HDFS-10656. Optimize conversion of byte arrays back to path string. Contributed by Daryn Sharp.
Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/bebf10d2 Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/bebf10d2 Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/bebf10d2 Branch: refs/heads/YARN-2915 Commit: bebf10d2455cad1aa8985553417d4d74a61150ee Parents: 2d82276 Author: Kihwal Lee <kih...@apache.org> Authored: Wed Aug 3 11:53:41 2016 -0500 Committer: Kihwal Lee <kih...@apache.org> Committed: Wed Aug 3 11:53:41 2016 -0500 ---------------------------------------------------------------------- .../java/org/apache/hadoop/hdfs/DFSUtil.java | 52 ++++++++++++-------- 1 file changed, 32 insertions(+), 20 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/hadoop/blob/bebf10d2/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java ---------------------------------------------------------------------- diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java index 5ab6978..3fe944e 100644 --- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java +++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java @@ -84,7 +84,6 @@ import org.apache.hadoop.security.authorize.AccessControlList; import org.apache.hadoop.util.ToolRunner; import com.google.common.annotations.VisibleForTesting; -import com.google.common.base.Charsets; import com.google.common.base.Joiner; import com.google.common.base.Preconditions; import com.google.common.collect.Lists; @@ -267,27 +266,40 @@ public class DFSUtil { /** * Given a list of path components returns a path as a UTF8 String */ - public static String byteArray2PathString(byte[][] pathComponents, - int offset, int length) { - if (pathComponents.length == 0) { + public static String byteArray2PathString(final byte[][] components, + final int offset, final int length) { + // specifically not using StringBuilder to more efficiently build + // string w/o excessive byte[] copies and charset conversions. + final int range = offset + length; + Preconditions.checkPositionIndexes(offset, range, components.length); + if (length == 0) { return ""; } - Preconditions.checkArgument(offset >= 0 && offset < pathComponents.length); - Preconditions.checkArgument(length >= 0 && offset + length <= - pathComponents.length); - if (offset == 0 && length == 1 - && (pathComponents[0] == null || pathComponents[0].length == 0)) { - return Path.SEPARATOR; - } - StringBuilder result = new StringBuilder(); - int lastIndex = offset + length - 1; - for (int i = offset; i <= lastIndex; i++) { - result.append(new String(pathComponents[i], Charsets.UTF_8)); - if (i < lastIndex) { - result.append(Path.SEPARATOR_CHAR); - } - } - return result.toString(); + // absolute paths start with either null or empty byte[] + byte[] firstComponent = components[offset]; + boolean isAbsolute = (offset == 0 && + (firstComponent == null || firstComponent.length == 0)); + if (offset == 0 && length == 1) { + return isAbsolute ? Path.SEPARATOR : bytes2String(firstComponent); + } + // compute length of full byte[], seed with 1st component and delimiters + int pos = isAbsolute ? 0 : firstComponent.length; + int size = pos + length - 1; + for (int i=offset + 1; i < range; i++) { + size += components[i].length; + } + final byte[] result = new byte[size]; + if (!isAbsolute) { + System.arraycopy(firstComponent, 0, result, 0, firstComponent.length); + } + // append remaining components as "/component". + for (int i=offset + 1; i < range; i++) { + result[pos++] = (byte)Path.SEPARATOR_CHAR; + int len = components[i].length; + System.arraycopy(components[i], 0, result, pos, len); + pos += len; + } + return bytes2String(result); } public static String byteArray2PathString(byte[][] pathComponents) { --------------------------------------------------------------------- To unsubscribe, e-mail: common-commits-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-commits-h...@hadoop.apache.org
