Merge pull request #4 from InsanusMokrassar/0.2.1

0.2.1

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## 0.2.1
+
+* `Pagination`
+    * `Common`:
+        * Extension `Pagination#reverse` has been added
+        * Factory `PaginationByIndexes`
+        * Shortcut `calculatePagesNumber` with reversed parameters
+
 ## 0.2.0
 
 * `Repos`

gradle.properties

@@ -19,4 +19,4 @@ github_release_plugin_version=2.2.12
 uuidVersion=0.2.2
 
 group=dev.inmo
-version=0.2.0
+version=0.2.1

pagination/common/src/commonMain/kotlin/dev/inmo/micro_utils/pagination/Pagination.kt

@@ -43,6 +43,11 @@ val Pagination.lastIndex: Int
 fun calculatePagesNumber(datasetSize: Long, pageSize: Int): Int {
     return ceil(datasetSize.toDouble() / pageSize).toInt()
 }
+/**
+ * Calculates pages count for given [datasetSize]. As a fact, it is shortcut for [calculatePagesNumber]
+ * @return calculated page number which can be correctly used in [PaginationResult] as [PaginationResult.page] value
+ */
+fun calculatePagesNumber(pageSize: Int, datasetSize: Long): Int = calculatePagesNumber(datasetSize, pageSize)
 /**
  * Calculates pages count for given [datasetSize]
  */

pagination/common/src/commonMain/kotlin/dev/inmo/micro_utils/pagination/SimplePagination.kt

@@ -27,7 +27,21 @@ data class SimplePagination(
     override val size: Int
 ) : Pagination
 
+/**
+ * Factory for [SimplePagination]
+ */
 fun Pagination(
     page: Int,
     size: Int
 ) = SimplePagination(page, size)
+
+/**
+ * @param firstIndex Inclusive first index of pagination
+ * @param lastIndex INCLUSIVE last index of pagination (last index of object covered by result [SimplePagination])
+ */
+fun PaginationByIndexes(
+    firstIndex: Int,
+    lastIndex: Int
+) = maxOf(0, (lastIndex - firstIndex + 1)).let { size ->
+    Pagination(calculatePage(firstIndex, size), size)
+}

pagination/common/src/commonMain/kotlin/dev/inmo/micro_utils/pagination/utils/PaginationReversing.kt

@@ -0,0 +1,34 @@
+package dev.inmo.micro_utils.pagination.utils
+
+import dev.inmo.micro_utils.pagination.*
+
+/**
+ * Example:
+ *
+ * * `|__f__l_______________________|` will be transformed to `|_______________________f__l__|`
+ * * `|__f__l_|` will be transformed to `|__f__l_|`
+ *
+ * @return Reversed version of this [Pagination]
+ */
+fun Pagination.reverse(objectsCount: Long): SimplePagination {
+    val firstIndex = (objectsCount - (this.lastIndex + 1)).let {
+        when {
+            it < 0 -> it
+            it > objectsCount -> objectsCount
+            else -> it
+        }
+    }.toInt()
+    val lastIndex = (objectsCount - (this.firstIndex + 1)).let {
+        when {
+            it < 0 -> it
+            it > objectsCount -> objectsCount
+            else -> it
+        }
+    }.toInt()
+    return PaginationByIndexes(firstIndex, lastIndex)
+}
+
+/**
+ * Shortcut for [reverse]
+ */
+fun Pagination.reverse(objectsCount: Int) = reverse(objectsCount.toLong())

pagination/common/src/commonTest/kotlin/dev/inmo/micro_utils/pagination/utils/PaginationReversing.kt

@@ -0,0 +1,24 @@
+package dev.inmo.micro_utils.pagination.utils
+
+import dev.inmo.micro_utils.pagination.*
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class PaginationReversingTests {
+    @Test
+    fun testThatCommonCaseWorksOk() {
+        val pageSize = 2
+        val collectionSize = 8
+        val pages = calculatePage(collectionSize, pageSize)
+
+        doWithPagination(FirstPagePagination(pageSize)) {
+            val reversed = it.reverse(collectionSize.toLong())
+            assertEquals(Pagination(calculatePage(collectionSize - it.firstIndex - it.size, it.size), it.size), reversed)
+            if (it.page < pages) {
+                it.nextPage()
+            } else {
+                null
+            }
+        }
+    }
+}

repos/inmemory/src/commonMain/kotlin/dev/inmo/micro_utils/repos/MapKeyValueRepo.kt

@@ -2,6 +2,8 @@ package dev.inmo.micro_utils.repos
 
 import dev.inmo.micro_utils.coroutines.BroadcastFlow
 import dev.inmo.micro_utils.pagination.*
+import dev.inmo.micro_utils.pagination.utils.paginate
+import dev.inmo.micro_utils.pagination.utils.reverse
 import kotlinx.coroutines.flow.Flow
 
 class ReadMapKeyValueRepo<Key, Value>(
@@ -13,31 +15,27 @@ class ReadMapKeyValueRepo<Key, Value>(
         pagination: Pagination,
         reversed: Boolean
     ): PaginationResult<Value> {
-        val firstIndex: Int = if (reversed) {
+        val values = map.values
-            val size = map.size
+        val actualPagination = if (reversed) pagination.reverse(values.size) else pagination
-            (size - pagination.lastIndex).let { if (it < 0) 0 else it }
+        return values.paginate(actualPagination).let {
-        } else {
+            if (reversed) {
-            pagination.firstIndex
+                it.copy(results = it.results.reversed())
+            } else {
+                it
+            }
         }
-
-        return map.keys.drop(firstIndex).take(pagination.size).mapNotNull { map[it] }.createPaginationResult(
-            firstIndex,
-            count()
-        )
     }
 
     override suspend fun keys(pagination: Pagination, reversed: Boolean): PaginationResult<Key> {
-        val firstIndex: Int = if (reversed) {
+        val keys = map.keys
-            val size = map.size
+        val actualPagination = if (reversed) pagination.reverse(keys.size) else pagination
-            (size - pagination.lastIndex).let { if (it < 0) 0 else it }
+        return keys.paginate(actualPagination).let {
-        } else {
+            if (reversed) {
-            pagination.firstIndex
+                it.copy(results = it.results.reversed())
+            } else {
+                it
+            }
         }
-
-        return map.keys.drop(firstIndex).take(pagination.size).createPaginationResult(
-            firstIndex,
-            count()
-        )
     }
 
     override suspend fun contains(key: Key): Boolean = map.containsKey(key)

repos/inmemory/src/commonMain/kotlin/dev/inmo/micro_utils/repos/MapOneToManyKeyValueRepo.kt

@@ -3,6 +3,7 @@ package dev.inmo.micro_utils.repos
 import dev.inmo.micro_utils.coroutines.BroadcastFlow
 import dev.inmo.micro_utils.pagination.*
 import dev.inmo.micro_utils.pagination.utils.paginate
+import dev.inmo.micro_utils.pagination.utils.reverse
 import kotlinx.coroutines.flow.Flow
 
 class MapReadOneToManyKeyValueRepo<Key, Value>(
@@ -13,8 +14,7 @@ class MapReadOneToManyKeyValueRepo<Key, Value>(
 
         return list.paginate(
             if (reversed) {
-                val firstIndex = (map.size - pagination.lastIndex).let { if (it < 0) 0 else it }
+                pagination.reverse(list.size)
-                SimplePagination(firstIndex, pagination.size)
             } else {
                 pagination
             }
@@ -22,17 +22,15 @@ class MapReadOneToManyKeyValueRepo<Key, Value>(
     }
 
     override suspend fun keys(pagination: Pagination, reversed: Boolean): PaginationResult<Key> {
-        val firstIndex: Int = if (reversed) {
+        val keys = map.keys
-            val size = map.size
+        val actualPagination = if (reversed) pagination.reverse(keys.size) else pagination
-            (size - pagination.lastIndex).let { if (it < 0) 0 else it }
+        return keys.paginate(actualPagination).let {
-        } else {
+            if (reversed) {
-            pagination.firstIndex
+                it.copy(results = it.results.reversed())
+            } else {
+                it
+            }
         }
-
-        return map.keys.drop(firstIndex).take(pagination.size).createPaginationResult(
-            firstIndex,
-            count()
-        )
     }
 
     override suspend fun contains(k: Key): Boolean = map.containsKey(k)