JPEGView/Independent JPEG Group/filelist.doc

IJG JPEG LIBRARY:  FILE LIST

Copyright (C) 1994, Thomas G. Lane.
This file is part of the Independent JPEG Group's software.
For conditions of distribution and use, see the accompanying README file.


Here is a road map to the files in the IJG JPEG distribution.  The
distribution includes the JPEG library proper, plus two application
programs ("cjpeg" and "djpeg") which use the library to convert JPEG
files to and from some other popular image formats.


THE JPEG LIBRARY
================

Include files:

jpeglib.h	JPEG library's exported data and function declarations.
jconfig.h	Configuration declarations.  Note: this file is not present
		in the distribution; it is generated during installation.
jmorecfg.h	Additional configuration declarations; need not be changed
		for a standard installation.
jerror.h	Declares JPEG library's error and trace message codes.
jinclude.h	Central include file used by library's .c files.
jpegint.h	JPEG library's internal data structures.
jdct.h		Private declarations for forward & reverse DCT subsystems.
jmemsys.h	Private declarations for memory management subsystem.
jversion.h	Version information.

Applications using the library should include jpeglib.h (which in turn
includes jconfig.h and jmorecfg.h).  Optionally, jerror.h may be included
if the application needs to reference individual JPEG error codes.  The
other include files are intended for internal use and would not normally
be included by an application program.  (cjpeg/djpeg do use jinclude.h,
since its function is to improve portability of the whole IJG distribution.
Most other applications will directly include the system include files they
want, and hence won't need jinclude.h.)


C source code files:

These files contain most of the functions intended to be called directly by
an application program:

jcapi.c		Application program interface routines for compression.
jdapi.c		Application program interface routines for decompression.
jcomapi.c	Application program interface routines common to compression
		and decompression.
jcparam.c	Compression parameter setting helper routines.

Compression side of the library:

jcmaster.c	Master control: determines which other modules to use.
jcmainct.c	Main buffer controller (preprocessor => JPEG compressor).
jcprepct.c	Preprocessor buffer controller.
jccoefct.c	Buffer controller for DCT coefficient buffer.
jccolor.c	Color space conversion.
jcsample.c	Downsampling.
jcdctmgr.c	DCT manager (DCT implementation selection & control).
jfdctllm.c	Forward DCT using LL&M algorithm (very high quality).
jchuff.c	Huffman entropy coding.
jcmarker.c	JPEG marker writing.
jdatadst.c	Data destination manager for stdio output.

Decompression side of the library:

jdmaster.c	Master control: determines which other modules to use.
jdmainct.c	Main buffer controller (JPEG decompressor => postprocessor).
jdcoefct.c	Buffer controller for DCT coefficient buffer.
jdpostct.c	Postprocessor buffer controller.
jdmarker.c	JPEG marker reading.
jdhuff.c	Huffman entropy decoding.
jddctmgr.c	IDCT manager (IDCT implementation selection & control).
jidctllm.c	Inverse DCT using LL&M algorithm (very high quality).
jidctred.c	Inverse DCTs with reduced-size outputs.
jdsample.c	Upsampling.
jdcolor.c	Color space conversion.
jquant1.c	One-pass color quantization using a fixed-spacing colormap.
jquant2.c	Two-pass color quantization using a custom-generated colormap.
		Also handles one-pass quantization to an externally given map.
jdatasrc.c	Data source manager for stdio input.

Support files for both compression and decompression:

jerror.c	Standard error handling routines (application replaceable).
jmemmgr.c	System-independent (more or less) memory management code.
jutils.c	Miscellaneous utility routines.

jmemmgr.c relies on a system-dependent memory management module.  The IJG
distribution includes the following implementations of the system-dependent
module:

jmemnobs.c	"No backing store": assumes adequate virtual memory exists.
jmemansi.c	Makes temporary files with ANSI-standard routine tmpfile().
jmemname.c	Makes temporary files wi