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Diffstat (limited to 'gnu/usr.bin/awk/re.c')
| -rw-r--r-- | gnu/usr.bin/awk/re.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/gnu/usr.bin/awk/re.c b/gnu/usr.bin/awk/re.c new file mode 100644 index 0000000..495b096 --- /dev/null +++ b/gnu/usr.bin/awk/re.c @@ -0,0 +1,208 @@ +/* + * re.c - compile regular expressions. + */ + +/* + * Copyright (C) 1991, 1992 the Free Software Foundation, Inc. + * + * This file is part of GAWK, the GNU implementation of the + * AWK Progamming Language. + * + * GAWK is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * GAWK is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GAWK; see the file COPYING. If not, write to + * the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include "awk.h" + +/* Generate compiled regular expressions */ + +Regexp * +make_regexp(s, len, ignorecase, dfa) +char *s; +int len; +int ignorecase; +int dfa; +{ + Regexp *rp; + char *err; + char *src = s; + char *temp; + char *end = s + len; + register char *dest; + register int c; + + /* Handle escaped characters first. */ + + /* Build a copy of the string (in dest) with the + escaped characters translated, and generate the regex + from that. + */ + emalloc(dest, char *, len + 2, "make_regexp"); + temp = dest; + + while (src < end) { + if (*src == '\\') { + c = *++src; + switch (c) { + case 'a': + case 'b': + case 'f': + case 'n': + case 'r': + case 't': + case 'v': + case 'x': + case '0': + case '1': + case '2': + case '3': + case '4': + case '5': + case '6': + case '7': + c = parse_escape(&src); + if (c < 0) + cant_happen(); + *dest++ = (char)c; + break; + default: + *dest++ = '\\'; + *dest++ = (char)c; + src++; + break; + } /* switch */ + } else { + *dest++ = *src++; /* not '\\' */ + } + } /* for */ + + *dest = '\0' ; /* Only necessary if we print dest ? */ + emalloc(rp, Regexp *, sizeof(*rp), "make_regexp"); + memset((char *) rp, 0, sizeof(*rp)); + emalloc(rp->pat.buffer, char *, 16, "make_regexp"); + rp->pat.allocated = 16; + emalloc(rp->pat.fastmap, char *, 256, "make_regexp"); + + if (ignorecase) + rp->pat.translate = casetable; + else + rp->pat.translate = NULL; + len = dest - temp; + if ((err = re_compile_pattern(temp, (size_t) len, &(rp->pat))) != NULL) + fatal("%s: /%s/", err, temp); + if (dfa && !ignorecase) { + regcompile(temp, len, &(rp->dfareg), 1); + rp->dfa = 1; + } else + rp->dfa = 0; + free(temp); + return rp; +} + +int +research(rp, str, start, len, need_start) +Regexp *rp; +register char *str; +int start; +register int len; +int need_start; +{ + char *ret = str; + + if (rp->dfa) { + char save1; + char save2; + int count = 0; + int try_backref; + + save1 = str[start+len]; + str[start+len] = '\n'; + save2 = str[start+len+1]; + ret = regexecute(&(rp->dfareg), str+start, str+start+len+1, 1, + &count, &try_backref); + str[start+len] = save1; + str[start+len+1] = save2; + } + if (ret) { + if (need_start || rp->dfa == 0) + return re_search(&(rp->pat), str, start+len, start, + len, &(rp->regs)); + else + return 1; + } else + return -1; +} + +void +refree(rp) +Regexp *rp; +{ + free(rp->pat.buffer); + free(rp->pat.fastmap); + if (rp->dfa) + reg_free(&(rp->dfareg)); + free(rp); +} + +void +reg_error(s) +const char *s; +{ + fatal(s); +} + +Regexp * +re_update(t) +NODE *t; +{ + NODE *t1; + +# define CASE 1 + if ((t->re_flags & CASE) == IGNORECASE) { + if (t->re_flags & CONST) + return t->re_reg; + t1 = force_string(tree_eval(t->re_exp)); + if (t->re_text) { + if (cmp_nodes(t->re_text, t1) == 0) { + free_temp(t1); + return t->re_reg; + } + unref(t->re_text); + } + t->re_text = dupnode(t1); + free_temp(t1); + } + if (t->re_reg) + refree(t->re_reg); + if (t->re_cnt) + t->re_cnt++; + if (t->re_cnt > 10) + t->re_cnt = 0; + if (!t->re_text) { + t1 = force_string(tree_eval(t->re_exp)); + t->re_text = dupnode(t1); + free_temp(t1); + } + t->re_reg = make_regexp(t->re_text->stptr, t->re_text->stlen, IGNORECASE, t->re_cnt); + t->re_flags &= ~CASE; + t->re_flags |= IGNORECASE; + return t->re_reg; +} + +void +resetup() +{ + (void) re_set_syntax(RE_SYNTAX_AWK); + regsyntax(RE_SYNTAX_AWK, 0); +} |
