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https://gitlab.gnome.org/GNOME/libxml2.git
synced 2025-07-14 20:01:04 +03:00
enhanced the handling of subexpression ranges which have a minOccurs of 0
* xmlregexp.c: enhanced the handling of subexpression ranges which have a minOccurs of 0 (bug 140478 again); cleaned up comments throughout the module.
This commit is contained in:
William M. Brack
108
xmlregexp.c
108
xmlregexp.c
@ -3,7 +3,7 @@
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*
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* Basically designed with the purpose of compiling regexps for
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* the variety of validation/shemas mechanisms now available in
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* XML related specifications thise includes:
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* XML related specifications these include:
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* - XML-1.0 DTD validation
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* - XML Schemas structure part 1
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* - XML Schemas Datatypes part 2 especially Appendix F
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@ -267,7 +267,7 @@ struct _xmlRegExecRollback {
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xmlRegStatePtr state;/* the current state */
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int index; /* the index in the input stack */
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int nextbranch; /* the next transition to explore in that state */
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int *counts; /* save the automate state if it has some */
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int *counts; /* save the automata state if it has some */
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};
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typedef struct _xmlRegInputToken xmlRegInputToken;
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@ -280,14 +280,14 @@ struct _xmlRegInputToken {
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struct _xmlRegExecCtxt {
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int status; /* execution status != 0 indicate an error */
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int determinist; /* did we found an inderterministic behaviour */
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int determinist; /* did we find an indeterministic behaviour */
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xmlRegexpPtr comp; /* the compiled regexp */
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xmlRegExecCallbacks callback;
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void *data;
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xmlRegStatePtr state;/* the current state */
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int transno; /* the current transition on that state */
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int transcount; /* the number of char in char counted transitions */
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int transcount; /* the number of chars in char counted transitions */
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/*
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* A stack of rollback states
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@ -327,7 +327,7 @@ static void xmlRegFreeAtom(xmlRegAtomPtr atom);
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************************************************************************/
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/**
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* xmlRegexpErrMemory:
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* @extra: extra informations
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* @extra: extra information
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*
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* Handle an out of memory condition
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*/
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@ -347,9 +347,9 @@ xmlRegexpErrMemory(xmlRegParserCtxtPtr ctxt, const char *extra)
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/**
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* xmlRegexpErrCompile:
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* @extra: extra informations
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* @extra: extra information
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*
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* Handle an compilation failure
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* Handle a compilation failure
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*/
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static void
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xmlRegexpErrCompile(xmlRegParserCtxtPtr ctxt, const char *extra)
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@ -379,7 +379,7 @@ static int xmlFAComputesDeterminism(xmlRegParserCtxtPtr ctxt);
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* xmlRegEpxFromParse:
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* @ctxt: the parser context used to build it
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*
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* Allocate a new regexp and fill it with the reult from the parser
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* Allocate a new regexp and fill it with the result from the parser
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*
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* Returns the new regexp or NULL in case of error
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*/
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@ -418,7 +418,7 @@ xmlRegEpxFromParse(xmlRegParserCtxtPtr ctxt) {
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/*
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* Switch to a compact representation
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* 1/ counting the effective number of states left
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* 2/ conting the unique number of atoms, and check that
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* 2/ counting the unique number of atoms, and check that
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* they are all of the string type
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* 3/ build a table state x atom for the transitions
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*/
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@ -505,7 +505,7 @@ xmlRegEpxFromParse(xmlRegParserCtxtPtr ctxt) {
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/*
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* Allocate the transition table. The first entry for each
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* state correspond to the state type.
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* state corresponds to the state type.
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*/
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transdata = NULL;
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@ -539,7 +539,7 @@ xmlRegEpxFromParse(xmlRegParserCtxtPtr ctxt) {
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}
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targetno = stateRemap[trans->to];
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/*
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* if the same atome can generate transition to 2 different
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* if the same atom can generate transitions to 2 different
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* states then it means the automata is not determinist and
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* the compact form can't be used !
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*/
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@ -1347,7 +1347,7 @@ xmlFAGenerateCountedTransition(xmlRegParserCtxtPtr ctxt,
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* @to: the target state or NULL for building a new one
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* @atom: the atom generating the transition
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*
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* Returns 0 if succes and -1 in case of error.
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* Returns 0 if success and -1 in case of error.
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*/
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static int
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xmlFAGenerateTransitions(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr from,
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@ -1359,7 +1359,7 @@ xmlFAGenerateTransitions(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr from,
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if (atom->type == XML_REGEXP_SUBREG) {
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/*
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* this is a subexpression handling one should not need to
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* create a new node excep for XML_REGEXP_QUANT_RANGE.
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* create a new node except for XML_REGEXP_QUANT_RANGE.
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*/
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if (xmlRegAtomPush(ctxt, atom) < 0) {
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return(-1);
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@ -1391,13 +1391,26 @@ xmlFAGenerateTransitions(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr from,
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/*
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* This one is nasty:
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* 1/ register a new counter
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* 2/ register an epsilon transition associated to
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* 1/ if range has minOccurs == 0, create a new state
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* and create epsilon transitions from atom->start
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* to atom->stop, as well as atom->start to the new
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* state
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* 2/ register a new counter
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* 3/ register an epsilon transition associated to
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* this counter going from atom->stop to atom->start
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* 3/ create a new state
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* 4/ generate a counted transition from atom->stop to
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* 4/ create a new state
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* 5/ generate a counted transition from atom->stop to
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* that state
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*/
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if (atom->min == 0) {
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xmlFAGenerateEpsilonTransition(ctxt, atom->start,
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atom->stop);
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newstate = xmlRegNewState(ctxt);
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xmlRegStatePush(ctxt, newstate);
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ctxt->state = newstate;
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xmlFAGenerateEpsilonTransition(ctxt, atom->start,
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newstate);
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}
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counter = xmlRegGetCounter(ctxt);
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ctxt->counters[counter].min = atom->min - 1;
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ctxt->counters[counter].max = atom->max - 1;
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@ -1460,7 +1473,7 @@ xmlFAGenerateTransitions(xmlRegParserCtxtPtr ctxt, xmlRegStatePtr from,
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* @ctxt: a regexp parser context
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* @fromnr: the from state
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* @tonr: the to state
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* @cpunter: should that transition be associted to a counted
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* @counter: should that transition be associated to a counted
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*
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*/
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static void
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@ -1616,7 +1629,7 @@ xmlFAEliminateEpsilonTransitions(xmlRegParserCtxtPtr ctxt) {
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xmlRegStatePtr target = NULL;
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state->reached = XML_REGEXP_MARK_VISITED;
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/*
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* Mark all state reachable from the current reachable state
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* Mark all states reachable from the current reachable state
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*/
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for (transnr = 0;transnr < state->nbTrans;transnr++) {
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if ((state->trans[transnr].to >= 0) &&
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@ -1665,7 +1678,7 @@ xmlFAEliminateEpsilonTransitions(xmlRegParserCtxtPtr ctxt) {
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* @atom1: an atom
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* @atom2: an atom
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*
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* Compares two atoms to check whether they are equivatents
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* Compares two atoms to check whether they are equivalents
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*
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* Returns 1 if yes and 0 otherwise
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*/
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@ -1758,7 +1771,7 @@ xmlFAComputesDeterminism(xmlRegParserCtxtPtr ctxt) {
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return(ctxt->determinist);
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/*
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* Check for all states that there isn't 2 transitions
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* Check for all states that there aren't 2 transitions
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* with the same atom and a different target.
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*/
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for (statenr = 0;statenr < ctxt->nbStates;statenr++) {
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@ -1782,7 +1795,7 @@ xmlFAComputesDeterminism(xmlRegParserCtxtPtr ctxt) {
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if (t2->atom != NULL) {
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if (t1->to == t2->to) {
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if (xmlFACompareAtoms(t1->atom, t2->atom))
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t2->to = -1; /* eliminate */
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t2->to = -1; /* eliminated */
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} else {
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/* not determinist ! */
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if (xmlFACompareAtoms(t1->atom, t2->atom))
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@ -2090,7 +2103,7 @@ xmlRegCheckCharacter(xmlRegAtomPtr atom, int codepoint) {
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/************************************************************************
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* *
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* Saving an restoring state of an execution context *
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* Saving and restoring state of an execution context *
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* *
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************************************************************************/
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@ -2196,7 +2209,7 @@ xmlFARegExecRollBack(xmlRegExecCtxtPtr exec) {
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/************************************************************************
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* *
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* Verifyer, running an input against a compiled regexp *
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* Verifier, running an input against a compiled regexp *
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* *
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************************************************************************/
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@ -2242,8 +2255,11 @@ xmlFARegExec(xmlRegexpPtr comp, const xmlChar *content) {
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* we don't want to break.
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*/
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if ((exec->inputString[exec->index] == 0) && (exec->counts == NULL)) {
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/* must check if atom allows minOccurs of 0 */
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if (exec->transno < exec->state->nbTrans) { /* there is a transition */
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/*
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* if there is a transition, we must check if
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* atom allows minOccurs of 0
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*/
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if (exec->transno < exec->state->nbTrans) {
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trans = &exec->state->trans[exec->transno];
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if (trans->to >=0) {
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atom = trans->atom;
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@ -2410,7 +2426,7 @@ progress:
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/************************************************************************
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* *
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* Progressive interface to the verifyer one atom at a time *
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* Progressive interface to the verifier one atom at a time *
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* *
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************************************************************************/
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@ -2578,7 +2594,7 @@ xmlRegCompactPushString(xmlRegExecCtxtPtr exec,
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#endif
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/*
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* Examine all outside transition from current state
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* Examine all outside transitions from current state
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*/
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for (i = 0;i < comp->nbstrings;i++) {
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target = comp->compact[state * (comp->nbstrings + 1) + i + 1];
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@ -3125,7 +3141,7 @@ progress:
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#endif
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/************************************************************************
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* *
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* Parser for the Shemas Datatype Regular Expressions *
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* Parser for the Schemas Datatype Regular Expressions *
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* http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#regexs *
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* *
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************************************************************************/
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@ -3922,7 +3938,7 @@ xmlFAParseBranch(xmlRegParserCtxtPtr ctxt) {
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/**
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* xmlFAParseRegExp:
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* @ctxt: a regexp parser context
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* @top: is that the top-level expressions ?
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* @top: is this the top-level expression ?
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*
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* [1] regExp ::= branch ( '|' branch )*
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*/
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@ -4014,7 +4030,7 @@ xmlRegexpPrint(FILE *output, xmlRegexpPtr regexp) {
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* @regexp: a regular expression string
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*
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* Parses a regular expression conforming to XML Schemas Part 2 Datatype
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* Appendix F and build an automata suitable for testing strings against
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* Appendix F and builds an automata suitable for testing strings against
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* that regular expression
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*
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* Returns the compiled expression or NULL in case of error
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@ -4060,9 +4076,9 @@ xmlRegexpCompile(const xmlChar *regexp) {
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* @comp: the compiled regular expression
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* @content: the value to check against the regular expression
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*
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* Check if the regular expression generate the value
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* Check if the regular expression generates the value
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*
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* Returns 1 if it matches, 0 if not and a negativa value in case of error
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* Returns 1 if it matches, 0 if not and a negative value in case of error
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*/
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int
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xmlRegexpExec(xmlRegexpPtr comp, const xmlChar *content) {
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@ -4077,7 +4093,7 @@ xmlRegexpExec(xmlRegexpPtr comp, const xmlChar *content) {
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*
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* Check if the regular expression is determinist
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*
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* Returns 1 if it yes, 0 if not and a negativa value in case of error
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* Returns 1 if it yes, 0 if not and a negative value in case of error
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*/
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int
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xmlRegexpIsDeterminist(xmlRegexpPtr comp) {
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@ -4239,7 +4255,7 @@ xmlAutomataSetFinalState(xmlAutomataPtr am, xmlAutomataStatePtr state) {
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* @token: the input string associated to that transition
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* @data: data passed to the callback function if the transition is activated
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*
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* If @to is NULL, this create first a new target state in the automata
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* If @to is NULL, this creates first a new target state in the automata
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* and then adds a transition from the @from state to the target state
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* activated by the value of @token
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*
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@ -4279,7 +4295,7 @@ xmlAutomataNewTransition(xmlAutomataPtr am, xmlAutomataStatePtr from,
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* @token2: the second input string associated to that transition
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* @data: data passed to the callback function if the transition is activated
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*
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* If @to is NULL, this create first a new target state in the automata
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* If @to is NULL, this creates first a new target state in the automata
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* and then adds a transition from the @from state to the target state
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* activated by the value of @token
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*
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@ -4338,7 +4354,7 @@ xmlAutomataNewTransition2(xmlAutomataPtr am, xmlAutomataStatePtr from,
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* @max: the maximum successive occurences of token
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* @data: data associated to the transition
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*
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* If @to is NULL, this create first a new target state in the automata
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* If @to is NULL, this creates first a new target state in the automata
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* and then adds a transition from the @from state to the target state
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* activated by a succession of input of value @token and whose number
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* is between @min and @max
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@ -4404,10 +4420,10 @@ xmlAutomataNewCountTrans(xmlAutomataPtr am, xmlAutomataStatePtr from,
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* @max: the maximum successive occurences of token
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* @data: data associated to the transition
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*
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* If @to is NULL, this create first a new target state in the automata
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* If @to is NULL, this creates first a new target state in the automata
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* and then adds a transition from the @from state to the target state
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* activated by a succession of input of value @token and whose number
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* is between @min and @max, moreover that transistion can only be crossed
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* is between @min and @max, moreover that transition can only be crossed
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* once.
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*
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* Returns the target state or NULL in case of error
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@ -4451,10 +4467,6 @@ xmlAutomataNewOnceTrans(xmlAutomataPtr am, xmlAutomataStatePtr from,
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xmlRegStateAddTrans(am, from, atom, to, counter, -1);
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xmlRegAtomPush(am, atom);
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am->state = to;
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if (to == NULL)
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to = am->state;
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if (to == NULL)
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return(NULL);
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return(to);
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}
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@ -4483,8 +4495,8 @@ xmlAutomataNewState(xmlAutomataPtr am) {
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* @from: the starting point of the transition
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* @to: the target point of the transition or NULL
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*
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* If @to is NULL, this create first a new target state in the automata
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* and then adds a an epsilon transition from the @from state to the
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* If @to is NULL, this creates first a new target state in the automata
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* and then adds an epsilon transition from the @from state to the
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* target state
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*
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* Returns the target state or NULL in case of error
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@ -4507,7 +4519,7 @@ xmlAutomataNewEpsilon(xmlAutomataPtr am, xmlAutomataStatePtr from,
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* @to: the target point of the transition or NULL
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* @lax: allow to transition if not all all transitions have been activated
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*
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* If @to is NULL, this create first a new target state in the automata
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* If @to is NULL, this creates first a new target state in the automata
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* and then adds a an ALL transition from the @from state to the
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* target state. That transition is an epsilon transition allowed only when
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* all transitions from the @from node have been activated.
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@ -4557,7 +4569,7 @@ xmlAutomataNewCounter(xmlAutomataPtr am, int min, int max) {
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* @to: the target point of the transition or NULL
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* @counter: the counter associated to that transition
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*
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* If @to is NULL, this create first a new target state in the automata
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* If @to is NULL, this creates first a new target state in the automata
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* and then adds an epsilon transition from the @from state to the target state
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* which will increment the counter provided
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*
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@ -4581,7 +4593,7 @@ xmlAutomataNewCountedTrans(xmlAutomataPtr am, xmlAutomataStatePtr from,
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* @to: the target point of the transition or NULL
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* @counter: the counter associated to that transition
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*
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* If @to is NULL, this create first a new target state in the automata
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* If @to is NULL, this creates first a new target state in the automata
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* and then adds an epsilon transition from the @from state to the target state
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* which will be allowed only if the counter is within the right range.
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*
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