granicus.if.org Git - postgresql/blob - src/backend/utils/adt/quote.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * quote.c
   4  *        Functions for quoting identifiers and literals
   5  *
   6  * Portions Copyright (c) 2000-2004, PostgreSQL Global Development Group
   7  *
   8  *
   9  * IDENTIFICATION
  10  *        $PostgreSQL: pgsql/src/backend/utils/adt/quote.c,v 1.13 2004/08/29 04:12:52 momjian Exp $
  11  *
  12  *-------------------------------------------------------------------------
  13  */
  14 #include "postgres.h"
  15
  16 #include <ctype.h>
  17
  18 #include "mb/pg_wchar.h"
  19 #include "utils/builtins.h"
  20
  21
  22 static bool quote_ident_required(text *iptr);
  23 static text *do_quote_ident(text *iptr);
  24 static text *do_quote_literal(text *iptr);
  25
  26
  27 /*
  28  * quote_ident -
  29  *        returns a properly quoted identifier
  30  */
  31 Datum
  32 quote_ident(PG_FUNCTION_ARGS)
  33 {
  34         text       *t = PG_GETARG_TEXT_P(0);
  35         text       *result;
  36
  37         if (quote_ident_required(t))
  38                 result = do_quote_ident(t);
  39         else
  40         {
  41                 result = (text *) palloc(VARSIZE(t));
  42                 memcpy(result, t, VARSIZE(t));
  43         }
  44
  45         PG_FREE_IF_COPY(t, 0);
  46
  47         PG_RETURN_TEXT_P(result);
  48 }
  49
  50 /*
  51  * quote_literal -
  52  *        returns a properly quoted literal
  53  */
  54 Datum
  55 quote_literal(PG_FUNCTION_ARGS)
  56 {
  57         text       *t = PG_GETARG_TEXT_P(0);
  58         text       *result;
  59
  60         result = do_quote_literal(t);
  61
  62         PG_FREE_IF_COPY(t, 0);
  63
  64         PG_RETURN_TEXT_P(result);
  65 }
  66
  67 /*
  68  * Check if a given identifier needs quoting
  69  */
  70 static bool
  71 quote_ident_required(text *iptr)
  72 {
  73         char       *cp;
  74         char       *ep;
  75
  76         cp = VARDATA(iptr);
  77         ep = VARDATA(iptr) + VARSIZE(iptr) - VARHDRSZ;
  78
  79         if (cp >= ep)
  80                 return true;
  81
  82         if (pg_mblen(cp) != 1)
  83                 return true;
  84         if (!(*cp == '_' || (*cp >= 'a' && *cp <= 'z')))
  85                 return true;
  86
  87         while ((++cp) < ep)
  88         {
  89                 if (pg_mblen(cp) != 1)
  90                         return true;
  91
  92                 if (*cp >= 'a' && *cp <= 'z')
  93                         continue;
  94                 if (*cp >= '0' && *cp <= '9')
  95                         continue;
  96                 if (*cp == '_')
  97                         continue;
  98
  99                 return true;
 100         }
 101
 102         return false;
 103 }
 104
 105 /*
 106  * Return a properly quoted identifier
 107  */
 108 static text *
 109 do_quote_ident(text *iptr)
 110 {
 111         text       *result;
 112         char       *cp1;
 113         char       *cp2;
 114         int                     len;
 115         int                     wl;
 116
 117         len = VARSIZE(iptr) - VARHDRSZ;
 118         result = (text *) palloc(len * 2 + VARHDRSZ + 2);
 119
 120         cp1 = VARDATA(iptr);
 121         cp2 = VARDATA(result);
 122
 123         *cp2++ = '"';
 124         while (len > 0)
 125         {
 126                 if ((wl = pg_mblen(cp1)) != 1)
 127                 {
 128                         len -= wl;
 129
 130                         while (wl-- > 0)
 131                                 *cp2++ = *cp1++;
 132                         continue;
 133                 }
 134
 135                 if (*cp1 == '"')
 136                         *cp2++ = '"';
 137                 *cp2++ = *cp1++;
 138
 139                 len--;
 140         }
 141         *cp2++ = '"';
 142
 143         VARATT_SIZEP(result) = cp2 - ((char *) result);
 144
 145         return result;
 146 }
 147
 148 /*
 149  * Return a properly quoted literal value
 150  */
 151 static text *
 152 do_quote_literal(text *lptr)
 153 {
 154         text       *result;
 155         char       *cp1;
 156         char       *cp2;
 157         int                     len;
 158         int                     wl;
 159
 160         len = VARSIZE(lptr) - VARHDRSZ;
 161         result = (text *) palloc(len * 2 + VARHDRSZ + 2);
 162
 163         cp1 = VARDATA(lptr);
 164         cp2 = VARDATA(result);
 165
 166         *cp2++ = '\'';
 167         while (len > 0)
 168         {
 169                 if ((wl = pg_mblen(cp1)) != 1)
 170                 {
 171                         len -= wl;
 172
 173                         while (wl-- > 0)
 174                                 *cp2++ = *cp1++;
 175                         continue;
 176                 }
 177
 178                 if (*cp1 == '\'')
 179                         *cp2++ = '\'';
 180                 if (*cp1 == '\\')
 181                         *cp2++ = '\\';
 182                 *cp2++ = *cp1++;
 183
 184                 len--;
 185         }
 186         *cp2++ = '\'';
 187
 188         VARATT_SIZEP(result) = cp2 - ((char *) result);
 189
 190         return result;
 191 }