1 #include <u.h> 2 #include <libc.h> 3 #include "regexp.h" 4 #include "regcomp.h" 5 6 /* 7 * return 0 if no match 8 * >0 if a match 9 * <0 if we ran out of _relist space 10 */ 11 static int 12 rregexec1(Reprog *progp, /* program to run */ 13 Rune *bol, /* string to run machine on */ 14 Resub *mp, /* subexpression elements */ 15 int ms, /* number of elements at mp */ 16 Reljunk *j) 17 { 18 int flag=0; 19 Reinst *inst; 20 Relist *tlp; 21 Rune *s; 22 int i, checkstart; 23 Rune r, *rp, *ep; 24 Relist* tl; /* This list, next list */ 25 Relist* nl; 26 Relist* tle; /* ends of this and next list */ 27 Relist* nle; 28 int match; 29 30 match = 0; 31 checkstart = j->startchar; 32 if(mp) 33 for(i=0; i<ms; i++) { 34 mp[i].rsp = 0; 35 mp[i].rep = 0; 36 } 37 j->relist[0][0].inst = 0; 38 j->relist[1][0].inst = 0; 39 40 /* Execute machine once for each character, including terminal NUL */ 41 s = j->rstarts; 42 do{ 43 44 /* fast check for first char */ 45 if(checkstart) { 46 switch(j->starttype) { 47 case RUNE: 48 while(*s != j->startchar) { 49 if(*s == 0) 50 return match; 51 s++; 52 } 53 break; 54 case BOL: 55 if(s == bol) 56 break; 57 while(*s != '\n') { 58 if(*s == 0) 59 return match; 60 s++; 61 } 62 break; 63 } 64 } 65 66 r = *s; 67 68 /* switch run lists */ 69 tl = j->relist[flag]; 70 tle = j->reliste[flag]; 71 nl = j->relist[flag^=1]; 72 nle = j->reliste[flag]; 73 nl->inst = 0; 74 75 /* Add first instruction to current list */ 76 _rrenewemptythread(tl, progp->startinst, s); 77 78 /* Execute machine until current list is empty */ 79 for(tlp=tl; tlp->inst; tlp++){ 80 if(s == j->reol) 81 break; 82 83 for(inst=tlp->inst; ; inst = inst->next){ 84 switch(inst->type){ 85 case RUNE: /* regular character */ 86 if(inst->r == r) 87 if(_renewthread(nl, inst->next, &tlp->se)==nle) 88 return -1; 89 break; 90 case LBRA: 91 tlp->se.m[inst->subid].rsp = s; 92 continue; 93 case RBRA: 94 tlp->se.m[inst->subid].rep = s; 95 continue; 96 case ANY: 97 if(r != '\n') 98 if(_renewthread(nl, inst->next, &tlp->se)==nle) 99 return -1; 100 break; 101 case ANYNL: 102 if(_renewthread(nl, inst->next, &tlp->se)==nle) 103 return -1; 104 break; 105 case BOL: 106 if(s == bol || *(s-1) == '\n') 107 continue; 108 break; 109 case EOL: 110 if(r == 0 || r == '\n') 111 continue; 112 break; 113 case CCLASS: 114 ep = inst->cp->end; 115 for(rp = inst->cp->spans; rp < ep; rp += 2) 116 if(r >= rp[0] && r <= rp[1]){ 117 if(_renewthread(nl, inst->next, &tlp->se)==nle) 118 return -1; 119 break; 120 } 121 break; 122 case NCCLASS: 123 ep = inst->cp->end; 124 for(rp = inst->cp->spans; rp < ep; rp += 2) 125 if(r >= rp[0] && r <= rp[1]) 126 break; 127 if(rp == ep) 128 if(_renewthread(nl, inst->next, &tlp->se)==nle) 129 return -1; 130 break; 131 case OR: 132 /* evaluate right choice later */ 133 if(_renewthread(tlp, inst->right, &tlp->se) == tle) 134 return -1; 135 /* efficiency: advance and re-evaluate */ 136 continue; 137 case END: /* Match! */ 138 match = 1; 139 tlp->se.m[0].rep = s; 140 if(mp != 0) 141 _renewmatch(mp, ms, &tlp->se); 142 break; 143 } 144 break; 145 } 146 } 147 checkstart = j->startchar && nl->inst==0; 148 s++; 149 }while(r); 150 return match; 151 } 152 153 static int 154 rregexec2(Reprog *progp, /* program to run */ 155 Rune *bol, /* string to run machine on */ 156 Resub *mp, /* subexpression elements */ 157 int ms, /* number of elements at mp */ 158 Reljunk *j 159 ) 160 { 161 Relist relist0[5*LISTSIZE], relist1[5*LISTSIZE]; 162 163 /* mark space */ 164 j->relist[0] = relist0; 165 j->relist[1] = relist1; 166 j->reliste[0] = relist0 + nelem(relist0) - 2; 167 j->reliste[1] = relist1 + nelem(relist1) - 2; 168 169 return rregexec1(progp, bol, mp, ms, j); 170 } 171 172 extern int 173 rregexec(Reprog *progp, /* program to run */ 174 Rune *bol, /* string to run machine on */ 175 Resub *mp, /* subexpression elements */ 176 int ms) /* number of elements at mp */ 177 { 178 Reljunk j; 179 Relist relist0[LISTSIZE], relist1[LISTSIZE]; 180 int rv; 181 182 /* 183 * use user-specified starting/ending location if specified 184 */ 185 j.rstarts = bol; 186 j.reol = 0; 187 if(mp && ms>0){ 188 if(mp->sp) 189 j.rstarts = mp->rsp; 190 if(mp->ep) 191 j.reol = mp->rep; 192 } 193 j.starttype = 0; 194 j.startchar = 0; 195 if(progp->startinst->type == RUNE && progp->startinst->r < Runeself) { 196 j.starttype = RUNE; 197 j.startchar = progp->startinst->r; 198 } 199 if(progp->startinst->type == BOL) 200 j.starttype = BOL; 201 202 /* mark space */ 203 j.relist[0] = relist0; 204 j.relist[1] = relist1; 205 j.reliste[0] = relist0 + nelem(relist0) - 2; 206 j.reliste[1] = relist1 + nelem(relist1) - 2; 207 208 rv = rregexec1(progp, bol, mp, ms, &j); 209 if(rv >= 0) 210 return rv; 211 rv = rregexec2(progp, bol, mp, ms, &j); 212 if(rv >= 0) 213 return rv; 214 return -1; 215 } 216