Brotli Compression Algorithm

The TIFF software distribution includes a collection of programs designed for converting non-TIFF images to TIFF, as well as manipulating and interrogating existing TIFF files. These tools serve two primary purposes:

1. Image Conversion and Manipulation: Tools for converting formats (e.g., ppm2tiff, raw2tiff, tiff2pdf, tiff2ps) and modifying image properties (e.g., tiff2bw for grayscale, tiff2rgba for RGBA).
2. Programming Examples: Many tools are intended as reference implementations for developers learning to use the TIFF library API.

The tools are categorized into Device-dependent (e.g., tiffgt for OpenGL-based display) and Device-independent (standard command-line utilities) programs.

Ghostscript's core is written in C, but it provides language bindings for several high-level languages. These bindings mirror the functionality of the core C API, allowing developers to integrate Ghostscript into various application environments.

Supported languages include:

• C#
• Java
• Python

Note that Java and C# bindings include additional helper methods beyond the standard C API to simplify common application tasks. They also include example viewers for demonstration purposes.

Expat is a C99, stream-oriented XML 1.0 parser. It works by having the developer register handlers (e.g., for start tags) before starting the parse process. When the parser encounters these structures in the XML document, it calls the registered handlers.

Supported Compilers:

• GNU GCC >= 4.5
• LLVM Clang >= 3.5
• Microsoft Visual Studio >= 16.0 (2019 or newer)

GhostPDL is a modular interpreter framework designed to handle multiple input "languages" (file formats) within a single build. It is intended to behave similarly to Ghostscript but is optimized to transparently manage various input formats by swapping or adding interpreters.

Key characteristics:

• Modular Design: New interpreters can be swapped in or out to extend capabilities.
• Job Separation: Jobs must be separated by UEL (Universal End of Language) code sequences or PJL fragments (which implicitly start with a UEL marker).
• Deployment: It can be built as a dynamic link library (DLL) on Windows or a shared object on Linux, Unix, and MacOS X.

DotZLib is a .NET wrapper class library for ZLib1.dll. It provides managed access to several zlib functionalities, including:

• Memory Buffer Operations: Support for inflating and deflating memory buffers.
• Streaming: .NET streaming wrappers for the gz streams part of zlib.
• Checksums: Wrappers for the checksum components of zlib.

For implementation details and usage examples, refer to DotZLib/UnitTests.cs.

The Ghostscript library provides C procedures to implement graphics and filtering capabilities used in PostScript and PDF. It is divided into two main layers:

1. High-level API (gs_ prefix): Directly implements PostScript graphics operators (e.g., gs_moveto, gs_fill). Most procedures take a graphics state object (gs_state *) as their first argument and return an integer code. A return value >= 0 indicates success, while < 0 indicates a failure corresponding to a PostScript error defined in gserrors.h.
2. Lower-level API (gx_ prefix): Exposes more implementation details and is less stable. Unlike the high-level API which uses floating-point user coordinates, the gx_ level generally uses device coordinates in an internal fixed-point representation.

This set of tools provides functionality to manage Brotli dictionaries. Specifically, you can use these tools to:

• Download the Brotli RFC.
• Extract and validate binary dictionaries.
• Generate dictionary derivatives, such as the Java DictionaryData class constants.

Brotli is a generic-purpose lossless compression algorithm that uses a combination of a modern variant of the LZ77 algorithm, Huffman coding, and 2nd order context modeling. It provides compression ratios comparable to the best general-purpose methods and is similar in speed to deflate but offers denser compression.

Important Note on Data Integrity: Brotli is a "stream" format. It does not contain meta-information such as checksums or uncompressed data length. Consequently, it is possible to modify raw ranges of the compressed stream without the decoder noticing the corruption.

Ghostscript is an interpreter for the PostScript® language and PDF files. It consists of two primary components:

1. PostScript interpreter layer: Handles the execution of PostScript code.
2. Graphics library: Provides the underlying rendering capabilities.

Ghostscript is available under the GNU GPL Affero license or via a commercial license from Artifex Software, Inc.

The zlibpas unit provides a Pascal (Delphi, Kylix) interface to the zlib data compression library. It allows Pascal developers to access the full functionality of zlib, including features like checksums that might be missing from standard Borland class wrappers.

Key components in this directory:

• zlibpas.pas: The core Pascal interface unit.
• example.pas: A usage example demonstrating how to implement the interface.
• zlibd32.mak: A makefile for Borland C++.