RosettaCodeData/Task/Bitwise-IO/Seed7/bitwise-io.seed7

$ include "seed7_05.s7i";
  include "bitdata.s7i";
  include "strifile.s7i";

const proc: initWriteAscii (inout file: outFile, inout integer: bitPos) is func
  begin
    outFile.bufferChar := '\0;';
    bitPos := 0;
  end func;

const proc: writeAscii (inout file: outFile, inout integer: bitPos, in string: ascii) is func
  local
    var char: ch is ' ';
  begin
    for ch range ascii do
      if ch > '\127;' then
        raise RANGE_ERROR;
      else
        putBitsMsb(outFile, bitPos, ord(ch), 7);
      end if;
    end for;
  end func;

const proc: finishWriteAscii (inout file: outFile, inout integer: bitPos) is func
  begin
    putBitsMsb(outFile, bitPos, 0, 7);  # Write a terminating NUL char.
    write(outFile, chr(ord(outFile.bufferChar)));
  end func;

const func string: readAscii (inout msbBitStream: aBitStream) is func
  result
    var string: stri is "";
  local
    var char: ch is ' ';
  begin
    while ch <> '\0;' do
      ch := chr(getBits(aBitStream, 7));
      if ch <> '\0;' then
        stri &:= ch;
      end if;
    end while;
  end func;

const proc: main is func
  local
    var file: aFile is STD_NULL;
    var integer: bitPos is 0;
    var msbBitStream: aBitStream is msbBitStream.value;
  begin
    aFile := openStriFile;
    initWriteAscii(aFile, bitPos);
    writeAscii(aFile, bitPos, "Hello, Rosetta Code!");
    finishWriteAscii(aFile, bitPos);
    seek(aFile, 1);
    aBitStream := openMsbBitStream(aFile);
    writeln(literal(readAscii(aBitStream)));
  end func;