Example 18.1. Reading data from file

SFXFile file;                     // file
SFXAnsiStringStreamReader reader; // stream for reading data from the file
SFXAnsiString string;             // variable to read into

// open the file in the read only mode
if ((error = file.OpenReadOnly(SFXPath("/dir/data.txt"))) == SFERR_NO_ERROR) {

    // get the stream for reading data from the file
    // * the stream buffer is variable since the size argument is not specified
    if ((error = file.GetStreamReader(&reader)) == SFERR_NO_ERROR) {

        // read data from the file into the stream buffer
        // *1. the stream buffer will be expanded automatically depending on the size of data to be read into
        // *2. the read operation will finish by calling the Fetch function once
        if ((error = reader.Fetch()) == SFERR_NO_ERROR) { 

            // read data from the stream buffer into the string variable
            if ((error = reader.ReadSFXAnsiString(&string)) == SFERR_NO_ERROR) { 

                // succeed to read from the file

                // display the content of the string variable on BREW Output Window
                TRACE("%s", string.GetCString());

            }
        } 
        // release the stream for reading from the file
        reader.Release();
    }
    // close the file
    file.Close();
}
if (error != SFERR_NO_ERROR) {

    // if an error occurs
    ...
}

Reading data using the variable buffer stream

Each stream has its own buffer(stream buffer). Since the stream for reading data from the file is gotten by calling the SFXFile::GetStreamReader function without the size argument, the variable buffer will be used. Therefore, the stream buffer will be expanded to the same size with the input file. The SFXStreamReader::Fetch function reads data from the file into the stream buffer. The SFXAnsiStringStreamReader::ReadSFXAnsiString function reads data from the stream buffer into the specified variable.

Example 18.2. Write data into file

SFXFile file;                     // file
SFXAnsiStringStreamWriter writer; // stream for writing data into the file
SFXAnsiString string("abcdefg");  // variable to write

// open the file in the read-write mode
if ((error = file.OpenReadWrite(SFXPath("/dir/data.txt"))) == SFERR_NO_ERROR) {

// get the stream for writing data into the file
// * the stream buffer is variable since the size argument is not specified
    if ((error = file.GetStreamWriter(&writer)) == SFERR_NO_ERROR) {

        // write data from the string variable into the stream buffer
        // * the stream buffer will be expanded automatically depending on the size of data to be written
        if ((error = writer.WriteSFXAnsiString(string)) == SFERR_NO_ERROR) {

            // write data from the stream buffer into the file
            // * the write operation will finish by calling the Flush function once
            error = writer.Flush();
        } 
        // release the stream for writing into the file
        writer.Release();
    } 
    // close the file
    file.Close();
} 
if (error != SFERR_NO_ERROR) {

    // if an error occurs
    ...
}

Write data using the variable buffer stream

Each stream has its own buffer(stream buffer). Since the stream for writing data into the file is gotten by calling the SFXFile::GetStreamWriter function without the size argument, the variable buffer will be used. Therefore, the stream buffer will be expanded to the same size with the output file. The SFXAnsiStringStreamWriter::WriteSFXAnsiString function writes data from the string variable into the stream buffer. The SFXStreamWriter::Flush function writes data from the stream buffer into the file.