[Cyan]<Imaging>XeroxCompress>FEPSIvOutput.mesa!2

FEPSIvOutput.mesa

last edited by castillo 19-Jun-85 10:04:22

DIRECTORY

FEPSMergerOps USING [OutputH],

Interpress USING [LongOperator],

NSSegment USING [PageCount, PageNumber],

Stream USING [Handle],

XeroxCompress USING [PutBitsProc];

FEPSIvOutput: DEFINITIONS

SHARES Interpress =

BEGIN OPEN IP: Interpress;

This module defines the interface to FEPS output routines whose

primary job is to write data to the output. This

interface was created to hide various output and efficiency

specifics from rest of FEPS merge routine. The implementation is

assumed NOT to be reentrant.

Initialize must be called first to start things off.

outputH ... is the handle to output object. Usually it

is FEPSMergerOps.OutputH which contains NSFile

handle. It could be different for the test

environment.

initialSize ... is the initial size of the output file in pages.

growIncrement ... is the size that the file should grow every

time the size is exceeded.

bufferSize ... is the size of the buffer to be used.

PutBits writes the specified number of bits to the output. The

bits can be up to 16 bits. This routine exists mainly for the

Xerox compression algorthm which deals with nibbles (ugh!).

PutBits can only be called while in Bit Mode. Bit Mode is

entered with EnterBitMode call; it is ended with ExitBitMode

call. All other output routine cannot be called while in Bit

Mode. (Primarily done for efficiency)

PutByte writes the specified number bytes to the output.

Retrieve reads, from the input stream, specified number of bytes

and writes it out to the output.

GetCurrentPosition is called to retrieve the current output

position of the output. SetPosition is called to set the current

position.

CloseOutput will get rid of output buffers and excess pages

allocated to the file. It should be called after all output has

been completed.

EmptyOutput will get rid of output buffers and set the size to

zero.

IP* calls are used to put Interpress operands and operators into

the output.

=====

TYPES

=====

Position: TYPE = RECORD [

page: NSSegment.PageNumber,

offset: LONG CARDINAL];

========

CONSTANTS

=========

startPos: Position = [0,0];

=======

SIGNALS

=======

ExceptionKind: TYPE = {noResources, unknown};

Exception: SIGNAL [code: ExceptionKind];

This signal is resumable if code is noResources

==========

PROCEDURES

==========

General output routines

Initialize: PROCEDURE [

output: FEPSMergerOps.OutputH,

initialSize: NSSegment.PageCount,

growIncrement: NSSegment.PageCount,

bufferSize: NSSegment.PageCount];

PutBits: XeroxCompress.PutBitsProc;

PutByte: PROCEDURE [val: CARDINAL];

PutWord: PROCEDURE [val: CARDINAL];

Retrieve: PROCEDURE [inputSH: Stream.Handle, byteCount: LONG CARDINAL];

GetCurrentPosition: PROCEDURE RETURNS [pos: Position];

SetPosition: PROCEDURE [pos: Position];

CloseOutput: PROCEDURE;

EmptyOutput: PROCEDURE;

Interpress output routines

IPDo: PROCEDURE = INLINE {OpOnly[do]};

IPFindDecompressor: PROCEDURE = INLINE {OpOnly[findDecompressor]};

IPIdentifier: PROCEDURE [s: LONG STRING];

IPInteger: PROCEDURE [n: LONG INTEGER, length: CARDINAL � 0];

IPMakePixelArray: PROCEDURE = INLINE {OpOnly[makePixelArray]};

IPMaskPixel: PROCEDURE = INLINE {OpOnly[maskPixel]};

IPRational: PROCEDURE [num: LONG INTEGER, den: LONG CARDINAL];

IPScale: PROCEDURE = INLINE {OpOnly[scale]};

IPSeqCompressedPixel: PROCEDURE [size: LONG CARDINAL];

OpOnly: PRIVATE PROCEDURE [code: IP.LongOperator];

END...

LOG

6Sep84 - Okamoto - Conceived and created.

20Nov84 - Okamoto - Changed FreeOutput to CloseOutput and added EmptyOutput.