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postgresql/src/backend/utils/adt/regexp.c

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/*-------------------------------------------------------------------------
*
* regexp.c
* Postgres' interface to the regular expression package.
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/utils/adt/regexp.c
*
* Alistair Crooks added the code for the regex caching
* agc - cached the regular expressions used - there's a good chance
* that we'll get a hit, so this saves a compile step for every
* attempted match. I haven't actually measured the speed improvement,
* but it `looks' a lot quicker visually when watching regression
* test output.
*
* agc - incorporated Keith Bostic's Berkeley regex code into
* the tree for all ports. To distinguish this regex code from any that
* is existent on a platform, I've prepended the string "pg_" to
* the functions regcomp, regerror, regexec and regfree.
* Fixed a bug that was originally a typo by me, where `i' was used
* instead of `oldest' when compiling regular expressions - benign
* results mostly, although occasionally it bit you...
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "regex/regex.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/memutils.h"
#include "utils/varlena.h"
#define PG_GETARG_TEXT_PP_IF_EXISTS(_n) \
(PG_NARGS() > (_n) ? PG_GETARG_TEXT_PP(_n) : NULL)
/* all the options of interest for regex functions */
typedef struct pg_re_flags
{
int cflags; /* compile flags for Spencer's regex code */
bool glob; /* do it globally (for each occurrence) */
} pg_re_flags;
/* cross-call state for regexp_match and regexp_split functions */
typedef struct regexp_matches_ctx
{
text *orig_str; /* data string in original TEXT form */
int nmatches; /* number of places where pattern matched */
int npatterns; /* number of capturing subpatterns */
/* We store start char index and end+1 char index for each match */
/* so the number of entries in match_locs is nmatches * npatterns * 2 */
int *match_locs; /* 0-based character indexes */
int next_match; /* 0-based index of next match to process */
/* workspace for build_regexp_match_result() */
Datum *elems; /* has npatterns elements */
bool *nulls; /* has npatterns elements */
pg_wchar *wide_str; /* wide-char version of original string */
char *conv_buf; /* conversion buffer */
int conv_bufsiz; /* size thereof */
} regexp_matches_ctx;
/*
* We cache precompiled regular expressions using a "self organizing list"
* structure, in which recently-used items tend to be near the front.
* Whenever we use an entry, it's moved up to the front of the list.
* Over time, an item's average position corresponds to its frequency of use.
*
* When we first create an entry, it's inserted at the front of
* the array, dropping the entry at the end of the array if necessary to
* make room. (This might seem to be weighting the new entry too heavily,
* but if we insert new entries further back, we'll be unable to adjust to
* a sudden shift in the query mix where we are presented with MAX_CACHED_RES
* never-before-seen items used circularly. We ought to be able to handle
* that case, so we have to insert at the front.)
*
* Knuth mentions a variant strategy in which a used item is moved up just
* one place in the list. Although he says this uses fewer comparisons on
* average, it seems not to adapt very well to the situation where you have
* both some reusable patterns and a steady stream of non-reusable patterns.
* A reusable pattern that isn't used at least as often as non-reusable
* patterns are seen will "fail to keep up" and will drop off the end of the
* cache. With move-to-front, a reusable pattern is guaranteed to stay in
* the cache as long as it's used at least once in every MAX_CACHED_RES uses.
*/
/* this is the maximum number of cached regular expressions */
#ifndef MAX_CACHED_RES
#define MAX_CACHED_RES 32
#endif
/* this structure describes one cached regular expression */
typedef struct cached_re_str
{
char *cre_pat; /* original RE (not null terminated!) */
int cre_pat_len; /* length of original RE, in bytes */
int cre_flags; /* compile flags: extended,icase etc */
Oid cre_collation; /* collation to use */
regex_t cre_re; /* the compiled regular expression */
} cached_re_str;
static int num_res = 0; /* # of cached re's */
static cached_re_str re_array[MAX_CACHED_RES]; /* cached re's */
/* Local functions */
static regexp_matches_ctx *setup_regexp_matches(text *orig_str, text *pattern,
pg_re_flags *flags,
Oid collation,
bool use_subpatterns,
bool ignore_degenerate,
bool fetching_unmatched);
static ArrayType *build_regexp_match_result(regexp_matches_ctx *matchctx);
static Datum build_regexp_split_result(regexp_matches_ctx *splitctx);
/*
* RE_compile_and_cache - compile a RE, caching if possible
*
* Returns regex_t *
*
* text_re --- the pattern, expressed as a TEXT object
* cflags --- compile options for the pattern
* collation --- collation to use for LC_CTYPE-dependent behavior
*
* Pattern is given in the database encoding. We internally convert to
* an array of pg_wchar, which is what Spencer's regex package wants.
*/
regex_t *
RE_compile_and_cache(text *text_re, int cflags, Oid collation)
{
int text_re_len = VARSIZE_ANY_EXHDR(text_re);
char *text_re_val = VARDATA_ANY(text_re);
pg_wchar *pattern;
int pattern_len;
int i;
int regcomp_result;
cached_re_str re_temp;
char errMsg[100];
/*
* Look for a match among previously compiled REs. Since the data
* structure is self-organizing with most-used entries at the front, our
* search strategy can just be to scan from the front.
*/
for (i = 0; i < num_res; i++)
{
if (re_array[i].cre_pat_len == text_re_len &&
re_array[i].cre_flags == cflags &&
re_array[i].cre_collation == collation &&
memcmp(re_array[i].cre_pat, text_re_val, text_re_len) == 0)
{
/*
* Found a match; move it to front if not there already.
*/
if (i > 0)
{
re_temp = re_array[i];
memmove(&re_array[1], &re_array[0], i * sizeof(cached_re_str));
re_array[0] = re_temp;
}
return &re_array[0].cre_re;
}
}
/*
* Couldn't find it, so try to compile the new RE. To avoid leaking
* resources on failure, we build into the re_temp local.
*/
/* Convert pattern string to wide characters */
pattern = (pg_wchar *) palloc((text_re_len + 1) * sizeof(pg_wchar));
pattern_len = pg_mb2wchar_with_len(text_re_val,
pattern,
text_re_len);
regcomp_result = pg_regcomp(&re_temp.cre_re,
pattern,
pattern_len,
cflags,
collation);
pfree(pattern);
if (regcomp_result != REG_OKAY)
{
/* re didn't compile (no need for pg_regfree, if so) */
/*
* Here and in other places in this file, do CHECK_FOR_INTERRUPTS
* before reporting a regex error. This is so that if the regex
* library aborts and returns REG_CANCEL, we don't print an error
* message that implies the regex was invalid.
*/
CHECK_FOR_INTERRUPTS();
pg_regerror(regcomp_result, &re_temp.cre_re, errMsg, sizeof(errMsg));
ereport(ERROR,
(errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
errmsg("invalid regular expression: %s", errMsg)));
}
/*
* We use malloc/free for the cre_pat field because the storage has to
* persist across transactions, and because we want to get control back on
* out-of-memory. The Max() is because some malloc implementations return
* NULL for malloc(0).
*/
re_temp.cre_pat = malloc(Max(text_re_len, 1));
if (re_temp.cre_pat == NULL)
{
pg_regfree(&re_temp.cre_re);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory")));
}
memcpy(re_temp.cre_pat, text_re_val, text_re_len);
re_temp.cre_pat_len = text_re_len;
re_temp.cre_flags = cflags;
re_temp.cre_collation = collation;
/*
* Okay, we have a valid new item in re_temp; insert it into the storage
* array. Discard last entry if needed.
*/
if (num_res >= MAX_CACHED_RES)
{
--num_res;
Assert(num_res < MAX_CACHED_RES);
pg_regfree(&re_array[num_res].cre_re);
free(re_array[num_res].cre_pat);
}
if (num_res > 0)
memmove(&re_array[1], &re_array[0], num_res * sizeof(cached_re_str));
re_array[0] = re_temp;
num_res++;
return &re_array[0].cre_re;
}
/*
* RE_wchar_execute - execute a RE on pg_wchar data
*
* Returns true on match, false on no match
*
* re --- the compiled pattern as returned by RE_compile_and_cache
* data --- the data to match against (need not be null-terminated)
* data_len --- the length of the data string
* start_search -- the offset in the data to start searching
* nmatch, pmatch --- optional return area for match details
*
* Data is given as array of pg_wchar which is what Spencer's regex package
* wants.
*/
static bool
RE_wchar_execute(regex_t *re, pg_wchar *data, int data_len,
int start_search, int nmatch, regmatch_t *pmatch)
{
int regexec_result;
char errMsg[100];
/* Perform RE match and return result */
regexec_result = pg_regexec(re,
data,
data_len,
start_search,
NULL, /* no details */
nmatch,
pmatch,
0);
if (regexec_result != REG_OKAY && regexec_result != REG_NOMATCH)
{
/* re failed??? */
CHECK_FOR_INTERRUPTS();
pg_regerror(regexec_result, re, errMsg, sizeof(errMsg));
ereport(ERROR,
(errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
errmsg("regular expression failed: %s", errMsg)));
}
return (regexec_result == REG_OKAY);
}
/*
* RE_execute - execute a RE
*
* Returns true on match, false on no match
*
* re --- the compiled pattern as returned by RE_compile_and_cache
* dat --- the data to match against (need not be null-terminated)
* dat_len --- the length of the data string
* nmatch, pmatch --- optional return area for match details
*
* Data is given in the database encoding. We internally
* convert to array of pg_wchar which is what Spencer's regex package wants.
*/
static bool
RE_execute(regex_t *re, char *dat, int dat_len,
int nmatch, regmatch_t *pmatch)
{
pg_wchar *data;
int data_len;
bool match;
/* Convert data string to wide characters */
data = (pg_wchar *) palloc((dat_len + 1) * sizeof(pg_wchar));
data_len = pg_mb2wchar_with_len(dat, data, dat_len);
/* Perform RE match and return result */
match = RE_wchar_execute(re, data, data_len, 0, nmatch, pmatch);
pfree(data);
return match;
}
/*
* RE_compile_and_execute - compile and execute a RE
*
* Returns true on match, false on no match
*
* text_re --- the pattern, expressed as a TEXT object
* dat --- the data to match against (need not be null-terminated)
* dat_len --- the length of the data string
* cflags --- compile options for the pattern
* collation --- collation to use for LC_CTYPE-dependent behavior
* nmatch, pmatch --- optional return area for match details
*
* Both pattern and data are given in the database encoding. We internally
* convert to array of pg_wchar which is what Spencer's regex package wants.
*/
bool
RE_compile_and_execute(text *text_re, char *dat, int dat_len,
int cflags, Oid collation,
int nmatch, regmatch_t *pmatch)
{
regex_t *re;
/* Compile RE */
re = RE_compile_and_cache(text_re, cflags, collation);
return RE_execute(re, dat, dat_len, nmatch, pmatch);
}
/*
* parse_re_flags - parse the options argument of regexp_match and friends
*
* flags --- output argument, filled with desired options
* opts --- TEXT object, or NULL for defaults
*
* This accepts all the options allowed by any of the callers; callers that
* don't want some have to reject them after the fact.
*/
static void
parse_re_flags(pg_re_flags *flags, text *opts)
{
/* regex flavor is always folded into the compile flags */
flags->cflags = REG_ADVANCED;
flags->glob = false;
if (opts)
{
char *opt_p = VARDATA_ANY(opts);
int opt_len = VARSIZE_ANY_EXHDR(opts);
int i;
for (i = 0; i < opt_len; i++)
{
switch (opt_p[i])
{
case 'g':
flags->glob = true;
break;
case 'b': /* BREs (but why???) */
flags->cflags &= ~(REG_ADVANCED | REG_EXTENDED | REG_QUOTE);
break;
case 'c': /* case sensitive */
flags->cflags &= ~REG_ICASE;
break;
case 'e': /* plain EREs */
flags->cflags |= REG_EXTENDED;
flags->cflags &= ~(REG_ADVANCED | REG_QUOTE);
break;
case 'i': /* case insensitive */
flags->cflags |= REG_ICASE;
break;
case 'm': /* Perloid synonym for n */
case 'n': /* \n affects ^ $ . [^ */
flags->cflags |= REG_NEWLINE;
break;
case 'p': /* ~Perl, \n affects . [^ */
flags->cflags |= REG_NLSTOP;
flags->cflags &= ~REG_NLANCH;
break;
case 'q': /* literal string */
flags->cflags |= REG_QUOTE;
flags->cflags &= ~(REG_ADVANCED | REG_EXTENDED);
break;
case 's': /* single line, \n ordinary */
flags->cflags &= ~REG_NEWLINE;
break;
case 't': /* tight syntax */
flags->cflags &= ~REG_EXPANDED;
break;
case 'w': /* weird, \n affects ^ $ only */
flags->cflags &= ~REG_NLSTOP;
flags->cflags |= REG_NLANCH;
break;
case 'x': /* expanded syntax */
flags->cflags |= REG_EXPANDED;
break;
default:
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("invalid regular expression option: \"%c\"",
opt_p[i])));
break;
}
}
}
}
/*
* interface routines called by the function manager
*/
Datum
nameregexeq(PG_FUNCTION_ARGS)
{
Name n = PG_GETARG_NAME(0);
text *p = PG_GETARG_TEXT_PP(1);
PG_RETURN_BOOL(RE_compile_and_execute(p,
NameStr(*n),
strlen(NameStr(*n)),
REG_ADVANCED,
PG_GET_COLLATION(),
0, NULL));
}
Datum
nameregexne(PG_FUNCTION_ARGS)
{
Name n = PG_GETARG_NAME(0);
text *p = PG_GETARG_TEXT_PP(1);
PG_RETURN_BOOL(!RE_compile_and_execute(p,
NameStr(*n),
strlen(NameStr(*n)),
REG_ADVANCED,
PG_GET_COLLATION(),
0, NULL));
}
Datum
textregexeq(PG_FUNCTION_ARGS)
{
text *s = PG_GETARG_TEXT_PP(0);
text *p = PG_GETARG_TEXT_PP(1);
PG_RETURN_BOOL(RE_compile_and_execute(p,
VARDATA_ANY(s),
VARSIZE_ANY_EXHDR(s),
REG_ADVANCED,
PG_GET_COLLATION(),
0, NULL));
}
Datum
textregexne(PG_FUNCTION_ARGS)
{
text *s = PG_GETARG_TEXT_PP(0);
text *p = PG_GETARG_TEXT_PP(1);
PG_RETURN_BOOL(!RE_compile_and_execute(p,
VARDATA_ANY(s),
VARSIZE_ANY_EXHDR(s),
REG_ADVANCED,
PG_GET_COLLATION(),
0, NULL));
}
/*
* routines that use the regexp stuff, but ignore the case.
* for this, we use the REG_ICASE flag to pg_regcomp
*/
Datum
nameicregexeq(PG_FUNCTION_ARGS)
{
Name n = PG_GETARG_NAME(0);
text *p = PG_GETARG_TEXT_PP(1);
PG_RETURN_BOOL(RE_compile_and_execute(p,
NameStr(*n),
strlen(NameStr(*n)),
REG_ADVANCED | REG_ICASE,
PG_GET_COLLATION(),
0, NULL));
}
Datum
nameicregexne(PG_FUNCTION_ARGS)
{
Name n = PG_GETARG_NAME(0);
text *p = PG_GETARG_TEXT_PP(1);
PG_RETURN_BOOL(!RE_compile_and_execute(p,
NameStr(*n),
strlen(NameStr(*n)),
REG_ADVANCED | REG_ICASE,
PG_GET_COLLATION(),
0, NULL));
}
Datum
texticregexeq(PG_FUNCTION_ARGS)
{
text *s = PG_GETARG_TEXT_PP(0);
text *p = PG_GETARG_TEXT_PP(1);
PG_RETURN_BOOL(RE_compile_and_execute(p,
VARDATA_ANY(s),
VARSIZE_ANY_EXHDR(s),
REG_ADVANCED | REG_ICASE,
PG_GET_COLLATION(),
0, NULL));
}
Datum
texticregexne(PG_FUNCTION_ARGS)
{
text *s = PG_GETARG_TEXT_PP(0);
text *p = PG_GETARG_TEXT_PP(1);
PG_RETURN_BOOL(!RE_compile_and_execute(p,
VARDATA_ANY(s),
VARSIZE_ANY_EXHDR(s),
REG_ADVANCED | REG_ICASE,
PG_GET_COLLATION(),
0, NULL));
}
/*
* textregexsubstr()
* Return a substring matched by a regular expression.
*/
Datum
textregexsubstr(PG_FUNCTION_ARGS)
{
text *s = PG_GETARG_TEXT_PP(0);
text *p = PG_GETARG_TEXT_PP(1);
regex_t *re;
regmatch_t pmatch[2];
int so,
eo;
/* Compile RE */
re = RE_compile_and_cache(p, REG_ADVANCED, PG_GET_COLLATION());
/*
* We pass two regmatch_t structs to get info about the overall match and
* the match for the first parenthesized subexpression (if any). If there
* is a parenthesized subexpression, we return what it matched; else
* return what the whole regexp matched.
*/
if (!RE_execute(re,
VARDATA_ANY(s), VARSIZE_ANY_EXHDR(s),
2, pmatch))
PG_RETURN_NULL(); /* definitely no match */
if (re->re_nsub > 0)
{
/* has parenthesized subexpressions, use the first one */
so = pmatch[1].rm_so;
eo = pmatch[1].rm_eo;
}
else
{
/* no parenthesized subexpression, use whole match */
so = pmatch[0].rm_so;
eo = pmatch[0].rm_eo;
}
/*
* It is possible to have a match to the whole pattern but no match for a
* subexpression; for example 'foo(bar)?' is considered to match 'foo' but
* there is no subexpression match. So this extra test for match failure
* is not redundant.
*/
if (so < 0 || eo < 0)
PG_RETURN_NULL();
return DirectFunctionCall3(text_substr,
PointerGetDatum(s),
Int32GetDatum(so + 1),
Int32GetDatum(eo - so));
}
/*
* textregexreplace_noopt()
* Return a string matched by a regular expression, with replacement.
*
* This version doesn't have an option argument: we default to case
* sensitive match, replace the first instance only.
*/
Datum
textregexreplace_noopt(PG_FUNCTION_ARGS)
{
text *s = PG_GETARG_TEXT_PP(0);
text *p = PG_GETARG_TEXT_PP(1);
text *r = PG_GETARG_TEXT_PP(2);
regex_t *re;
re = RE_compile_and_cache(p, REG_ADVANCED, PG_GET_COLLATION());
PG_RETURN_TEXT_P(replace_text_regexp(s, (void *) re, r, false));
}
/*
* textregexreplace()
* Return a string matched by a regular expression, with replacement.
*/
Datum
textregexreplace(PG_FUNCTION_ARGS)
{
text *s = PG_GETARG_TEXT_PP(0);
text *p = PG_GETARG_TEXT_PP(1);
text *r = PG_GETARG_TEXT_PP(2);
text *opt = PG_GETARG_TEXT_PP(3);
regex_t *re;
pg_re_flags flags;
parse_re_flags(&flags, opt);
re = RE_compile_and_cache(p, flags.cflags, PG_GET_COLLATION());
PG_RETURN_TEXT_P(replace_text_regexp(s, (void *) re, r, flags.glob));
}
/*
* similar_to_escape(), similar_escape()
*
* Convert a SQL "SIMILAR TO" regexp pattern to POSIX style, so it can be
* used by our regexp engine.
*
* similar_escape_internal() is the common workhorse for three SQL-exposed
* functions. esc_text can be passed as NULL to select the default escape
* (which is '\'), or as an empty string to select no escape character.
*/
static text *
similar_escape_internal(text *pat_text, text *esc_text)
{
text *result;
char *p,
*e,
*r;
int plen,
elen;
bool afterescape = false;
bool incharclass = false;
int nquotes = 0;
p = VARDATA_ANY(pat_text);
plen = VARSIZE_ANY_EXHDR(pat_text);
if (esc_text == NULL)
{
/* No ESCAPE clause provided; default to backslash as escape */
e = "\\";
elen = 1;
}
else
{
e = VARDATA_ANY(esc_text);
elen = VARSIZE_ANY_EXHDR(esc_text);
if (elen == 0)
e = NULL; /* no escape character */
else if (elen > 1)
{
int escape_mblen = pg_mbstrlen_with_len(e, elen);
if (escape_mblen > 1)
ereport(ERROR,
(errcode(ERRCODE_INVALID_ESCAPE_SEQUENCE),
errmsg("invalid escape string"),
errhint("Escape string must be empty or one character.")));
}
}
/*----------
* We surround the transformed input string with
* ^(?: ... )$
* which requires some explanation. We need "^" and "$" to force
* the pattern to match the entire input string as per the SQL spec.
* The "(?:" and ")" are a non-capturing set of parens; we have to have
* parens in case the string contains "|", else the "^" and "$" will
* be bound into the first and last alternatives which is not what we
* want, and the parens must be non capturing because we don't want them
* to count when selecting output for SUBSTRING.
*
* When the pattern is divided into three parts by escape-double-quotes,
* what we emit is
* ^(?:part1){1,1}?(part2){1,1}(?:part3)$
* which requires even more explanation. The "{1,1}?" on part1 makes it
* non-greedy so that it will match the smallest possible amount of text
* not the largest, as required by SQL. The plain parens around part2
* are capturing parens so that that part is what controls the result of
* SUBSTRING. The "{1,1}" forces part2 to be greedy, so that it matches
* the largest possible amount of text; hence part3 must match the
* smallest amount of text, as required by SQL. We don't need an explicit
* greediness marker on part3. Note that this also confines the effects
* of any "|" characters to the respective part, which is what we want.
*
* The SQL spec says that SUBSTRING's pattern must contain exactly two
* escape-double-quotes, but we only complain if there's more than two.
* With none, we act as though part1 and part3 are empty; with one, we
* act as though part3 is empty. Both behaviors fall out of omitting
* the relevant part separators in the above expansion. If the result
* of this function is used in a plain regexp match (SIMILAR TO), the
* escape-double-quotes have no effect on the match behavior.
*----------
*/
/*
* We need room for the prefix/postfix and part separators, plus as many
* as 3 output bytes per input byte; since the input is at most 1GB this
* can't overflow size_t.
*/
result = (text *) palloc(VARHDRSZ + 23 + 3 * (size_t) plen);
r = VARDATA(result);
*r++ = '^';
*r++ = '(';
*r++ = '?';
*r++ = ':';
while (plen > 0)
{
char pchar = *p;
/*
* If both the escape character and the current character from the
* pattern are multi-byte, we need to take the slow path.
*
* But if one of them is single-byte, we can process the pattern one
* byte at a time, ignoring multi-byte characters. (This works
* because all server-encodings have the property that a valid
* multi-byte character representation cannot contain the
* representation of a valid single-byte character.)
*/
if (elen > 1)
{
int mblen = pg_mblen(p);
if (mblen > 1)
{
/* slow, multi-byte path */
if (afterescape)
{
*r++ = '\\';
memcpy(r, p, mblen);
r += mblen;
afterescape = false;
}
else if (e && elen == mblen && memcmp(e, p, mblen) == 0)
{
/* SQL escape character; do not send to output */
afterescape = true;
}
else
{
/*
* We know it's a multi-byte character, so we don't need
* to do all the comparisons to single-byte characters
* that we do below.
*/
memcpy(r, p, mblen);
r += mblen;
}
p += mblen;
plen -= mblen;
continue;
}
}
/* fast path */
if (afterescape)
{
if (pchar == '"' && !incharclass) /* escape-double-quote? */
{
/* emit appropriate part separator, per notes above */
if (nquotes == 0)
{
*r++ = ')';
*r++ = '{';
*r++ = '1';
*r++ = ',';
*r++ = '1';
*r++ = '}';
*r++ = '?';
*r++ = '(';
}
else if (nquotes == 1)
{
*r++ = ')';
*r++ = '{';
*r++ = '1';
*r++ = ',';
*r++ = '1';
*r++ = '}';
*r++ = '(';
*r++ = '?';
*r++ = ':';
}
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_USE_OF_ESCAPE_CHARACTER),
errmsg("SQL regular expression may not contain more than two escape-double-quote separators")));
nquotes++;
}
else
{
/*
* We allow any character at all to be escaped; notably, this
* allows access to POSIX character-class escapes such as
* "\d". The SQL spec is considerably more restrictive.
*/
*r++ = '\\';
*r++ = pchar;
}
afterescape = false;
}
else if (e && pchar == *e)
{
/* SQL escape character; do not send to output */
afterescape = true;
}
else if (incharclass)
{
if (pchar == '\\')
*r++ = '\\';
*r++ = pchar;
if (pchar == ']')
incharclass = false;
}
else if (pchar == '[')
{
*r++ = pchar;
incharclass = true;
}
else if (pchar == '%')
{
*r++ = '.';
*r++ = '*';
}
else if (pchar == '_')
*r++ = '.';
else if (pchar == '(')
{
/* convert to non-capturing parenthesis */
*r++ = '(';
*r++ = '?';
*r++ = ':';
}
else if (pchar == '\\' || pchar == '.' ||
pchar == '^' || pchar == '$')
{
*r++ = '\\';
*r++ = pchar;
}
else
*r++ = pchar;
p++, plen--;
}
*r++ = ')';
*r++ = '$';
SET_VARSIZE(result, r - ((char *) result));
return result;
}
/*
* similar_to_escape(pattern, escape)
*/
Datum
similar_to_escape_2(PG_FUNCTION_ARGS)
{
text *pat_text = PG_GETARG_TEXT_PP(0);
text *esc_text = PG_GETARG_TEXT_PP(1);
text *result;
result = similar_escape_internal(pat_text, esc_text);
PG_RETURN_TEXT_P(result);
}
/*
* similar_to_escape(pattern)
* Inserts a default escape character.
*/
Datum
similar_to_escape_1(PG_FUNCTION_ARGS)
{
text *pat_text = PG_GETARG_TEXT_PP(0);
text *result;
result = similar_escape_internal(pat_text, NULL);
PG_RETURN_TEXT_P(result);
}
/*
* similar_escape(pattern, escape)
*
* Legacy function for compatibility with views stored using the
* pre-v13 expansion of SIMILAR TO. Unlike the above functions, this
* is non-strict, which leads to not-per-spec handling of "ESCAPE NULL".
*/
Datum
similar_escape(PG_FUNCTION_ARGS)
{
text *pat_text;
text *esc_text;
text *result;
/* This function is not strict, so must test explicitly */
if (PG_ARGISNULL(0))
PG_RETURN_NULL();
pat_text = PG_GETARG_TEXT_PP(0);
if (PG_ARGISNULL(1))
esc_text = NULL; /* use default escape character */
else
esc_text = PG_GETARG_TEXT_PP(1);
result = similar_escape_internal(pat_text, esc_text);
PG_RETURN_TEXT_P(result);
}
/*
* regexp_match()
* Return the first substring(s) matching a pattern within a string.
*/
Datum
regexp_match(PG_FUNCTION_ARGS)
{
text *orig_str = PG_GETARG_TEXT_PP(0);
text *pattern = PG_GETARG_TEXT_PP(1);
text *flags = PG_GETARG_TEXT_PP_IF_EXISTS(2);
pg_re_flags re_flags;
regexp_matches_ctx *matchctx;
/* Determine options */
parse_re_flags(&re_flags, flags);
/* User mustn't specify 'g' */
if (re_flags.glob)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
/* translator: %s is a SQL function name */
errmsg("%s does not support the \"global\" option",
"regexp_match()"),
errhint("Use the regexp_matches function instead.")));
matchctx = setup_regexp_matches(orig_str, pattern, &re_flags,
PG_GET_COLLATION(), true, false, false);
if (matchctx->nmatches == 0)
PG_RETURN_NULL();
Assert(matchctx->nmatches == 1);
/* Create workspace that build_regexp_match_result needs */
matchctx->elems = (Datum *) palloc(sizeof(Datum) * matchctx->npatterns);
matchctx->nulls = (bool *) palloc(sizeof(bool) * matchctx->npatterns);
PG_RETURN_DATUM(PointerGetDatum(build_regexp_match_result(matchctx)));
}
/* This is separate to keep the opr_sanity regression test from complaining */
Datum
regexp_match_no_flags(PG_FUNCTION_ARGS)
{
return regexp_match(fcinfo);
}
/*
* regexp_matches()
* Return a table of all matches of a pattern within a string.
*/
Datum
regexp_matches(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
regexp_matches_ctx *matchctx;
if (SRF_IS_FIRSTCALL())
{
text *pattern = PG_GETARG_TEXT_PP(1);
text *flags = PG_GETARG_TEXT_PP_IF_EXISTS(2);
pg_re_flags re_flags;
MemoryContext oldcontext;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* Determine options */
parse_re_flags(&re_flags, flags);
/* be sure to copy the input string into the multi-call ctx */
matchctx = setup_regexp_matches(PG_GETARG_TEXT_P_COPY(0), pattern,
&re_flags,
PG_GET_COLLATION(),
true, false, false);
/* Pre-create workspace that build_regexp_match_result needs */
matchctx->elems = (Datum *) palloc(sizeof(Datum) * matchctx->npatterns);
matchctx->nulls = (bool *) palloc(sizeof(bool) * matchctx->npatterns);
MemoryContextSwitchTo(oldcontext);
funcctx->user_fctx = (void *) matchctx;
}
funcctx = SRF_PERCALL_SETUP();
matchctx = (regexp_matches_ctx *) funcctx->user_fctx;
if (matchctx->next_match < matchctx->nmatches)
{
ArrayType *result_ary;
result_ary = build_regexp_match_result(matchctx);
matchctx->next_match++;
SRF_RETURN_NEXT(funcctx, PointerGetDatum(result_ary));
}
SRF_RETURN_DONE(funcctx);
}
/* This is separate to keep the opr_sanity regression test from complaining */
Datum
regexp_matches_no_flags(PG_FUNCTION_ARGS)
{
return regexp_matches(fcinfo);
}
/*
* setup_regexp_matches --- do the initial matching for regexp_match
* and regexp_split functions
*
* To avoid having to re-find the compiled pattern on each call, we do
* all the matching in one swoop. The returned regexp_matches_ctx contains
* the locations of all the substrings matching the pattern.
*
* The three bool parameters have only two patterns (one for matching, one for
* splitting) but it seems clearer to distinguish the functionality this way
* than to key it all off one "is_split" flag. We don't currently assume that
* fetching_unmatched is exclusive of fetching the matched text too; if it's
* set, the conversion buffer is large enough to fetch any single matched or
* unmatched string, but not any larger substring. (In practice, when splitting
* the matches are usually small anyway, and it didn't seem worth complicating
* the code further.)
*/
static regexp_matches_ctx *
setup_regexp_matches(text *orig_str, text *pattern, pg_re_flags *re_flags,
Oid collation,
bool use_subpatterns,
bool ignore_degenerate,
bool fetching_unmatched)
{
regexp_matches_ctx *matchctx = palloc0(sizeof(regexp_matches_ctx));
int eml = pg_database_encoding_max_length();
int orig_len;
pg_wchar *wide_str;
int wide_len;
regex_t *cpattern;
regmatch_t *pmatch;
int pmatch_len;
int array_len;
int array_idx;
int prev_match_end;
int prev_valid_match_end;
int start_search;
int maxlen = 0; /* largest fetch length in characters */
/* save original string --- we'll extract result substrings from it */
matchctx->orig_str = orig_str;
/* convert string to pg_wchar form for matching */
orig_len = VARSIZE_ANY_EXHDR(orig_str);
wide_str = (pg_wchar *) palloc(sizeof(pg_wchar) * (orig_len + 1));
wide_len = pg_mb2wchar_with_len(VARDATA_ANY(orig_str), wide_str, orig_len);
/* set up the compiled pattern */
cpattern = RE_compile_and_cache(pattern, re_flags->cflags, collation);
/* do we want to remember subpatterns? */
if (use_subpatterns && cpattern->re_nsub > 0)
{
matchctx->npatterns = cpattern->re_nsub;
pmatch_len = cpattern->re_nsub + 1;
}
else
{
use_subpatterns = false;
matchctx->npatterns = 1;
pmatch_len = 1;
}
/* temporary output space for RE package */
pmatch = palloc(sizeof(regmatch_t) * pmatch_len);
/*
* the real output space (grown dynamically if needed)
*
* use values 2^n-1, not 2^n, so that we hit the limit at 2^28-1 rather
* than at 2^27
*/
array_len = re_flags->glob ? 255 : 31;
matchctx->match_locs = (int *) palloc(sizeof(int) * array_len);
array_idx = 0;
/* search for the pattern, perhaps repeatedly */
prev_match_end = 0;
prev_valid_match_end = 0;
start_search = 0;
while (RE_wchar_execute(cpattern, wide_str, wide_len, start_search,
pmatch_len, pmatch))
{
/*
* If requested, ignore degenerate matches, which are zero-length
* matches occurring at the start or end of a string or just after a
* previous match.
*/
if (!ignore_degenerate ||
(pmatch[0].rm_so < wide_len &&
pmatch[0].rm_eo > prev_match_end))
{
/* enlarge output space if needed */
while (array_idx + matchctx->npatterns * 2 + 1 > array_len)
{
array_len += array_len + 1; /* 2^n-1 => 2^(n+1)-1 */
if (array_len > MaxAllocSize / sizeof(int))
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("too many regular expression matches")));
matchctx->match_locs = (int *) repalloc(matchctx->match_locs,
sizeof(int) * array_len);
}
/* save this match's locations */
if (use_subpatterns)
{
int i;
for (i = 1; i <= matchctx->npatterns; i++)
{
int so = pmatch[i].rm_so;
int eo = pmatch[i].rm_eo;
matchctx->match_locs[array_idx++] = so;
matchctx->match_locs[array_idx++] = eo;
if (so >= 0 && eo >= 0 && (eo - so) > maxlen)
maxlen = (eo - so);
}
}
else
{
int so = pmatch[0].rm_so;
int eo = pmatch[0].rm_eo;
matchctx->match_locs[array_idx++] = so;
matchctx->match_locs[array_idx++] = eo;
if (so >= 0 && eo >= 0 && (eo - so) > maxlen)
maxlen = (eo - so);
}
matchctx->nmatches++;
/*
* check length of unmatched portion between end of previous valid
* (nondegenerate, or degenerate but not ignored) match and start
* of current one
*/
if (fetching_unmatched &&
pmatch[0].rm_so >= 0 &&
(pmatch[0].rm_so - prev_valid_match_end) > maxlen)
maxlen = (pmatch[0].rm_so - prev_valid_match_end);
prev_valid_match_end = pmatch[0].rm_eo;
}
prev_match_end = pmatch[0].rm_eo;
/* if not glob, stop after one match */
if (!re_flags->glob)
break;
/*
* Advance search position. Normally we start the next search at the
* end of the previous match; but if the match was of zero length, we
* have to advance by one character, or we'd just find the same match
* again.
*/
start_search = prev_match_end;
if (pmatch[0].rm_so == pmatch[0].rm_eo)
start_search++;
if (start_search > wide_len)
break;
}
/*
* check length of unmatched portion between end of last match and end of
* input string
*/
if (fetching_unmatched &&
(wide_len - prev_valid_match_end) > maxlen)
maxlen = (wide_len - prev_valid_match_end);
/*
* Keep a note of the end position of the string for the benefit of
* splitting code.
*/
matchctx->match_locs[array_idx] = wide_len;
if (eml > 1)
{
int64 maxsiz = eml * (int64) maxlen;
int conv_bufsiz;
/*
* Make the conversion buffer large enough for any substring of
* interest.
*
* Worst case: assume we need the maximum size (maxlen*eml), but take
* advantage of the fact that the original string length in bytes is
* an upper bound on the byte length of any fetched substring (and we
* know that len+1 is safe to allocate because the varlena header is
* longer than 1 byte).
*/
if (maxsiz > orig_len)
conv_bufsiz = orig_len + 1;
else
conv_bufsiz = maxsiz + 1; /* safe since maxsiz < 2^30 */
matchctx->conv_buf = palloc(conv_bufsiz);
matchctx->conv_bufsiz = conv_bufsiz;
matchctx->wide_str = wide_str;
}
else
{
/* No need to keep the wide string if we're in a single-byte charset. */
pfree(wide_str);
matchctx->wide_str = NULL;
matchctx->conv_buf = NULL;
matchctx->conv_bufsiz = 0;
}
/* Clean up temp storage */
pfree(pmatch);
return matchctx;
}
/*
* build_regexp_match_result - build output array for current match
*/
static ArrayType *
build_regexp_match_result(regexp_matches_ctx *matchctx)
{
char *buf = matchctx->conv_buf;
int bufsiz PG_USED_FOR_ASSERTS_ONLY = matchctx->conv_bufsiz;
Datum *elems = matchctx->elems;
bool *nulls = matchctx->nulls;
int dims[1];
int lbs[1];
int loc;
int i;
/* Extract matching substrings from the original string */
loc = matchctx->next_match * matchctx->npatterns * 2;
for (i = 0; i < matchctx->npatterns; i++)
{
int so = matchctx->match_locs[loc++];
int eo = matchctx->match_locs[loc++];
if (so < 0 || eo < 0)
{
elems[i] = (Datum) 0;
nulls[i] = true;
}
else if (buf)
{
int len = pg_wchar2mb_with_len(matchctx->wide_str + so,
buf,
eo - so);
Assert(len < bufsiz);
elems[i] = PointerGetDatum(cstring_to_text_with_len(buf, len));
nulls[i] = false;
}
else
{
elems[i] = DirectFunctionCall3(text_substr,
PointerGetDatum(matchctx->orig_str),
Int32GetDatum(so + 1),
Int32GetDatum(eo - so));
nulls[i] = false;
}
}
/* And form an array */
dims[0] = matchctx->npatterns;
lbs[0] = 1;
/* XXX: this hardcodes assumptions about the text type */
return construct_md_array(elems, nulls, 1, dims, lbs,
TEXTOID, -1, false, 'i');
}
/*
* regexp_split_to_table()
* Split the string at matches of the pattern, returning the
* split-out substrings as a table.
*/
Datum
regexp_split_to_table(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
regexp_matches_ctx *splitctx;
if (SRF_IS_FIRSTCALL())
{
text *pattern = PG_GETARG_TEXT_PP(1);
text *flags = PG_GETARG_TEXT_PP_IF_EXISTS(2);
pg_re_flags re_flags;
MemoryContext oldcontext;
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* Determine options */
parse_re_flags(&re_flags, flags);
/* User mustn't specify 'g' */
if (re_flags.glob)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
/* translator: %s is a SQL function name */
errmsg("%s does not support the \"global\" option",
"regexp_split_to_table()")));
/* But we find all the matches anyway */
re_flags.glob = true;
/* be sure to copy the input string into the multi-call ctx */
splitctx = setup_regexp_matches(PG_GETARG_TEXT_P_COPY(0), pattern,
&re_flags,
PG_GET_COLLATION(),
false, true, true);
MemoryContextSwitchTo(oldcontext);
funcctx->user_fctx = (void *) splitctx;
}
funcctx = SRF_PERCALL_SETUP();
splitctx = (regexp_matches_ctx *) funcctx->user_fctx;
if (splitctx->next_match <= splitctx->nmatches)
{
Datum result = build_regexp_split_result(splitctx);
splitctx->next_match++;
SRF_RETURN_NEXT(funcctx, result);
}
SRF_RETURN_DONE(funcctx);
}
/* This is separate to keep the opr_sanity regression test from complaining */
Datum
regexp_split_to_table_no_flags(PG_FUNCTION_ARGS)
{
return regexp_split_to_table(fcinfo);
}
/*
* regexp_split_to_array()
* Split the string at matches of the pattern, returning the
* split-out substrings as an array.
*/
Datum
regexp_split_to_array(PG_FUNCTION_ARGS)
{
ArrayBuildState *astate = NULL;
pg_re_flags re_flags;
regexp_matches_ctx *splitctx;
/* Determine options */
parse_re_flags(&re_flags, PG_GETARG_TEXT_PP_IF_EXISTS(2));
/* User mustn't specify 'g' */
if (re_flags.glob)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
/* translator: %s is a SQL function name */
errmsg("%s does not support the \"global\" option",
"regexp_split_to_array()")));
/* But we find all the matches anyway */
re_flags.glob = true;
splitctx = setup_regexp_matches(PG_GETARG_TEXT_PP(0),
PG_GETARG_TEXT_PP(1),
&re_flags,
PG_GET_COLLATION(),
false, true, true);
while (splitctx->next_match <= splitctx->nmatches)
{
astate = accumArrayResult(astate,
build_regexp_split_result(splitctx),
false,
TEXTOID,
CurrentMemoryContext);
splitctx->next_match++;
}
PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate, CurrentMemoryContext));
}
/* This is separate to keep the opr_sanity regression test from complaining */
Datum
regexp_split_to_array_no_flags(PG_FUNCTION_ARGS)
{
return regexp_split_to_array(fcinfo);
}
/*
* build_regexp_split_result - build output string for current match
*
* We return the string between the current match and the previous one,
* or the string after the last match when next_match == nmatches.
*/
static Datum
build_regexp_split_result(regexp_matches_ctx *splitctx)
{
char *buf = splitctx->conv_buf;
int startpos;
int endpos;
if (splitctx->next_match > 0)
startpos = splitctx->match_locs[splitctx->next_match * 2 - 1];
else
startpos = 0;
if (startpos < 0)
elog(ERROR, "invalid match ending position");
if (buf)
{
int bufsiz PG_USED_FOR_ASSERTS_ONLY = splitctx->conv_bufsiz;
int len;
endpos = splitctx->match_locs[splitctx->next_match * 2];
if (endpos < startpos)
elog(ERROR, "invalid match starting position");
len = pg_wchar2mb_with_len(splitctx->wide_str + startpos,
buf,
endpos - startpos);
Assert(len < bufsiz);
return PointerGetDatum(cstring_to_text_with_len(buf, len));
}
else
{
endpos = splitctx->match_locs[splitctx->next_match * 2];
if (endpos < startpos)
elog(ERROR, "invalid match starting position");
return DirectFunctionCall3(text_substr,
PointerGetDatum(splitctx->orig_str),
Int32GetDatum(startpos + 1),
Int32GetDatum(endpos - startpos));
}
}
/*
* regexp_fixed_prefix - extract fixed prefix, if any, for a regexp
*
* The result is NULL if there is no fixed prefix, else a palloc'd string.
* If it is an exact match, not just a prefix, *exact is returned as true.
*/
char *
regexp_fixed_prefix(text *text_re, bool case_insensitive, Oid collation,
bool *exact)
{
char *result;
regex_t *re;
int cflags;
int re_result;
pg_wchar *str;
size_t slen;
size_t maxlen;
char errMsg[100];
*exact = false; /* default result */
/* Compile RE */
cflags = REG_ADVANCED;
if (case_insensitive)
cflags |= REG_ICASE;
re = RE_compile_and_cache(text_re, cflags, collation);
/* Examine it to see if there's a fixed prefix */
re_result = pg_regprefix(re, &str, &slen);
switch (re_result)
{
case REG_NOMATCH:
return NULL;
case REG_PREFIX:
/* continue with wchar conversion */
break;
case REG_EXACT:
*exact = true;
/* continue with wchar conversion */
break;
default:
/* re failed??? */
CHECK_FOR_INTERRUPTS();
pg_regerror(re_result, re, errMsg, sizeof(errMsg));
ereport(ERROR,
(errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
errmsg("regular expression failed: %s", errMsg)));
break;
}
/* Convert pg_wchar result back to database encoding */
maxlen = pg_database_encoding_max_length() * slen + 1;
result = (char *) palloc(maxlen);
slen = pg_wchar2mb_with_len(str, result, slen);
Assert(slen < maxlen);
free(str);
return result;
}
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