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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package com.sun.tools.javac.util;


Utility class for static conversion methods between numbers
 and strings in various formats.
 
Note regarding UTF-8.
 The JVMS defines its own version of the UTF-8 format so that it
 contains no zero bytes (modified UTF-8). This is not actually the same
 as Charset.forName("UTF-8").
 

 See also:
 

 The methods here support modified UTF-8.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.

/** Utility class for static conversion methods between numbers
 *  and strings in various formats.
 *
 *  <p>Note regarding UTF-8.
 *  The JVMS defines its own version of the UTF-8 format so that it
 *  contains no zero bytes (modified UTF-8). This is not actually the same
 *  as Charset.forName("UTF-8").
 *
 *  <p>
 *  See also:
 *  <ul>
 *  <li><a href="http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html#jvms-4.4.7">
 *    JVMS 4.4.7 </a></li>
 *  <li><a href="http://docs.oracle.com/javase/7/docs/api/java/io/DataInput.html#modified-utf-8">
      java.io.DataInput: Modified UTF-8 </a></li>
    <li><a href="https://en.wikipedia.org/wiki/UTF-8#Modified_UTF-8">
      Modified UTF-8 (wikipedia) </a></li>
 *  </ul>
 *
 *  The methods here support modified UTF-8.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class Convert {

    
Convert string to integer.

/** Convert string to integer.
     */
    public static int string2int(String s, int radix)
        throws NumberFormatException {
        if (radix == 10) {
            return Integer.parseInt(s, radix);
        } else {
            char[] cs = s.toCharArray();
            int limit = Integer.MAX_VALUE / (radix/2);
            int n = 0;
            for (char c : cs) {
                int d = Character.digit(c, radix);
                if (n < 0 ||
                    n > limit ||
                    n * radix > Integer.MAX_VALUE - d)
                    throw new NumberFormatException();
                n = n * radix + d;
            }
            return n;
        }
    }

    
Convert string to long integer.

/** Convert string to long integer.
     */
    public static long string2long(String s, int radix)
        throws NumberFormatException {
        if (radix == 10) {
            return Long.parseLong(s, radix);
        } else {
            char[] cs = s.toCharArray();
            long limit = Long.MAX_VALUE / (radix/2);
            long n = 0;
            for (char c : cs) {
                int d = Character.digit(c, radix);
                if (n < 0 ||
                    n > limit ||
                    n * radix > Long.MAX_VALUE - d)
                    throw new NumberFormatException();
                n = n * radix + d;
            }
            return n;
        }
    }

/* Conversion routines between names, strings, and byte arrays in Utf8 format
 */

    
Convert `len' bytes from utf8 to characters.
 Parameters are as in System.arraycopy
 Return first index in `dst' past the last copied char.
 @param src        The array holding the bytes to convert.
 @param sindex     The start index from which bytes are converted.
 @param dst        The array holding the converted characters..
 @param dindex     The start index from which converted characters
                   are written.
 @param len        The maximum number of bytes to convert.

/** Convert `len' bytes from utf8 to characters.
     *  Parameters are as in System.arraycopy
     *  Return first index in `dst' past the last copied char.
     *  @param src        The array holding the bytes to convert.
     *  @param sindex     The start index from which bytes are converted.
     *  @param dst        The array holding the converted characters..
     *  @param dindex     The start index from which converted characters
     *                    are written.
     *  @param len        The maximum number of bytes to convert.
     */
    public static int utf2chars(byte[] src, int sindex,
                                char[] dst, int dindex,
                                int len) {
        int i = sindex;
        int j = dindex;
        int limit = sindex + len;
        while (i < limit) {
            int b = src[i++] & 0xFF;
            if (b >= 0xE0) {
                b = (b & 0x0F) << 12;
                b = b | (src[i++] & 0x3F) << 6;
                b = b | (src[i++] & 0x3F);
            } else if (b >= 0xC0) {
                b = (b & 0x1F) << 6;
                b = b | (src[i++] & 0x3F);
            }
            dst[j++] = (char)b;
        }
        return j;
    }

    
Return bytes in Utf8 representation as an array of characters.
 @param src        The array holding the bytes.
 @param sindex     The start index from which bytes are converted.
 @param len        The maximum number of bytes to convert.

/** Return bytes in Utf8 representation as an array of characters.
     *  @param src        The array holding the bytes.
     *  @param sindex     The start index from which bytes are converted.
     *  @param len        The maximum number of bytes to convert.
     */
    public static char[] utf2chars(byte[] src, int sindex, int len) {
        char[] dst = new char[len];
        int len1 = utf2chars(src, sindex, dst, 0, len);
        char[] result = new char[len1];
        System.arraycopy(dst, 0, result, 0, len1);
        return result;
    }

    
Return all bytes of a given array in Utf8 representation
 as an array of characters.
 @param src        The array holding the bytes.

/** Return all bytes of a given array in Utf8 representation
     *  as an array of characters.
     *  @param src        The array holding the bytes.
     */
    public static char[] utf2chars(byte[] src) {
        return utf2chars(src, 0, src.length);
    }

    
Return bytes in Utf8 representation as a string.
 @param src        The array holding the bytes.
 @param sindex     The start index from which bytes are converted.
 @param len        The maximum number of bytes to convert.

/** Return bytes in Utf8 representation as a string.
     *  @param src        The array holding the bytes.
     *  @param sindex     The start index from which bytes are converted.
     *  @param len        The maximum number of bytes to convert.
     */
    public static String utf2string(byte[] src, int sindex, int len) {
        char dst[] = new char[len];
        int len1 = utf2chars(src, sindex, dst, 0, len);
        return new String(dst, 0, len1);
    }

    
Return all bytes of a given array in Utf8 representation
 as a string.
 @param src        The array holding the bytes.

/** Return all bytes of a given array in Utf8 representation
     *  as a string.
     *  @param src        The array holding the bytes.
     */
    public static String utf2string(byte[] src) {
        return utf2string(src, 0, src.length);
    }

    
Copy characters in source array to bytes in target array,
 converting them to Utf8 representation.
 The target array must be large enough to hold the result.
 returns first index in `dst' past the last copied byte.
 @param src        The array holding the characters to convert.
 @param sindex     The start index from which characters are converted.
 @param dst        The array holding the converted characters..
 @param dindex     The start index from which converted bytes
                   are written.
 @param len        The maximum number of characters to convert.

/** Copy characters in source array to bytes in target array,
     *  converting them to Utf8 representation.
     *  The target array must be large enough to hold the result.
     *  returns first index in `dst' past the last copied byte.
     *  @param src        The array holding the characters to convert.
     *  @param sindex     The start index from which characters are converted.
     *  @param dst        The array holding the converted characters..
     *  @param dindex     The start index from which converted bytes
     *                    are written.
     *  @param len        The maximum number of characters to convert.
     */
    public static int chars2utf(char[] src, int sindex,
                                byte[] dst, int dindex,
                                int len) {
        int j = dindex;
        int limit = sindex + len;
        for (int i = sindex; i < limit; i++) {
            char ch = src[i];
            if (1 <= ch && ch <= 0x7F) {
                dst[j++] = (byte)ch;
            } else if (ch <= 0x7FF) {
                dst[j++] = (byte)(0xC0 | (ch >> 6));
                dst[j++] = (byte)(0x80 | (ch & 0x3F));
            } else {
                dst[j++] = (byte)(0xE0 | (ch >> 12));
                dst[j++] = (byte)(0x80 | ((ch >> 6) & 0x3F));
                dst[j++] = (byte)(0x80 | (ch & 0x3F));
            }
        }
        return j;
    }

    
Return characters as an array of bytes in Utf8 representation.
 @param src        The array holding the characters.
 @param sindex     The start index from which characters are converted.
 @param len        The maximum number of characters to convert.

/** Return characters as an array of bytes in Utf8 representation.
     *  @param src        The array holding the characters.
     *  @param sindex     The start index from which characters are converted.
     *  @param len        The maximum number of characters to convert.
     */
    public static byte[] chars2utf(char[] src, int sindex, int len) {
        byte[] dst = new byte[len * 3];
        int len1 = chars2utf(src, sindex, dst, 0, len);
        byte[] result = new byte[len1];
        System.arraycopy(dst, 0, result, 0, len1);
        return result;
    }

    
Return all characters in given array as an array of bytes
 in Utf8 representation.
 @param src        The array holding the characters.

/** Return all characters in given array as an array of bytes
     *  in Utf8 representation.
     *  @param src        The array holding the characters.
     */
    public static byte[] chars2utf(char[] src) {
        return chars2utf(src, 0, src.length);
    }

    
Return string as an array of bytes in in Utf8 representation.

/** Return string as an array of bytes in in Utf8 representation.
     */
    public static byte[] string2utf(String s) {
        return chars2utf(s.toCharArray());
    }

    
Escapes each character in a string that has an escape sequence or
is non-printable ASCII.  Leaves non-ASCII characters alone.

/**
     * Escapes each character in a string that has an escape sequence or
     * is non-printable ASCII.  Leaves non-ASCII characters alone.
     */
    public static String quote(String s) {
        StringBuilder buf = new StringBuilder();
        for (int i = 0; i < s.length(); i++) {
            buf.append(quote(s.charAt(i)));
        }
        return buf.toString();
    }

    
Escapes a character if it has an escape sequence or is
non-printable ASCII.  Leaves non-ASCII characters alone.

/**
     * Escapes a character if it has an escape sequence or is
     * non-printable ASCII.  Leaves non-ASCII characters alone.
     */
    public static String quote(char ch) {
        switch (ch) {
        case '\b':  return "\\b";
        case '\f':  return "\\f";
        case '\n':  return "\\n";
        case '\r':  return "\\r";
        case '\t':  return "\\t";
        case '\'':  return "\\'";
        case '\"':  return "\\\"";
        case '\\':  return "\\\\";
        default:
            return (isPrintableAscii(ch))
                ? String.valueOf(ch)
                : String.format("\\u%04x", (int) ch);
        }
    }

    
Is a character printable ASCII?

/**
     * Is a character printable ASCII?
     */
    private static boolean isPrintableAscii(char ch) {
        return ch >= ' ' && ch <= '~';
    }

    
Escape all unicode characters in string.

/** Escape all unicode characters in string.
     */
    public static String escapeUnicode(String s) {
        int len = s.length();
        int i = 0;
        while (i < len) {
            char ch = s.charAt(i);
            if (ch > 255) {
                StringBuilder buf = new StringBuilder();
                buf.append(s.substring(0, i));
                while (i < len) {
                    ch = s.charAt(i);
                    if (ch > 255) {
                        buf.append("\\u");
                        buf.append(Character.forDigit((ch >> 12) % 16, 16));
                        buf.append(Character.forDigit((ch >>  8) % 16, 16));
                        buf.append(Character.forDigit((ch >>  4) % 16, 16));
                        buf.append(Character.forDigit((ch      ) % 16, 16));
                    } else {
                        buf.append(ch);
                    }
                    i++;
                }
                s = buf.toString();
            } else {
                i++;
            }
        }
        return s;
    }

/* Conversion routines for qualified name splitting
 */
    
Return the last part of a class name.

/** Return the last part of a class name.
     */
    public static Name shortName(Name classname) {
        return classname.subName(
            classname.lastIndexOf((byte)'.') + 1, classname.getByteLength());
    }

    public static String shortName(String classname) {
        return classname.substring(classname.lastIndexOf('.') + 1);
    }

    
Return the package name of a class name, excluding the trailing '.',
 "" if not existent.

/** Return the package name of a class name, excluding the trailing '.',
     *  "" if not existent.
     */
    public static Name packagePart(Name classname) {
        return classname.subName(0, classname.lastIndexOf((byte)'.'));
    }

    public static String packagePart(String classname) {
        int lastDot = classname.lastIndexOf('.');
        return (lastDot < 0 ? "" : classname.substring(0, lastDot));
    }

    public static List<Name> enclosingCandidates(Name name) {
        List<Name> names = List.nil();
        int index;
        while ((index = name.lastIndexOf((byte)'$')) > 0) {
            name = name.subName(0, index);
            names = names.prepend(name);
        }
        return names;
    }

    public static List<Name> classCandidates(Name name) {
        List<Name> names = List.nil();
        String nameStr = name.toString();
        int index = -1;
        while ((index = nameStr.indexOf('.', index + 1)) > 0) {
            String pack = nameStr.substring(0, index + 1);
            String clz = nameStr.substring(index + 1).replace('.', '$');
            names = names.prepend(name.table.names.fromString(pack + clz));
        }
        return names.reverse();
    }
}