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Diffstat (limited to 'src/java/org/apache/fop/text/linebreak/LineBreakStatus.java')
| -rw-r--r-- | src/java/org/apache/fop/text/linebreak/LineBreakStatus.java | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/src/java/org/apache/fop/text/linebreak/LineBreakStatus.java b/src/java/org/apache/fop/text/linebreak/LineBreakStatus.java new file mode 100644 index 000000000..29583a9d0 --- /dev/null +++ b/src/java/org/apache/fop/text/linebreak/LineBreakStatus.java @@ -0,0 +1,160 @@ +/* + * 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. + */ + +/* $Id$ */ + +package org.apache.fop.text.linebreak; + +/** + * This class is meant for supporting the Unicode line breaking algorithm. + * See <a href="http://unicode.org/reports/tr14/">UTR 14</a>. + * + */ +public class LineBreakStatus { + + /** Constant indicating a Direct Break */ + public static final byte DIRECT_BREAK = LineBreakUtils.DIRECT_BREAK; + /** Constant indicating an Indirect Break */ + public static final byte INDIRECT_BREAK = LineBreakUtils.INDIRECT_BREAK; + /** Constant indicating a Combining Indirect Break */ + public static final byte COMBINING_INDIRECT_BREAK = LineBreakUtils.COMBINING_INDIRECT_BREAK; + /** Constant indicating a Combining Prohibited Break */ + public static final byte COMBINING_PROHIBITED_BREAK = LineBreakUtils.COMBINING_PROHIBITED_BREAK; + /** Constant indicating a Prohibited Break */ + public static final byte PROHIBITED_BREAK = LineBreakUtils.PROHIBITED_BREAK; + /** Constant indicating a Explicit Break */ + public static final byte EXPLICIT_BREAK = LineBreakUtils.EXPLICIT_BREAK; + + private byte leftClass; + private boolean hadSpace; + + /** + * Resets the class to the same state as if new LineBreakStatus() had just been called. + */ + public LineBreakStatus() { + reset(); + } + + + /** + * Reset the status. + * This method will reset the status to the initial state. It is meant + * for recycling objects. + */ + public void reset() { + leftClass = -1; + hadSpace = false; + } + + /** + * Check whether a line break may happen. + * The function returns the line breaking status of the point before the given character. + * The algorithm is the table driven algorithm described in the Unicode + * <a href="http://unicode.org/reports/tr14/#PairBasedImplementation">technical report #14</a>. + * The pair table is taken from @see LineBreakUtils + * + * TODO: Better handling for AI, SA, CB and other line break classes. + * + * @param c The character. + * @return the break action to be taken + */ + public byte nextChar(char c) { + byte currentClass = LineBreakUtils.getLineBreakProperty(c); + if (currentClass == LineBreakUtils.LINE_BREAK_PROPERTY_AI + || leftClass == LineBreakUtils.LINE_BREAK_PROPERTY_XX) { + currentClass = LineBreakUtils.LINE_BREAK_PROPERTY_AL; + } else if (currentClass == LineBreakUtils.LINE_BREAK_PROPERTY_NL) { + currentClass = LineBreakUtils.LINE_BREAK_PROPERTY_BK; + } + if (leftClass == -1) { + if (currentClass == LineBreakUtils.LINE_BREAK_PROPERTY_LF) { + leftClass = LineBreakUtils.LINE_BREAK_PROPERTY_BK; + } else { + leftClass = currentClass; + if (leftClass == LineBreakUtils.LINE_BREAK_PROPERTY_CM) { + leftClass = LineBreakUtils.LINE_BREAK_PROPERTY_ID; + } + } + // LB 2a + return PROHIBITED_BREAK; + } else if (!(leftClass != LineBreakUtils.LINE_BREAK_PROPERTY_BK + && (leftClass != LineBreakUtils.LINE_BREAK_PROPERTY_CR + || currentClass == LineBreakUtils.LINE_BREAK_PROPERTY_LF) + )) { + reset(); + if (currentClass == LineBreakUtils.LINE_BREAK_PROPERTY_LF) { + leftClass = LineBreakUtils.LINE_BREAK_PROPERTY_BK; + } + return EXPLICIT_BREAK; + } else if (currentClass == LineBreakUtils.LINE_BREAK_PROPERTY_BK + || currentClass == LineBreakUtils.LINE_BREAK_PROPERTY_LF) { + leftClass = LineBreakUtils.LINE_BREAK_PROPERTY_BK; + return PROHIBITED_BREAK; + } else if (currentClass == LineBreakUtils.LINE_BREAK_PROPERTY_CR) { + leftClass = LineBreakUtils.LINE_BREAK_PROPERTY_CR; + return PROHIBITED_BREAK; + } else if (currentClass == LineBreakUtils.LINE_BREAK_PROPERTY_SP) { + hadSpace = true; + return PROHIBITED_BREAK; + } else { + boolean savedHadSpace = hadSpace; + hadSpace = false; + switch (LineBreakUtils.getLineBreakPairProperty(leftClass, currentClass)) { + case LineBreakUtils.PROHIBITED_BREAK : + leftClass = currentClass; + return PROHIBITED_BREAK; + case LineBreakUtils.DIRECT_BREAK : + leftClass = currentClass; + return DIRECT_BREAK; + case LineBreakUtils.INDIRECT_BREAK : + leftClass = currentClass; + if (savedHadSpace) { + return INDIRECT_BREAK; + } else { + return PROHIBITED_BREAK; + } + case LineBreakUtils.COMBINING_INDIRECT_BREAK : + if (savedHadSpace) { + leftClass = currentClass; + return COMBINING_INDIRECT_BREAK; + } else { + return PROHIBITED_BREAK; + } + case LineBreakUtils.COMBINING_PROHIBITED_BREAK : + if (savedHadSpace) { + leftClass = currentClass; + } + return COMBINING_PROHIBITED_BREAK; + default : + throw new RuntimeException("duh"); + } + + } + } + + /** + * for debugging only + */ + /* + public static void main(String args[]) { + LineBreakStatus lbs = new LineBreakStatus(); + lbs.nextChar('\n'); + lbs.nextChar('\n'); + lbs.nextChar('x'); + } + */ +} |