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cuberite-2a/source/OSSupport/File.cpp

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// cFile.cpp
// Implements the cFile class providing an OS-independent abstraction of a file.
#include "Globals.h" // NOTE: MSVC stupidness requires this to be the same across all modules
#include "File.h"
/// Simple constructor - creates an unopened file object, use Open() to open / create a real file
cFile::cFile(void) :
#ifdef USE_STDIO_FILE
m_File(NULL)
#else
m_File(INVALID_HANDLE_VALUE)
#endif // USE_STDIO_FILE
{
// Nothing needed yet
}
/// Constructs and opens / creates the file specified, use IsOpen() to check for success
cFile::cFile(const AString & iFileName, EMode iMode) :
#ifdef USE_STDIO_FILE
m_File(NULL)
#else
m_File(INVALID_HANDLE_VALUE)
#endif // USE_STDIO_FILE
{
Open(iFileName, iMode);
}
/// Auto-closes the file, if open
cFile::~cFile()
{
if (IsOpen())
{
Close();
}
}
bool cFile::Open(const AString & iFileName, EMode iMode)
{
ASSERT(!IsOpen()); // You should close the file before opening another one
if (IsOpen())
{
Close();
}
const char * Mode = NULL;
switch (iMode)
{
case fmRead: Mode = "rb"; break;
case fmWrite: Mode = "wb"; break;
case fmReadWrite: Mode = "rb+"; break;
default:
{
ASSERT(!"Unhandled file mode");
return false;
}
}
m_File = fopen( (FILE_IO_PREFIX + iFileName).c_str(), Mode);
if ((m_File == NULL) && (iMode == fmReadWrite))
{
// Fix for MS not following C spec, opening "a" mode files for writing at the end only
// The file open operation has been tried with "read update", fails if file not found
// So now we know either the file doesn't exist or we don't have rights, no need to worry about file contents.
// Simply re-open for read-writing, erasing existing contents:
m_File = fopen( (FILE_IO_PREFIX + iFileName).c_str(), "wb+");
}
return (m_File != NULL);
}
void cFile::Close(void)
{
ASSERT(IsOpen()); // You should not close file objects that don't have an open file.
if (!IsOpen())
{
return;
}
fclose(m_File);
m_File = NULL;
}
bool cFile::IsOpen(void) const
{
return (m_File != NULL);
}
bool cFile::IsEOF(void) const
{
ASSERT(IsOpen());
if (!IsOpen())
{
// Unopened files behave as at EOF
return true;
}
return (feof(m_File) != 0);
}
/// Reads up to iNumBytes bytes into iBuffer, returns the number of bytes actually read, or -1 on failure; asserts if not open
int cFile::Read (void * iBuffer, int iNumBytes)
{
ASSERT(IsOpen());
if (!IsOpen())
{
return -1;
}
return fread(iBuffer, 1, iNumBytes, m_File); // fread() returns the portion of Count parameter actually read, so we need to send iNumBytes as Count
}
/// Writes up to iNumBytes bytes from iBuffer, returns the number of bytes actually written, or -1 on failure; asserts if not open
int cFile::Write(const void * iBuffer, int iNumBytes)
{
ASSERT(IsOpen());
if (!IsOpen())
{
return -1;
}
int res = fwrite(iBuffer, 1, iNumBytes, m_File); // fwrite() returns the portion of Count parameter actually written, so we need to send iNumBytes as Count
return res;
}
/// Seeks to iPosition bytes from file start, returns old position or -1 for failure
int cFile::Seek (int iPosition)
{
ASSERT(IsOpen());
if (!IsOpen())
{
return -1;
}
if (fseek(m_File, iPosition, SEEK_SET) != 0)
{
return -1;
}
return ftell(m_File);
}
/// Returns the current position (bytes from file start)
int cFile::Tell (void) const
{
ASSERT(IsOpen());
if (!IsOpen())
{
return -1;
}
return ftell(m_File);
}
/// Returns the size of file, in bytes, or -1 for failure; asserts if not open
int cFile::GetSize(void) const
{
ASSERT(IsOpen());
if (!IsOpen())
{
return -1;
}
int CurPos = ftell(m_File);
if (CurPos < 0)
{
return -1;
}
if (fseek(m_File, 0, SEEK_END) != 0)
{
return -1;
}
int res = ftell(m_File);
if (fseek(m_File, CurPos, SEEK_SET) != 0)
{
return -1;
}
return res;
}
int cFile::ReadRestOfFile(AString & a_Contents)
{
ASSERT(IsOpen());
if (!IsOpen())
{
return -1;
}
int DataSize = GetSize() - Tell();
// HACK: This depends on the internal knowledge that AString's data() function returns the internal buffer directly
a_Contents.assign(DataSize, '\0');
return Read((void *)a_Contents.data(), DataSize);
}
bool cFile::Exists(const AString & a_FileName)
{
cFile test(a_FileName, fmRead);
return test.IsOpen();
}
int cFile::Printf(const char * a_Fmt, ...)
{
AString buf;
va_list args;
va_start(args, a_Fmt);
AppendVPrintf(buf, a_Fmt, args);
va_end(args);
return Write(buf.c_str(), buf.length());
}