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Geohash-specific relays (#306)

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* per-relay-chat

* normalize relay URL

* turn off default relays

* add relay list

* fetch relay list from the internet
This commit is contained in:
callebtc
2025-08-24 12:52:31 +02:00
committed by GitHub
parent cb7b01ad81
commit 23c397fe7b
6 changed files with 774 additions and 13 deletions
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app/src/main/java/com/bitchat/android/geohash/Geohash.kt
+39
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@@ -9,6 +9,7 @@ package com.bitchat.android.geohash
object Geohash {
private val base32Chars = "0123456789bcdefghjkmnpqrstuvwxyz".toCharArray()
private val charToValue: Map<Char, Int> = base32Chars.withIndex().associate { it.value to it.index }
/**
* Encodes the provided coordinates into a geohash string.
@@ -62,4 +63,42 @@ object Geohash {
return geohash.toString()
}
/**
* Decodes a geohash string to the center latitude/longitude of its cell.
* @return Pair(latitude, longitude)
*/
fun decodeToCenter(geohash: String): Pair<Double, Double> {
if (geohash.isEmpty()) return 0.0 to 0.0
var latInterval = -90.0 to 90.0
var lonInterval = -180.0 to 180.0
var isEven = true
geohash.lowercase().forEach { ch ->
val cd = charToValue[ch] ?: return 0.0 to 0.0
for (mask in intArrayOf(16, 8, 4, 2, 1)) {
if (isEven) {
val mid = (lonInterval.first + lonInterval.second) / 2
if ((cd and mask) != 0) {
lonInterval = mid to lonInterval.second
} else {
lonInterval = lonInterval.first to mid
}
} else {
val mid = (latInterval.first + latInterval.second) / 2
if ((cd and mask) != 0) {
latInterval = mid to latInterval.second
} else {
latInterval = latInterval.first to mid
}
}
isEven = !isEven
}
}
val latCenter = (latInterval.first + latInterval.second) / 2
val lonCenter = (lonInterval.first + lonInterval.second) / 2
return latCenter to lonCenter
}
}