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darling-cocotron/AppKit/NSTextView.subproj/NSBidiHelper.m

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//
// NSBidiHelper.c
// AppKit
//
// Created by Airy ANDRE on 05/12/12.
//
//
// Based on Reference implementation for Unicode Bidirectional Algorithm
// Bidi.cpp - version 26
// Most of the code here (except for the table files processing) is coming
// from unicode.org, just modified so it compiles properly using some recent
// compiler (+ a few types changes, static.. added, and using real unicode
// tables for char types and mirroring info instead of the demo hard-coded
// ones)
#include "NSBidiHelper.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
/*------------------------------------------------------------------------
Bidirectional Character Types
as defined by the Unicode Bidirectional Algorithm Table 3-7.
Note:
The list of bidirectional character types here is not grouped the
same way as the table 3-7, since the numberic values for the types
are chosen to keep the state and action tables compact.
------------------------------------------------------------------------*/
enum bidi_class
{
// input types
// ON MUST be zero, code relies on ON = N = 0
ON = 0, // Other Neutral
L, // Left Letter
R, // Right Letter
AN, // Arabic Number
EN, // European Number
AL, // Arabic Letter (Right-to-left)
NSM, // Non-spacing Mark
CS, // Common Separator
ES, // European Separator
ET, // European Terminator (post/prefix e.g. $ and %)
// resolved types
BN, // Boundary neutral (type of RLE etc after explicit levels)
// input types,
S, // Segment Separator (TAB) // used only in L1
WS, // White space // used only in L1
B, // Paragraph Separator (aka as PS)
// types for explicit controls
RLO, // these are used only in X1-X9
RLE,
LRO,
LRE,
PDF,
// resolved types, also resolved directions
N = ON, // alias, where ON, WS and S are treated the same
};
// Mirrored chars mapping (ex: "{" -> "}")
typedef struct mirroring_info {
unsigned short from;
unsigned short to;
} NSBidiUnicodeCharMirrorInfo;
// Info about unicode char :
// - bidi type
// - if the char has some mirrored twin
typedef struct {
uint8_t bidiType:5;
uint8_t mirrored:1;
} NSBidiUnicodeCharInfo;
static NSBidiUnicodeCharMirrorInfo *sUnicharMirrorData = NULL;
static NSBidiUnicodeCharInfo *sUnicharData = NULL;
static BOOL sUnicodeDataAbsent = NO;
static void buildUnicodeData();
// Returns the mirror character for the given glyph [ "(" -> ")" ]
static unichar mirror_character(unichar c)
{
NSInteger i = 0;
while (sUnicharMirrorData[i].from != sUnicharMirrorData[i].to) {
if (sUnicharMirrorData[i].from == c) {
c = sUnicharMirrorData[i].to;
break;
}
if (sUnicharMirrorData[i].from > c) {
break;
}
i++;
}
return c;
}
/// Read and parse the Unicode tables
void buildUnicharData()
{
if (sUnicodeDataAbsent || sUnicharData) {
return;
}
// read the mirror table
// Format
// # <comment>
// <hexa of char>;<hexa of mirrored char> # comment
NSString *path = [[NSBundle bundleForClass:NSClassFromString(@"NSTypesetter")] pathForResource:@"BidiMirroring" ofType:@"txt" inDirectory:@"UNIDATA"];
NSString *fileContents = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
if (fileContents == nil) {
sUnicodeDataAbsent = YES;
return;
}
NSArray * fileLines = [fileContents componentsSeparatedByString:@"\n"];
// Get the number of elements in the file
NSInteger count = 0;
for (NSString *line in fileLines) {
// Strip comments
if ([line length] == 0 || [line characterAtIndex:0] == '#') {
continue;
}
NSArray *elements = [line componentsSeparatedByString:@";"];
if (elements.count == 2) {
count++;
}
}
// Alloc our struct and do the real processing
sUnicharMirrorData = malloc(sizeof(NSBidiUnicodeCharMirrorInfo) * (count + 1));
count = 0;
for (NSString *line in fileLines) {
// Strip comments
if ([line length] == 0 || [line characterAtIndex:0] == '#') {
continue;
}
NSArray *elements = [line componentsSeparatedByString:@";"];
if (elements.count == 2) {
unichar from = (unichar)strtol([[elements objectAtIndex:0] UTF8String], NULL, 16);
unichar to = (unichar)strtol([[elements objectAtIndex:1] UTF8String], NULL, 16);
sUnicharMirrorData[count].from = from;
sUnicharMirrorData[count].to = to;
count++;
}
}
sUnicharMirrorData[count].to = sUnicharMirrorData[count].from = 0; // End-of-table
// read the unicode char type info table
// Format : various fields on each line, separated by ";"
// We're interested by fields 0 (hexa of char), 4 (bidi type) and 9 (the char has some mirrored char)
// macro to help building the text->const dictionary -> [NSNumber numberWithInt:ON], @"ON"
#define BIDI_ENTRY(X) [NSNumber numberWithInt:X], @#X
NSDictionary *bidiDictionary = [NSDictionary dictionaryWithObjectsAndKeys:
BIDI_ENTRY(ON),
BIDI_ENTRY(L),
BIDI_ENTRY(R),
BIDI_ENTRY(AN),
BIDI_ENTRY(EN),
BIDI_ENTRY(AL),
BIDI_ENTRY(NSM),
BIDI_ENTRY(CS),
BIDI_ENTRY(ES),
BIDI_ENTRY(ET),
BIDI_ENTRY(BN),
BIDI_ENTRY(S),
BIDI_ENTRY(WS),
BIDI_ENTRY(B),
BIDI_ENTRY(RLO),
BIDI_ENTRY(RLE),
BIDI_ENTRY(LRO),
BIDI_ENTRY(LRE),
BIDI_ENTRY(PDF),
nil
];
NSDictionary *mirroredDictionary = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:1], @"Y",
[NSNumber numberWithInt:0], @"N",
nil
];
path = [[NSBundle bundleForClass:NSClassFromString(@"NSTypesetter")] pathForResource:@"UnicodeData" ofType:@"txt" inDirectory:@"UNIDATA"];
fileContents = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
if (fileContents == nil) {
sUnicodeDataAbsent = YES;
return;
}
// At most 65536 unichar values
sUnicharData = malloc(sizeof(NSBidiUnicodeCharInfo) * 65536);
fileLines = [fileContents componentsSeparatedByString:@"\n"];
for (NSString *line in fileLines) {
NSArray *elements = [line componentsSeparatedByString:@";"];
if (elements.count >= 10) {
NSString *bidiType = [elements objectAtIndex:4];
NSString *mirrored = [elements objectAtIndex:9];
unichar character = (unichar)strtol([[elements objectAtIndex:0] UTF8String], NULL, 16);
NSInteger bidiTypeValue = [[bidiDictionary objectForKey:bidiType] intValue];
NSInteger mirrorValue = [[mirroredDictionary objectForKey:mirrored] intValue];
sUnicharData[character].bidiType = bidiTypeValue;
sUnicharData[character].mirrored = mirrorValue;
}
}
}
// Reference implementation for Unicode Bidirectional Algorithm
/*------------------------------------------------------------------------
Description
-----------
Sample Implementation of the Unicode Bidirectional Algorithm as it
was revised by Revision 5 of the Uniode Technical Report # 9
(1999-8-17)
Verified for changes to the algorithm up through Unicode 5.2.0 (2009).
This implementation is organized into several passes, each implemen-
ting one or more of the rules of the Unicode Bidi Algorithm. The
resolution of Weak Types and of Neutrals each use a state table
approach.
Both a printf based interface and a Windows DlgProc are provided for
interactive testing.
A stress harness comparing this implementation (v24) to a Java based
implementation was used by Doug Felt to verify that the two
implementations produce identical results for all strings up to six
bidi classes and stochastic strings up to length 20.
Version 26 was verified by the author against the Unicode 5.2.0
file BidiTest.txt, which provides an exhaustive text of strings of
length 4 or less, but covers some important cases where the language
in UAX#9 had been clarified.
To see this code running in an actual Windows program,
download the free Unibook uitlity from http://unicode.org/unibook
The bidi demo is executed from the tools menu. It is build from
this source file.
Implementation Note
-------------------
NOTE: The Unicode Bidirectional Algorithm removes all explicit
formatting codes in rule X9, but states that this can be
simulated by conformant implementations. This implementation
attempts to demonstrate such a simulation
To demonstrate this, the current implementation does the
following:
in resolveExplicit()
- change LRE, LRO, RLE, RLO, PDF to BN
- assign nested levels to BN
in resolveWeak and resolveNeutrals
- assign L and R to BN's where they exist in place of
sor and eor by changing the last BN in front of a
level change to a strong type
- skip over BN's for the purpose of determining actions
- include BN in the count of deferred runs
which will resolve some of them to EN, AN and N
in resolveWhiteSpace
- set the level of any surviving BN to the base level,
or the level of the preceding character
- include LRE,LRO, RLE, RLO, PDF and BN in the count
whitespace to be reset
This will result in the same order for non-BN characters as
if the BN characters had been removed.
Notation
--------
Pointer variables generally start with the letter p
Counter variables generally start with the letter c
Index variables generally start with the letter i
Boolean variables generally start with the letter f
The enumerated bidirectional types have the same name as in the
description for the Unicode Bidirectional Algorithm
Update History
--------------
Version 24 is the initial published and verified version of this
reference implementation. Version 25 and its updates fix various
minor issues with the scaffolding used for demonstrating the
algorithm using pseudo-alphabets from the command line or dialog
box. No changes to the implementation of the actual bidi algrithm
are made in any of the minor updates to version 25. Version 26
also makes no change to the actual algorithm but was verified
against the official BidiTest.txt file for Unicode 5.2.0.
- updated pseudo-alphabet
- Last Revised 12-10-99 (25)
- enable demo mode for release builds - no other changes
- Last Revised 12-10-00 (25a)
- fix regression in pseudo alphabet use for Windows UI
- Last Revised 02-01-01 (25b)
- fixed a few comments, renamed a variable
- Last Revised 03-04-01 (25c)
- make base level settable, enable mirror by default,
fix dialog size
- Last Revised 06-02-01 (25e)
- fixed some comments
- Last Revised 09-29-01 (25f)
- fixed classification for LS,RLM,LRM in pseudo alphabet,
focus issues in UI, regression fix to commandline from 25(e)
fix DEMO switch
- Last Revised 11-07-01 (25g)
- fixed classification for plus/minus in pseudo alphabet
to track changes made in Unicode 4.0.1
- Last Revised 12-03-04 (25h)
- now compiles as dialog-only program for WINDOWS_UI==1
using new bidimain.cpp
- Last Revised 12-02-07 (25i)
- cleaned up whitespace and indenting in the source,
fixed two comments (table headers)
- Last Revised 15-03-07 (25j)
- named enumerations
- Last Revised 30-05-07 (25k)
- added usage notes, minor edits to comments, indentation, etc
throughout. Added the bidiParagraph function. Checked against
changes in the Unicode Bidi Algorithm for Unicode 5.2.0. No
changes needed to this implementation to match the values in
the BidiTest.txt file in the Unicode Character Database.
Minor fixes to dialog/windows proc, updated preprocessor directives.
- Last Revised 03-08-09 (26)
Credits:
-------
Written by: Asmus Freytag
Command line interface by: Rick McGowan
Verification (v24): Doug Felt
Disclaimer and legal rights:
---------------------------
Copyright (C) 1999-2009, ASMUS, Inc. All Rights Reserved.
Distributed under the Terms of Use in http://www.unicode.org/copyright.html.
THIS SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS NOTICE
BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES,
OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THE SOFTWARE.
The file bid.rc is included in the software covered by the above.
------------------------------------------------------------------------*/
#define ASSERT(x) if (!(x)) fprintf(stdout, "assert failed: %s\n", #x); else ;
// === HELPER FUNCTIONS AND DECLARATIONS =================================
#define odd(x) ((x) & 1)
// WS, LS and S are not explicitly needed except for L1. Therefore this
// table conflates ON, S, WS, and LS to N, all others unchanged
static int NTypes[] = {
N, // ON,
L, // L,
R, // R,
AN, // AN,
EN, // EN,
AL, // AL
NSM, // NSM
CS, // CS
ES, // ES
ET, // ET
BN, // BN
N, // S
N, // WS
B, // B
RLO, // RLO
RLE, // RLE
LRO, // LRO
LRE, // LRE
PDF, // PDF
ON, // LS
};
static int ClassFromChN(unichar ch)
{
int bidType = sUnicharData[ch].bidiType;
return NTypes[bidType];
}
static int ClassFromChWS(unichar ch)
{
int bidType = sUnicharData[ch].bidiType;
return bidType;
}
// === HELPER FUNCTIONS ================================================
// reverse cch characters
static void reverse(NSUInteger * psz, NSUInteger cch)
{
NSUInteger chTemp;
NSUInteger ich;
for (ich = 0; ich < --cch; ich++)
{
chTemp = psz[ich];
psz[ich] = psz[cch];
psz[cch] = chTemp;
}
}
// Set a run of cval values at locations all prior to, but not including
// iStart, to the new value nval.
static void SetDeferredRun(uint8_t *pval, int cval, int iStart, int nval)
{
for (int i = iStart - 1; i >= iStart - cval; i--)
{
pval[i] = nval;
}
}
// === ASSIGNING BIDI CLASSES ============================================
/*------------------------------------------------------------------------
Function: classify
Determines the character classes for all following
passes of the algorithm
Input: Text string
Character count
Whether to report types as WS, ON, S or as N (false)
Output: Array of directional classes
------------------------------------------------------------------------*/
static int classify(const unichar * pszText, uint8_t * pcls, unsigned long cch, bool fWS)
{
if (fWS)
{
unsigned long ich;
for (ich = 0; ich < cch; ich++)
{
pcls[ich] = ClassFromChWS(pszText[ich]);
}
return ich;
}
else
{
unsigned long ich;
for (ich = 0; ich < cch; ich++)
{
pcls[ich] = ClassFromChN(pszText[ich]);
}
return ich;
}
}
// === THE PARAGRAPH LEVEL ===============================================
/*------------------------------------------------------------------------
Function: resolveParagraphs
Resolves the input strings into blocks over which the algorithm
is then applied.
Implements Rule P1 of the Unicode Bidi Algorithm
Input: Text string
Character count
Output: revised character count
------------------------------------------------------------------------*/
unsigned long resolveParagraphs(uint8_t * types, unsigned long cch)
{
// skip characters not of type B
unsigned long ich = 0;
for (ich = 0; ich < cch && types[ich] != B; ich++)
;
// stop after first B, make it a BN for use in the next steps
// replace all of the next B
while (ich < cch && types[ich] == B)
types[ich++] = BN;
return ich;
}
/*------------------------------------------------------------------------
Function: baseLevel
Determines the base level
Implements rule P2 of the Unicode Bidi Algorithm.
Input: Array of directional classes
Character count
Note: Ignores explicit embeddings
------------------------------------------------------------------------*/
int baseLevel(const uint8_t * pcls, unsigned long cch)
{
unsigned long ich;
for (ich = 0; ich < cch; ich++)
{
switch (pcls[ich])
{
// strong left
case L:
return 0;
break;
// strong right
case R:
case AL:
return 1;
break;
}
}
return 0;
}
//====== RESOLVE EXPLICIT ================================================
static int GreaterEven(int i)
{
return odd(i) ? i + 1 : i + 2;
}
static int GreaterOdd(int i)
{
return odd(i) ? i + 2 : i + 1;
}
static int EmbeddingDirection(int level)
{
return odd(level) ? R : L;
}
/*------------------------------------------------------------------------
Function: resolveExplicit
Recursively resolves explicit embedding levels and overrides.
Implements rules X1-X9, of the Unicode Bidirectional Algorithm.
Input: Base embedding level and direction
Character count
Output: Array of embedding levels
Caller must allocate (one level per input character)
In/Out: Array of direction classes
Note: The function uses two simple counters to keep track of
matching explicit codes and PDF. Use the default argument for
the outermost call. The nesting counter counts the recursion
depth and not the embedding level.
------------------------------------------------------------------------*/
const int MAX_LEVEL = 61; // the real value
unsigned long resolveExplicit(int level, int dir, uint8_t * pcls, uint8_t * plevel, unsigned long cch,
int nNest)
{
// always called with a valid nesting level
// nesting levels are != embedding levels
int nLastValid = nNest;
// check input values
ASSERT(nNest >= 0 && level >= 0 && level <= MAX_LEVEL);
// process the text
unsigned long ich; for (ich = 0; ich < cch; ich++)
{
int cls = pcls[ich];
switch (cls)
{
case LRO:
case LRE:
nNest++;
if (GreaterEven(level) <= MAX_LEVEL)
{
plevel[ich] = GreaterEven(level);
pcls[ich] = BN;
ich += resolveExplicit(plevel[ich], (cls == LRE ? N : L),
&pcls[ich+1], &plevel[ich+1],
cch - (ich+1), nNest);
nNest--;
continue;
}
cls = pcls[ich] = BN;
break;
case RLO:
case RLE:
nNest++;
if (GreaterOdd(level) <= MAX_LEVEL)
{
plevel[ich] = GreaterOdd(level);
pcls[ich] = BN;
ich += resolveExplicit(plevel[ich], (cls == RLE ? N : R),
&pcls[ich+1], &plevel[ich+1],
cch - (ich+1), nNest);
nNest--;
continue;
}
cls = pcls[ich] = BN;
break;
case PDF:
cls = pcls[ich] = BN;
if (nNest)
{
if (nLastValid < nNest)
{
nNest--;
}
else
{
cch = ich; // break the loop, but complete body
}
}
break;
}
// Apply the override
if (dir != N)
{
cls = dir;
}
plevel[ich] = level;
if (pcls[ich] != BN)
pcls[ich] = cls;
}
return ich;
}
// === RESOLVE WEAK TYPES ================================================
enum bidi_state // possible states
{
xa, // arabic letter
xr, // right leter
xl, // left letter
ao, // arabic lett. foll by ON
ro, // right lett. foll by ON
lo, // left lett. foll by ON
rt, // ET following R
lt, // ET following L
cn, // EN, AN following AL
ra, // arabic number foll R
re, // european number foll R
la, // arabic number foll L
le, // european number foll L
ac, // CS following cn
rc, // CS following ra
rs, // CS,ES following re
lc, // CS following la
ls, // CS,ES following le
ret, // ET following re
let, // ET following le
} ;
static int stateWeak[][10] =
{
// N, L, R, AN, EN, AL,NSM, CS, ES, ET,
/*xa*/ ao, xl, xr, cn, cn, xa, xa, ao, ao, ao, /* arabic letter */
/*xr*/ ro, xl, xr, ra, re, xa, xr, ro, ro, rt, /* right letter */
/*xl*/ lo, xl, xr, la, le, xa, xl, lo, lo, lt, /* left letter */
/*ao*/ ao, xl, xr, cn, cn, xa, ao, ao, ao, ao, /* arabic lett. foll by ON*/
/*ro*/ ro, xl, xr, ra, re, xa, ro, ro, ro, rt, /* right lett. foll by ON */
/*lo*/ lo, xl, xr, la, le, xa, lo, lo, lo, lt, /* left lett. foll by ON */
/*rt*/ ro, xl, xr, ra, re, xa, rt, ro, ro, rt, /* ET following R */
/*lt*/ lo, xl, xr, la, le, xa, lt, lo, lo, lt, /* ET following L */
/*cn*/ ao, xl, xr, cn, cn, xa, cn, ac, ao, ao, /* EN, AN following AL */
/*ra*/ ro, xl, xr, ra, re, xa, ra, rc, ro, rt, /* arabic number foll R */
/*re*/ ro, xl, xr, ra, re, xa, re, rs, rs,ret, /* european number foll R */
/*la*/ lo, xl, xr, la, le, xa, la, lc, lo, lt, /* arabic number foll L */
/*le*/ lo, xl, xr, la, le, xa, le, ls, ls,let, /* european number foll L */
/*ac*/ ao, xl, xr, cn, cn, xa, ao, ao, ao, ao, /* CS following cn */
/*rc*/ ro, xl, xr, ra, re, xa, ro, ro, ro, rt, /* CS following ra */
/*rs*/ ro, xl, xr, ra, re, xa, ro, ro, ro, rt, /* CS,ES following re */
/*lc*/ lo, xl, xr, la, le, xa, lo, lo, lo, lt, /* CS following la */
/*ls*/ lo, xl, xr, la, le, xa, lo, lo, lo, lt, /* CS,ES following le */
/*ret*/ ro, xl, xr, ra, re, xa,ret, ro, ro,ret, /* ET following re */
/*let*/ lo, xl, xr, la, le, xa,let, lo, lo,let, /* ET following le */
};
enum bidi_action // possible actions
{
// primitives
IX = 0x100, // increment
XX = 0xF, // no-op
// actions
xxx = (XX << 4) + XX, // no-op
xIx = IX + xxx, // increment run
xxN = (XX << 4) + ON, // set current to N
xxE = (XX << 4) + EN, // set current to EN
xxA = (XX << 4) + AN, // set current to AN
xxR = (XX << 4) + R, // set current to R
xxL = (XX << 4) + L, // set current to L
Nxx = (ON << 4) + 0xF, // set run to neutral
Axx = (AN << 4) + 0xF, // set run to AN
ExE = (EN << 4) + EN, // set run to EN, set current to EN
NIx = (ON << 4) + 0xF + IX, // set run to N, increment
NxN = (ON << 4) + ON, // set run to N, set current to N
NxR = (ON << 4) + R, // set run to N, set current to R
NxE = (ON << 4) + EN, // set run to N, set current to EN
AxA = (AN << 4) + AN, // set run to AN, set current to AN
NxL = (ON << 4) + L, // set run to N, set current to L
LxL = (L << 4) + L, // set run to L, set current to L
};
static int actionWeak[][10] =
{
// N,.. L, R, AN, EN, AL, NSM, CS,..ES, ET,
/*xa*/ xxx, xxx, xxx, xxx, xxA, xxR, xxR, xxN, xxN, xxN, /* arabic letter */
/*xr*/ xxx, xxx, xxx, xxx, xxE, xxR, xxR, xxN, xxN, xIx, /* right leter */
/*xl*/ xxx, xxx, xxx, xxx, xxL, xxR, xxL, xxN, xxN, xIx, /* left letter */
/*ao*/ xxx, xxx, xxx, xxx, xxA, xxR, xxN, xxN, xxN, xxN, /* arabic lett. foll by ON */
/*ro*/ xxx, xxx, xxx, xxx, xxE, xxR, xxN, xxN, xxN, xIx, /* right lett. foll by ON */
/*lo*/ xxx, xxx, xxx, xxx, xxL, xxR, xxN, xxN, xxN, xIx, /* left lett. foll by ON */
/*rt*/ Nxx, Nxx, Nxx, Nxx, ExE, NxR, xIx, NxN, NxN, xIx, /* ET following R */
/*lt*/ Nxx, Nxx, Nxx, Nxx, LxL, NxR, xIx, NxN, NxN, xIx, /* ET following L */
/*cn*/ xxx, xxx, xxx, xxx, xxA, xxR, xxA, xIx, xxN, xxN, /* EN, AN following AL */
/*ra*/ xxx, xxx, xxx, xxx, xxE, xxR, xxA, xIx, xxN, xIx, /* arabic number foll R */
/*re*/ xxx, xxx, xxx, xxx, xxE, xxR, xxE, xIx, xIx, xxE, /* european number foll R */
/*la*/ xxx, xxx, xxx, xxx, xxL, xxR, xxA, xIx, xxN, xIx, /* arabic number foll L */
/*le*/ xxx, xxx, xxx, xxx, xxL, xxR, xxL, xIx, xIx, xxL, /* european number foll L */
/*ac*/ Nxx, Nxx, Nxx, Axx, AxA, NxR, NxN, NxN, NxN, NxN, /* CS following cn */
/*rc*/ Nxx, Nxx, Nxx, Axx, NxE, NxR, NxN, NxN, NxN, NIx, /* CS following ra */
/*rs*/ Nxx, Nxx, Nxx, Nxx, ExE, NxR, NxN, NxN, NxN, NIx, /* CS,ES following re */
/*lc*/ Nxx, Nxx, Nxx, Axx, NxL, NxR, NxN, NxN, NxN, NIx, /* CS following la */
/*ls*/ Nxx, Nxx, Nxx, Nxx, LxL, NxR, NxN, NxN, NxN, NIx, /* CS,ES following le */
/*ret*/xxx, xxx, xxx, xxx, xxE, xxR, xxE, xxN, xxN, xxE, /* ET following re */
/*let*/xxx, xxx, xxx, xxx, xxL, xxR, xxL, xxN, xxN, xxL, /* ET following le */
};
static int GetDeferredType(int action)
{
return (action >> 4) & 0xF;
}
static int GetResolvedType(int action)
{
return action & 0xF;
}
/* Note on action table:
States can be of two kinds:
- Immediate Resolution State, where each input token
is resolved as soon as it is seen. These states havve
only single action codes (xxN) or the no-op (xxx)
for static input tokens.
- Deferred Resolution State, where input tokens either
either extend the run (xIx) or resolve its Type (e.g. Nxx).
Input classes are of three kinds
- Static Input Token, where the class of the token remains
unchanged on output (AN, L, N, R)
- Replaced Input Token, where the class of the token is
always replaced on output (AL, BN, NSM, CS, ES, ET)
- Conditional Input Token, where the class of the token is
changed on output in some but not all cases (EN)
Where tokens are subject to change, a double action
(e.g. NxA, or NxN) is _required_ after deferred states,
resolving both the deferred state and changing the current token.
These properties of the table are verified by assertions below.
This code is needed only during debugging and maintenance
*/
#if ASSERT_ENABLED
static bool IsDeferredState(int state)
{
switch(state)
{
case rt: // this needs to be a deferred
case lt:
case ac:
case rc:
case rs:
case lc:
case ls:
return true;
}
return false;
}
static bool IsModifiedClass(int cls)
{
switch(cls)
{
case AL:
case NSM:
case ES:
case CS:
case ET:
case EN: // sometimes 'modified' to EN
return true;
}
return false;
}
static const int state_first = xa;
static const int state_last = let;
static const int cls_first = N;
static const int cls_last = ET;
// Verify these properties of the tables
static int VerifyTables()
{
int done = 1;
for (int cls = cls_first; cls <= cls_last; cls++)
{
for (int state = state_first; state <= state_last; state++)
{
int action= actionWeak[state][cls];
int nextstate = stateWeak[state][cls];
if (IX & action)
{
// make sure when we defer we get to a
// deferred state
ASSERT(IsDeferredState(nextstate));
// Make sure permanent classes are not deferred
ASSERT(IsModifiedClass(cls));
}
else
{
// make sure we are not deferring without
// incrementing a run
ASSERT(!IsDeferredState(nextstate));
// make sure modified classes are modified
if (IsModifiedClass(cls))
{
ASSERT(GetResolvedType(action) != XX);
}
else
{
ASSERT(GetResolvedType(action) == XX);
}
}
// if we are deferring, make sure things are resolved
if (IsDeferredState(state))
{
// Deferred states must increment or have deferred type
ASSERT(action == xIx || GetDeferredType(action) != XX);
}
else
{
ASSERT(GetDeferredType(action) == XX);
}
}
};
return done;
}
#endif
/*------------------------------------------------------------------------
Function: resolveWeak
Resolves the directionality of numeric and other weak character types
Implements rules X10 and W1-W6 of the Unicode Bidirectional Algorithm.
Input: Array of embedding levels
Character count
In/Out: Array of directional classes
Note: On input only these directional classes are expected
AL, HL, R, L, ON, BN, NSM, AN, EN, ES, ET, CS,
------------------------------------------------------------------------*/
static void resolveWeak(int baselevel, uint8_t *pcls, uint8_t *plevel, unsigned long cch)
{
int state = odd(baselevel) ? xr : xl;
int cls;
int level = baselevel;
int cchRun = 0;
unsigned long ich; for (ich = 0; ich < cch; ich++)
{
// ignore boundary neutrals
if (pcls[ich] == BN)
{
// must flatten levels unless at a level change;
plevel[ich] = level;
// lookahead for level changes
if (ich + 1 == cch && level != baselevel)
{
// have to fixup last BN before end of the loop, since
// its fix-upped value will be needed below the assert
pcls[ich] = EmbeddingDirection(level);
}
else if (ich + 1 < cch && level != plevel[ich+1] && pcls[ich+1] != BN)
{
// fixup LAST BN in front / after a level run to make
// it act like the SOR/EOR in rule X10
int newlevel = plevel[ich+1];
if (level > newlevel) {
newlevel = level;
}
plevel[ich] = newlevel;
// must match assigned level
pcls[ich] = EmbeddingDirection(newlevel);
level = plevel[ich+1];
}
else
{
// don't interrupt runs
if (cchRun)
{
cchRun++;
}
continue;
}
}
ASSERT(pcls[ich] <= BN);
cls = pcls[ich];
int action = actionWeak[state][cls];
// resolve the directionality for deferred runs
int clsRun = GetDeferredType(action);
if (clsRun != XX)
{
SetDeferredRun(pcls, cchRun, ich, clsRun);
cchRun = 0;
}
// resolve the directionality class at the current location
int clsNew = GetResolvedType(action);
if (clsNew != XX)
pcls[ich] = clsNew;
// increment a deferred run
if (IX & action)
cchRun++;
state = stateWeak[state][cls];
}
// resolve any deferred runs
// use the direction of the current level to emulate PDF
cls = EmbeddingDirection(level);
// resolve the directionality for deferred runs
int clsRun = GetDeferredType(actionWeak[state][cls]);
if (clsRun != XX)
SetDeferredRun(pcls, cchRun, ich, clsRun);
}
// === RESOLVE NEUTAL TYPES ==============================================
// action values
enum neutral_action
{
// action to resolve previous input
nL = L, // resolve EN to L
En = 3 << 4, // resolve neutrals run to embedding level direction
Rn = R << 4, // resolve neutrals run to strong right
Ln = L << 4, // resolved neutrals run to strong left
In = (1<<8), // increment count of deferred neutrals
LnL = (1<<4)+L, // set run and EN to L
};
static int GetDeferredNeutrals(int action, int level)
{
action = (action >> 4) & 0xF;
if (action == (En >> 4))
return EmbeddingDirection(level);
else
return action;
}
static int GetResolvedNeutrals(int action)
{
action = action & 0xF;
if (action == In)
return 0;
else
return action;
}
// state values
enum neutral_state
{
// new temporary class
r, // R and characters resolved to R
l, // L and characters resolved to L
rn, // N preceded by right
ln, // N preceded by left
a, // AN preceded by left (the abbrev 'la' is used up above)
na, // N preceeded by a
} ;
/*------------------------------------------------------------------------
Notes:
By rule W7, whenever a EN is 'dominated' by an L (including start of
run with embedding direction = L) it is resolved to, and further treated
as L.
This leads to the need for 'a' and 'na' states.
------------------------------------------------------------------------*/
static int actionNeutrals[][5] =
{
// N, L, R, AN, EN, = cls
// state =
In, 0, 0, 0, 0, // r right
In, 0, 0, 0, L, // l left
In, En, Rn, Rn, Rn, // rn N preceded by right
In, Ln, En, En, LnL, // ln N preceded by left
In, 0, 0, 0, L, // a AN preceded by left
In, En, Rn, Rn, En, // na N preceded by a
} ;
static int stateNeutrals[][5] =
{
// N, L, R, AN, EN = cls
// state =
rn, l, r, r, r, // r right
ln, l, r, a, l, // l left
rn, l, r, r, r, // rn N preceded by right
ln, l, r, a, l, // ln N preceded by left
na, l, r, a, l, // a AN preceded by left
na, l, r, a, l, // na N preceded by la
} ;
/*------------------------------------------------------------------------
Function: resolveNeutrals
Resolves the directionality of neutral character types.
Implements rules W7, N1 and N2 of the Unicode Bidi Algorithm.
Input: Array of embedding levels
Character count
Baselevel
In/Out: Array of directional classes
Note: On input only these directional classes are expected
R, L, N, AN, EN and BN
W8 resolves a number of ENs to L
------------------------------------------------------------------------*/
static void resolveNeutrals(int baselevel, uint8_t *pcls, const uint8_t *plevel, unsigned long cch)
{
// the state at the start of text depends on the base level
int state = odd(baselevel) ? r : l;
int cls;
int cchRun = 0;
int level = baselevel;
unsigned long ich;
for (ich = 0; ich < cch; ich++)
{
// ignore boundary neutrals
if (pcls[ich] == BN)
{
// include in the count for a deferred run
if (cchRun)
cchRun++;
// skip any further processing
continue;
}
ASSERT(pcls[ich] < 5); // "Only N, L, R, AN, EN are allowed"
cls = pcls[ich];
int action = actionNeutrals[state][cls];
// resolve the directionality for deferred runs
int clsRun = GetDeferredNeutrals(action, level);
if (clsRun != N)
{
SetDeferredRun(pcls, cchRun, ich, clsRun);
cchRun = 0;
}
// resolve the directionality class at the current location
int clsNew = GetResolvedNeutrals(action);
if (clsNew != N)
pcls[ich] = clsNew;
if (In & action)
cchRun++;
state = stateNeutrals[state][cls];
level = plevel[ich];
}
// resolve any deferred runs
cls = EmbeddingDirection(level); // eor has type of current level
// resolve the directionality for deferred runs
int clsRun = GetDeferredNeutrals(actionNeutrals[state][cls], level);
if (clsRun != N)
SetDeferredRun(pcls, cchRun, ich, clsRun);
}
// === RESOLVE IMPLLICIT =================================================
/*------------------------------------------------------------------------
Function: resolveImplicit
Recursively resolves implicit embedding levels.
Implements rules I1 and I2 of the Unicode Bidirectional Algorithm.
Input: Array of direction classes
Character count
Base level
In/Out: Array of embedding levels
Note: levels may exceed 15 on output.
Accepted subset of direction classes
R, L, AN, EN
------------------------------------------------------------------------*/
static int addLevel[][4] =
{
// L, R, AN, EN = cls
// level =
/* even */ 0, 1, 2, 2, // EVEN
/* odd */ 1, 0, 1, 1, // ODD
};
static void resolveImplicit(const uint8_t * pcls, uint8_t * plevel, unsigned long cch)
{
unsigned long ich;
for (ich = 0; ich < cch; ich++)
{
// cannot resolve bn here, since some bn were resolved to strong
// types in resolveWeak. To remove these we need the original
// types, which are available again in resolveWhiteSpace
if (pcls[ich] == BN)
{
continue;
}
ASSERT(pcls[ich] > 0); // "No Neutrals allowed to survive here."
ASSERT(pcls[ich] < 5); // "Out of range."
plevel[ich] += addLevel[odd(plevel[ich])][pcls[ich] - 1];
}
}
// === REORDER ===========================================================
/*------------------------------------------------------------------------
Function: resolveLines
Breaks a paragraph into lines
Input: Character count
Array of line break flags
In/Out: Array of characters
Returns the count of characters on the first line
Note: This function only breaks lines at hard line breaks. Other
line breaks can be passed in. If pbrk[n] is true, then a break
occurs after the character in pszInput[n]. Breaks before the first
character are not allowed.
------------------------------------------------------------------------*/
static const int chLS = 0x15;
static unsigned long resolveLines(unichar * pszInput, bool * pbrk, unsigned long cch)
{
// skip characters not of type LS
unsigned long ich;
for (ich = 0; ich < cch; ich++)
{
if (pszInput[ich] == chLS || (pbrk && pbrk[ich]))
{
ich++;
break;
}
}
return ich;
}
/*------------------------------------------------------------------------
Function: resolveWhiteSpace
Resolves levels for WS and S
Implements rule L1 of the Unicode bidi Algorithm.
Input: Base embedding level
Character count
Array of direction classes (for one line of text)
In/Out: Array of embedding levels (for one line of text)
Note: this should be applied a line at a time.
------------------------------------------------------------------------*/
static void resolveWhitespace(int baselevel, const uint8_t *pcls, uint8_t *plevel,
unsigned long cch)
{
int cchrun = 0;
int oldlevel = baselevel;
unsigned long ich;
for (ich = 0; ich < cch; ich++)
{
switch(pcls[ich])
{
default:
cchrun = 0; // any other character breaks the run
break;
case WS:
cchrun++;
break;
case RLE:
case LRE:
case LRO:
case RLO:
case PDF:
case BN:
plevel[ich] = oldlevel;
cchrun++;
break;
case S:
case B:
// reset levels for WS before eot
SetDeferredRun(plevel, cchrun, ich, baselevel);
cchrun = 0;
plevel[ich] = baselevel;
break;
}
oldlevel = plevel[ich];
}
// reset level before eot
SetDeferredRun(plevel, cchrun, ich, baselevel);
}
/*------------------------------------------------------------------------
Functions: reorder/reorderLevel
Recursively reorders the display string
"From the highest level down, reverse all characters at that level and
higher, down to the lowest odd level"
Implements rule L2 of the Unicode bidi Algorithm.
Input: Array of embedding levels
Character count
Flag enabling reversal (set to false by initial caller)
In/Out: Text to reorder
Note: levels may exceed 15 resp. 61 on input.
Rule L3 - reorder combining marks is not implemented here
Rule L4 - glyph mirroring is implemented as a display option below
Note: this should be applied a line at a time
-------------------------------------------------------------------------*/
static unsigned long reorderLevel(int level, NSUInteger * pszText, const uint8_t * plevel, unsigned long cch,
bool fReverse)
{
// true as soon as first odd level encountered
fReverse = fReverse || odd(level);
unsigned long ich;
for (ich = 0; ich < cch; ich++)
{
if (plevel[ich] < level)
{
break;
}
else if (plevel[ich] > level)
{
ich += reorderLevel(level + 1, pszText + ich, plevel + ich,
cch - ich, fReverse) - 1;
}
}
if (fReverse)
{
reverse(pszText, ich);
}
return ich;
}
static unsigned long reorder(NSInteger baselevel, NSUInteger * pszText, const uint8_t * plevel, unsigned long cch)
{
unsigned long ich = 0;
while (ich < cch)
{
ich += reorderLevel(baselevel, pszText + ich, plevel + ich,
cch - ich, false);
}
return ich;
}
// === DISPLAY OPTIONS ================================================
/*-----------------------------------------------------------------------
Function: mirror
Crudely implements rule L4 of the Unicode Bidirectional Algorithm
Input: Array of levels
Count of characters
In/Out: Array of characters (should be array of glyph ids)
Note;
A full implementation would need to substitute mirrored glyphs even
for characters that are not paired (e.g. integral sign).
-----------------------------------------------------------------------*/
static void mirror(unichar * pszInput, const uint8_t * plevel, unsigned long cch)
{
unsigned long ich;
for (ich = 0; ich < cch; ich ++)
{
if (!odd(plevel[ich])) {
continue;
}
if (sUnicharData[pszInput[ich]].mirrored == 0) {
continue;
}
pszInput[ich] = mirror_character(pszInput[ich]);
}
}
// === BIDI INTERFACE FUNCTIONS ========================================
/*------------------------------------------------------------------------
Function: ProcessLine
Implements the Line-by-Line phases of the Unicode Bidi Algorithm
------------------------------------------------------------------------*/
void NSBidiHelperProcessLine(NSInteger baselevel, NSUInteger* pszLine, unichar *text, uint8_t * plevelLine, NSInteger fMirror, NSUInteger length)
{
buildUnicharData();
if (sUnicodeDataAbsent == YES) {
return;
}
if (text) {
// get the types for the glyphs
uint8_t *types = malloc(length * sizeof(uint8_t));
if (types) {
// fetch the bidi types for the text
classify(text, types, length, true);
// resolve whitespace
resolveWhitespace(baselevel, types, plevelLine, length);
free(types);
}
if (fMirror) {
mirror(text, plevelLine, length);
}
}
if (pszLine) {
// reorder each line in place
reorder(baselevel, pszLine, plevelLine, length);
}
}
/*------------------------------------------------------------------------
Function: BidiParagraph
Implements the per paragraph phases of the Unicode Bidi Algorithm
Process all of the paragraphs from the text
Input:
Input text
Count of characters
In/Out:
Base paragraph level (negative value on input means implicit)
Array of levels
Returns: 1
------------------------------------------------------------------------*/
NSUInteger NSBidiHelperParagraph(NSInteger *baselevel, unichar *text, uint8_t * levels, NSUInteger cch)
{
NSUInteger result = 0;
if (cch == 0) {
return 0;
}
buildUnicharData();
if (sUnicodeDataAbsent == YES) {
return 0;
}
NSInteger initialBaseBaselevel = *baselevel;
// get the types for the glyphs
uint8_t *types = malloc(cch * sizeof(uint8_t));
if (types) {
// fetch the bidi types for the text
classify(text, types, cch, false);
uint8_t *currentTypes = types;
while (cch > 0) {
// set baselevel
NSInteger level = initialBaseBaselevel;
if (level < 0) {
level = baseLevel(currentTypes, cch);
*baselevel = level;
}
// change B into BN and return length including
NSUInteger cchPara = resolveParagraphs(currentTypes, cch);
// resolve explicit
resolveExplicit(level, N, currentTypes, levels, cchPara, 0);
// resolve weak
resolveWeak(level, currentTypes, levels, cchPara);
// resolve neutrals
resolveNeutrals(level,currentTypes, levels, cchPara);
// resolveImplicit
resolveImplicit(currentTypes, levels, cchPara);
cch -= cchPara;
levels += cchPara;
text += cchPara;
currentTypes += cchPara;
}
free(types);
result = 1;
}
return result;
}
/*------------------------------------------------------------------------*/
BOOL NSBidiHelperBidiInfoAvailable()
{
buildUnicharData();
return sUnicodeDataAbsent == NO;
}
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