MYSQL教程PostgreSQL 正则表达式 常用函数的总结

MYSQL教程
[root@localhost regex]# pwd
/opt/hgdb-core/src/include/regex
[root@localhost regex]# ll
total 40
-rw-r--r--. 1 postgres postgres 3490 Mar 19 19:00 regcustom.h
-rw-r--r--. 1 postgres postgres 1332 Mar 19 18:59 regerrs.h
-rw-r--r--. 1 postgres postgres 6703 Mar 19 19:00 regex.h
-rw-r--r--. 1 postgres postgres 2353 Mar 19 19:00 regexport.h
-rw-r--r--. 1 postgres postgres 16454 Mar 19 19:00 regguts.h

MYSQL教程
[root@localhost regex]# pwd
/opt/hgdb-core/src/backend/regex
[root@localhost regex]# ll reg*.c
-rw-r--r--. 1 postgres postgres 55851 Mar 19 19:00 regcomp.c
-rw-r--r--. 1 postgres postgres 3671 Mar 19 18:59 regerror.c
-rw-r--r--. 1 postgres postgres 34873 Mar 19 19:00 regexec.c
-rw-r--r--. 1 postgres postgres 2123 Mar 19 18:59 regfree.c
[root@localhost regex]# 

MYSQL教程
[root@localhost adt]# pwd
/opt/hgdb-core/src/backend/utils/adt
[root@localhost adt]# ll regexp.c
-rw-r--r--. 1 postgres postgres 34863 Apr 12 02:29 regexp.c
[root@localhost adt]#

MYSQL教程
/* src/include/catalog/pg_proc.h */
DATA(insert OID = 2073 ( substring  PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 25 "25 25" _null_ _null_ _null_ _null_ _null_ textregexsubstr _null_ _null_ _null_ ));
DESCR("extract text matching regular expression");
DATA(insert OID = 2074 ( substring  PGNSP PGUID 14 1 0 0 0 f f f f t f i 3 0 25 "25 25 25" _null_ _null_ _null_ _null_ _null_ "select pg_catalog.substring($1, pg_catalog.similar_escape($2, $3))" _null_ _null_ _null_ ));
DESCR("extract text matching SQL99 regular expression");
DATA(insert OID = 2284 ( regexp_replace  PGNSP PGUID 12 1 0 0 0 f f f f t f i 3 0 25 "25 25 25" _null_ _null_ _null_ _null_ _null_ textregexreplace_noopt _null_ _null_ _null_ ));
DESCR("replace text using regexp");
DATA(insert OID = 2285 ( regexp_replace  PGNSP PGUID 12 1 0 0 0 f f f f t f i 4 0 25 "25 25 25 25" _null_ _null_ _null_ _null_ _null_ textregexreplace _null_ _null_ _null_ ));
DESCR("replace text using regexp");
DATA(insert OID = 2763 ( regexp_matches  PGNSP PGUID 12 1 1 0 0 f f f f t t i 2 0 1009 "25 25" _null_ _null_ _null_ _null_ _null_ regexp_matches_no_flags _null_ _null_ _null_ ));
DESCR("find all match groups for regexp");
DATA(insert OID = 2764 ( regexp_matches  PGNSP PGUID 12 1 10 0 0 f f f f t t i 3 0 1009 "25 25 25" _null_ _null_ _null_ _null_ _null_ regexp_matches _null_ _null_ _null_ ));
DESCR("find all match groups for regexp");
DATA(insert OID = 2765 ( regexp_split_to_table PGNSP PGUID 12 1 1000 0 0 f f f f t t i 2 0 25 "25 25" _null_ _null_ _null_ _null_ _null_ regexp_split_to_table_no_flags _null_ _null_ _null_ ));
DESCR("split string by pattern");
DATA(insert OID = 2766 ( regexp_split_to_table PGNSP PGUID 12 1 1000 0 0 f f f f t t i 3 0 25 "25 25 25" _null_ _null_ _null_ _null_ _null_ regexp_split_to_table _null_ _null_ _null_ ));
DESCR("split string by pattern");
DATA(insert OID = 2767 ( regexp_split_to_array PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 1009 "25 25" _null_ _null_ _null_ _null_ _null_ regexp_split_to_array_no_flags _null_ _null_ _null_ ));
DESCR("split string by pattern");
DATA(insert OID = 2768 ( regexp_split_to_array PGNSP PGUID 12 1 0 0 0 f f f f t f i 3 0 1009 "25 25 25" _null_ _null_ _null_ _null_ _null_ regexp_split_to_array _null_ _null_ _null_ ));

MYSQL教程
postgres=# select oid,typname from pg_type where oid = 25 or oid = 1009;
 oid | typname 
------+---------
  25 | text
 1009 | _text
(2 rows)

MYSQL教程
/* the biggie, a compiled RE (or rather, a front end to same) */
typedef struct
{
 int  re_magic; /* magic number */
 size_t re_nsub; /* number of subexpressions */
 long re_info; /* information about RE */
#define REG_UBACKREF  000001
#define REG_ULOOKAHEAD  000002
#define REG_UBOUNDS 000004
#define REG_UBRACES 000010
#define REG_UBSALNUM  000020
#define REG_UPBOTCH 000040
#define REG_UBBS  000100
#define REG_UNONPOSIX  000200
#define REG_UUNSPEC 000400
#define REG_UUNPORT 001000
#define REG_ULOCALE 002000
#define REG_UEMPTYMATCH 004000
#define REG_UIMPOSSIBLE 010000
#define REG_USHORTEST  020000
 int  re_csize; /* sizeof(character) */
 char  *re_endp; /* backward compatibility kludge */
 Oid  re_collation; /* Collation that defines LC_CTYPE behavior */
 /* the rest is opaque pointers to hidden innards */
 char  *re_guts; /* `char *' is more portable than `void *' */
 char  *re_fns;
} regex_t;

MYSQL教程
/* result reporting (may acquire more fields later) */
typedef struct
{
 regoff_t rm_so;  /* start of substring */
 regoff_t rm_eo;  /* end of substring */
} regmatch_t;
typedef long regoff_t;

MYSQL教程
/*
 * the prototypes for exported functions
 */
extern int pg_regcomp(regex_t *, const pg_wchar *, size_t, int, Oid);
extern int pg_regexec(regex_t *, const pg_wchar *, size_t, size_t, rm_detail_t *, size_t, regmatch_t[], int);
extern int pg_regprefix(regex_t *, pg_wchar **, size_t *);
extern void pg_regfree(regex_t *);
extern size_t pg_regerror(int, const regex_t *, char *, size_t);
extern void pg_set_regex_collation(Oid collation);

MYSQL教程
int
pg_regcomp(regex_t *re,
   const chr *string, /* 正则表达式字符串 */
   size_t len, /* 正则表达式字符串长度 */
   int flags,
   Oid collation)
int
pg_regexec(regex_t *re, /* 已经用regcomp函数编译好的正则表达式 */
   const chr *string, /* 目标字符串 */
   size_t len, /* 目标字符串长度 */
   size_t search_start, /* 匹配开始位置 */
   rm_detail_t *details, /* NULL */
   size_t nmatch, /* 是regmatch_t结构体数组的长度 */
   regmatch_t pmatch[], /* regmatch_t类型的结构体数组,存放匹配文本串的位置信息 */
   int flags)

MYSQL教程
/* 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;

MYSQL教程
/*
 * parse_re_flags - parse the options argument of regexp_matches 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 regexp option: \"%c\"",
     opt_p[i])));
   break;
  }
 }
 }
}