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/*
 * Copyright 2010-2015 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jetbrains.kotlin.utils

import java.util.ArrayList
import java.util.HashMap
import java.util.HashSet
import java.util.LinkedHashMap

public fun  Sequence.valuesToMap(key: (V) -> K): Map {
    val map = LinkedHashMap()
    for (v in this) {
        map[key(v)] = v
    }
    return map
}

public fun  Sequence.keysToMap(value: (K) -> V): Map {
    val map = LinkedHashMap()
    for (k in this) {
        map[k] = value(k)
    }
    return map
}

public fun  Sequence.keysToMapExceptNulls(value: (K) -> V?): Map {
    val map = LinkedHashMap()
    for (k in this) {
        val v = value(k)
        if (v != null) {
            map[k] = v
        }
    }
    return map
}

public fun  Iterable.valuesToMap(key: (V) -> K): Map {
    val map = LinkedHashMap()
    for (v in this) {
        map[key(v)] = v
    }
    return map
}

public fun  Iterable.keysToMap(value: (K) -> V): Map {
    val map = LinkedHashMap()
    for (k in this) {
        map[k] = value(k)
    }
    return map
}

public fun  Iterable.keysToMapExceptNulls(value: (K) -> V?): Map {
    val map = LinkedHashMap()
    for (k in this) {
        val v = value(k)
        if (v != null) {
            map[k] = v
        }
    }
    return map
}

public fun  Iterable.mapToIndex(): Map {
    val map = LinkedHashMap()
    for ((index, k) in this.withIndex()) {
        map[k] = index
    }
    return map
}

public inline fun > C.ifEmpty(body: () -> C): C = if (isEmpty()) body() else this

public fun  emptyOrSingletonList(item: T?): List = if (item == null) listOf() else listOf(item)

public fun  MutableCollection.addIfNotNull(t: T?) {
    if (t != null) add(t)
}

public fun  newHashMapWithExpectedSize(expectedSize: Int): HashMap {
    return HashMap(if (expectedSize < 3) 3 else expectedSize + expectedSize / 3 + 1)
}

public fun  newHashSetWithExpectedSize(expectedSize: Int): HashSet {
    return HashSet(if (expectedSize < 3) 3 else expectedSize + expectedSize / 3 + 1)
}

public fun  Collection.toReadOnlyList(): List =
        when (size()) {
            0 -> emptyList()
            1 -> listOf(first())
            else -> ArrayList(this)
        }

public fun  T?.singletonOrEmptyList(): List =
        if (this != null) listOf(this) else emptyList()




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