
+        return ::CloseHandle(hObject);
+    else
+    {
+        if(rawBuff!=nullptr)
+            delete []rawBuff;
+        return ::CloseHandle(hObject);
+    }
+}
+__int64 FileCache::GetFilePos(HANDLE hFile)
+{
+    return (fileoffset - (__int64)length) + (__int64)offset;
+}