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deflate_add

(PHP 7, PHP 8)

deflate_add — Incrementally deflate data

Description

deflate_add(DeflateContext $context, string $data, int $flush_mode = ZLIB_SYNC_FLUSH): string|false

Incrementally deflates data in the specified context.

Parameters

context: A context created with deflate_init().
data: A chunk of data to compress.
flush_mode: One of ZLIB_BLOCK, ZLIB_NO_FLUSH, ZLIB_PARTIAL_FLUSH, ZLIB_SYNC_FLUSH (default), ZLIB_FULL_FLUSH, ZLIB_FINISH. Normally you will want to set ZLIB_NO_FLUSH to maximize compression, and ZLIB_FINISH to terminate with the last chunk of data. See the » zlib manual for a detailed description of these constants.

Return Values

Returns a chunk of compressed data, or false on failure.

Errors/Exceptions

If invalid arguments are given, an error of level E_WARNING is generated.

Changelog

Version	Description
8.0.0	`context` expects a DeflateContext instance now; previously, a resource was expected.

User Contributed Notes 1 note

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douglasjam at gmail dot com ¶

6 years ago


Example about to use deflate functions to write a gzip encoded file in chunks.

<?php

$handler = fopen('/tmp/test.csv', 'w');
$deflateContext = deflate_init(ZLIB_ENCODING_GZIP, ['level' => 9]);

$strings = [
    'Hello, how are you?' . PHP_EOL,
    'I am fine thanks' . PHP_EOL,
    'Hello, how are you?' . PHP_EOL,
];

foreach ($strings as $string) {
    fwrite($handler, deflate_add($deflateContext, $string, ZLIB_NO_FLUSH));
}

fwrite($handler, deflate_add($deflateContext, '', ZLIB_FINISH));
fclose($handler);

echo gzdecode(file_get_contents('/tmp/test.csv'));

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