1 2 /*--------------------------------------------------------------------*/ 3 /*--- A simple sequence matching facility. ---*/ 4 /*--- m_seqmatch.c ---*/ 5 /*--------------------------------------------------------------------*/ 6 7 /* 8 This file is part of Valgrind, a dynamic binary instrumentation 9 framework. 10 11 Copyright (C) 2008-2017 OpenWorks Ltd 12 info (at) open-works.co.uk 13 14 This program is free software; you can redistribute it and/or 15 modify it under the terms of the GNU General Public License as 16 published by the Free Software Foundation; either version 2 of the 17 License, or (at your option) any later version. 18 19 This program is distributed in the hope that it will be useful, but 20 WITHOUT ANY WARRANTY; without even the implied warranty of 21 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 22 General Public License for more details. 23 24 You should have received a copy of the GNU General Public License 25 along with this program; if not, write to the Free Software 26 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 27 02111-1307, USA. 28 29 The GNU General Public License is contained in the file COPYING. 30 */ 31 32 #include "pub_core_basics.h" 33 #include "pub_core_libcassert.h" 34 #include "pub_core_libcbase.h" // VG_(strlen) 35 #include "pub_core_seqmatch.h" // self 36 37 /* --------------------------------------------------------------------- 38 A simple sequence matching facility 39 ------------------------------------------------------------------ */ 40 41 /* See detailed comment in include/pub_tool_seqmatch.h about this. */ 42 Bool VG_(generic_match) ( 43 Bool matchAll, 44 const void* patt, SizeT szbPatt, UWord nPatt, UWord ixPatt, 45 const void* input, SizeT szbInput, UWord nInput, UWord ixInput, 46 Bool (*pIsStar)(const void*), 47 Bool (*pIsQuery)(const void*), 48 Bool (*pattEQinp)(const void*,const void*,void*,UWord), 49 void* inputCompleter, Bool (*haveInputInpC)(void*,UWord) 50 ) 51 { 52 /* This is the spec, written in my favourite formal specification 53 language. It specifies non-greedy matching of '*'s. 54 55 ma ('*':ps) (i:is) = ma ps (i:is) || ma ('*':ps) is 56 ma ('*':ps) [] = ma ps [] 57 58 ma ('?':ps) (i:is) = ma ps is 59 ma ('?':ps) [] = False 60 61 ma (p:ps) (i:is) = p == i && ma ps is 62 63 ma (p:ps) [] = False 64 ma [] (i:is) = False -- m-all, True for m-prefix 65 ma [] [] = True 66 */ 67 Bool havePatt, haveInput; 68 const HChar *currPatt, *currInput; 69 tailcall: 70 vg_assert(nPatt >= 0 && nPatt < 1000000); /* arbitrary */ 71 vg_assert(inputCompleter 72 || (nInput >= 0 && nInput < 1000000)); /* arbitrary */ 73 vg_assert(ixPatt >= 0 && ixPatt <= nPatt); 74 vg_assert(ixInput >= 0 && (inputCompleter || ixInput <= nInput)); 75 76 havePatt = ixPatt < nPatt; 77 haveInput = inputCompleter ? 78 (*haveInputInpC)(inputCompleter, ixInput) 79 : ixInput < nInput; 80 81 /* No specific need to set NULL when !have{Patt,Input}, but guards 82 against inadvertantly dereferencing an out of range pointer to 83 the pattern or input arrays. */ 84 currPatt = havePatt ? ((const HChar*)patt) + szbPatt * ixPatt : NULL; 85 currInput = haveInput && !inputCompleter ? 86 ((const HChar*)input) + szbInput * ixInput : NULL; 87 88 // Deal with the complex case first: wildcards. Do frugal 89 // matching. When encountering a '*', first skip no characters 90 // at all, and see if the rest of the match still works. Only if 91 // that fails do we then skip a character, and retry at the next 92 // position. 93 // 94 // ma ('*':ps) (i:is) = ma ps (i:is) || ma ('*':ps) is 95 // 96 // If we're out of input, check the rest of the pattern matches 97 // the empty input. This really means can only be be empty or 98 // composed entirely of '*'s. 99 // 100 // ma ('*':ps) [] = ma ps [] 101 // 102 if (havePatt && pIsStar(currPatt)) { 103 if (haveInput) { 104 // ma ('*':ps) (i:is) = ma ps (i:is) || ma ('*':ps) is 105 // we unavoidably have to make a real recursive call for the 106 // first half of the OR, since this isn't straight tail-recursion. 107 if (VG_(generic_match)( matchAll, 108 patt, szbPatt, nPatt, ixPatt+1, 109 input,szbInput,nInput, ixInput+0, 110 pIsStar,pIsQuery,pattEQinp, 111 inputCompleter,haveInputInpC) ) { 112 return True; 113 } 114 // but we can tail-recurse for the second call 115 ixInput++; goto tailcall; 116 } else { 117 // ma ('*':ps) [] = ma ps [] 118 ixPatt++; goto tailcall; 119 } 120 } 121 122 // simpler cases now. Deal with '?' wildcards. 123 // 124 // ma ('?':ps) (i:is) = ma ps is 125 // ma ('?':ps) [] = False 126 if (havePatt && pIsQuery(currPatt)) { 127 if (haveInput) { 128 ixPatt++; ixInput++; goto tailcall; 129 } else { 130 return False; 131 } 132 } 133 134 // obvious case with literal chars in the pattern 135 // 136 // ma (p:ps) (i:is) = p == i && ma ps is 137 if (havePatt && haveInput) { 138 if (!pattEQinp(currPatt,currInput,inputCompleter,ixInput)) return False; 139 ixPatt++; ixInput++; goto tailcall; 140 } 141 142 // if we run out of input before we run out of pattern, we must fail 143 // ma (p:ps) [] = False 144 if (havePatt && !haveInput) return False; 145 146 // if we run out of pattern before we run out of input, the 147 // verdict depends on the matching mode. If we are trying to 148 // match exactly (the pattern must consume the entire input) 149 // then the outcome is failure. However, if we're merely attempting 150 // to match some prefix of the input, then we have been successful. 151 // 152 // ma [] (i:is) = False -- m-all, True for m-prefix 153 if (!havePatt && haveInput) { 154 return matchAll ? False // match-all 155 : True; // match-prefix 156 } 157 158 // finally, if both sequence and input are both completely 159 // consumed, then we were successful, regardless of matching mode. 160 if (!havePatt && !haveInput) return True; 161 162 // end of cases 163 vg_assert(0); 164 } 165 166 167 /* And a parameterization of the above, to make it do 168 string matching. 169 */ 170 static Bool charIsStar ( const void* pV ) { return *(const HChar*)pV == '*'; } 171 static Bool charIsQuery ( const void* pV ) { return *(const HChar*)pV == '?'; } 172 static Bool char_p_EQ_i ( const void* pV, const void* cV, 173 void* null_completer, UWord ixcV ) { 174 HChar p = *(const HChar*)pV; 175 HChar c = *(const HChar*)cV; 176 vg_assert(p != '*' && p != '?'); 177 return p == c; 178 } 179 Bool VG_(string_match) ( const HChar* patt, const HChar* input ) 180 { 181 return VG_(generic_match)( 182 True/* match-all */, 183 patt, sizeof(HChar), VG_(strlen)(patt), 0, 184 input, sizeof(HChar), VG_(strlen)(input), 0, 185 charIsStar, charIsQuery, char_p_EQ_i, 186 NULL, NULL 187 ); 188 } 189 190 191 // test cases for the matcher (in match-all mode) 192 // typedef struct { char* patt; char* input; Bool xres; } Test; 193 // 194 //static Test tests[] = 195 // { 196 // { "" ,"" , True }, 197 // { "a" ,"" , False }, 198 // { "a" ,"b" , False }, 199 // { "a" ,"a" , True }, 200 // { "a" ,"aa" , False }, 201 // { "*" ,"" , True }, 202 // { "**" ,"" , True }, 203 // { "*" ,"abc", True }, 204 // { "*a" ,"abc", False }, 205 // { "*b" ,"abc", False }, 206 // { "*bc" ,"abc", True }, 207 // { "a*b" ,"abc", False }, 208 // { "a*c" ,"abc", True }, 209 // { "*c" ,"abc", True }, 210 // { "c*c" ,"abc", False }, 211 // { "abc*" ,"abc", True }, 212 // { "abc**" ,"abc", True }, 213 // { "**abc" ,"abc", True }, 214 // { "**a*b*c**" ,"abc", True }, 215 // { "**a*b*d**" ,"abc", False }, 216 // { "a?b" ,"abc", False }, 217 // { "a?c" ,"abc", True }, 218 // { "?" ,"" , False }, 219 // { "?" ,"a" , True }, 220 // { "?" ,"ab" , False }, 221 // { "abcd" ,"abc", False }, 222 // { "ab" ,"abc", False }, 223 // { NULL ,NULL , False } 224 // }; 225 // 226 //int main ( void ) 227 //{ 228 // Test* t; 229 // for (t = tests; t->patt; t++) { 230 // printf("%-10s %-6s %s\n", 231 // t->patt, t->input, 232 // match_string_all((UChar*)t->patt,(UChar*)t->input,True) 233 // == t->xres 234 // ? "pass" : "FAIL" ); 235 // } 236 // return 0; 237 //} 238 239 /*--------------------------------------------------------------------*/ 240 /*--- end m_seqmatch.c ---*/ 241 /*--------------------------------------------------------------------*/ 242
