Magic-Mirror/gecko-dev
1
0
Fork 0
mirror of https://github.com/mozilla/gecko-dev.git synced 2024-10-29 21:25:35 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity
86eec1927c
gecko-dev/gfx/public/nsCompressedCharMap.h

356 lines
14 KiB
C++
Raw Blame History

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: NPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Netscape Public License
* Version 1.1 (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.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Brian Stell <bstell@netscape.com>
*
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the NPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the NPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef NSCOMPRESSEDCHARMAP_H
#define NSCOMPRESSEDCHARMAP_H
#include "prtypes.h"
#include "nsICharRepresentable.h"
#define ALU_SIZE PR_BITS_PER_LONG
//#define ALU_SIZE 16
//#define ALU_SIZE 32
//#define ALU_SIZE 64
#if (ALU_SIZE==32)
# define ALU_TYPE PRUint32
# define CCMAP_POW2(n) (1L<<(n))
# define CCMAP_BITS_PER_ALU_LOG2 5
#elif (ALU_SIZE==64)
# define ALU_TYPE PRUint64
# define CCMAP_POW2(n) (1L<<(n))
# define CCMAP_BITS_PER_ALU_LOG2 6
#else
# define ALU_TYPE PRUint16
# define CCMAP_POW2(n) (1<<(n))
# define CCMAP_BITS_PER_ALU_LOG2 4
#endif
class nsICharRepresentable;
extern PRUint16* CreateEmptyCCMap();
extern PRUint16* MapToCCMap(PRUint32* aMap);
extern PRUint16* MapperToCCMap(nsICharRepresentable *aMapper);
extern void FreeCCMap(PRUint16* &aMap);
extern PRBool NextNonEmptyCCMapPage(const PRUint16 *, PRUint32 *);
extern PRBool IsSameCCMap(PRUint16* ccmap1, PRUint16* ccmap2);
#ifdef DEBUG
void printCCMap(PRUint16* aCCMap);
#endif
// surrogate support extension
extern PRUint16*
MapToCCMapExt(PRUint32* aBmpPlaneMap, PRUint32** aOtherPlaneMaps, PRUint32 aOtherPlaneNum);
//
// nsCompressedCharMap
//
// A Compressed Char Map (CCMap) saves memory by folding all
// the empty portions of the map on top of each other.
//
// Building a Compressed Char Map (CCMap) is more complex than
// accessing it. We use the nsCompressedCharMap object to
// build the CCMap. Once nsCompressedCharMap has built the CCMap
// we get a copy of the CCMap and discard the nsCompressedCharMap
// object. The CCMap is an array of PRUint16 and is accessed by
// a macro.
//
// See "Character Map Compression" below for a discussion of
// what the array looks like.
//
// The maximum size a CCMap:
// (16 upper pointers) + (16 empty mid pointers) +
// (16 empty page) + (16*16 max mid pointers) +
// (256*16 max pages) = 4400 PRUint16
#define CCMAP_MAX_LEN (16+16+16+256+4096)
// non-bmp unicode support extension
#define EXTENDED_UNICODE_PLANES 16
class nsCompressedCharMap {
public:
nsCompressedCharMap();
~nsCompressedCharMap();
PRUint16* NewCCMap();
PRUint16* FillCCMap(PRUint16* aCCMap);
PRUint16 GetSize() {return mUsedLen;};
void SetChar(PRUint32);
void SetChars(PRUint16*);
void SetChars(PRUint16, ALU_TYPE*);
void SetChars(PRUint32*);
void Extend() {mExtended = PR_TRUE;} // enable surrogate area
protected:
union {
PRUint16 mCCMap[CCMAP_MAX_LEN];
ALU_TYPE used_for_align; // do not use; only here to cause
// alignment
} u;
PRUint16 mUsedLen; // in PRUint16
PRUint16 mAllOnesPage;
PRBool mExtended;
// for surrogate support
PRUint32* mExtMap[EXTENDED_UNICODE_PLANES+1];
PRUint32 mMap[UCS2_MAP_LEN];
};
//
// Character Map Compression
//
// Each font requires its own 8k charmap. On a system with 200
// fonts this would take: 200 * 8K = 1600K memory.
//
// Since most char maps are mostly empty a significant amount
// of memory can be saved by not allocating the unused sections.
//
// If the map has one or more levels of indirection then the
// the empty sections of the map can all be folded to a single
// common empty element. In this way only the non-empty sections
// need space. Because the empty sections actually point to a
// common empty section every entry in the map can be valid
// without requiring actually allocating space.
// Some larger CJK fonts have large sections where every bit
// is set. In the same way that the empty sections are folded
// onto one "empty page", the sections where all bits are set are
// folded on to one "all bits set page" .
//
// Break up the Unicode range bits 0x0000 - 0xFFFF
// into 3 bit ranges:
//
// upper bits: bit15 - bit12
// mid bits: bit11 - bit8
// page bits: bit7 - bit0
//
// within a page, (assumming a 4 byte ALU)
// bits 7-5 select one of the 8 longs
// bits 4-0 select one of the 32 bits within the long
//
// There is exactly one upper "pointers" array.
//
// The upper pointers each point to a mid array. If there are no chars
// in an upper pointer's block that pointer points to the empty mid.
// Thus all upper pointers are "valid" even if they do not have space
// allocated; eg: the accessor macro does not need to test if the
// pointer is zero.
//
// Each mid pointer in the mid array points to a page. If there are no
// chars in a mid pointer's page that pointer points to the empty page.
// Thus all mid pointers are "valid" even if they do not have space
// allocated; eg: the accessor macro does not need to test if the
// pointer is zero.
//
// Since the array will be less than 5K PRUint16 the "pointers" can
// be implemented as 2 byte offsets from the base instead of
// real pointers.
//
// the format of the CCMap is
// the upper pointers (16 PRUint16)
// the empty mid pointers (16 PRUint16)
// the empty page (16 PRUint16)
// non-empty mid pointers and pages as needed
// One minor note: for a completely empty map it is actually
// possible to fold the upper, empty mid, and empty page
// on top of each other and make a map of only 32 bytes.
#define CCMAP_EMPTY_SIZE_PER_INT16 16
// offsets to the empty mid and empty page
#define CCMAP_EMPTY_MID CCMAP_NUM_UPPER_POINTERS
#define CCMAP_EMPTY_PAGE CCMAP_EMPTY_MID+CCMAP_NUM_MID_POINTERS
//
// Because the table is offset based the code can build the table in a
// temp space (max table size on the stack) and then do one alloc of
// the actual needed size and simply copy over the data.
//
//
// Compressed Char map surrogate extension
//
// The design goal of surrogate support extension is to keep efficiency
// and compatibility of existing compressed charmap operations. Most of
// existing operation are untouched. For BMP support, very little memory
// overhead (4 bytes) is added. Runtime efficiency of BMP support is
// unchanged.
//
// structure of extended charmap:
// ccmap flag 1 PRUint16 , indication if this is extended one or not
// bmp ccmap size 1 PRUint16 , the size of BMP ccmap,
// BMP ccmap size varies,
// plane index 16 PRUint32, use to index ccmap for non-BMP plane
// empty ccmap 16 PRUint16, a total empty ccmap
// non-BMP ccmaps size varies, other non-empty, non-BMP ccmap
//
// Changes to basic ccmap
// 2 PRUint16 are added in the very beginning. One is used to descript the size
// of the ccmap, the other is used as a flag. But these 2 fields are indexed
// negatively so that all other operation remain unchanged to keep efficiency.
// ccmap memory allocation is moved from nsCompressedCharMap::NewCCMap to
// MapToCCMap.
//
// Extended ccmap
// A 16*PRUint32 array was put at the end of basic ccmap, each PRUint32 either
// pointed to the empty ccmap or a independent plane ccmap. Directly after this
// array is a empty ccmap. All planes that has no character will share this ccmap.
// All non-empty plane will have a ccmap.
// "MapToCCMapExt" is added to created an extended ccmap, each plane ccmap is
// created the same as basic one, but without 2 additional fields.
// "HasGlyphExt" is used to access extended ccmap, it first need to locate the
// plane ccmap, and then operated the same way as "HasGlyph".
//
// Compatibility between old and new one
// Because extended ccmap include an exactly identical basic ccmap in its head,
// basic ccmap operation (HasGlyph) can be applied on extended ccmap without
// problem.
// Because basic ccmap is now have a flag to indicate if it is a extended one,
// Extended ccmap operation (HasGlyphExt) can check the flag before it does
// extended ccmap specific operation. So HasGlyphExt can be applied to basic ccmap
// too.
//
// Page bits
//
#define CCMAP_BITS_PER_PAGE_LOG2 8
#define CCMAP_BITS_PER_PAGE CCMAP_POW2(CCMAP_BITS_PER_PAGE_LOG2)
#define CCMAP_BIT_INDEX(c) ((c) & PR_BITMASK(CCMAP_BITS_PER_ALU_LOG2))
#define CCMAP_ALU_INDEX(c) (((c)>>CCMAP_BITS_PER_ALU_LOG2) \
& PR_BITMASK(CCMAP_BITS_PER_PAGE_LOG2 - CCMAP_BITS_PER_ALU_LOG2))
#define CCMAP_PAGE_MASK PR_BITMASK(CCMAP_BITS_PER_PAGE_LOG2)
#define CCMAP_NUM_PRUINT16S_PER_PAGE \
(CCMAP_BITS_PER_PAGE/CCMAP_BITS_PER_PRUINT16)
// one bit per char
#define CCMAP_NUM_ALUS_PER_PAGE (CCMAP_BITS_PER_PAGE/CCMAP_BITS_PER_ALU)
#define CCMAP_NUM_UCHARS_PER_PAGE CCMAP_BITS_PER_PAGE
//
// Mid bits
//
#define CCMAP_BITS_PER_MID_LOG2 4
#define CCMAP_MID_INDEX(c) \
(((c)>>CCMAP_BITS_PER_PAGE_LOG2) & PR_BITMASK(CCMAP_BITS_PER_MID_LOG2))
#define CCMAP_NUM_MID_POINTERS CCMAP_POW2(CCMAP_BITS_PER_MID_LOG2)
#define CCMAP_NUM_UCHARS_PER_MID \
CCMAP_POW2(CCMAP_BITS_PER_MID_LOG2+CCMAP_BITS_PER_PAGE_LOG2)
//
// Upper bits
//
#define CCMAP_BITS_PER_UPPER_LOG2 4
#define CCMAP_UPPER_INDEX(c) \
(((c)>>(CCMAP_BITS_PER_MID_LOG2+CCMAP_BITS_PER_PAGE_LOG2)) \
& PR_BITMASK(CCMAP_BITS_PER_UPPER_LOG2))
#define CCMAP_NUM_UPPER_POINTERS CCMAP_POW2(CCMAP_BITS_PER_UPPER_LOG2)
//
// Misc
//
#define CCMAP_BITS_PER_PRUINT16_LOG2 4
#define CCMAP_BITS_PER_PRUINT32_LOG2 5
#define CCMAP_BITS_PER_PRUINT16 CCMAP_POW2(CCMAP_BITS_PER_PRUINT16_LOG2)
#define CCMAP_BITS_PER_PRUINT32 CCMAP_POW2(CCMAP_BITS_PER_PRUINT32_LOG2)
#define CCMAP_BITS_PER_ALU CCMAP_POW2(CCMAP_BITS_PER_ALU_LOG2)
#define CCMAP_ALUS_PER_PRUINT32 (CCMAP_BITS_PER_PRUINT32/CCMAP_BITS_PER_ALU)
#define CCMAP_PRUINT32S_PER_ALU (CCMAP_BITS_PER_ALU/CCMAP_BITS_PER_PRUINT32)
#define CCMAP_PRUINT32S_PER_PAGE (CCMAP_BITS_PER_PAGE/CCMAP_BITS_PER_PRUINT32)
#define CCMAP_ALU_MASK PR_BITMASK(CCMAP_BITS_PER_ALU)
#define CCMAP_ALUS_PER_PAGE CCMAP_POW2(CCMAP_BITS_PER_PAGE_LOG2 \
- CCMAP_BITS_PER_ALU_LOG2)
#define NUM_UNICODE_CHARS CCMAP_POW2(CCMAP_BITS_PER_UPPER_LOG2 \
+CCMAP_BITS_PER_MID_LOG2 \
+CCMAP_BITS_PER_PAGE_LOG2)
#define CCMAP_TOTAL_PAGES CCMAP_POW2(CCMAP_BITS_PER_UPPER_LOG2 \
+CCMAP_BITS_PER_MID_LOG2)
#define CCMAP_BEGIN_AT_START_OF_MAP 0xFFFFFFFF
//
// Finally, build up the macro to test the bit for a given char
//
// offset from base to mid array
#define CCMAP_TO_MID(m,c) ((m)[CCMAP_UPPER_INDEX(c)])
// offset from base to page
#define CCMAP_TO_PAGE(m,c) ((m)[CCMAP_TO_MID((m),(c)) + CCMAP_MID_INDEX(c)])
// offset from base to alu
#define CCMAP_TO_ALU(m,c) \
(*((ALU_TYPE*)(&((m)[CCMAP_TO_PAGE((m),(c))])) + CCMAP_ALU_INDEX(c)))
// test the bit
#define CCMAP_HAS_CHAR(m,c) (((CCMAP_TO_ALU(m,c))>>CCMAP_BIT_INDEX(c)) & 1)
// unset the bit
#define CCMAP_UNSET_CHAR(m,c) (CCMAP_TO_ALU(m,c) &= ~(CCMAP_POW2(CCMAP_BIT_INDEX(c))))
#define CCMAP_SIZE(m) (*((m)-1))
#define CCMAP_FLAG(m) (*((m)-2))
#define CCMAP_EXTRA (sizeof(ALU_TYPE)/sizeof(PRUint16)>2? sizeof(ALU_TYPE)/sizeof(PRUint16): 2)
#define CCMAP_SURROGATE_FLAG 0x0001
#define CCMAP_NONE_FLAG 0x0000
// get plane number from ccmap, bmp excluded, so plane 1's number is 0.
#define CCMAP_PLANE_FROM_SURROGATE(h) ((((PRUint16)(h) - (PRUint16)0xd800) >> 6) + 1)
// same as above, but get plane number from a ucs4 char
#define CCMAP_PLANE(u) ((((PRUint32)(u))>>16))
// scalar value inside the plane
#define CCMAP_INPLANE_OFFSET(h, l) (((((PRUint16)(h) - (PRUint16)0xd800) & 0x3f) << 10) + ((PRUint16)(l) - (PRUint16)0xdc00))
// get ccmap for that plane
#define CCMAP_FOR_PLANE_EXT(m, i) ((m) + ((PRUint32*)((m) + CCMAP_SIZE(m)))[(i)-1])
// test the bit for surrogate pair
#define CCMAP_HAS_CHAR_EXT2(m, h, l) (CCMAP_FLAG(m) & CCMAP_SURROGATE_FLAG && \
CCMAP_HAS_CHAR(CCMAP_FOR_PLANE_EXT((m), CCMAP_PLANE_FROM_SURROGATE(h)), CCMAP_INPLANE_OFFSET(h, l)))
// test the bit for a character in UCS4
#define CCMAP_HAS_CHAR_EXT(m, ucs4) (((ucs4)&0xffff0000) ? \
(CCMAP_FLAG(m) & CCMAP_SURROGATE_FLAG) && CCMAP_HAS_CHAR(CCMAP_FOR_PLANE_EXT((m), CCMAP_PLANE(ucs4)), (ucs4) & 0xffff) : \
CCMAP_HAS_CHAR(m, (PRUnichar)(ucs4)) )
#endif // NSCOMPRESSEDCHARMAP_H
Reference in New Issue View Git Blame Copy Permalink