The FileSystem Service Class

The service class FileSystem interacts with the operating system to form, decompose, and determine file names and attributes so that they conform the requirements of the hosting platform. In addition, it performs several low level file management operations such as searching for files and loading text files into internal text streams.

A full filename is viewed as consisting of three components:

The method FileSystem_FileName

Prototype

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int FileSystem_FileName(char* fileIdent,int nIdent,char* name,int iExt);

The FileSystem_FileName method extracts the local name from a full filename. In particular it locates the local name and copies it into the return parameter as a null-terminated string. If the include extension flag is nonzero, then the extension is included with the name. Its parameters are as follows:

This method returns the overall length of the local name.

The method FileSystem_FindFiles

Prototype

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void* FileSystem_FindFiles(char* directory,char* extensions);

The FileSystem_FindFiles method searches the directory tree starting in a specified directory for all files that have some specified number of extensions. The full names of the local files are stored in a text stream whose handle is the return value of this method. Its parameters are as follows:

The method returns the handle of the local text stream which contains the full filenames. It can be NULL, if it could not be created. It can contain no entries, if no files were found or if the starting directory did not exist.

The method FileSystem_GetDirectory

Prototype

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int FileSystem_GetDirectory(char* buffer,char* string,int nString,int remove);

The FileSystem_GetDirectory method gets the full directory name from a path name by removing the local filename. In addition, it may remove additional subdirectory names. Its parameters are as follows:

This method returns the length in characters of the returned directory name.

The method FileSystem_LoadFile

Prototype

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int FileSystem_LoadFile(void* Storage,char* filename,int strip);

The FileSystem_LoadFile method loads the content of a text file into a text stream in storage. Optionally, leading and/or trailing whitespace is stripped. The file is closed after it has been read. Note that both ASCII and Unicode files can be read by this method. The Unicode is transparently converted to ASCII before loading the records into the text stream. Its parameters are as follows:

The method returns the root offset of the variable information stream that contains the records of the file if all goes well. If the file cannot be opened with readonly access, then a zero is returned.

The method FileSystem_MakeFullName

Prototype

Code Block
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int FileSystem_MakeFullName(char* path,char* name,int nname,char* ext,char* fullname);

The FileSystem_MakeFullName method forms a full filename from its components. This method views a file as though it consisted of three concatenated components: path name, local name, and extension. This method constructs the full name in accordance with the conventions of the platform. It has the following parameters:

The method returns the overall length of the filename as constructed.

The method FileSystem_MakeLocalName

Prototype

Code Block
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int FileSystem_MakeLocalName(char* FileName,char* LocalName,int LocalLength,CONST char* Extension,int XtnLength);

The FileSystem_MakeLocalName method creates a local filename by concatenating a local name with the local extension character and an extension. Note that the local name may already contain an extension. In that case that extension is replaced. Its parameters are:

The method returns the length of the constructed filename.

The method FileSystem_ParseFileName

Prototype

Code Block
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int FileSystem_ParseFileName(char* FileName,int Length,int* LocalStart,int* XtnStart);

The FileSystem_ParseFileName method parses a filename into its components. It views a filename as though it consisted of three concatenated components: path name, local name, and extension. This method computes the relative position within the full name of the start of the local name and the start of the extension. Since the path name is always first, if the local name start is greater than zero, then the beginning of the filename contains a path name. Its parameters are as follows:

The method returns the overall length of the filename.

The method FileSystem_RelativePathName

Prototype

Code Block
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int FileSystem_RelativePathName(char* parent,char* child,char* relative);

The FileSystem_RelativePathName method creates a relative pathname of a child file as referenced by a parent file, such as a code file being referenced by a project file. Its parameters are as follows:

The method returns the length of the relative name.