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Diffstat (limited to '')
| -rw-r--r-- | src/backend/regex/regc_cvec.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/src/backend/regex/regc_cvec.c b/src/backend/regex/regc_cvec.c new file mode 100644 index 0000000..1030621 --- /dev/null +++ b/src/backend/regex/regc_cvec.c @@ -0,0 +1,138 @@ +/* + * Utility functions for handling cvecs + * This file is #included by regcomp.c. + * + * Copyright (c) 1998, 1999 Henry Spencer. All rights reserved. + * + * Development of this software was funded, in part, by Cray Research Inc., + * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics + * Corporation, none of whom are responsible for the results. The author + * thanks all of them. + * + * Redistribution and use in source and binary forms -- with or without + * modification -- are permitted for any purpose, provided that + * redistributions in source form retain this entire copyright notice and + * indicate the origin and nature of any modifications. + * + * I'd appreciate being given credit for this package in the documentation + * of software which uses it, but that is not a requirement. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, + * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL + * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; + * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, + * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR + * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF + * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * src/backend/regex/regc_cvec.c + * + */ + +/* + * Notes: + * Only (selected) functions in _this_ file should treat the chr arrays + * of a cvec as non-constant. + */ + +/* + * newcvec - allocate a new cvec + */ +static struct cvec * +newcvec(int nchrs, /* to hold this many chrs... */ + int nranges) /* ... and this many ranges */ +{ + size_t nc = (size_t) nchrs + (size_t) nranges * 2; + size_t n = sizeof(struct cvec) + nc * sizeof(chr); + struct cvec *cv = (struct cvec *) MALLOC(n); + + if (cv == NULL) + return NULL; + cv->chrspace = nchrs; + cv->chrs = (chr *) (((char *) cv) + sizeof(struct cvec)); + cv->ranges = cv->chrs + nchrs; + cv->rangespace = nranges; + return clearcvec(cv); +} + +/* + * clearcvec - clear a possibly-new cvec + * Returns pointer as convenience. + */ +static struct cvec * +clearcvec(struct cvec *cv) +{ + assert(cv != NULL); + cv->nchrs = 0; + cv->nranges = 0; + cv->cclasscode = -1; + return cv; +} + +/* + * addchr - add a chr to a cvec + */ +static void +addchr(struct cvec *cv, /* character vector */ + chr c) /* character to add */ +{ + assert(cv->nchrs < cv->chrspace); + cv->chrs[cv->nchrs++] = c; +} + +/* + * addrange - add a range to a cvec + */ +static void +addrange(struct cvec *cv, /* character vector */ + chr from, /* first character of range */ + chr to) /* last character of range */ +{ + assert(cv->nranges < cv->rangespace); + cv->ranges[cv->nranges * 2] = from; + cv->ranges[cv->nranges * 2 + 1] = to; + cv->nranges++; +} + +/* + * getcvec - get a transient cvec, initialized to empty + * + * The returned cvec is valid only until the next call of getcvec, which + * typically will recycle the space. Callers should *not* free the cvec + * explicitly; it will be cleaned up when the struct vars is destroyed. + * + * This is typically used while interpreting bracket expressions. In that + * usage the cvec is only needed momentarily until we build arcs from it, + * so transientness is a convenient behavior. + */ +static struct cvec * +getcvec(struct vars *v, /* context */ + int nchrs, /* to hold this many chrs... */ + int nranges) /* ... and this many ranges */ +{ + /* recycle existing transient cvec if large enough */ + if (v->cv != NULL && nchrs <= v->cv->chrspace && + nranges <= v->cv->rangespace) + return clearcvec(v->cv); + + /* nope, make a new one */ + if (v->cv != NULL) + freecvec(v->cv); + v->cv = newcvec(nchrs, nranges); + if (v->cv == NULL) + ERR(REG_ESPACE); + + return v->cv; +} + +/* + * freecvec - free a cvec + */ +static void +freecvec(struct cvec *cv) +{ + FREE(cv); +} |