/* This code is slightly modified from: Bidi.cpp - version 25h Reference implementation for Unicode Bidirectional Algorithm Using no language extensions, and providing commandline only with no debugging support. Not verified against the other implementations. */ #include #define ASSERT(x) if (!(x)) fprintf(stdout, "assert failed: %s\n", #x); else ; #define TCHAR char #define LPTSTR 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. 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: -------------- 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. - 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) Credits: ------- Written by: Asmus Freytag Command line interface by: Rick McGowan Verification and Test Harness: Doug Felt Disclaimer and legal rights: --------------------------- Copyright (C) 1999-2005, 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. ------------------------------------------------------------------------*/ // === 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 numberic 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 chLRM 4 #define chRLM 5 #define chLS 0x15 #define chRLO '}' #define chLRO '{' #define chRLE ']' #define chLRE '[' #define chPDF '^' #define chBN '~' int TypesFromChar[] = { //0 1 2 3 4 5 6 7 8 9 a b c d e f BN, BN, BN, BN, L, R, BN, BN, BN, S, B, S, WS, B, BN, BN, /*00-0f*/ LRO,LRE,PDF,RLO,RLE, WS, L, R, BN, BN, BN, BN, B, B, B, S, /*10-1f*/ WS, ON, ON, ET, ET, ET, ON, ON, ON, ON, ON, ES, CS, ES, CS, ES, /*20-2f*/ EN, EN, EN, EN, EN, EN, AN, AN, AN, AN, CS, ON, ON, ON, ON, ON, /*30-3f*/ ON, AL, AL, AL, AL, AL, AL, R, R, R, R, R, R, R, R, R, /*40-4f*/ R, R, R, R, R, R, R, R, R, R, R,LRE, ON,RLE,PDF, S, /*50-5f*/ NSM, 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,LRO, B,RLO, BN, ON, /*70-7f*/ }; /*************************************** Reverse, human readable reference: LRM: 0x4 RLM: 0x5 L: 0x16,a-z LRE: 0x11,[ LRO: 0x10,{ R: 0x17,G-Z AL: A-F RLE: 0x14,] RLO: 0x13,} PDF: 0x12,^ EN: 0-5 ES: /,+,[hyphen] ET: #,$,% AN: 6-9 CS: [comma],.,: NSM: ` BN: 0x0-0x8,0xe,0xf,0x18-0x1b,~ B: 0xa,0xd,0x1c-0x1e,| S: 0x9,0xb,0x1f,_ WS: 0xc,0x15,[space] ON: !,",&,',(,),*,;,<,=,>,?,@,\,0x7f ****************************************/ // WS, LS and S are not explicitly needed except for L1. Therefore this // Table conflates ON, S, WS, and LS to N, all others unchanged int NTypes[] = { N, // ON, L, // L, R, // R, AN, // AN, EN, // EN, AL, // AL NSM, // NSM CS, // CS ES, // ES ET, // ET BN, // BN N, // S N, // WS B, // B RLO, // RLO RLE, // RLE LRO, // LRO LRE, // LRE PDF, // PDF ON, // LS }; int ClassFromChN(TCHAR ch) { ASSERT(ch < 0x7f && ch >= 0); return NTypes[TypesFromChar[ch & 0x7f]]; } int ClassFromChWS(TCHAR ch) { ASSERT(ch < 0x7f && ch >= 0); return TypesFromChar[ch & 0x7f]; } // === DISPLAY SUPPORT ================================================= enum // Display character codes { RIGHT = '<', // rtl arrow LEFT = '>', // ltr arrow PUSH = '+', // dn arrow POP = '-', // up arrow LSEP = '=', // double dagger NEUTRAL = ' ', // rtl/ltr dbl headed arrow ALPHA = 'a', }; // display support: TCHAR CharFromTypes[] = { NEUTRAL, // ON, LEFT, // L, RIGHT, // R, '9', // AN, '1', // EN, ALPHA, // AL '@', // NSM '.', // CS ',', // ES '$', // 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.... TCHAR 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(LPTSTR psz, int cch) { TCHAR chTemp; int ich = 0; for (; 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 = iStart - 1; for (; 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 LPTSTR pszText, int * pcls, int cch, BOOL fWS) { if (fWS) { int ich = 0; for (; ich < cch; ich++) { pcls[ich] = ClassFromChWS(pszText[ich]); } return ich; } else { int ich = 0; for (; 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) { // skip characters not of type B int ich = 0; for(; 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 = 0; for (; 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. ------------------------------------------------------------------------*/ #define 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 = 0; // check input values ASSERT(nNest >= 0 && level >= 0 && level <= MAX_LEVEL); // process the text for (; 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 } } } // 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[][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 // 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[][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 */ }; int GetDeferredType(int action) { return (action >> 4) & 0xF; } 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. */ /*------------------------------------------------------------------------ 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, ------------------------------------------------------------------------*/ void resolveWeak(int baselevel, int *pcls, int *plevel, int cch) { int state = odd(baselevel) ? xr : xl; int cls; int level = baselevel; int action, clsRun, clsNew; int cchRun = 0; int ich = 0; for (; 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 NEUTAL 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[][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[][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; int cchRun = 0; int level = baselevel; int action, clsRun, clsNew; int ich = 0; for (; 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 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 ------------------------------------------------------------------------*/ int addLevel[][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 = 0; for (; 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) { // skip characters not of type LS int ich = 0; for(; 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. 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 cchrun = 0; int oldlevel = baselevel; int ich = 0; for (; 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 -------------------------------------------------------------------------*/ int reorderLevel(int level, LPTSTR pszText, const int * plevel, int cch, BOOL fReverse) { int ich = 0; // true as soon as first odd level encountered fReverse = fReverse || odd(level); for (; 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, LPTSTR 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(LPTSTR pszInput, const int * plevel, int cch) { int ich = 0; for (; 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] = ')'; } } } /*----------------------------------------------------------------------- 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(LPTSTR pszInput, int cch) { int cchMove = 0; int ich = 0; for (; ich < cch; ich ++) { int ch = pszInput[ich]; switch (ch) { default: if (pszInput[ich] < 0x20) { cchMove++; } else { pszInput[ich - cchMove] = pszInput[ich]; } break; case chRLO: case chLRO: case chRLE: case chLRE: case chPDF: case chBN: cchMove++; break; } } 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 #include // An alternate CharFromTypes array may be needed to use the command // line version, #define MAX_CCH 256 void ShowInputTypes(FILE* f, LPTSTR pszInput, int cch) { TCHAR pszTypes[MAX_CCH+1]; int ich = 0; for (; 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 = 0; for (; ich < cch; ich++) { pszTypes[ich] = CharFromTypes[types[ich]]; } pszTypes[ich] = 0; fprintf(f, pszTypes); } void ShowLevels(FILE* f, int * levels, int cch) { #if DEMO // do nothing if levels are not limited to 15 as for debugging // since we can't show 0-61 in a single character TCHAR pszLevel[MAX_CCH+1]; int ich = 0; for (; ich < cch; ich++) { pszLevel[ich] = CharFromLevel[levels[ich]]; } pszLevel[ich] = 0; fprintf(f, pszLevel); #else // squelch compiler warnings f; levels; cch; #endif } void usage(char *s) { printf("Usage: %s [-verbose] [-nomirror] [-level #] [-clean] strings...\n", s); printf("\t-verbose = verbose debugging output.\n"); printf("\t-level # = specify # as the base level.\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"); } int main(int argc, char** argv) { int realArg = 0; int doMirror = 1; int doClean = 0; int doLevel = 1; int baselevel = 0; int beVerbose = 0; int i, cch; TCHAR pszInput[MAX_CCH+1]; int types[MAX_CCH]; int levels[MAX_CCH]; FILE* f = stdout; if (argc == 1) { usage(argv[0]); exit(0); } for (i = 1; i < argc; ++i) { if (doLevel == -1) { baselevel = atoi(argv[i]); doLevel = 0; continue; } else if (strcmp(argv[i], "-verbose") == 0) { beVerbose = 1; continue; } else if (strcmp(argv[i], "-nomirror") == 0) { doMirror = 0; continue; } else if (strcmp(argv[i], "-clean") == 0) { doClean = 1; continue; } else if (strcmp(argv[i], "-level") == 0) { if (argc - 1 == i) { usage(argv[0]); exit(0); } doLevel = -1; continue; } else { ++realArg; } cch = strlen(argv[i]); if (cch > MAX_CCH) cch = MAX_CCH; strncpy(pszInput, argv[i], cch); pszInput[cch] = 0; fprintf(f, "Input %2d: %s\n", realArg, pszInput); // assign directional types classify(pszInput, types, cch, FALSE); if (beVerbose) { fprintf(f, "Input Types: "); ShowInputTypes(f, pszInput, cch); fprintf(f, "\n"); } // limit text to first block cch = resolveParagraphs(types, cch); // set base level if (doLevel) baselevel = baseLevel(types, cch); if (beVerbose) { fprintf(f, "Base Level : %d\n", baselevel); } // resolve explicit resolveExplicit(baselevel, N, types, levels, cch, 0); if (beVerbose) { fprintf(f, "Levels (A) : "); ShowLevels(f, levels, cch); fprintf(f, "\n"); } // resolve weak resolveWeak(baselevel, types, levels, cch); if (beVerbose) { fprintf(f, "Types (A) : "); ShowTypes(f, types, cch); fprintf(f, "\n"); } // resolve neutrals resolveNeutrals(baselevel,types, levels, cch); if (beVerbose) { fprintf(f, "Types (B) : "); ShowTypes(f, types, cch); fprintf(f, "\n"); } // resolveImplicit resolveImplicit(types, levels, cch); if (beVerbose) { fprintf(f, "Levels (B) : "); ShowLevels(f, levels, cch); fprintf(f, "\n"); } // assign directional types again, but for WS, S this time classify(pszInput, types, cch, TRUE); BidiLines(baselevel, pszInput, types, levels, cch, doMirror, 0); if (doClean) { cch = clean(pszInput, cch); } fprintf(f, "Output %2d: %s\n\n", realArg, pszInput); } return 0; } //[EOF] .