/*

 * Copyright 2004 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * 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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package com.sun.tools.apt.mirror.declaration;

import java.util.Collection;

import com.sun.mirror.declaration.*;

import com.sun.mirror.type.TypeMirror;

import com.sun.tools.apt.mirror.type.TypeMirrorImpl;

import com.sun.tools.javac.code.Type;

import static com.sun.tools.javac.code.TypeTags.*;

/**

 * Utility class for operating on constant expressions.

 */

class Constants {

    /**

     * Converts a constant in javac's internal representation (in which

     * boolean, char, byte, short, and int are each represented by an Integer)

     * into standard representation.  Other values (including null) are

     * returned unchanged.

     */

    static Object decodeConstant(Object value, Type type) {

        if (value instanceof Integer) {

            int i = ((Integer) value).intValue();

            switch (type.tag) {

            case BOOLEAN:  return Boolean.valueOf(i != 0);

            case CHAR:     return Character.valueOf((char) i);

            case BYTE:     return Byte.valueOf((byte) i);

            case SHORT:    return Short.valueOf((short) i);

            }

        }

        return value;

    }

    /**

     * Returns a formatter for generating the text of constant

     * expressions.  Equivalent to

     * <tt>getFormatter(new StringBuilder())</tt>.

     */

    static Formatter getFormatter() {

        return new Formatter(new StringBuilder());

    }

    /**

     * Returns a formatter for generating the text of constant

     * expressions.  Also generates the text of constant

     * "pseudo-expressions" for annotations and array-valued

     * annotation elements.

     *

     * @param buf  where the expression is written

     */

    static Formatter getFormatter(StringBuilder buf) {

        return new Formatter(buf);

    }

    /**

     * Utility class used to generate the text of constant

     * expressions.  Also generates the text of constant

     * "pseudo-expressions" for annotations and array-valued

     * annotation elements.

     */

    static class Formatter {

        private StringBuilder buf;      // where the output goes

        private Formatter(StringBuilder buf) {

            this.buf = buf;

        }

        public String toString() {

            return buf.toString();

        }

        /**

         * Appends a constant whose type is not statically known

         * by dispatching to the appropriate overloaded append method.

         */

        void append(Object val) {

            if (val instanceof String) {

                append((String) val);

            } else if (val instanceof Character) {

                append((Character) val);

            } else if (val instanceof Boolean) {

                append((Boolean) val);

            } else if (val instanceof Byte) {

                append((Byte) val);

            } else if (val instanceof Short) {

                append((Short) val);

            } else if (val instanceof Integer) {

                append((Integer) val);

            } else if (val instanceof Long) {

                append((Long) val);

            } else if (val instanceof Float) {

                append((Float) val);

            } else if (val instanceof Double) {

                append((Double) val);

            } else if (val instanceof TypeMirror) {

                append((TypeMirrorImpl) val);

            } else if (val instanceof EnumConstantDeclaration) {

                append((EnumConstantDeclarationImpl) val);

            } else if (val instanceof AnnotationMirror) {

                append((AnnotationMirrorImpl) val);

            } else {

                appendUnquoted(val.toString());

            }

        }

        /**

         * Appends a string, escaped (as needed) and quoted.

         */

        void append(String val) {

            buf.append('"');

            appendUnquoted(val);

            buf.append('"');

        }

        /**

         * Appends a Character, escaped (as needed) and quoted.

         */

        void append(Character val) {

            buf.append('\'');

            appendUnquoted(val.charValue());

            buf.append('\'');

        }

        void append(Boolean val) {

            buf.append(val);

        }

        void append(Byte val) {

            buf.append(String.format("0x%02x", val));

        }

        void append(Short val) {

            buf.append(val);

        }

        void append(Integer val) {

            buf.append(val);

        }

        void append(Long val) {

            buf.append(val).append('L');

        }

        void append(Float val) {

            if (val.isNaN()) {

                buf.append("0.0f/0.0f");

            } else if (val.isInfinite()) {

                if (val.floatValue() < 0) {

                    buf.append('-');

                }

                buf.append("1.0f/0.0f");

            } else {

                buf.append(val).append('f');

            }

        }

        void append(Double val) {

            if (val.isNaN()) {

                buf.append("0.0/0.0");

            } else if (val.isInfinite()) {

                if (val.doubleValue() < 0) {

                    buf.append('-');

                }

                buf.append("1.0/0.0");

            } else {

                buf.append(val);

            }

        }

        /**

         * Appends the class literal corresponding to a type.  Should

         * only be invoked for types that have an associated literal.

         * e.g:  "java.lang.String.class"

         *       "boolean.class"

         *       "int[].class"

         */

        void append(TypeMirrorImpl t) {

            appendUnquoted(t.type.toString());

            buf.append(".class");

        }

        /**

         * Appends the fully qualified name of an enum constant.

         * e.g:  "java.math.RoundingMode.UP"

         */

        void append(EnumConstantDeclarationImpl e) {

            appendUnquoted(e.sym.enclClass() + "." + e);

        }

        /**

         * Appends the text of an annotation pseudo-expression.

         * e.g:  "@pkg.Format(linesep='\n')"

         */

        void append(AnnotationMirrorImpl anno) {

            appendUnquoted(anno.toString());

        }

        /**

         * Appends the elements of a collection, enclosed within braces

         * and separated by ", ".  Useful for array-valued annotation

         * elements.

         */

            buf.append('{');

            boolean first = true;

            for (Object val : vals) {

                if (first) {

                    first = false;

                } else {

                    buf.append(", ");

                }

                append(((AnnotationValue) val).getValue());

            }

            buf.append('}');

        }

        /**

         * For each char of a string, append using appendUnquoted(char).

         */

        private void appendUnquoted(String s) {

            for (char c : s.toCharArray()) {

                appendUnquoted(c);

            }

        }

        /**

         * Appends a char (unquoted), using escapes for those that are not

         * printable ASCII.  We don't know what is actually printable in

         * the locale in which this result will be used, so ASCII is our

         * best guess as to the least common denominator.

         */

        private void appendUnquoted(char c) {

            switch (c) {

            case '\b': buf.append("\\b");  break;

            case '\t': buf.append("\\t");  break;

            case '\n': buf.append("\\n");  break;

            case '\f': buf.append("\\f");  break;

            case '\r': buf.append("\\r");  break;

            case '\"': buf.append("\\\""); break;

            case '\'': buf.append("\\\'"); break;

            case '\\': buf.append("\\\\"); break;

            default:

                if (isPrintableAscii(c)) {

                    buf.append(c);

                } else {

                    buf.append(String.format("\\u%04x", (int) c));

                }

            }

        }

        /**

         * Is c a printable ASCII character?

         */

        private static boolean isPrintableAscii(char c) {

            return c >= ' ' && c <= '~';

        }

    }

}