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//
// file: rbbiscan.cpp
//
// Copyright (C) 2002-2003, International Business Machines Corporation and others.
// All Rights Reserved.
//
// This file contains the Rule Based Break Iterator Rule Builder functions for
// scanning the rules and assembling a parse tree. This is the first phase
// of compiling the rules.
//
// The overall of the rules is managed by class RBBIRuleBuilder, which will
// create and use an instance of this class as part of the process.
//
#include "unicode/utypes.h"
#if !UCONFIG_NO_BREAK_ITERATION
#include "unicode/unistr.h"
#include "unicode/uniset.h"
#include "unicode/uchar.h"
#include "unicode/uchriter.h"
#include "unicode/parsepos.h"
#include "unicode/parseerr.h"
#include "uprops.h"
#include "cmemory.h"
#include "cstring.h"
#include "rbbirpt.h" // Contains state table for the rbbi rules parser.
// generated by a Perl script.
#include "rbbirb.h"
#include "rbbinode.h"
#include "rbbiscan.h"
#include "uassert.h"
//----------------------------------------------------------------------------------------
//
// Unicode Set init strings for each of the character classes needed for parsing a rule file.
// (Initialized with hex values for portability to EBCDIC based machines.
// Really ugly, but there's no good way to avoid it.)
//
// The sets are referred to by name in the rbbirpt.txt, which is the
// source form of the state transition table for the RBBI rule parser.
//
//----------------------------------------------------------------------------------------
static const UChar gRuleSet_rule_char_pattern[] = {
// [ ^ [ \ p { Z } \ u 0 0 2 0
0x5b, 0x5e, 0x5b, 0x5c, 0x70, 0x7b, 0x5a, 0x7d, 0x5c, 0x75, 0x30, 0x30, 0x32, 0x30,
// - \ u 0 0 7 f ] - [ \ p
0x2d, 0x5c, 0x75, 0x30, 0x30, 0x37, 0x66, 0x5d, 0x2d, 0x5b, 0x5c, 0x70,
// { L } ] - [ \ p { N } ] ]
0x7b, 0x4c, 0x7d, 0x5d, 0x2d, 0x5b, 0x5c, 0x70, 0x7b, 0x4e, 0x7d, 0x5d, 0x5d, 0};
static const UChar gRuleSet_name_char_pattern[] = {
// [ _ \ p { L } \ p { N } ]
0x5b, 0x5f, 0x5c, 0x70, 0x7b, 0x4c, 0x7d, 0x5c, 0x70, 0x7b, 0x4e, 0x7d, 0x5d, 0};
static const UChar gRuleSet_digit_char_pattern[] = {
// [ 0 - 9 ]
0x5b, 0x30, 0x2d, 0x39, 0x5d, 0};
static const UChar gRuleSet_name_start_char_pattern[] = {
// [ _ \ p { L } ]
0x5b, 0x5f, 0x5c, 0x70, 0x7b, 0x4c, 0x7d, 0x5d, 0 };
static const UChar kAny[] = {0x61, 0x6e, 0x79, 0x00}; // "any"
U_CDECL_BEGIN
static void U_EXPORT2 U_CALLCONV RBBISetTable_deleter(void *p) {
RBBISetTableEl *px = (RBBISetTableEl *)p;
delete px->key;
// Note: px->val is owned by the linked list "fSetsListHead" in scanner.
// Don't delete the value nodes here.
uprv_free(px);
}
U_CDECL_END
U_NAMESPACE_BEGIN
//----------------------------------------------------------------------------------------
//
// Constructor.
//
//----------------------------------------------------------------------------------------
RBBIRuleScanner::RBBIRuleScanner(RBBIRuleBuilder *rb)
{
if (U_FAILURE(*rb->fStatus)) {
return;
}
fRB = rb;
fStackPtr = 0;
fStack[fStackPtr] = 0;
fNodeStackPtr = 0;
fRuleNum = 0;
fNodeStack[0] = NULL;
fRuleSets[kRuleSet_rule_char-128] = NULL;
fRuleSets[kRuleSet_white_space-128] = NULL;
fRuleSets[kRuleSet_name_char-128] = NULL;
fRuleSets[kRuleSet_name_start_char-128] = NULL;
fRuleSets[kRuleSet_digit_char-128] = NULL;
fSymbolTable = NULL;
fSetTable = NULL;
fScanIndex = 0;
fNextIndex = 0;
fReverseRule = FALSE;
fLookAheadRule = FALSE;
fLineNum = 1;
fCharNum = 0;
fQuoteMode = FALSE;
//
// Set up the constant Unicode Sets.
// Note: These could be made static, lazily initialized, and shared among
// all instances of RBBIRuleScanners. BUT this is quite a bit simpler,
// and the time to build these few sets should be small compared to a
// full break iterator build.
fRuleSets[kRuleSet_rule_char-128] = new UnicodeSet(gRuleSet_rule_char_pattern, *rb->fStatus);
fRuleSets[kRuleSet_white_space-128] = (UnicodeSet*) uprv_openRuleWhiteSpaceSet(rb->fStatus);
fRuleSets[kRuleSet_name_char-128] = new UnicodeSet(gRuleSet_name_char_pattern, *rb->fStatus);
fRuleSets[kRuleSet_name_start_char-128] = new UnicodeSet(gRuleSet_name_start_char_pattern, *rb->fStatus);
fRuleSets[kRuleSet_digit_char-128] = new UnicodeSet(gRuleSet_digit_char_pattern, *rb->fStatus);
if (*rb->fStatus == U_ILLEGAL_ARGUMENT_ERROR) {
// This case happens if ICU's data is missing. UnicodeSet tries to look up property
// names from the init string, can't find them, and claims an illegal arguement.
// Change the error so that the actual problem will be clearer to users.
*rb->fStatus = U_BRK_INIT_ERROR;
}
if (U_FAILURE(*rb->fStatus)) {
return;
}
fSymbolTable = new RBBISymbolTable(this, rb->fRules, *rb->fStatus);
fSetTable = uhash_open(uhash_hashUnicodeString, uhash_compareUnicodeString, rb->fStatus);
uhash_setValueDeleter(fSetTable, RBBISetTable_deleter);
}
//----------------------------------------------------------------------------------------
//
// Destructor
//
//----------------------------------------------------------------------------------------
RBBIRuleScanner::~RBBIRuleScanner() {
delete fRuleSets[kRuleSet_rule_char-128];
delete fRuleSets[kRuleSet_white_space-128];
delete fRuleSets[kRuleSet_name_char-128];
delete fRuleSets[kRuleSet_name_start_char-128];
delete fRuleSets[kRuleSet_digit_char-128];
delete fSymbolTable;
if (fSetTable != NULL) {
uhash_close(fSetTable);
fSetTable = NULL;
}
// Node Stack.
// Normally has one entry, which is the entire parse tree for the rules.
// If errors occured, there may be additional subtrees left on the stack.
while (fNodeStackPtr > 0) {
delete fNodeStack[fNodeStackPtr];
fNodeStackPtr--;
}
}
//----------------------------------------------------------------------------------------
//
// doParseAction Do some action during rule parsing.
// Called by the parse state machine.
// Actions build the parse tree and Unicode Sets,
// and maintain the parse stack for nested expressions.
//
// TODO: unify EParseAction and RBBI_RuleParseAction enum types.
// They represent exactly the same thing. They're separate
// only to work around enum forward declaration restrictions
// in some compilers, while at the same time avoiding multiple
// definitions problems. I'm sure that there's a better way.
//
//----------------------------------------------------------------------------------------
UBool RBBIRuleScanner::doParseActions(EParseAction action)
{
RBBINode *n = NULL;
UBool returnVal = TRUE;
switch ((RBBI_RuleParseAction)action) {
case doExprStart:
pushNewNode(RBBINode::opStart);
fRuleNum++;
break;
case doExprOrOperator:
{
fixOpStack(RBBINode::precOpCat);
RBBINode *operandNode = fNodeStack[fNodeStackPtr--];
RBBINode *orNode = pushNewNode(RBBINode::opOr);
orNode->fLeftChild = operandNode;
operandNode->fParent = orNode;
}
break;
case doExprCatOperator:
// concatenation operator.
// For the implicit concatenation of adjacent terms in an expression that are
// not separated by any other operator. Action is invoked between the
// actions for the two terms.
{
fixOpStack(RBBINode::precOpCat);
RBBINode *operandNode = fNodeStack[fNodeStackPtr--];
RBBINode *catNode = pushNewNode(RBBINode::opCat);
catNode->fLeftChild = operandNode;
operandNode->fParent = catNode;
}
break;
case doLParen:
// Open Paren.
// The openParen node is a dummy operation type with a low precedence,
// which has the affect of ensuring that any real binary op that
// follows within the parens binds more tightly to the operands than
// stuff outside of the parens.
pushNewNode(RBBINode::opLParen);
break;
case doExprRParen:
fixOpStack(RBBINode::precLParen);
break;
case doNOP:
break;
case doStartAssign:
// We've just scanned "$variable = "
// The top of the node stack has the $variable ref node.
// Save the start position of the RHS text in the StartExpression node
// that precedes the $variableReference node on the stack.
// This will eventually be used when saving the full $variable replacement
// text as a string.
n = fNodeStack[fNodeStackPtr-1];
n->fFirstPos = fNextIndex; // move past the '='
// Push a new start-of-expression node; needed to keep parse of the
// RHS expression happy.
pushNewNode(RBBINode::opStart);
break;
case doEndAssign:
{
// We have reached the end of an assignement statement.
// Current scan char is the ';' that terminates the assignment.
// Terminate expression, leaves expression parse tree rooted in TOS node.
fixOpStack(RBBINode::precStart);
RBBINode *startExprNode = fNodeStack[fNodeStackPtr-2];
RBBINode *varRefNode = fNodeStack[fNodeStackPtr-1];
RBBINode *RHSExprNode = fNodeStack[fNodeStackPtr];
// Save original text of right side of assignment, excluding the terminating ';'
// in the root of the node for the right-hand-side expression.
RHSExprNode->fFirstPos = startExprNode->fFirstPos;
RHSExprNode->fLastPos = fScanIndex;
fRB->fRules.extractBetween(RHSExprNode->fFirstPos, RHSExprNode->fLastPos, RHSExprNode->fText);
// Expression parse tree becomes l. child of the $variable reference node.
varRefNode->fLeftChild = RHSExprNode;
RHSExprNode->fParent = varRefNode;
// Make a symbol table entry for the $variableRef node.
fSymbolTable->addEntry(varRefNode->fText, varRefNode, *fRB->fStatus);
// Clean up the stack.
delete startExprNode;
fNodeStackPtr-=3;
break;
}
case doEndOfRule:
{
fixOpStack(RBBINode::precStart); // Terminate expression, leaves expression
if (U_FAILURE(*fRB->fStatus)) { // parse tree rooted in TOS node.
break;
}
if (fRB->fDebugEnv && uprv_strstr(fRB->fDebugEnv, "rtree")) {printNodeStack("end of rule");}
U_ASSERT(fNodeStackPtr == 1);
// If this rule includes a look-ahead '/', add a endMark node to the
// expression tree.
if (fLookAheadRule) {
RBBINode *thisRule = fNodeStack[fNodeStackPtr];
RBBINode *endNode = pushNewNode(RBBINode::endMark);
RBBINode *catNode = pushNewNode(RBBINode::opCat);
fNodeStackPtr -= 2;
catNode->fLeftChild = thisRule;
catNode->fRightChild = endNode;
fNodeStack[fNodeStackPtr] = catNode;
endNode->fVal = fRuleNum;
endNode->fLookAheadEnd = TRUE;
}
// All rule expressions are ORed together.
// The ';' that terminates an expression really just functions as a '|' with
// a low operator prededence.
//
// Each of the four sets of rules are collected separately.
// (forward, reverse, safe_forward, safe_reverse)
// OR this rule into the appropriate group of them.
//
RBBINode **destRules = (fReverseRule? &fRB->fReverseTree : fRB->fDefaultTree);
if (*destRules != NULL) {
// This is not the first rule encounted.
// OR previous stuff (from *destRules)
// with the current rule expression (on the Node Stack)
// with the resulting OR expression going to *destRules
//
RBBINode *thisRule = fNodeStack[fNodeStackPtr];
RBBINode *prevRules = *destRules;
RBBINode *orNode = pushNewNode(RBBINode::opOr);
orNode->fLeftChild = prevRules;
prevRules->fParent = orNode;
orNode->fRightChild = thisRule;
thisRule->fParent = orNode;
*destRules = orNode;
}
else
{
// This is the first rule encountered (for this direction).
// Just move its parse tree from the stack to *destRules.
*destRules = fNodeStack[fNodeStackPtr];
}
fReverseRule = FALSE; // in preparation for the next rule.
fLookAheadRule = FALSE;
fNodeStackPtr = 0;
}
break;
case doRuleError:
error(U_BRK_RULE_SYNTAX);
returnVal = FALSE;
break;
case doVariableNameExpectedErr:
error(U_BRK_RULE_SYNTAX);
break;
//
// Unary operands + ? *
// These all appear after the operand to which they apply.
// When we hit one, the operand (may be a whole sub expression)
// will be on the top of the stack.
// Unary Operator becomes TOS, with the old TOS as its one child.
case doUnaryOpPlus:
{
RBBINode *operandNode = fNodeStack[fNodeStackPtr--];
RBBINode *plusNode = pushNewNode(RBBINode::opPlus);
plusNode->fLeftChild = operandNode;
operandNode->fParent = plusNode;
}
break;
case doUnaryOpQuestion:
{
RBBINode *operandNode = fNodeStack[fNodeStackPtr--];
RBBINode *qNode = pushNewNode(RBBINode::opQuestion);
qNode->fLeftChild = operandNode;
operandNode->fParent = qNode;
}
break;
case doUnaryOpStar:
{
RBBINode *operandNode = fNodeStack[fNodeStackPtr--];
RBBINode *starNode = pushNewNode(RBBINode::opStar);
starNode->fLeftChild = operandNode;
operandNode->fParent = starNode;
}
break;
case doRuleChar:
// A "Rule Character" is any single character that is a literal part
// of the regular expression. Like a, b and c in the expression "(abc*) | [:L:]"
// These are pretty uncommon in break rules; the terms are more commonly
// sets. To keep things uniform, treat these characters like as
// sets that just happen to contain only one character.
{
n = pushNewNode(RBBINode::setRef);
findSetFor(fC.fChar, n);
n->fFirstPos = fScanIndex;
n->fLastPos = fNextIndex;
fRB->fRules.extractBetween(n->fFirstPos, n->fLastPos, n->fText);
break;
}
case doDotAny:
// scanned a ".", meaning match any single character.
{
n = pushNewNode(RBBINode::setRef);
findSetFor(kAny, n);
n->fFirstPos = fScanIndex;
n->fLastPos = fNextIndex;
fRB->fRules.extractBetween(n->fFirstPos, n->fLastPos, n->fText);
break;
}
break;
case doSlash:
// Scanned a '/', which identifies a look-ahead break position in a rule.
n = pushNewNode(RBBINode::lookAhead);
n->fVal = fRuleNum;
n->fFirstPos = fScanIndex;
n->fLastPos = fNextIndex;
fRB->fRules.extractBetween(n->fFirstPos, n->fLastPos, n->fText);
fLookAheadRule = TRUE;
break;
case doStartTagValue:
// Scanned a '{', the opening delimiter for a tag value within a rule.
n = pushNewNode(RBBINode::tag);
n->fVal = 0;
n->fFirstPos = fScanIndex;
n->fLastPos = fNextIndex;
break;
case doTagDigit:
// Just scanned a decimal digit that's part of a tag value
{
n = fNodeStack[fNodeStackPtr];
uint32_t v = u_charDigitValue(fC.fChar);
U_ASSERT(v < 10);
n->fVal = n->fVal*10 + v;
break;
}
case doTagValue:
n = fNodeStack[fNodeStackPtr];
n->fLastPos = fNextIndex;
fRB->fRules.extractBetween(n->fFirstPos, n->fLastPos, n->fText);
break;
case doOptionStart:
// Scanning a !!option. At the start of string.
fOptionStart = fScanIndex;
break;
case doOptionEnd:
{
UnicodeString opt(fRB->fRules, fOptionStart, fScanIndex-fOptionStart);
if (opt == "chain") {
fRB->fChainRules = TRUE;
} else if (opt == "LBCMNoChain") {
fRB->fLBCMNoChain = TRUE;
} else if (opt == "forward") {
fRB->fDefaultTree = &fRB->fForwardTree;
} else if (opt == "reverse") {
fRB->fDefaultTree = &fRB->fReverseTree;
} else if (opt == "safe_forward") {
fRB->fDefaultTree = &fRB->fSafeFwdTree;
} else if (opt == "safe_reverse") {
fRB->fDefaultTree = &fRB->fSafeRevTree;
} else if (opt == "lookAheadHardBreak") {
// at the moment do nothing for this
// the code is handled in rbbi.cpp
// todo: think about how to handle this
} else {
error(U_BRK_UNRECOGNIZED_OPTION);
}
}
break;
case doReverseDir:
fReverseRule = TRUE;
break;
case doStartVariableName:
n = pushNewNode(RBBINode::varRef);
if (U_FAILURE(*fRB->fStatus)) {
break;
}
n->fFirstPos = fScanIndex;
break;
case doEndVariableName:
n = fNodeStack[fNodeStackPtr];
if (n==NULL || n->fType != RBBINode::varRef) {
error(U_BRK_INTERNAL_ERROR);
break;
}
n->fLastPos = fScanIndex;
fRB->fRules.extractBetween(n->fFirstPos+1, n->fLastPos, n->fText);
// Look the newly scanned name up in the symbol table
// If there's an entry, set the l. child of the var ref to the replacement expression.
// (We also pass through here when scanning assignments, but no harm is done, other
// than a slight wasted effort that seems hard to avoid. Lookup will be null)
n->fLeftChild = fSymbolTable->lookupNode(n->fText);
break;
case doCheckVarDef:
n = fNodeStack[fNodeStackPtr];
if (n->fLeftChild == NULL) {
error(U_BRK_UNDEFINED_VARIABLE);
returnVal = FALSE;
}
break;
case doExprFinished:
break;
case doRuleErrorAssignExpr:
error(U_BRK_ASSIGN_ERROR);
returnVal = FALSE;
break;
case doExit:
returnVal = FALSE;
break;
case doScanUnicodeSet:
scanSet();
break;
default:
error(U_BRK_INTERNAL_ERROR);
returnVal = FALSE;
break;
}
return returnVal;
}
//----------------------------------------------------------------------------------------
//
// Error Report a rule parse error.
// Only report it if no previous error has been recorded.
//
//----------------------------------------------------------------------------------------
void RBBIRuleScanner::error(UErrorCode e) {
if (U_SUCCESS(*fRB->fStatus)) {
*fRB->fStatus = e;
fRB->fParseError->line = fLineNum;
fRB->fParseError->offset = fCharNum;
fRB->fParseError->preContext[0] = 0;
fRB->fParseError->preContext[0] = 0;
}
}
//----------------------------------------------------------------------------------------
//
// fixOpStack The parse stack holds partially assembled chunks of the parse tree.
// An entry on the stack may be as small as a single setRef node,
// or as large as the parse tree
// for an entire expression (this will be the one item left on the stack
// when the parsing of an RBBI rule completes.
//
// This function is called when a binary operator is encountered.
// It looks back up the stack for operators that are not yet associated
// with a right operand, and if the precedence of the stacked operator >=
// the precedence of the current operator, binds the operand left,
// to the previously encountered operator.
//
//----------------------------------------------------------------------------------------
void RBBIRuleScanner::fixOpStack(RBBINode::OpPrecedence p) {
RBBINode *n;
// printNodeStack("entering fixOpStack()");
for (;;) {
n = fNodeStack[fNodeStackPtr-1]; // an operator node
if (n->fPrecedence == 0) {
RBBIDebugPrintf("RBBIRuleScanner::fixOpStack, bad operator node\n");
error(U_BRK_INTERNAL_ERROR);
return;
}
if (n->fPrecedence < p || n->fPrecedence <= RBBINode::precLParen) {
// The most recent operand goes with the current operator,
// not with the previously stacked one.
break;
}
// Stack operator is a binary op ( '|' or concatenation)
// TOS operand becomes right child of this operator.
// Resulting subexpression becomes the TOS operand.
n->fRightChild = fNodeStack[fNodeStackPtr];
fNodeStack[fNodeStackPtr]->fParent = n;
fNodeStackPtr--;
// printNodeStack("looping in fixOpStack() ");
}
if (p <= RBBINode::precLParen) {
// Scan is at a right paren or end of expression.
// The scanned item must match the stack, or else there was an error.
// Discard the left paren (or start expr) node from the stack,
// leaving the completed (sub)expression as TOS.
if (n->fPrecedence != p) {
// Right paren encountered matched start of expression node, or
// end of expression matched with a left paren node.
error(U_BRK_MISMATCHED_PAREN);
}
fNodeStack[fNodeStackPtr-1] = fNodeStack[fNodeStackPtr];
fNodeStackPtr--;
// Delete the now-discarded LParen or Start node.
delete n;
}
// printNodeStack("leaving fixOpStack()");
}
//----------------------------------------------------------------------------------------
//
// findSetFor given a UnicodeString,
// - find the corresponding Unicode Set (uset node)
// (create one if necessary)
// - Set fLeftChild of the caller's node (should be a setRef node)
// to the uset node
// Maintain a hash table of uset nodes, so the same one is always used
// for the same string.
// If a "to adopt" set is provided and we haven't seen this key before,
// add the provided set to the hash table.
// If the string is one (32 bit) char in length, the set contains
// just one element which is the char in question.
// If the string is "any", return a set containing all chars.
//
//----------------------------------------------------------------------------------------
void RBBIRuleScanner::findSetFor(const UnicodeString &s, RBBINode *node, UnicodeSet *setToAdopt) {
RBBISetTableEl *el;
// First check whether we've already cached a set for this string.
// If so, just use the cached set in the new node.
// delete any set provided by the caller, since we own it.
el = (RBBISetTableEl *)uhash_get(fSetTable, &s);
if (el != NULL) {
delete setToAdopt;
node->fLeftChild = el->val;
U_ASSERT(node->fLeftChild->fType == RBBINode::uset);
return;
}
// Haven't seen this set before.
// If the caller didn't provide us with a prebuilt set,
// create a new UnicodeSet now.
if (setToAdopt == NULL) {
if (s.compare(kAny, -1) == 0) {
setToAdopt = new UnicodeSet(0x000000, 0x10ffff);
} else {
UChar32 c;
c = s.char32At(0);
setToAdopt = new UnicodeSet(c, c);
}
}
//
// Make a new uset node to refer to this UnicodeSet
// This new uset node becomes the child of the caller's setReference node.
//
RBBINode *usetNode = new RBBINode(RBBINode::uset);
usetNode->fInputSet = setToAdopt;
usetNode->fParent = node;
node->fLeftChild = usetNode;
usetNode->fText = s;
//
// Add the new uset node to the list of all uset nodes.
//
fRB->fUSetNodes->addElement(usetNode, *fRB->fStatus);
//
// Add the new set to the set hash table.
//
el = (RBBISetTableEl *)uprv_malloc(sizeof(RBBISetTableEl));
UnicodeString *tkey = new UnicodeString(s);
if (tkey == NULL || el == NULL || setToAdopt == NULL) {
error(U_MEMORY_ALLOCATION_ERROR);
return;
}
el->key = tkey;
el->val = usetNode;
uhash_put(fSetTable, el->key, el, fRB->fStatus);
return;
}
//
// Assorted Unicode character constants.
// Numeric because there is no portable way to enter them as literals.
// (Think EBCDIC).
//
static const UChar chCR = 0x0d; // New lines, for terminating comments.
static const UChar chLF = 0x0a;
static const UChar chNEL = 0x85; // NEL newline variant
static const UChar chLS = 0x2028; // Unicode Line Separator
static const UChar chApos = 0x27; // single quote, for quoted chars.
static const UChar chPound = 0x23; // '#', introduces a comment.
static const UChar chBackSlash = 0x5c; // '\' introduces a char escape
static const UChar chLParen = 0x28;
static const UChar chRParen = 0x29;
//----------------------------------------------------------------------------------------
//
// stripRules Return a rules string without unnecessary
// characters.
//
//----------------------------------------------------------------------------------------
UnicodeString RBBIRuleScanner::stripRules(const UnicodeString &rules) {
UnicodeString strippedRules;
int rulesLength = rules.length();
for (int idx = 0; idx < rulesLength; ) {
UChar ch = rules[idx++];
if (ch == chPound) {
while (idx < rulesLength
&& ch != chCR && ch != chLF && ch != chNEL)
{
ch = rules[idx++];
}
}
if (!u_isISOControl(ch)) {
strippedRules.append(ch);
}
}
// strippedRules = strippedRules.unescape();
return strippedRules;
}
//----------------------------------------------------------------------------------------
//
// nextCharLL Low Level Next Char from rule input source.
// Get a char from the input character iterator,
// keep track of input position for error reporting.
//
//----------------------------------------------------------------------------------------
UChar32 RBBIRuleScanner::nextCharLL() {
UChar32 ch;
if (fNextIndex >= fRB->fRules.length()) {
return (UChar32)-1;
}
ch = fRB->fRules.char32At(fNextIndex);
fNextIndex = fRB->fRules.moveIndex32(fNextIndex, 1);
if (ch == chCR ||
ch == chNEL ||
ch == chLS ||
ch == chLF && fLastChar != chCR) {
// Character is starting a new line. Bump up the line number, and
// reset the column to 0.
fLineNum++;
fCharNum=0;
if (fQuoteMode) {
error(U_BRK_NEW_LINE_IN_QUOTED_STRING);
fQuoteMode = FALSE;
}
}
else {
// Character is not starting a new line. Except in the case of a
// LF following a CR, increment the column position.
if (ch != chLF) {
fCharNum++;
}
}
fLastChar = ch;
return ch;
}
//---------------------------------------------------------------------------------
//
// nextChar for rules scanning. At this level, we handle stripping
// out comments and processing backslash character escapes.
// The rest of the rules grammar is handled at the next level up.
//
//---------------------------------------------------------------------------------
void RBBIRuleScanner::nextChar(RBBIRuleChar &c) {
// Unicode Character constants needed for the processing done by nextChar(),
// in hex because literals wont work on EBCDIC machines.
fScanIndex = fNextIndex;
c.fChar = nextCharLL();
c.fEscaped = FALSE;
//
// check for '' sequence.
// These are recognized in all contexts, whether in quoted text or not.
//
if (c.fChar == chApos) {
if (fRB->fRules.char32At(fNextIndex) == chApos) {
c.fChar = nextCharLL(); // get nextChar officially so character counts
c.fEscaped = TRUE; // stay correct.
}
else
{
// Single quote, by itself.
// Toggle quoting mode.
// Return either '(' or ')', because quotes cause a grouping of the quoted text.
fQuoteMode = !fQuoteMode;
if (fQuoteMode == TRUE) {
c.fChar = chLParen;
} else {
c.fChar = chRParen;
}
c.fEscaped = FALSE; // The paren that we return is not escaped.
return;
}
}
if (fQuoteMode) {
c.fEscaped = TRUE;
}
else
{
// We are not in a 'quoted region' of the source.
//
if (c.fChar == chPound) {
// Start of a comment. Consume the rest of it.
// The new-line char that terminates the comment is always returned.
// It will be treated as white-space, and serves to break up anything
// that might otherwise incorrectly clump together with a comment in
// the middle (a variable name, for example.)
for (;;) {
c.fChar = nextCharLL();
if (c.fChar == (UChar32)-1 || // EOF
c.fChar == chCR ||
c.fChar == chLF ||
c.fChar == chNEL ||
c.fChar == chLS) {break;}
}
}
if (c.fChar == (UChar32)-1) {
return;
}
//
// check for backslash escaped characters.
// Use UnicodeString::unescapeAt() to handle them.
//
if (c.fChar == chBackSlash) {
c.fEscaped = TRUE;
int32_t startX = fNextIndex;
c.fChar = fRB->fRules.unescapeAt(fNextIndex);
if (fNextIndex == startX) {
error(U_BRK_HEX_DIGITS_EXPECTED);
}
fCharNum += fNextIndex-startX;
}
}
// putc(c.fChar, stdout);
}
//---------------------------------------------------------------------------------
//
// Parse RBBI rules. The state machine for rules parsing is here.
// The state tables are hand-written in the file rbbirpt.txt,
// and converted to the form used here by a perl
// script rbbicst.pl
//
//---------------------------------------------------------------------------------
void RBBIRuleScanner::parse() {
uint16_t state;
const RBBIRuleTableEl *tableEl;
if (U_FAILURE(*fRB->fStatus)) {
return;
}
state = 1;
nextChar(fC);
//
// Main loop for the rule parsing state machine.
// Runs once per state transition.
// Each time through optionally performs, depending on the state table,
// - an advance to the the next input char
// - an action to be performed.
// - pushing or popping a state to/from the local state return stack.
//
for (;;) {
// Bail out if anything has gone wrong.
// RBBI rule file parsing stops on the first error encountered.
if (U_FAILURE(*fRB->fStatus)) {
break;
}
// Quit if state == 0. This is the normal way to exit the state machine.
//
if (state == 0) {
break;
}
// Find the state table element that matches the input char from the rule, or the
// class of the input character. Start with the first table row for this
// state, then linearly scan forward until we find a row that matches the
// character. The last row for each state always matches all characters, so
// the search will stop there, if not before.
//
tableEl = &gRuleParseStateTable[state];
if (fRB->fDebugEnv && uprv_strstr(fRB->fDebugEnv, "scan")) {
RBBIDebugPrintf("char, line, col = (\'%c\', %d, %d) state=%s ",
fC.fChar, fLineNum, fCharNum, RBBIRuleStateNames[state]);
}
for (;;) {
if (fRB->fDebugEnv && uprv_strstr(fRB->fDebugEnv, "scan")) { RBBIDebugPrintf(".");}
if (tableEl->fCharClass < 127 && fC.fEscaped == FALSE && tableEl->fCharClass == fC.fChar) {
// Table row specified an individual character, not a set, and
// the input character is not escaped, and
// the input character matched it.
break;
}
if (tableEl->fCharClass == 255) {
// Table row specified default, match anything character class.
break;
}
if (tableEl->fCharClass == 254 && fC.fEscaped) {
// Table row specified "escaped" and the char was escaped.
break;
}
if (tableEl->fCharClass == 253 && fC.fEscaped &&
(fC.fChar == 0x50 || fC.fChar == 0x70 )) {
// Table row specified "escaped P" and the char is either 'p' or 'P'.
break;
}
if (tableEl->fCharClass == 252 && fC.fChar == (UChar32)-1) {
// Table row specified eof and we hit eof on the input.
break;
}
if (tableEl->fCharClass >= 128 && tableEl->fCharClass < 240 && // Table specs a char class &&
fC.fEscaped == FALSE && // char is not escaped &&
fC.fChar != (UChar32)-1) { // char is not EOF
UnicodeSet *uniset = fRuleSets[tableEl->fCharClass-128];
if (uniset->contains(fC.fChar)) {
// Table row specified a character class, or set of characters,
// and the current char matches it.
break;
}
}
// No match on this row, advance to the next row for this state,
tableEl++;
}
if (fRB->fDebugEnv && uprv_strstr(fRB->fDebugEnv, "scan")) { RBBIDebugPrintf("\n");}
//
// We've found the row of the state table that matches the current input
// character from the rules string.
// Perform any action specified by this row in the state table.
if (doParseActions((EParseAction)tableEl->fAction) == FALSE) {
// Break out of the state machine loop if the
// the action signalled some kind of error, or
// the action was to exit, occurs on normal end-of-rules-input.
break;
}
if (tableEl->fPushState != 0) {
fStackPtr++;
if (fStackPtr >= kStackSize) {
error(U_BRK_INTERNAL_ERROR);
RBBIDebugPrintf("RBBIRuleScanner::parse() - state stack overflow.\n");
fStackPtr--;
}
fStack[fStackPtr] = tableEl->fPushState;
}
if (tableEl->fNextChar) {
nextChar(fC);
}
// Get the next state from the table entry, or from the
// state stack if the next state was specified as "pop".
if (tableEl->fNextState != 255) {
state = tableEl->fNextState;
} else {
state = fStack[fStackPtr];
fStackPtr--;
if (fStackPtr < 0) {
error(U_BRK_INTERNAL_ERROR);
RBBIDebugPrintf("RBBIRuleScanner::parse() - state stack underflow.\n");
fStackPtr++;
}
}
}
//
// If there were NO user specified reverse rules, set up the equivalent of ".*;"
//
if (fRB->fReverseTree == NULL) {
fRB->fReverseTree = pushNewNode(RBBINode::opStar);
RBBINode *operand = pushNewNode(RBBINode::setRef);
findSetFor(kAny, operand);
fRB->fReverseTree->fLeftChild = operand;
operand->fParent = fRB->fReverseTree;
fNodeStackPtr -= 2;
}
//
// Parsing of the input RBBI rules is complete.
// We now have a parse tree for the rule expressions
// and a list of all UnicodeSets that are referenced.
//
if (fRB->fDebugEnv && uprv_strstr(fRB->fDebugEnv, "symbols")) {fSymbolTable->print();}
if (fRB->fDebugEnv && uprv_strstr(fRB->fDebugEnv, "ptree"))
{
RBBIDebugPrintf("Completed Forward Rules Parse Tree...\n");
fRB->fForwardTree->printTree();
RBBIDebugPrintf("\nCompleted Reverse Rules Parse Tree...\n");
fRB->fReverseTree->printTree();
RBBIDebugPrintf("\nCompleted Safe Point Forward Rules Parse Tree...\n");
fRB->fSafeFwdTree->printTree();
RBBIDebugPrintf("\nCompleted Safe Point Reverse Rules Parse Tree...\n");
fRB->fSafeRevTree->printTree();
}
}
//---------------------------------------------------------------------------------
//
// printNodeStack for debugging...
//
//---------------------------------------------------------------------------------
void RBBIRuleScanner::printNodeStack(const char *title) {
int i;
RBBIDebugPrintf("%s. Dumping node stack...\n", title);
for (i=fNodeStackPtr; i>0; i--) {fNodeStack[i]->printTree();}
}
//---------------------------------------------------------------------------------
//
// pushNewNode create a new RBBINode of the specified type and push it
// onto the stack of nodes.
//
//---------------------------------------------------------------------------------
RBBINode *RBBIRuleScanner::pushNewNode(RBBINode::NodeType t) {
fNodeStackPtr++;
if (fNodeStackPtr >= kStackSize) {
error(U_BRK_INTERNAL_ERROR);
RBBIDebugPrintf("RBBIRuleScanner::pushNewNode - stack overflow.\n");
*fRB->fStatus = U_BRK_INTERNAL_ERROR;
return NULL;
}
fNodeStack[fNodeStackPtr] = new RBBINode(t);
if (fNodeStack[fNodeStackPtr] == NULL) {
*fRB->fStatus = U_MEMORY_ALLOCATION_ERROR;
}
return fNodeStack[fNodeStackPtr];
}
//---------------------------------------------------------------------------------
//
// scanSet Construct a UnicodeSet from the text at the current scan
// position. Advance the scan position to the first character
// after the set.
//
// A new RBBI setref node referring to the set is pushed onto the node
// stack.
//
// The scan position is normally under the control of the state machine
// that controls rule parsing. UnicodeSets, however, are parsed by
// the UnicodeSet constructor, not by the RBBI rule parser.
//
//---------------------------------------------------------------------------------
void RBBIRuleScanner::scanSet() {
UnicodeSet *uset;
ParsePosition pos;
int startPos;
int i;
if (U_FAILURE(*fRB->fStatus)) {
return;
}
pos.setIndex(fScanIndex);
startPos = fScanIndex;
UErrorCode localStatus = U_ZERO_ERROR;
uset = new UnicodeSet(fRB->fRules, pos, USET_IGNORE_SPACE,
fSymbolTable,
localStatus);
if (U_FAILURE(localStatus)) {
// TODO: Get more accurate position of the error from UnicodeSet's return info.
// UnicodeSet appears to not be reporting correctly at this time.
RBBIDebugPrintf("UnicodeSet parse postion.ErrorIndex = %d\n", pos.getIndex());
error(localStatus);
delete uset;
return;
}
// Verify that the set contains at least one code point.
//
if (uset->charAt(0) == -1) {
// This set is empty.
// Make it an error, because it almost certainly is not what the user wanted.
// Also, avoids having to think about corner cases in the tree manipulation code
// that occurs later on.
error(U_BRK_RULE_EMPTY_SET);
delete uset;
return;
}
// Advance the RBBI parse postion over the UnicodeSet pattern.
// Don't just set fScanIndex because the line/char positions maintained
// for error reporting would be thrown off.
i = pos.getIndex();
for (;;) {
if (fNextIndex >= i) {
break;
}
nextCharLL();
}
if (U_SUCCESS(*fRB->fStatus)) {
RBBINode *n;
n = pushNewNode(RBBINode::setRef);
n->fFirstPos = startPos;
n->fLastPos = fNextIndex;
fRB->fRules.extractBetween(n->fFirstPos, n->fLastPos, n->fText);
// findSetFor() serves several purposes here:
// - Adopts storage for the UnicodeSet, will be responsible for deleting.
// - Mantains collection of all sets in use, needed later for establishing
// character categories for run time engine.
// - Eliminates mulitiple instances of the same set.
// - Creates a new uset node if necessary (if this isn't a duplicate.)
findSetFor(n->fText, n, uset);
}
}
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_BREAK_ITERATION */