Add utility function to create name based uuid without namespace

If the value is same, I don't want the generated UUID to be unique. This will generate the same output every time if the input is same.

shared/src/androidMain/kotlin/dev/sasikanth/rss/reader/utils/uuid.android.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2024 Sasikanth Miriyampalli
+ *
+ * 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 dev.sasikanth.rss.reader.utils
+
+import com.benasher44.uuid.UuidHasher
+import java.security.MessageDigest
+
+internal actual fun hasher(): UuidHasher {
+  return JvmHasher("SHA-1", 5)
+}
+
+// Copied from:
+// https://github.com/benasher44/uuid/blob/f3768dd19fdd58ac01711733923d7db5a433ac79/src/jvmMain/kotlin/namebased.kt#L33
+private class JvmHasher(
+  algorithmName: String,
+  override val version: Int,
+) : UuidHasher {
+  private val digest = MessageDigest.getInstance(algorithmName)
+
+  override fun update(input: ByteArray) {
+    digest.update(input)
+  }
+
+  override fun digest(): ByteArray {
+    return digest.digest()
+  }
+}

shared/src/commonMain/kotlin/dev/sasikanth/rss/reader/utils/uuid.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2024 Sasikanth Miriyampalli
+ *
+ * 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 dev.sasikanth.rss.reader.utils
+
+import com.benasher44.uuid.Uuid
+import com.benasher44.uuid.UuidHasher
+import com.benasher44.uuid.uuidOf
+import kotlin.experimental.and
+import kotlin.experimental.or
+
+// Number of bytes in a UUID
+internal const val UUID_BYTES = 16
+
+internal fun nameBasedUuidOf(value: String): Uuid {
+  val hasher = hasher()
+  hasher.update(value.encodeToByteArray())
+  val hashedBytes = hasher.digest()
+  hashedBytes[6] =
+    hashedBytes[6]
+      .and(0b00001111) // clear the 4 most sig bits
+      .or(hasher.version.shl(4).toByte())
+  hashedBytes[8] =
+    hashedBytes[8]
+      .and(0b00111111) // clear the 2 most sig bits
+      .or(-0b10000000) // set 2 most sig to 10
+  return uuidOf(hashedBytes.copyOf(UUID_BYTES))
+}
+
+internal expect fun hasher(): UuidHasher

shared/src/iosMain/kotlin/dev/sasikanth/rss/reader/utils/uuid.ios.kt

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2024 Sasikanth Miriyampalli
+ *
+ * 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 dev.sasikanth.rss.reader.utils
+
+import com.benasher44.uuid.UuidHasher
+import kotlinx.cinterop.ExperimentalForeignApi
+import kotlinx.cinterop.addressOf
+import kotlinx.cinterop.reinterpret
+import kotlinx.cinterop.usePinned
+import platform.CoreCrypto.CC_SHA1
+import platform.CoreCrypto.CC_SHA1_DIGEST_LENGTH
+
+internal actual fun hasher(): UuidHasher {
+  return AppleHasher(AppleHasher.Companion::sha1Digest, 5)
+}
+
+// Copied from:
+// https://github.com/benasher44/uuid/blob/f3768dd19fdd58ac01711733923d7db5a433ac79/src/appleMain/kotlin/namebased.kt#L40
+@OptIn(ExperimentalForeignApi::class)
+private class AppleHasher(
+  private val digestFunc: (ByteArray) -> ByteArray,
+  override val version: Int,
+) : UuidHasher {
+  private var data = ByteArray(0)
+
+  override fun update(input: ByteArray) {
+    val prevLength = data.size
+    data = data.copyOf(data.size + input.size)
+    input.copyInto(data, prevLength)
+  }
+
+  override fun digest(): ByteArray {
+    return digestFunc(data)
+  }
+
+  companion object {
+    fun sha1Digest(data: ByteArray): ByteArray {
+      return ByteArray(CC_SHA1_DIGEST_LENGTH).also { bytes ->
+        bytes.usePinned { digestPin ->
+          data.usePinned { dataPin ->
+            CC_SHA1(dataPin.addressOf(0), data.size.toUInt(), digestPin.addressOf(0).reinterpret())
+          }
+        }
+      }
+    }
+  }
+}