/*
 * Copyright 2008, Haiku.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *              Michael Pfeiffer        <laplace@users.sourceforge.net>
 *              Fredrik Modéen         <fredrik@modeen.se>
 */
#include "FileReadWrite.h"

#include <UTF8.h>
#include <Path.h>


FileReadWrite::FileReadWrite(BFile* file, int32 sourceEncoding)
        : fFile(file),
          fSourceEncoding(sourceEncoding),
          fPositionInBuffer(0),
          fAmtRead(0)
{
}


void
FileReadWrite::SetEncoding(int32 sourceEncoding)
{
        fSourceEncoding = sourceEncoding;
}


uint32 
FileReadWrite::GetEncoding() const
{
        return fSourceEncoding;
}


status_t 
FileReadWrite::Write(const BString& contents) const
{
        ssize_t written = fFile->Write(contents.String(), contents.Length());
        if (written != contents.Length())
                return written < 0 ? (status_t)written : B_IO_ERROR;

        return B_OK;
}


// returns true when '\n' found and false otherwise
bool
FileReadWrite::Next(BString& string)
{
        // Fill up the buffer with the first chunk of data
        if (fPositionInBuffer == 0)
                fAmtRead = fFile->Read(&fBuffer, sizeof(fBuffer));
        while (fAmtRead > 0) {
                // TODO: If the source file is expected to have different encoding,
                // don't we need to check for the line endings in that encoding?!

                int32 remainingLength = fAmtRead - fPositionInBuffer;
                char* currentPosition = fBuffer + fPositionInBuffer;
                char* endLinePosition = (char*)memchr(currentPosition, '\n', remainingLength);

                if (endLinePosition != NULL) {
                        int32 appendLength = endLinePosition - currentPosition;
                        string.Append(currentPosition, appendLength);

                        if (fSourceEncoding != -1) {
                                int32 state = 0;
                                int32 bufferLen = string.Length();
                                int32 destBufferLen = bufferLen;
                                char destination[destBufferLen];
                                convert_to_utf8(fSourceEncoding, string.String(), &bufferLen, destination,
                                        &destBufferLen, &state);
                                string = destination;
                        }

                        fPositionInBuffer += (appendLength + 1) % fAmtRead;

                        return true;
                } else
                        string.Append(currentPosition, remainingLength);

                // Once the buffer runs out, grab some more and start again
                fAmtRead = fFile->Read(&fBuffer, sizeof(fBuffer));
                fPositionInBuffer = 0;
        }
        return false;
}