SIMPLE_COMPRESSION - Documentation

Overview

SIMPLE_COMPRESSION provides easy-to-use compression for Eiffel applications, wrapping the ISE zlib library.

Key Features

String compression/decompression
Base64-encoded compression for text storage
Byte array support
File compression
Streaming for large files
Configurable compression levels (0-9)
CRC32/Adler32 checksums

Quick Start

<library name="simple_compression" location="$SIMPLE_COMPRESSION/simple_compression.ecf"/>

Basic Usage

local
    comp: SIMPLE_COMPRESSION
    compressed: STRING
do
    create comp.make

    -- Compress a string
    compressed := comp.compress_string ("Hello, World!")

    -- Decompress
    print (comp.decompress_string (compressed))

    -- Best compression
    comp.set_level_best
    compressed := comp.compress_string (large_data)
    print ("Saved " + comp.compression_percentage.out + "%%")
end

API Reference

Compression Levels

Feature	Description
`set_level (0-9)`	Set compression level
`set_level_fast`	Level 1 - fastest
`set_level_default`	Level 6 - balanced
`set_level_best`	Level 9 - smallest

String Operations

Feature	Description
`compress_string (str)`	Compress to raw bytes
`decompress_string (data)`	Decompress string
`compress_string_base64 (str)`	Compress to Base64
`decompress_string_base64 (b64)`	Decompress from Base64

File Operations

Feature	Description
`compress_file (src, dest)`	Compress file
`decompress_file (src, dest)`	Decompress file
`read_compressed_file (path)`	Read and decompress
`write_compressed_file (path, data)`	Compress and write

Checksums

Feature	Description
`crc32 (data)`	Calculate CRC32
`adler32 (data)`	Calculate Adler-32
`validate_checksum (data, crc)`	Verify CRC32

Statistics

Feature	Description
`compression_ratio`	Input/output ratio
`compression_percentage`	Size reduction %
`space_savings`	Human-readable summary

Streaming API

For large files, use SIMPLE_COMPRESSION_STREAM:

local
    stream: SIMPLE_COMPRESSION_STREAM
do
    create stream.make_compress ("output.gz")
    stream.write ("Chunk 1...")
    stream.write ("Chunk 2...")
    stream.close
end