LCOV - code coverage report
Current view: directory - gfx/thebes - gfxSkipChars.cpp (source / functions) Found Hit Coverage
Test: app.info Lines: 117 0 0.0 %
Date: 2012-06-02 Functions: 5 0 0.0 %

       1                 : /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
       2                 :  * ***** BEGIN LICENSE BLOCK *****
       3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       4                 :  *
       5                 :  * The contents of this file are subject to the Mozilla Public License Version
       6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       7                 :  * the License. You may obtain a copy of the License at
       8                 :  * http://www.mozilla.org/MPL/
       9                 :  *
      10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      12                 :  * for the specific language governing rights and limitations under the
      13                 :  * License.
      14                 :  *
      15                 :  * The Original Code is Novell code.
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is Novell.
      18                 :  * Portions created by the Initial Developer are Copyright (C) 2006
      19                 :  * the Initial Developer. All Rights Reserved.
      20                 :  *
      21                 :  * Contributor(s):
      22                 :  *   Robert O'Callahan <robert@ocallahan.org>
      23                 :  *
      24                 :  * Alternatively, the contents of this file may be used under the terms of
      25                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      26                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      27                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      28                 :  * of those above. If you wish to allow use of your version of this file only
      29                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      30                 :  * use your version of this file under the terms of the MPL, indicate your
      31                 :  * decision by deleting the provisions above and replace them with the notice
      32                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      33                 :  * the provisions above, a recipient may use your version of this file under
      34                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      35                 :  *
      36                 :  * ***** END LICENSE BLOCK ***** */
      37                 : 
      38                 : #include "gfxSkipChars.h"
      39                 : 
      40                 : #include <stdlib.h>
      41                 : 
      42                 : #define SHORTCUT_FREQUENCY 256
      43                 : 
      44                 : // Even numbered list entries are "keep" entries
      45                 : static bool
      46               0 : IsKeepEntry(PRUint32 aEntry)
      47                 : {
      48               0 :     return !(aEntry & 1);
      49                 : }
      50                 : 
      51                 : void
      52               0 : gfxSkipChars::BuildShortcuts()
      53                 : {
      54               0 :     if (!mList || mCharCount < SHORTCUT_FREQUENCY)
      55               0 :         return;
      56                 :   
      57               0 :     mShortcuts = new Shortcut[mCharCount/SHORTCUT_FREQUENCY];
      58               0 :     if (!mShortcuts)
      59               0 :         return;
      60                 :   
      61                 :     PRUint32 i;
      62               0 :     PRUint32 nextShortcutIndex = 0;
      63               0 :     PRUint32 originalCharOffset = 0;
      64               0 :     PRUint32 skippedCharOffset = 0;
      65               0 :     for (i = 0; i < mListLength; ++i) {
      66               0 :         PRUint8 len = mList[i];
      67                 :     
      68                 :         // We use >= here to ensure that when mCharCount is a multiple of
      69                 :         // SHORTCUT_FREQUENCY, we fill in the final shortcut with a reference
      70                 :         // to the last element of mList. This means that in general when a list
      71                 :         // element ends on an offset that's a multiple of SHORTCUT_FREQUENCY,
      72                 :         // that list element is the shortcut for that offset, which is
      73                 :         // slightly suboptimal (the *next* element is the one we really want),
      74                 :         // but it's all correct and simpler this way.
      75               0 :         while (originalCharOffset + len >= (nextShortcutIndex + 1)*SHORTCUT_FREQUENCY) {
      76               0 :             mShortcuts[nextShortcutIndex] =
      77               0 :                 Shortcut(i, originalCharOffset, skippedCharOffset);
      78               0 :             ++nextShortcutIndex;
      79                 :         }
      80                 :     
      81               0 :         originalCharOffset += len;
      82               0 :         if (IsKeepEntry(i)) {
      83               0 :             skippedCharOffset += len;
      84                 :         }
      85                 :     }
      86                 : }
      87                 : 
      88                 : void
      89               0 : gfxSkipCharsIterator::SetOffsets(PRUint32 aOffset, bool aInOriginalString)
      90                 : {
      91               0 :     NS_ASSERTION(aOffset <= mSkipChars->mCharCount,
      92                 :                  "Invalid offset");
      93                 : 
      94               0 :     if (mSkipChars->mListLength == 0) {
      95               0 :         mOriginalStringOffset = mSkippedStringOffset = aOffset;
      96               0 :         return;
      97                 :     }
      98                 :   
      99               0 :     if (aOffset == 0) {
     100                 :         // Start from the beginning of the string.
     101               0 :         mSkippedStringOffset = 0;
     102               0 :         mOriginalStringOffset = 0;
     103               0 :         mListPrefixLength = 0;
     104               0 :         mListPrefixKeepCharCount = 0;
     105               0 :         mListPrefixCharCount = 0;
     106               0 :         if (aInOriginalString) {
     107                 :             // Nothing more to do!
     108               0 :             return;
     109                 :         }
     110                 :     }
     111                 :   
     112               0 :     if (aInOriginalString && mSkipChars->mShortcuts &&
     113               0 :         abs(PRInt32(aOffset) - PRInt32(mListPrefixCharCount)) > SHORTCUT_FREQUENCY) {
     114                 :         // Take a shortcut. This makes SetOffsets(..., true) O(1) by bounding
     115                 :         // the iterations in the loop below to at most SHORTCUT_FREQUENCY iterations
     116               0 :         PRUint32 shortcutIndex = aOffset/SHORTCUT_FREQUENCY;
     117               0 :         if (shortcutIndex == 0) {
     118               0 :             mListPrefixLength = 0;
     119               0 :             mListPrefixKeepCharCount = 0;
     120               0 :             mListPrefixCharCount = 0;
     121                 :         } else {
     122               0 :             const gfxSkipChars::Shortcut& shortcut = mSkipChars->mShortcuts[shortcutIndex - 1];
     123               0 :             mListPrefixLength = shortcut.mListPrefixLength;
     124               0 :             mListPrefixKeepCharCount = shortcut.mListPrefixKeepCharCount;
     125               0 :             mListPrefixCharCount = shortcut.mListPrefixCharCount;
     126                 :         }
     127                 :     }
     128                 :   
     129               0 :     PRInt32 currentRunLength = mSkipChars->mList[mListPrefixLength];
     130               0 :     for (;;) {
     131                 :         // See if aOffset is in the string segment described by
     132                 :         // mSkipChars->mList[mListPrefixLength]
     133               0 :         PRUint32 segmentOffset = aInOriginalString ? mListPrefixCharCount : mListPrefixKeepCharCount;
     134               0 :         if ((aInOriginalString || IsKeepEntry(mListPrefixLength)) &&
     135                 :             aOffset >= segmentOffset && aOffset < segmentOffset + currentRunLength) {
     136               0 :             PRInt32 offsetInSegment = aOffset - segmentOffset;
     137               0 :             mOriginalStringOffset = mListPrefixCharCount + offsetInSegment;
     138               0 :             mSkippedStringOffset = mListPrefixKeepCharCount;
     139               0 :             if (IsKeepEntry(mListPrefixLength)) {
     140               0 :                 mSkippedStringOffset += offsetInSegment;
     141                 :             }
     142               0 :             return;
     143                 :         }
     144                 :         
     145               0 :         if (aOffset < segmentOffset) {
     146                 :             // We need to move backwards
     147               0 :             if (mListPrefixLength <= 0) {
     148                 :                 // nowhere to go backwards
     149               0 :                 mOriginalStringOffset = mSkippedStringOffset = 0;
     150               0 :                 return;
     151                 :             }
     152                 :             // Go backwards one segment and restore invariants
     153               0 :             --mListPrefixLength;
     154               0 :             currentRunLength = mSkipChars->mList[mListPrefixLength];
     155               0 :             mListPrefixCharCount -= currentRunLength;
     156               0 :             if (IsKeepEntry(mListPrefixLength)) {
     157               0 :                 mListPrefixKeepCharCount -= currentRunLength;
     158                 :             }
     159                 :         } else {
     160                 :             // We need to move forwards
     161               0 :             if (mListPrefixLength >= mSkipChars->mListLength - 1) {
     162                 :                 // nowhere to go forwards
     163               0 :                 mOriginalStringOffset = mListPrefixCharCount + currentRunLength;
     164               0 :                 mSkippedStringOffset = mListPrefixKeepCharCount;
     165               0 :                 if (IsKeepEntry(mListPrefixLength)) {
     166               0 :                     mSkippedStringOffset += currentRunLength;
     167                 :                 }
     168               0 :                 return;
     169                 :             }
     170                 :             // Go forwards one segment and restore invariants
     171               0 :             mListPrefixCharCount += currentRunLength;
     172               0 :             if (IsKeepEntry(mListPrefixLength)) {
     173               0 :                 mListPrefixKeepCharCount += currentRunLength;
     174                 :             }
     175               0 :             ++mListPrefixLength;
     176               0 :             currentRunLength = mSkipChars->mList[mListPrefixLength];
     177                 :         }
     178                 :     }
     179                 : }
     180                 : 
     181                 : bool
     182               0 : gfxSkipCharsIterator::IsOriginalCharSkipped(PRInt32* aRunLength) const
     183                 : {
     184               0 :     if (mSkipChars->mListLength == 0) {
     185               0 :         if (aRunLength) {
     186               0 :             *aRunLength = mSkipChars->mCharCount - mOriginalStringOffset;
     187                 :         }
     188               0 :         return mSkipChars->mCharCount == PRUint32(mOriginalStringOffset);
     189                 :     }
     190                 :   
     191               0 :     PRUint32 listPrefixLength = mListPrefixLength;
     192                 :     // figure out which segment we're in
     193               0 :     PRUint32 currentRunLength = mSkipChars->mList[listPrefixLength];
     194                 :     // Zero-length list entries are possible. Advance until mListPrefixLength
     195                 :     // is pointing to a run with real characters (or we're at the end of the
     196                 :     // string).
     197               0 :     while (currentRunLength == 0 && listPrefixLength < mSkipChars->mListLength - 1) {
     198               0 :         ++listPrefixLength;
     199                 :         // This does not break the iterator's invariant because no skipped
     200                 :         // or kept characters are being added
     201               0 :         currentRunLength = mSkipChars->mList[listPrefixLength];
     202                 :     }
     203               0 :     NS_ASSERTION(PRUint32(mOriginalStringOffset) >= mListPrefixCharCount,
     204                 :                  "Invariant violation");
     205                 :     PRUint32 offsetIntoCurrentRun =
     206               0 :       PRUint32(mOriginalStringOffset) - mListPrefixCharCount;
     207               0 :     if (listPrefixLength >= mSkipChars->mListLength - 1 &&
     208                 :         offsetIntoCurrentRun >= currentRunLength) {
     209               0 :         NS_ASSERTION(listPrefixLength == mSkipChars->mListLength - 1 &&
     210                 :                      offsetIntoCurrentRun == currentRunLength,
     211                 :                      "Overran end of string");
     212                 :         // We're at the end of the string
     213               0 :         if (aRunLength) {
     214               0 :             *aRunLength = 0;
     215                 :         }
     216               0 :         return true;
     217                 :     }
     218                 :   
     219               0 :     bool isSkipped = !IsKeepEntry(listPrefixLength);
     220               0 :     if (aRunLength) {
     221                 :         // Long runs of all-skipped or all-kept characters will be encoded as
     222                 :         // sequences of 255, 0, 255, 0 etc. Compute the maximum run length by skipping
     223                 :         // over zero entries.
     224               0 :         PRUint32 runLength = currentRunLength - offsetIntoCurrentRun;
     225               0 :         for (PRUint32 i = listPrefixLength + 2; i < mSkipChars->mListLength; i += 2) {
     226               0 :             if (mSkipChars->mList[i - 1] != 0)
     227               0 :                 break;
     228               0 :             runLength += mSkipChars->mList[i];
     229                 :         }
     230               0 :         *aRunLength = runLength;
     231                 :     }
     232               0 :     return isSkipped;
     233                 : }
     234                 : 
     235                 : void
     236               0 : gfxSkipCharsBuilder::FlushRun()
     237                 : {
     238               0 :     NS_ASSERTION((mBuffer.Length() & 1) == mRunSkipped,
     239                 :                  "out of sync?");
     240                 :     // Fill in buffer entries starting at mBufferLength, as many as necessary
     241               0 :     PRUint32 charCount = mRunCharCount;
     242               0 :     for (;;) {
     243               0 :         PRUint32 chars = NS_MIN<PRUint32>(255, charCount);
     244               0 :         if (!mBuffer.AppendElement(chars)) {
     245               0 :             mInErrorState = true;
     246               0 :             return;
     247                 :         }
     248               0 :         charCount -= chars;
     249               0 :         if (charCount == 0)
     250                 :             break;
     251               0 :         if (!mBuffer.AppendElement(0)) {
     252               0 :             mInErrorState = true;
     253               0 :             return;
     254                 :         }
     255                 :     }
     256                 :   
     257               0 :     NS_ASSERTION(mCharCount + mRunCharCount >= mCharCount,
     258                 :                  "String length overflow");
     259               0 :     mCharCount += mRunCharCount;
     260               0 :     mRunCharCount = 0;
     261               0 :     mRunSkipped = !mRunSkipped;
     262                 : }

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