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package java.lang;

Helper for string concatenation. These methods are mostly looked up with private lookups from StringConcatFactory, and used in MethodHandle combinators there. /**
 * Helper for string concatenation. These methods are mostly looked up with private lookups
 * from {@link java.lang.invoke.StringConcatFactory}, and used in {@link java.lang.invoke.MethodHandle}
 * combinators there.
 */
final class StringConcatHelper {

    private StringConcatHelper() {
        // no instantiation
    }

    
Check for overflow, throw the exception on overflow.
Params:
len – String length
Returns:
length/**
     * Check for overflow, throw the exception on overflow.
     * @param len String length
     * @return length
     */
    private static int checkOverflow(int len) {
        if (len < 0) {
            throw new OutOfMemoryError("Overflow: String length out of range");
        }
        return len;
    }

    
Mix value length into current length
Params:
current – current length
value –   value to mix in
Returns:
new length/**
     * Mix value length into current length
     * @param current current length
     * @param value   value to mix in
     * @return new length
     */
    static int mixLen(int current, boolean value) {
        return checkOverflow(current + (value ? 4 : 5));
    }

    
Mix value length into current length
Params:
current – current length
value –   value to mix in
Returns:
new length/**
     * Mix value length into current length
     * @param current current length
     * @param value   value to mix in
     * @return new length
     */
    static int mixLen(int current, byte value) {
        return mixLen(current, (int)value);
    }

    
Mix value length into current length
Params:
current – current length
value –   value to mix in
Returns:
new length/**
     * Mix value length into current length
     * @param current current length
     * @param value   value to mix in
     * @return new length
     */
    static int mixLen(int current, char value) {
        return checkOverflow(current + 1);
    }

    
Mix value length into current length
Params:
current – current length
value –   value to mix in
Returns:
new length/**
     * Mix value length into current length
     * @param current current length
     * @param value   value to mix in
     * @return new length
     */
    static int mixLen(int current, short value) {
        return mixLen(current, (int)value);
    }

    
Mix value length into current length
Params:
current – current length
value –   value to mix in
Returns:
new length/**
     * Mix value length into current length
     * @param current current length
     * @param value   value to mix in
     * @return new length
     */
    static int mixLen(int current, int value) {
        return checkOverflow(current + Integer.stringSize(value));
    }

    
Mix value length into current length
Params:
current – current length
value –   value to mix in
Returns:
new length/**
     * Mix value length into current length
     * @param current current length
     * @param value   value to mix in
     * @return new length
     */
    static int mixLen(int current, long value) {
        return checkOverflow(current + Long.stringSize(value));
    }

    
Mix value length into current length
Params:
current – current length
value –   value to mix in
Returns:
new length/**
     * Mix value length into current length
     * @param current current length
     * @param value   value to mix in
     * @return new length
     */
    static int mixLen(int current, String value) {
        return checkOverflow(current + value.length());
    }

    
Mix coder into current coder
Params:
current – current coder
value –   value to mix in
Returns:
new coder/**
     * Mix coder into current coder
     * @param current current coder
     * @param value   value to mix in
     * @return new coder
     */
    static byte mixCoder(byte current, char value) {
        return (byte)(current | (StringLatin1.canEncode(value) ? 0 : 1));
    }

    
Mix coder into current coder
Params:
current – current coder
value –   value to mix in
Returns:
new coder/**
     * Mix coder into current coder
     * @param current current coder
     * @param value   value to mix in
     * @return new coder
     */
    static byte mixCoder(byte current, String value) {
        return (byte)(current | value.coder());
    }

    
Mix coder into current coder
Params:
current – current coder
value –   value to mix in
Returns:
new coder/**
     * Mix coder into current coder
     * @param current current coder
     * @param value   value to mix in
     * @return new coder
     */
    static byte mixCoder(byte current, boolean value) {
        // Booleans are represented with Latin1
        return current;
    }

    
Mix coder into current coder
Params:
current – current coder
value –   value to mix in
Returns:
new coder/**
     * Mix coder into current coder
     * @param current current coder
     * @param value   value to mix in
     * @return new coder
     */
    static byte mixCoder(byte current, byte value) {
        // Bytes are represented with Latin1
        return current;
    }

    
Mix coder into current coder
Params:
current – current coder
value –   value to mix in
Returns:
new coder/**
     * Mix coder into current coder
     * @param current current coder
     * @param value   value to mix in
     * @return new coder
     */
    static byte mixCoder(byte current, short value) {
        // Shorts are represented with Latin1
        return current;
    }

    
Mix coder into current coder
Params:
current – current coder
value –   value to mix in
Returns:
new coder/**
     * Mix coder into current coder
     * @param current current coder
     * @param value   value to mix in
     * @return new coder
     */
    static byte mixCoder(byte current, int value) {
        // Ints are represented with Latin1
        return current;
    }

    
Mix coder into current coder
Params:
current – current coder
value –   value to mix in
Returns:
new coder/**
     * Mix coder into current coder
     * @param current current coder
     * @param value   value to mix in
     * @return new coder
     */
    static byte mixCoder(byte current, long value) {
        // Longs are represented with Latin1
        return current;
    }

    
Prepends the stringly representation of boolean value into buffer,
given the coder and final index. Index is measured in chars, not in bytes!
Params:
index – final char index in the buffer
buf –   buffer to append to
coder – coder to add with
value – boolean value to encode
Returns:
new index/**
     * Prepends the stringly representation of boolean value into buffer,
     * given the coder and final index. Index is measured in chars, not in bytes!
     *
     * @param index final char index in the buffer
     * @param buf   buffer to append to
     * @param coder coder to add with
     * @param value boolean value to encode
     * @return new index
     */
    static int prepend(int index, byte[] buf, byte coder, boolean value) {
        if (coder == String.LATIN1) {
            if (value) {
                buf[--index] = 'e';
                buf[--index] = 'u';
                buf[--index] = 'r';
                buf[--index] = 't';
            } else {
                buf[--index] = 'e';
                buf[--index] = 's';
                buf[--index] = 'l';
                buf[--index] = 'a';
                buf[--index] = 'f';
            }
        } else {
            if (value) {
                StringUTF16.putChar(buf, --index, 'e');
                StringUTF16.putChar(buf, --index, 'u');
                StringUTF16.putChar(buf, --index, 'r');
                StringUTF16.putChar(buf, --index, 't');
            } else {
                StringUTF16.putChar(buf, --index, 'e');
                StringUTF16.putChar(buf, --index, 's');
                StringUTF16.putChar(buf, --index, 'l');
                StringUTF16.putChar(buf, --index, 'a');
                StringUTF16.putChar(buf, --index, 'f');
            }
        }
        return index;
    }

    
Prepends the stringly representation of byte value into buffer,
given the coder and final index. Index is measured in chars, not in bytes!
Params:
index – final char index in the buffer
buf –   buffer to append to
coder – coder to add with
value – byte value to encode
Returns:
new index/**
     * Prepends the stringly representation of byte value into buffer,
     * given the coder and final index. Index is measured in chars, not in bytes!
     *
     * @param index final char index in the buffer
     * @param buf   buffer to append to
     * @param coder coder to add with
     * @param value byte value to encode
     * @return new index
     */
    static int prepend(int index, byte[] buf, byte coder, byte value) {
        return prepend(index, buf, coder, (int)value);
    }

    
Prepends the stringly representation of char value into buffer,
given the coder and final index. Index is measured in chars, not in bytes!
Params:
index – final char index in the buffer
buf –   buffer to append to
coder – coder to add with
value – char value to encode
Returns:
new index/**
     * Prepends the stringly representation of char value into buffer,
     * given the coder and final index. Index is measured in chars, not in bytes!
     *
     * @param index final char index in the buffer
     * @param buf   buffer to append to
     * @param coder coder to add with
     * @param value char value to encode
     * @return new index
     */
    static int prepend(int index, byte[] buf, byte coder, char value) {
        if (coder == String.LATIN1) {
            buf[--index] = (byte) (value & 0xFF);
        } else {
            StringUTF16.putChar(buf, --index, value);
        }
        return index;
    }

    
Prepends the stringly representation of short value into buffer,
given the coder and final index. Index is measured in chars, not in bytes!
Params:
index – final char index in the buffer
buf –   buffer to append to
coder – coder to add with
value – short value to encode
Returns:
new index/**
     * Prepends the stringly representation of short value into buffer,
     * given the coder and final index. Index is measured in chars, not in bytes!
     *
     * @param index final char index in the buffer
     * @param buf   buffer to append to
     * @param coder coder to add with
     * @param value short value to encode
     * @return new index
     */
    static int prepend(int index, byte[] buf, byte coder, short value) {
        return prepend(index, buf, coder, (int)value);
    }

    
Prepends the stringly representation of integer value into buffer,
given the coder and final index. Index is measured in chars, not in bytes!
Params:
index – final char index in the buffer
buf –   buffer to append to
coder – coder to add with
value – integer value to encode
Returns:
new index/**
     * Prepends the stringly representation of integer value into buffer,
     * given the coder and final index. Index is measured in chars, not in bytes!
     *
     * @param index final char index in the buffer
     * @param buf   buffer to append to
     * @param coder coder to add with
     * @param value integer value to encode
     * @return new index
     */
    static int prepend(int index, byte[] buf, byte coder, int value) {
        if (coder == String.LATIN1) {
            return Integer.getChars(value, index, buf);
        } else {
            return StringUTF16.getChars(value, index, buf);
        }
    }

    
Prepends the stringly representation of long value into buffer,
given the coder and final index. Index is measured in chars, not in bytes!
Params:
index – final char index in the buffer
buf –   buffer to append to
coder – coder to add with
value – long value to encode
Returns:
new index/**
     * Prepends the stringly representation of long value into buffer,
     * given the coder and final index. Index is measured in chars, not in bytes!
     *
     * @param index final char index in the buffer
     * @param buf   buffer to append to
     * @param coder coder to add with
     * @param value long value to encode
     * @return new index
     */
    static int prepend(int index, byte[] buf, byte coder, long value) {
        if (coder == String.LATIN1) {
            return Long.getChars(value, index, buf);
        } else {
            return StringUTF16.getChars(value, index, buf);
        }
    }

    
Prepends the stringly representation of String value into buffer,
given the coder and final index. Index is measured in chars, not in bytes!
Params:
index – final char index in the buffer
buf –   buffer to append to
coder – coder to add with
value – String value to encode
Returns:
new index/**
     * Prepends the stringly representation of String value into buffer,
     * given the coder and final index. Index is measured in chars, not in bytes!
     *
     * @param index final char index in the buffer
     * @param buf   buffer to append to
     * @param coder coder to add with
     * @param value String value to encode
     * @return new index
     */
    static int prepend(int index, byte[] buf, byte coder, String value) {
        index -= value.length();
        value.getBytes(buf, index, coder);
        return index;
    }

    
Instantiates the String with given buffer and coder
Params:
buf –     buffer to use
index –   remaining index
coder –   coder to use
Returns:
String resulting string/**
     * Instantiates the String with given buffer and coder
     * @param buf     buffer to use
     * @param index   remaining index
     * @param coder   coder to use
     * @return String resulting string
     */
    static String newString(byte[] buf, int index, byte coder) {
        // Use the private, non-copying constructor (unsafe!)
        if (index != 0) {
            throw new InternalError("Storage is not completely initialized, " + index + " bytes left");
        }
        return new String(buf, coder);
    }

    
Provides the initial coder for the String.
Returns:
initial coder/**
     * Provides the initial coder for the String.
     * @return initial coder
     */
    static byte initialCoder() {
        return String.COMPACT_STRINGS ? String.LATIN1 : String.UTF16;
    }

}