Add ByteUtil

src/main/kotlin/top/fatweb/api/util/ByteUtil.kt

@@ -0,0 +1,76 @@
+package top.fatweb.api.util
+
+import kotlin.math.floor
+
+object ByteUtil {
+    private const val BASE = 1024
+
+    enum class ByteUnit {
+        B, KiB, MiB, GiB, TiB, PiB, EiB, ZiB, YiB
+    }
+
+    fun formatByteSize(byteSize: Long): String {
+        if (byteSize <= -1) {
+            return byteSize.toString()
+        }
+
+        var size = byteSize.toDouble()
+        if (floor(size / BASE) <= 0) {
+            return format(size, ByteUnit.B)
+        }
+
+        size /= BASE
+        if (floor(size / BASE) <= 0) {
+            return format(size, ByteUnit.KiB)
+        }
+
+        size /= BASE
+        if (floor(size / BASE) <= 0) {
+            return format(size, ByteUnit.MiB)
+        }
+
+        size /= BASE
+        if (floor(size / BASE) <= 0) {
+            return format(size, ByteUnit.GiB)
+        }
+
+        size /= BASE
+        if (floor(size / BASE) <= 0) {
+            return format(size, ByteUnit.TiB)
+        }
+
+        size /= BASE
+        if (floor(size / BASE) <= 0) {
+            return format(size, ByteUnit.PiB)
+        }
+
+        size /= BASE
+        if (floor(size / BASE) <= 0) {
+            return format(size, ByteUnit.EiB)
+        }
+
+        size /= BASE
+        if (floor(size / BASE) <= 0) {
+            return format(size, ByteUnit.ZiB)
+        }
+
+        size /= BASE
+        return format(size, ByteUnit.YiB)
+    }
+
+    fun format(size: Double, unit: ByteUnit): String {
+        val precision = if (size * 1000 % 10 > 0) {
+            3
+        } else if (size * 100 % 10 > 0) {
+            2
+        } else if (size * 10 % 10 > 0) {
+            1
+        } else {
+            0
+        }
+
+        val formatStr = "%.${precision}f"
+
+        return String.format(formatStr, size) + unit.name
+    }
+}