From c3aabfcd1479b7dc9511c953c577468bf28f5fd5 Mon Sep 17 00:00:00 2001
From: Looly <loolly@aliyun.com>
Date: Wed, 12 Jun 2024 16:32:42 +0800
Subject: [PATCH] add LineCounter

---
 .../dromara/hutool/core/io/file/FileUtil.java |  43 +-------
 .../hutool/core/io/stream/LineCounter.java    | 102 ++++++++++++++++++
 2 files changed, 107 insertions(+), 38 deletions(-)
 create mode 100644 hutool-core/src/main/java/org/dromara/hutool/core/io/stream/LineCounter.java

diff --git a/hutool-core/src/main/java/org/dromara/hutool/core/io/file/FileUtil.java b/hutool-core/src/main/java/org/dromara/hutool/core/io/file/FileUtil.java
index 440110721..1a641adbc 100644
--- a/hutool-core/src/main/java/org/dromara/hutool/core/io/file/FileUtil.java
+++ b/hutool-core/src/main/java/org/dromara/hutool/core/io/file/FileUtil.java
@@ -23,6 +23,7 @@ import org.dromara.hutool.core.io.resource.FileResource;
 import org.dromara.hutool.core.io.resource.Resource;
 import org.dromara.hutool.core.io.resource.ResourceUtil;
 import org.dromara.hutool.core.io.stream.BOMInputStream;
+import org.dromara.hutool.core.io.stream.LineCounter;
 import org.dromara.hutool.core.io.unit.DataSizeUtil;
 import org.dromara.hutool.core.lang.Assert;
 import org.dromara.hutool.core.lang.Console;
@@ -551,7 +552,7 @@ public class FileUtil extends PathUtil {
 	 * @since 5.7.22
 	 */
 	public static int getTotalLines(final File file) {
-		return getTotalLines(file, 1024);
+		return getTotalLines(file, -1);
 	}
 
 	/**
@@ -563,46 +564,12 @@ public class FileUtil extends PathUtil {
 	 * @return 该文件总行数
 	 * @since 5.8.28
 	 */
-	public static int getTotalLines(final File file, int bufferSize) {
+	public static int getTotalLines(final File file, final int bufferSize) {
 		if (false == isFile(file)) {
 			throw new IORuntimeException("Input must be a File");
 		}
-		if (bufferSize < 1) {
-			bufferSize = 1024;
-		}
-		try (final InputStream is = getInputStream(file)) {
-			final byte[] c = new byte[bufferSize];
-			int readChars = is.read(c);
-			if (readChars == -1) {
-				// 空文件，返回0
-				return 0;
-			}
-
-			// 起始行为1
-			// 如果只有一行，无换行符，则读取结束后返回1
-			// 如果多行，最后一行无换行符，最后一行需要单独计数
-			// 如果多行，最后一行有换行符，则空行算作一行
-			int count = 1;
-			while (readChars == bufferSize) {
-				for (int i = 0; i < bufferSize; i++) {
-					if (c[i] == CharUtil.LF) {
-						++count;
-					}
-				}
-				readChars = is.read(c);
-			}
-
-			// count remaining characters
-			while (readChars != -1) {
-				for (int i = 0; i < readChars; i++) {
-					if (c[i] == CharUtil.LF) {
-						++count;
-					}
-				}
-				readChars = is.read(c);
-			}
-
-			return count;
+		try (final LineCounter lineCounter = new LineCounter(getInputStream(file), bufferSize)) {
+			return lineCounter.getCount();
 		} catch (final IOException e) {
 			throw new IORuntimeException(e);
 		}
diff --git a/hutool-core/src/main/java/org/dromara/hutool/core/io/stream/LineCounter.java b/hutool-core/src/main/java/org/dromara/hutool/core/io/stream/LineCounter.java
new file mode 100644
index 000000000..49b4b37d5
--- /dev/null
+++ b/hutool-core/src/main/java/org/dromara/hutool/core/io/stream/LineCounter.java
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2024. looly(loolly@aliyun.com)
+ * Hutool is licensed under Mulan PSL v2.
+ * You can use this software according to the terms and conditions of the Mulan PSL v2.
+ * You may obtain a copy of Mulan PSL v2 at:
+ *          https://license.coscl.org.cn/MulanPSL2
+ * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+ * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+ * See the Mulan PSL v2 for more details.
+ */
+
+package org.dromara.hutool.core.io.stream;
+
+import org.dromara.hutool.core.io.IORuntimeException;
+import org.dromara.hutool.core.text.CharUtil;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * 行数计数器
+ *
+ * @since 6.0.0
+ */
+public class LineCounter implements Closeable {
+
+	private final InputStream is;
+	private final int bufferSize;
+
+	private int count = -1;
+
+	/**
+	 * 构造
+	 *
+	 * @param is         输入流
+	 * @param bufferSize 缓存大小，小于1则使用默认的1024
+	 */
+	public LineCounter(final InputStream is, final int bufferSize) {
+		this.is = is;
+		this.bufferSize = bufferSize < 1 ? 1024 : bufferSize;
+	}
+
+	/**
+	 * 获取行数
+	 *
+	 * @return 行数
+	 */
+	public int getCount() {
+		if (this.count < 0) {
+			try {
+				this.count = count();
+			} catch (final IOException e) {
+				throw new IORuntimeException(e);
+			}
+		}
+		return this.count;
+	}
+
+	@Override
+	public void close() throws IOException {
+		if (null != this.is) {
+			this.is.close();
+		}
+	}
+
+	private int count() throws IOException {
+		final byte[] c = new byte[bufferSize];
+		int readChars = is.read(c);
+		if (readChars == -1) {
+			// 空文件，返回0
+			return 0;
+		}
+
+		// 起始行为1
+		// 如果只有一行，无换行符，则读取结束后返回1
+		// 如果多行，最后一行无换行符，最后一行需要单独计数
+		// 如果多行，最后一行有换行符，则空行算作一行
+		int count = 1;
+		while (readChars == bufferSize) {
+			for (int i = 0; i < bufferSize; i++) {
+				if (c[i] == CharUtil.LF) {
+					++count;
+				}
+			}
+			readChars = is.read(c);
+		}
+
+		// count remaining characters
+		while (readChars != -1) {
+			for (int i = 0; i < readChars; i++) {
+				if (c[i] == CharUtil.LF) {
+					++count;
+				}
+			}
+			readChars = is.read(c);
+		}
+
+		return count;
+	}
+}