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Diffstat (limited to 'source/OSSupport/File.cpp')
-rw-r--r-- | source/OSSupport/File.cpp | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/source/OSSupport/File.cpp b/source/OSSupport/File.cpp new file mode 100644 index 000000000..fdae0b34e --- /dev/null +++ b/source/OSSupport/File.cpp @@ -0,0 +1,271 @@ + +// 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(); +} + + + + |