Merge pull request #1717 from vitorpamplona/claude/ios-gzip-compression-iHfKC
Implement GZip compression/decompression for iOS using zlib
This commit is contained in:
Vitor Pamplona
@@ -0,0 +1,113 @@
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/*
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* Copyright (c) 2025 Vitor Pamplona
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
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* Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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package com.vitorpamplona.quartz.utils
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import kotlin.test.Test
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import kotlin.test.assertEquals
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import kotlin.test.assertFails
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import kotlin.test.assertTrue
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class GZipTest {
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@Test
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fun roundTripSimpleString() {
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val original = "Hello, Nostr!"
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val decompressed = GZip.decompress(GZip.compress(original))
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assertEquals(original, decompressed)
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}
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@Test
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fun roundTripEmptyString() {
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val original = ""
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val decompressed = GZip.decompress(GZip.compress(original))
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assertEquals(original, decompressed)
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}
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@Test
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fun roundTripLongRepetitiveString() {
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val original = "abcdefghij".repeat(1000)
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val compressed = GZip.compress(original)
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val decompressed = GZip.decompress(compressed)
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assertEquals(original, decompressed)
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}
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@Test
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fun compressedSizeIsSmallerForRepetitiveInput() {
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val original = "abcdefghij".repeat(1000)
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val compressed = GZip.compress(original)
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assertTrue(
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compressed.size < original.encodeToByteArray().size,
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"Expected compressed size (${compressed.size}) to be smaller than original (${original.encodeToByteArray().size})",
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)
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}
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@Test
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fun roundTripUnicodeString() {
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val original = "こんにちは世界 🌍 مرحبا Привет"
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val decompressed = GZip.decompress(GZip.compress(original))
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assertEquals(original, decompressed)
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}
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@Test
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fun roundTripNostrJsonEvent() {
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val original =
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"""{"id":"abc123","pubkey":"deadbeef","created_at":1700000000,"kind":1,""" +
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""""tags":[],"content":"Hello world","sig":"cafebabe"}"""
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val decompressed = GZip.decompress(GZip.compress(original))
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assertEquals(original, decompressed)
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}
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@Test
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fun compressedBytesStartWithGzipMagicNumber() {
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// gzip streams always begin with 0x1F 0x8B
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val compressed = GZip.compress("test")
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assertTrue(compressed.size >= 2, "Compressed output too short to contain gzip header")
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assertEquals(0x1F.toByte(), compressed[0], "Expected gzip magic byte 0 (0x1F)")
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assertEquals(0x8B.toByte(), compressed[1], "Expected gzip magic byte 1 (0x8B)")
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}
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@Test
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fun compressedOutputDiffersFromInput() {
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val original = "Hello, Nostr!"
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val compressed = GZip.compress(original)
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assertTrue(
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!compressed.contentEquals(original.encodeToByteArray()),
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"Compressed output should differ from the raw input bytes",
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)
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}
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@Test
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fun decompressInvalidDataThrows() {
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val garbage = byteArrayOf(0x00, 0x01, 0x02, 0x03, 0x04)
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assertFails { GZip.decompress(garbage) }
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}
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@Test
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fun roundTripSingleCharacter() {
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val original = "A"
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assertEquals(original, GZip.decompress(GZip.compress(original)))
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}
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@Test
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fun roundTripSpecialCharacters() {
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val original = "\t\n\r\u0000\u001F\u007F"
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assertEquals(original, GZip.decompress(GZip.compress(original)))
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}
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}
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@@ -20,12 +20,118 @@
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*/
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package com.vitorpamplona.quartz.utils
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import kotlinx.cinterop.ExperimentalForeignApi
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import kotlinx.cinterop.alloc
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import kotlinx.cinterop.memScoped
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import kotlinx.cinterop.ptr
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import kotlinx.cinterop.reinterpret
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import kotlinx.cinterop.usePinned
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import platform.zlib.Z_DEFAULT_COMPRESSION
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import platform.zlib.Z_DEFAULT_STRATEGY
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import platform.zlib.Z_DEFLATED
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import platform.zlib.Z_FINISH
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import platform.zlib.Z_NO_FLUSH
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import platform.zlib.Z_OK
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import platform.zlib.Z_STREAM_END
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import platform.zlib.deflate
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import platform.zlib.deflateBound
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import platform.zlib.deflateEnd
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import platform.zlib.deflateInit2
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import platform.zlib.inflate
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import platform.zlib.inflateEnd
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import platform.zlib.inflateInit2
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import platform.zlib.z_stream
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@OptIn(ExperimentalForeignApi::class)
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actual object GZip {
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/**
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* Compresses [content] into a gzip byte array using zlib's deflateInit2 with
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* windowBits=31 (MAX_WBITS + 16), which requests the gzip wrapper format.
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* deflateBound gives an upper-bound on output size so a single deflate call
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* with Z_FINISH is always sufficient.
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*/
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actual fun compress(content: String): ByteArray {
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TODO("Not yet implemented")
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val input = content.encodeToByteArray()
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return memScoped {
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val stream = alloc<z_stream>()
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// windowBits = 15 + 16 = 31 → gzip format
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deflateInit2(
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stream.ptr,
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Z_DEFAULT_COMPRESSION,
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Z_DEFLATED,
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31,
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8,
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Z_DEFAULT_STRATEGY,
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).let { check(it == Z_OK) { "deflateInit2 failed: $it" } }
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val maxSize = deflateBound(stream.ptr, input.size.toULong()).toInt()
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val output = ByteArray(maxSize)
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val written =
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input.usePinned { pinIn ->
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output.usePinned { pinOut ->
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stream.next_in = pinIn.addressOf(0).reinterpret()
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stream.avail_in = input.size.toUInt()
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stream.next_out = pinOut.addressOf(0).reinterpret()
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stream.avail_out = maxSize.toUInt()
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deflate(stream.ptr, Z_FINISH)
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.let { check(it == Z_STREAM_END) { "deflate failed: $it" } }
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maxSize - stream.avail_out.toInt()
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}
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}
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deflateEnd(stream.ptr)
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output.copyOf(written)
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}
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}
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/**
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* Decompresses a gzip [content] byte array back to a UTF-8 string using
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* zlib's inflateInit2 with windowBits=47 (MAX_WBITS + 32), which enables
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* automatic detection of both gzip and zlib formats.
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* Output is collected in fixed-size chunks to handle arbitrary output size.
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*/
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actual fun decompress(content: ByteArray): String {
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TODO("Not yet implemented")
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val chunks = ArrayList<ByteArray>()
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val chunkSize = maxOf(content.size * 4, 4096)
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memScoped {
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val stream = alloc<z_stream>()
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// windowBits = 15 + 32 = 47 → auto-detect gzip or zlib
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inflateInit2(stream.ptr, 47)
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.let { check(it == Z_OK) { "inflateInit2 failed: $it" } }
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content.usePinned { pinIn ->
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stream.next_in = pinIn.addressOf(0).reinterpret()
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stream.avail_in = content.size.toUInt()
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var status: Int
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do {
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val chunk = ByteArray(chunkSize)
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chunk.usePinned { pinOut ->
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stream.next_out = pinOut.addressOf(0).reinterpret()
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stream.avail_out = chunkSize.toUInt()
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status = inflate(stream.ptr, Z_NO_FLUSH)
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val produced = chunkSize - stream.avail_out.toInt()
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if (produced > 0) chunks.add(chunk.copyOf(produced))
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}
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} while (status == Z_OK)
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check(status == Z_STREAM_END) { "inflate failed: $status" }
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}
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inflateEnd(stream.ptr)
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}
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val totalSize = chunks.sumOf { it.size }
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val result = ByteArray(totalSize)
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var pos = 0
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chunks.forEach { chunk -> chunk.copyInto(result, pos); pos += chunk.size }
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return result.decodeToString()
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}
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}
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