chinwag-android/app/src/main/java/com/keylesspalace/tusky/util/StringUtils.kt
Ivan Kupalov 63952813c8 Fix incorrectly incrementing IDs before sending to server. (#1026)
* Fix incorrectly incrementing IDs before sending to server.

* Add TimelineRepositoryTest, fix adding placeholder, fix String#dec()

* Add more TimelineRepository tests, fix bugs

* Add tests for adding statuses from DB.
2019-02-05 20:06:00 +01:00

73 lines
1.7 KiB
Kotlin

@file:JvmName("StringUtils")
package com.keylesspalace.tusky.util
import java.util.Random
private const val POSSIBLE_CHARS = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
fun randomAlphanumericString(count: Int): String {
val chars = CharArray(count)
val random = Random()
for (i in 0 until count) {
chars[i] = POSSIBLE_CHARS[random.nextInt(POSSIBLE_CHARS.length)]
}
return String(chars)
}
// We sort statuses by ID. Something we need to invent some ID for placeholder.
// Not sure if inc()/dec() should be made `operator` or not
/**
* "Increment" string so that during sorting it's bigger than [this].
*/
fun String.inc(): String {
// We assume that we will stay in the safe range for now
val builder = this.toCharArray()
builder[lastIndex] = builder[lastIndex].inc()
return String(builder)
}
/**
* "Decrement" string so that during sorting it's smaller than [this].
*/
fun String.dec(): String {
if (this.isEmpty()) return this
val builder = this.toCharArray()
var i = builder.lastIndex
while (i > 0) {
if (builder[i] > '0') {
builder[i] = builder[i].dec()
return String(builder)
} else {
builder[i] = 'z'
}
i--
}
return if (builder[0] > '1') {
builder[0] = builder[0].dec()
String(builder)
} else {
String(builder.copyOfRange(1, builder.size))
}
}
/**
* A < B (strictly) by length and then by content.
* Examples:
* "abc" < "bcd"
* "ab" < "abc"
* "cb" < "abc"
* not: "ab" < "ab"
* not: "abc" > "cb"
*/
fun String.isLessThan(other: String): Boolean {
return when {
this.length < other.length -> true
this.length > other.length -> false
else -> this < other
}
}