org.apache.drill.common.util.DrillStringUtils.java Source code

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.drill.common.util;

import io.netty.buffer.ByteBuf;

import org.apache.commons.lang3.StringEscapeUtils;
import org.apache.commons.lang3.StringUtils;

public class DrillStringUtils {

    /**
     * Converts the long number into more human readable string.
     */
    public static String readable(long bytes) {
        int unit = 1024;
        long absBytes = Math.abs(bytes);
        if (absBytes < unit) {
            return bytes + " B";
        }
        int exp = (int) (Math.log(absBytes) / Math.log(unit));
        char pre = ("KMGTPE").charAt(exp - 1);
        return String.format("%s%.1f %ciB", (bytes == absBytes ? "" : "-"), absBytes / Math.pow(unit, exp), pre);
    }

    /**
     * Unescapes any Java literals found in the {@code String}.
     * For example, it will turn a sequence of {@code '\'} and
     * {@code 'n'} into a newline character, unless the {@code '\'}
     * is preceded by another {@code '\'}.
     *
     * @param input  the {@code String} to unescape, may be null
     * @return a new unescaped {@code String}, {@code null} if null string input
     */
    public static final String unescapeJava(String input) {
        return StringEscapeUtils.unescapeJava(input);
    }

    /**
     * Escapes the characters in a {@code String} according to Java string literal
     * rules.
     *
     * Deals correctly with quotes and control-chars (tab, backslash, cr, ff,
     * etc.) so, for example, a tab becomes the characters {@code '\\'} and
     * {@code 't'}.
     *
     * Example:
     * <pre>
     * input string: He didn't say, "Stop!"
     * output string: He didn't say, \"Stop!\"
     * </pre>
     *
     * @param input  String to escape values in, may be null
     * @return String with escaped values, {@code null} if null string input
     */
    public static final String escapeJava(String input) {
        return StringEscapeUtils.escapeJava(input);
    }

    public static final String escapeNewLines(String input) {
        if (input == null) {
            return null;
        }
        StringBuilder result = new StringBuilder();
        boolean sawNewline = false;
        for (int i = 0; i < input.length(); i++) {
            char curChar = input.charAt(i);
            if (curChar == '\r' || curChar == '\n') {
                if (sawNewline) {
                    continue;
                }
                sawNewline = true;
                result.append("\\n");
            } else {
                sawNewline = false;
                result.append(curChar);
            }
        }
        return result.toString();
    }

    /**
     * Copied form commons-lang 2.x code as common-lang 3.x has this API removed.
     * (http://commons.apache.org/proper/commons-lang/article3_0.html#StringEscapeUtils.escapeSql)
     * @param str
     * @return
     */
    public static String escapeSql(String str) {
        return (str == null) ? null : StringUtils.replace(str, "'", "''");
    }

    /**
     * Return a printable representation of a byte buffer, escaping the non-printable
     * bytes as '\\xNN' where NN is the hexadecimal representation of such bytes.
     *
     * This function does not modify  the {@code readerIndex} and {@code writerIndex}
     * of the byte buffer.
     */
    public static String toBinaryString(ByteBuf buf, int strStart, int strEnd) {
        StringBuilder result = new StringBuilder();
        for (int i = strStart; i < strEnd; ++i) {
            appendByte(result, buf.getByte(i));
        }
        return result.toString();
    }

    /**
     * Return a printable representation of a byte array, escaping the non-printable
     * bytes as '\\xNN' where NN is the hexadecimal representation of such bytes.
     */
    public static String toBinaryString(byte[] buf) {
        return toBinaryString(buf, 0, buf.length);
    }

    /**
     * Return a printable representation of a byte array, escaping the non-printable
     * bytes as '\\xNN' where NN is the hexadecimal representation of such bytes.
     */
    public static String toBinaryString(byte[] buf, int strStart, int strEnd) {
        StringBuilder result = new StringBuilder();
        for (int i = strStart; i < strEnd; ++i) {
            appendByte(result, buf[i]);
        }
        return result.toString();
    }

    private static void appendByte(StringBuilder result, byte b) {
        int ch = b & 0xFF;
        if ((ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z')
                || " `~!@#$%^&*()-_=+[]{}|;:'\",.<>/?".indexOf(ch) >= 0) {
            result.append((char) ch);
        } else {
            result.append(String.format("\\x%02X", ch));
        }
    }

    /**
     * In-place parsing of a hex encoded binary string.
     *
     * This function does not modify  the {@code readerIndex} and {@code writerIndex}
     * of the byte buffer.
     *
     * @return Index in the byte buffer just after the last written byte.
     */
    public static int parseBinaryString(ByteBuf str, int strStart, int strEnd) {
        int length = (strEnd - strStart);
        int dstEnd = strStart;
        for (int i = strStart; i < strStart + length; i++) {
            byte b = str.getByte(i);
            if (b == '\\' && strEnd > i + 3 && (str.getByte(i + 1) == 'x' || str.getByte(i + 1) == 'X')) {
                // ok, take next 2 hex digits.
                byte hd1 = str.getByte(i + 2);
                byte hd2 = str.getByte(i + 3);
                if (isHexDigit(hd1) && isHexDigit(hd2)) { // [a-fA-F0-9]
                    // turn hex ASCII digit -> number
                    b = (byte) ((toBinaryFromHex(hd1) << 4) + toBinaryFromHex(hd2));
                    i += 3; // skip 3
                }
            }
            str.setByte(dstEnd++, b);
        }
        return dstEnd;
    }

    /**
     * Takes a ASCII digit in the range A-F0-9 and returns
     * the corresponding integer/ordinal value.
     * @param ch  The hex digit.
     * @return The converted hex value as a byte.
     */
    private static byte toBinaryFromHex(byte ch) {
        if (ch >= 'A' && ch <= 'F') {
            return (byte) ((byte) 10 + (byte) (ch - 'A'));
        } else if (ch >= 'a' && ch <= 'f') {
            return (byte) ((byte) 10 + (byte) (ch - 'a'));
        }
        return (byte) (ch - '0');
    }

    private static boolean isHexDigit(byte c) {
        return (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F') || (c >= '0' && c <= '9');
    }

}