/* $File: //member/autrijus/Locale-Hebrew/bidi.c $ $Author: autrijus $
$Revision: #3 $ $Change: 11166 $ $DateTime: 2004/09/17 21:16:27 $ */
/* This code is slightly modified from:
Bidi.cpp - version 24
Reference implementation for Unicode Bidirectional Algorithm
*/
#include <stdio.h>
#define ASSERT(x) if (!(x)) { fprintf(stderr, "assert failed: %s\n", #x); exit(-1);} else ;
#define TCHAR unsigned char
#ifndef BOOL
#define BOOL char
#define FALSE 0
#define TRUE 1
#endif
/*------------------------------------------------------------------------
File: Bidi.C
Description
-----------
Sample Implementation of the Unicode Bidirectional Algorithm as it
was revised by Revision 5 of the Uniode Technical Report # 9
(1999-8-17)
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.
The file biditest.cpp contains hooks to link to a stress harness
comparing this implementation to a Java based implementation. This
harness was used to verify that the two implementations produce
identical results.
Implementation Note
-------------------
NOTE: The Unicode Birdirectional 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.
The clean() function can be used to remove boundary marks for
verification purposes.
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:
--------------
- clean version for publication
- new commandline interface
- Last Revised 11-4-99
Disclaimer and legal rights
---------------------------
NOTE: This c file is directly based on the C++ file, but has not
been exhaustively tested for compliance with the bidi
algorithm. We think that the only effect the changes
had was to comply with the differences in C++ vs C
syntax, but don't take our word for it.
This file contains bugs. All representations to the contrary are
void.
Source code in this file and the header file may be distributed free of
charge by anyone, as long as full credit is given and any and all
liabilities are assumed by the recipient.
Written by: Asmus Freytag
C++ and Windows dependencies removed, and
command line interface added by: Rick McGowan
Copyright (C) 1999, ASMUS, Inc. All Rights Reserved
------------------------------------------------------------------------*/
// === HELPER FUNCTIONS AND DECLARATIONS =================================
#define odd(x) ((x) & 1)
/*------------------------------------------------------------------------
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 numeric values for the types
are chosen to keep the state and action tables compact.
------------------------------------------------------------------------*/
enum
{
// 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
};
/*----------------------------------------------------------------------
The following array maps character codes to types for the purpose of
this sample implementation. The legend string gives a human readable
explanation of the pseudo alphabet.
For simplicity, characters entered by buttons are given a 1:1 mapping
between their type and pseudo character value. Pseudo characters that
can be typed from the keyboard are explained in the legend string.
Use the Unicode Character Database for the real values in real use.
---------------------------------------------------------------------*/
#define LRM 4
#define RLM 5
#define LS 0x13
int TypesFromChar[] =
{
//0 1 2 3 4 5 6 7 8 9 a b c d e f
ON, ON, ON, ON, ON, ON, ON, ON, ON, S, ON, ON, ON, ON, ON, ON, /*00-0f*/
ON,ON,ON,ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, /*10-1f*/
WS, ON, ON, ON, ET, ET, ON, ON, ON, ON, ON, ON, CS, ON, CS, CS, /*20-2f*/
EN, EN, EN, EN, EN, EN, EN, EN, EN, EN, CS, ON, ON, ON, ON, ON, /*30-3f*/
ON, L, L, L, L, L, L, L, L, L, L, L, L, L, L, L, /*40-4f*/
L, L, L, L, L, L, L, L, L, L, L, ON, B, ON, ON, ON, /*50-5f*/
ON, L, L, L, L, L, L, L, L, L, L, L, L, L, L, L, /*60-6f*/
L, L, L, L, L, L, L, L, L, L, L, ON, S, ON, ON, ON, /*70-7f*/
ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON,ON, ON, ON, /*80-8f*/
ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON,ON, ON, ON, /*90-9f*/
ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON,ON, ON, ON, /*a0-af*/
ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON,ON, ON, ON, /*b0-bf*/
ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON,ON, ON, ON, /*c0-cf*/
ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON, ON,ON, ON, ON, /*d0-df*/
R, R, R, R, R, R, R, R, R, R, R, R, R, R, R, R, /*e0-ef*/
R, R, R, R, R, R, R, R, R, R, R, ON, ON,ON, ON, ON, /*f0-ff*/
};
// 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
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
};
int ClassFromChN(TCHAR ch) {
/* ASSERT(ch < 0x7f && ch >= 0);*/
return NTypes[TypesFromChar[ch]];
}
int ClassFromChWS(TCHAR ch) {
/* ASSERT(ch < 0x7f && ch >= 0);*/
return TypesFromChar[ch];
}
// === DISPLAY SUPPORT =================================================
enum // Display character codes
{
RIGHT = '<', // rtl arrow
LEFT = '>', // ltr arrow
PUSH = '+', // dn arrow
POP = '-', // up arrow
LSEP = '=', // double dagger
NEUTRAL = ' ', // rtl/ltr dbl headed arrow
ALPHA = 'a',
};
// display support:
TCHAR CharFromTypes[] =
{
NEUTRAL, // ON,
LEFT, // L,
RIGHT, // R,
'9', // AN,
'1', // EN,
ALPHA, // AL
'@', // NSM
'.', // CS
',', // ES
'$', // ET
':', // BN
'X', // S
'_', // WS
'B', // B
PUSH, // RLO
PUSH, // RLE
PUSH, // LRO
PUSH, // LRE
POP, // PDF
LSEP, // LS
};
// This works only for testing
// a full implementation would need 61 levels....
int CharFromLevel[] =
{
'0', '1', '2', '3', '4',
'5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E',
'F', 'X', 'Y', 'Z' // overhang levels
};
// === HELPER FUNCTIONS ================================================
// reverse cch characters
void reverse(TCHAR *psz, int cch)
{
int ich;
TCHAR chTemp;
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.
void SetDeferredRun(int *pval, int cval, int iStart, int nval) {
int i;
for (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
------------------------------------------------------------------------*/
int classify(const TCHAR *pszText, int * pcls, int cch, BOOL fWS) {
int ich;
if (fWS) {
for (ich = 0; ich < cch; ich++) {
pcls[ich] = ClassFromChWS(pszText[ich]);
}
return ich;
} else {
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
Note: This is a very simplistic function. In effect it restricts
the action of the algorithm to the first paragraph in the input
where a paragraph ends at the end of the first block separator
or at the end of the input text.
------------------------------------------------------------------------*/
int resolveParagraphs(int * types, int cch) {
int ich;
// skip characters not of type B
for (ich = 0; ich < cch && types[ich] != B; ich++)
;
// stop after first B, make it a BN for use in the next steps
if (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 int * pcls, int cch) {
int 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 ================================================
int GreaterEven(int i) {
return odd(i) ? i + 1 : i + 2;
}
int GreaterOdd(int i) {
return odd(i) ? i + 2 : i + 1;
}
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
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
int resolveExplicit(int level, int dir, int * pcls, int * plevel, int cch, int
nNest) {
// always called with a valid nesting level
// nesting levels are != embedding levels
int nLastValid = nNest;
int ich, cls;
// check input values
ASSERT(nNest >= 0 && level >= 0 && level <= MAX_LEVEL);
// process the text
for (ich = 0; ich < cch; ich++) {
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
}
}
}
// Apply the override
if (dir != N) {
cls = dir;
}
plevel[ich] = level;
if (pcls[ich] != BN) {
pcls[ich] = cls;
}
}
return ich;
}
// === RESOLVE WEAK TYPES ================================================
enum // 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
} ;
int stateWeak[20][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 leter */
/*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 { // 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
};
int actionWeak[20][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 b
y 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 A
L */
/*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 fol
l 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 fol
l 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 inline int GetDeferredType(int action) {
return (action >> 4) & 0xF;
}
static inline 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
*/
/*------------------------------------------------------------------------
Function: resolveWeak
Resolves the directionality of numeric and other weak character types
Implements rules W1-W7 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,
------------------------------------------------------------------------*/
void resolveWeak(int baselevel, int *pcls, int *plevel, int cch) {
int state = odd(baselevel) ? xr : xl;
int cls, ich, action;
int level = baselevel;
int cchRun = 0;
int clsRun, clsNew;
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];
action = actionWeak[state][cls];
// resolve the directionality for deferred runs
clsRun = GetDeferredType(action);
if (clsRun != XX) {
SetDeferredRun(pcls, cchRun, ich, clsRun);
cchRun = 0;
}
// resolve the directionality class at the current location
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
clsRun = GetDeferredType(actionWeak[state][cls]);
if (clsRun != XX) {
SetDeferredRun(pcls, cchRun, ich, clsRun);
}
}
// === RESOLVE NEUTRAL TYPES ==============================================
// action values
enum {
// 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
};
int GetDeferredNeutrals(int action, int level) {
action = (action >> 4) & 0xF;
if (action == (En >> 4)) {
return EmbeddingDirection(level);
} else {
return action;
}
}
int GetResolvedNeutrals(int action) {
action = action & 0xF;
if (action == In) {
return 0;
} else {
return action;
}
}
// state values
enum {
// 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.
------------------------------------------------------------------------*/
int actionNeutrals[6][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
};
int stateNeutrals[6][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
------------------------------------------------------------------------*/
void resolveNeutrals(int baselevel, int *pcls, const int *plevel, int cch) {
// the state at the start of text depends on the base level
int state = odd(baselevel) ? r : l;
int cls, ich;
int cchRun = 0;
int level = baselevel;
int action, clsNew, clsRun;
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];
action = actionNeutrals[state][cls];
// resolve the directionality for deferred runs
clsRun = GetDeferredNeutrals(action, level);
if (clsRun != N) {
SetDeferredRun(pcls, cchRun, ich, clsRun);
cchRun = 0;
}
// resolve the directionality class at the current location
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
clsRun = GetDeferredNeutrals(actionNeutrals[state][cls], level);
if (clsRun != N)
SetDeferredRun(pcls, cchRun, ich, clsRun);
}
// === RESOLVE IMPLICIT =================================================
/*------------------------------------------------------------------------
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
------------------------------------------------------------------------*/
int addLevel[2][4] = {
// L, R, AN, EN = cls
// level =
/* even */ 0, 1, 2, 2, // EVEN
/* odd */ 1, 0, 1, 1, // ODD
};
void resolveImplicit(const int * pcls, int * plevel, int cch) {
int 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
In/Out: Array of characters
Array of line break flags
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.
------------------------------------------------------------------------*/
int resolveLines(TCHAR *pszInput, BOOL * pbrk, int cch) {
int ich;
// skip characters not of type LS
for(ich = 0; ich < cch; ich++) {
if (pszInput[ich] == LS || (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. The default driver
code supplied in this file assumes a single line of text; for
a real implementation, cch and the initial pointer values
would have to be adjusted.
------------------------------------------------------------------------*/
void resolveWhitespace(int baselevel, const int *pcls, int *plevel, int cch) {
int clevel = 0;
int oldlevel = baselevel;
int ich;
for (ich = 0; ich < cch; ich++) {
switch(pcls[ich]) {
default:
clevel = 0; // any other character breaks the run
break;
case WS:
clevel++;
break;
case RLE:
case LRE:
case LRO:
case RLO:
case PDF:
case BN:
plevel[ich] = oldlevel;
clevel++;
break;
case S:
case B:
// reset levels for WS before eot
SetDeferredRun(plevel, clevel, ich, baselevel);
clevel = 0;
plevel[ich] = baselevel;
break;
}
oldlevel = plevel[ich];
}
// reset level before eot
SetDeferredRun(plevel, clevel, 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
-------------------------------------------------------------------------*/
int reorderLevel(int level, TCHAR *pszText, const int * plevel, int cch, BOOL fReverse) {
int ich;
// TRUE as soon as first odd level encountered
fReverse = fReverse || odd(level);
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;
}
int reorder(int baselevel, TCHAR *pszText, const int * plevel, int cch) {
int 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
Demonstrate mirrored brackets, braces and parens
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).
-----------------------------------------------------------------------*/
void mirror(TCHAR *pszInput, const int * plevel, int cch) {
int ich;
for (ich = 0; ich < cch; ich ++) {
if (!odd(plevel[ich]))
continue;
if (pszInput[ich] == '[') {
pszInput[ich] = ']';
} else if (pszInput[ich] == ']') {
pszInput[ich] = '[';
} else if (pszInput[ich] == '{') {
pszInput[ich] = '}';
} else if (pszInput[ich] == '}') {
pszInput[ich] = '{';
} else if (pszInput[ich] == ')') {
pszInput[ich] = '(';
} else if (pszInput[ich] == '(') {
pszInput[ich] = ')';
}
}
}
/*-----------------------------------------------------------------------
Function: clean
remove formatting codes
In/Out: Array of characters
Count of characters
Note;
This function can be used to remove formatting codes so the
ordering of the string can be compared to implementations that
remove formatting codes. This implementation is limited to the
pseudo alphabet used for the demo version.
-----------------------------------------------------------------------*/
int clean(TCHAR *pszInput, int cch) {
int cchMove = 0;
int ich;
for (ich = 0; ich < cch; ich ++) {
if (pszInput[ich] < 0x20) {
cchMove++;
} else {
pszInput[ich - cchMove] = pszInput[ich];
}
}
pszInput[ich - cchMove] = 0;
return ich - cchMove;
}
/*------------------------------------------------------------------------
Function: BidiLines
Implements the Line-by-Line phases of the Unicode Bidi Algorithm
Input: Count of characters
flag whether to mirror
Inp/Out: Input text
Array of character directions
Array of levels
------------------------------------------------------------------------*/
void BidiLines(int baselevel, TCHAR *pszLine, int *pclsLine, int *plevelLine, int cchPara, int fMirror, BOOL *pbrk) {
int cchLine = 0;
do {
// break lines at LS
cchLine = resolveLines(pszLine, pbrk, cchPara);
// resolve whitespace
resolveWhitespace(baselevel, pclsLine, plevelLine, cchLine);
if (fMirror) {
mirror(pszLine, plevelLine, cchLine);
}
// reorder each line in place
reorder(baselevel, pszLine, plevelLine, cchLine);
pszLine += cchLine;
plevelLine += cchLine;
pbrk += pbrk ? cchLine : 0;
pclsLine += cchLine;
cchPara -= cchLine;
} while (cchPara);
}
// ===== FUNCTIONS FOR COMMAND LINE VERSION ==============================
#include <stdlib.h>
#include <string.h>
// An alternate CharFromTypes array may be needed to use the command
// line version,
#define MAX_CCH 256
void ShowInputTypes(FILE* f, TCHAR * pszInput, int cch) {
TCHAR pszTypes[MAX_CCH+1];
int ich;
for (ich = 0; ich < cch; ich++) {
pszTypes[ich] = CharFromTypes[ClassFromChWS(pszInput[ich])];
}
pszTypes[ich] = 0;
fprintf(f, pszTypes);
}
void ShowTypes(FILE* f, int * types, int cch) {
TCHAR pszTypes[MAX_CCH+1];
int ich;
for (ich = 0; ich < cch; ich++) {
pszTypes[ich] = CharFromTypes[types[ich]];
}
pszTypes[ich] = 0;
fprintf(f, pszTypes);
}
void ShowLevels(FILE* f, int * levels, int cch) {
TCHAR pszLevel[MAX_CCH+1];
int ich;
for (ich = 0; ich < cch; ich++) {
pszLevel[ich] = CharFromLevel[levels[ich]];
}
pszLevel[ich] = 0;
fprintf(f, pszLevel);
}
void usage(char *s) {
printf("Usage: %s [-verbose] [-nomirror] [-clean] strings...\n", s);
printf("\t-verbose = verbose debugging output.\n");
printf("\t-nomirror = refrain from glyph mirroring.\n");
printf("\t-clean = clean up the result.\n");
printf("\tOptions affect all subsequent arguments.\n");
printf("\tAll other arguments are interpreted as strings to process.\n");
}
void bidimain(char *string, int cch) {
int realArg = 0;
int doMirror = 1;
int doClean = 0;
int beVerbose = 0;
int i, baselevel;
int *types;
int *levels;
FILE* f = stdout;
types = calloc(sizeof(int), cch);
levels = calloc(sizeof(int), cch);
// assign directional types
classify(string, types, cch, FALSE);
// limit text to first block
cch = resolveParagraphs(types, cch);
// set base level and compute character types
baselevel = baseLevel(types, cch);
// resolve explicit
resolveExplicit(baselevel, 0, types, levels, cch, 0);
// resolve weak
resolveWeak(baselevel, types, levels, cch);
// resolve neutrals
resolveNeutrals(baselevel,types, levels, cch);
// resolveImplicit
resolveImplicit(types, levels, cch);
// assign directional types again, but for WS, S this time
classify(string, types, cch, TRUE);
BidiLines(baselevel, string, types, levels, cch, doMirror, 0);
free(types);
free(levels);
}
/* This code is slightly modified from:
Bidi.cpp - version 24
Reference implementation for Unicode Bidirectional Algorithm
*/
int main(int argc, char **argv) {
char s[8192];
if (argc != 2) exit(-1);
strcpy(s, argv[1]);
bidimain(s, strlen(s));
puts(s);
}