icuSources/common/rbbistbl.cpp

   1 //
   2 //  file:  rbbistbl.cpp    Implementation of the ICU RBBISymbolTable class
   3 //
   4 /*
   5 ***************************************************************************
   6 *   Copyright (C) 2002-2005 International Business Machines Corporation   *
   7 *   and others. All rights reserved.                                      *
   8 ***************************************************************************
   9 */
  10
  11 #include "unicode/utypes.h"
  12
  13 #if !UCONFIG_NO_BREAK_ITERATION
  14
  15 #include "unicode/unistr.h"
  16 #include "unicode/uniset.h"
  17 #include "unicode/uchar.h"
  18 #include "unicode/parsepos.h"
  19
  20 #include "umutex.h"
  21
  22 #include "rbbirb.h"
  23 #include "rbbinode.h"
  24
  25
  26 //
  27 //  RBBISymbolTableEntry_deleter    Used by the UHashTable to delete the contents
  28 //                                  when the hash table is deleted.
  29 //
  30 U_CDECL_BEGIN
  31 static void U_CALLCONV RBBISymbolTableEntry_deleter(void *p) {
  32     RBBISymbolTableEntry *px = (RBBISymbolTableEntry *)p;
  33     delete px;
  34 }
  35 U_CDECL_END
  36
  37
  38
  39 U_NAMESPACE_BEGIN
  40
  41 RBBISymbolTable::RBBISymbolTable(RBBIRuleScanner *rs, const UnicodeString &rules, UErrorCode &status)
  42     :fRules(rules), fRuleScanner(rs), ffffString(UChar(0xffff))
  43 {
  44     fHashTable       = NULL;
  45     fCachedSetLookup = NULL;
  46
  47     fHashTable = uhash_open(uhash_hashUnicodeString, uhash_compareUnicodeString, NULL, &status);
  48     // uhash_open checks status
  49     if (U_FAILURE(status)) {
  50         return;
  51     }
  52     uhash_setValueDeleter(fHashTable, RBBISymbolTableEntry_deleter);
  53 }
  54
  55
  56
  57 RBBISymbolTable::~RBBISymbolTable()
  58 {
  59     uhash_close(fHashTable);
  60 }
  61
  62
  63 //
  64 //  RBBISymbolTable::lookup       This function from the abstract symbol table inteface
  65 //                                looks up a variable name and returns a UnicodeString
  66 //                                containing the substitution text.
  67 //
  68 //                                The variable name does NOT include the leading $.
  69 //
  70 const UnicodeString  *RBBISymbolTable::lookup(const UnicodeString& s) const
  71 {
  72     RBBISymbolTableEntry  *el;
  73     RBBINode              *varRefNode;
  74     RBBINode              *exprNode;
  75     RBBINode              *usetNode;
  76     const UnicodeString   *retString;
  77     RBBISymbolTable       *This = (RBBISymbolTable *)this;   // cast off const
  78
  79     el = (RBBISymbolTableEntry *)uhash_get(fHashTable, &s);
  80     if (el == NULL) {
  81         return NULL;
  82     }
  83
  84     varRefNode = el->val;
  85     exprNode   = varRefNode->fLeftChild;     // Root node of expression for variable
  86     if (exprNode->fType == RBBINode::setRef) {
  87         // The $variable refers to a single UnicodeSet
  88         //   return the ffffString, which will subsequently be interpreted as a
  89         //   stand-in character for the set by RBBISymbolTable::lookupMatcher()
  90         usetNode = exprNode->fLeftChild;
  91         This->fCachedSetLookup = usetNode->fInputSet;
  92         retString = &ffffString;
  93     }
  94     else
  95     {
  96         // The variable refers to something other than just a set.
  97         // return the original source string for the expression
  98         retString = &exprNode->fText;
  99         This->fCachedSetLookup = NULL;
 100     }
 101     return retString;
 102 }
 103
 104
 105
 106 //
 107 //  RBBISymbolTable::lookupMatcher   This function from the abstract symbol table
 108 //                                   interface maps a single stand-in character to a
 109 //                                   pointer to a Unicode Set.   The Unicode Set code uses this
 110 //                                   mechanism to get all references to the same $variable
 111 //                                   name to refer to a single common Unicode Set instance.
 112 //
 113 //    This implementation cheats a little, and does not maintain a map of stand-in chars
 114 //    to sets.  Instead, it takes advantage of the fact that  the UnicodeSet
 115 //    constructor will always call this function right after calling lookup(),
 116 //    and we just need to remember what set to return between these two calls.
 117 const UnicodeFunctor *RBBISymbolTable::lookupMatcher(UChar32 ch) const
 118 {
 119     UnicodeSet *retVal = NULL;
 120     RBBISymbolTable *This = (RBBISymbolTable *)this;   // cast off const
 121     if (ch == 0xffff) {
 122         retVal = fCachedSetLookup;
 123         This->fCachedSetLookup = 0;
 124     }
 125     return retVal;
 126 }
 127
 128 //
 129 // RBBISymbolTable::parseReference   This function from the abstract symbol table interface
 130 //                                   looks for a $variable name in the source text.
 131 //                                   It does not look it up, only scans for it.
 132 //                                   It is used by the UnicodeSet parser.
 133 //
 134 //                                   This implementation is lifted pretty much verbatim
 135 //                                   from the rules based transliterator implementation.
 136 //                                   I didn't see an obvious way of sharing it.
 137 //
 138 UnicodeString   RBBISymbolTable::parseReference(const UnicodeString& text,
 139                                                 ParsePosition& pos, int32_t limit) const
 140 {
 141     int32_t start = pos.getIndex();
 142     int32_t i = start;
 143     UnicodeString result;
 144     while (i < limit) {
 145         UChar c = text.charAt(i);
 146         if ((i==start && !u_isIDStart(c)) || !u_isIDPart(c)) {
 147             break;
 148         }
 149         ++i;
 150     }
 151     if (i == start) { // No valid name chars
 152         return result; // Indicate failure with empty string
 153     }
 154     pos.setIndex(i);
 155     text.extractBetween(start, i, result);
 156     return result;
 157 }
 158
 159
 160
 161 //
 162 // RBBISymbolTable::lookupNode      Given a key (a variable name), return the
 163 //                                  corresponding RBBI Node.  If there is no entry
 164 //                                  in the table for this name, return NULL.
 165 //
 166 RBBINode       *RBBISymbolTable::lookupNode(const UnicodeString &key) const{
 167
 168     RBBINode             *retNode = NULL;
 169     RBBISymbolTableEntry *el;
 170
 171     el = (RBBISymbolTableEntry *)uhash_get(fHashTable, &key);
 172     if (el != NULL) {
 173         retNode = el->val;
 174     }
 175     return retNode;
 176 }
 177
 178
 179 //
 180 //    RBBISymbolTable::addEntry     Add a new entry to the symbol table.
 181 //                                  Indicate an error if the name already exists -
 182 //                                    this will only occur in the case of duplicate
 183 //                                    variable assignments.
 184 //
 185 void            RBBISymbolTable::addEntry  (const UnicodeString &key, RBBINode *val, UErrorCode &err) {
 186     RBBISymbolTableEntry *e;
 187     /* test for buffer overflows */
 188     if (U_FAILURE(err)) {
 189         return;
 190     }
 191     e = (RBBISymbolTableEntry *)uhash_get(fHashTable, &key);
 192     if (e != NULL) {
 193         err = U_BRK_VARIABLE_REDFINITION;
 194         return;
 195     }
 196
 197     e = new RBBISymbolTableEntry;
 198     if (e == NULL) {
 199         err = U_MEMORY_ALLOCATION_ERROR;
 200         return;
 201     }
 202     e->key = key;
 203     e->val = val;
 204     uhash_put( fHashTable, &e->key, e, &err);
 205 }
 206
 207
 208 RBBISymbolTableEntry::RBBISymbolTableEntry() : UMemory(), key(), val(NULL) {}
 209
 210 RBBISymbolTableEntry::~RBBISymbolTableEntry() {
 211     // The "val" of a symbol table entry is a variable reference node.
 212     // The l. child of the val is the rhs expression from the assignment.
 213     // Unlike other node types, children of variable reference nodes are not
 214     //    automatically recursively deleted.  We do it manually here.
 215     delete val->fLeftChild;
 216     val->fLeftChild = NULL;
 217
 218     delete  val;
 219
 220     // Note: the key UnicodeString is destructed by virtue of being in the object by value.
 221 }
 222
 223
 224 //
 225 //  RBBISymbolTable::print    Debugging function, dump out the symbol table contents.
 226 //
 227 #ifdef RBBI_DEBUG
 228 void RBBISymbolTable::rbbiSymtablePrint() const {
 229     RBBIDebugPrintf("Variable Definitions\n"
 230            "Name               Node Val     String Val\n"
 231            "----------------------------------------------------------------------\n");
 232
 233     int32_t pos = -1;
 234     const UHashElement  *e   = NULL;
 235     for (;;) {
 236         e = uhash_nextElement(fHashTable,  &pos);
 237         if (e == NULL ) {
 238             break;
 239         }
 240         RBBISymbolTableEntry  *s   = (RBBISymbolTableEntry *)e->value.pointer;
 241
 242         RBBI_DEBUG_printUnicodeString(s->key, 15);
 243         RBBIDebugPrintf("   %8p   ", (void *)s->val);
 244         RBBI_DEBUG_printUnicodeString(s->val->fLeftChild->fText);
 245         RBBIDebugPrintf("\n");
 246     }
 247
 248     RBBIDebugPrintf("\nParsed Variable Definitions\n");
 249     pos = -1;
 250     for (;;) {
 251         e = uhash_nextElement(fHashTable,  &pos);
 252         if (e == NULL ) {
 253             break;
 254         }
 255         RBBISymbolTableEntry  *s   = (RBBISymbolTableEntry *)e->value.pointer;
 256         RBBI_DEBUG_printUnicodeString(s->key);
 257         s->val->fLeftChild->printTree(TRUE);
 258         RBBIDebugPrintf("\n");
 259     }
 260 }
 261 #endif
 262
 263
 264
 265
 266
 267 U_NAMESPACE_END
 268
 269 #endif /* #if !UCONFIG_NO_BREAK_ITERATION */