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

   1 /*-----------------------------------------------------------------------
   2  * ascii.c
   3  *       The PostgreSQL routine for string to ascii conversion.
   4  *
   5  *       Portions Copyright (c) 1999-2019, PostgreSQL Global Development Group
   6  *
   7  * IDENTIFICATION
   8  *        src/backend/utils/adt/ascii.c
   9  *
  10  *-----------------------------------------------------------------------
  11  */
  12 #include "postgres.h"
  13
  14 #include "mb/pg_wchar.h"
  15 #include "utils/ascii.h"
  16 #include "utils/builtins.h"
  17
  18 static void pg_to_ascii(unsigned char *src, unsigned char *src_end,
  19                         unsigned char *dest, int enc);
  20 static text *encode_to_ascii(text *data, int enc);
  21
  22
  23 /* ----------
  24  * to_ascii
  25  * ----------
  26  */
  27 static void
  28 pg_to_ascii(unsigned char *src, unsigned char *src_end, unsigned char *dest, int enc)
  29 {
  30         unsigned char *x;
  31         const unsigned char *ascii;
  32         int                     range;
  33
  34         /*
  35          * relevant start for an encoding
  36          */
  37 #define RANGE_128       128
  38 #define RANGE_160       160
  39
  40         if (enc == PG_LATIN1)
  41         {
  42                 /*
  43                  * ISO-8859-1 <range: 160 -- 255>
  44                  */
  45                 ascii = (const unsigned char *) "  cL Y  \"Ca  -R     'u .,      ?AAAAAAACEEEEIIII NOOOOOxOUUUUYTBaaaaaaaceeeeiiii nooooo/ouuuuyty";
  46                 range = RANGE_160;
  47         }
  48         else if (enc == PG_LATIN2)
  49         {
  50                 /*
  51                  * ISO-8859-2 <range: 160 -- 255>
  52                  */
  53                 ascii = (const unsigned char *) " A L LS \"SSTZ-ZZ a,l'ls ,sstz\"zzRAAAALCCCEEEEIIDDNNOOOOxRUUUUYTBraaaalccceeeeiiddnnoooo/ruuuuyt.";
  54                 range = RANGE_160;
  55         }
  56         else if (enc == PG_LATIN9)
  57         {
  58                 /*
  59                  * ISO-8859-15 <range: 160 -- 255>
  60                  */
  61                 ascii = (const unsigned char *) "  cL YS sCa  -R     Zu .z   EeY?AAAAAAACEEEEIIII NOOOOOxOUUUUYTBaaaaaaaceeeeiiii nooooo/ouuuuyty";
  62                 range = RANGE_160;
  63         }
  64         else if (enc == PG_WIN1250)
  65         {
  66                 /*
  67                  * Window CP1250 <range: 128 -- 255>
  68                  */
  69                 ascii = (const unsigned char *) "  ' \"    %S<STZZ `'\"\".--  s>stzz   L A  \"CS  -RZ  ,l'u .,as L\"lzRAAAALCCCEEEEIIDDNNOOOOxRUUUUYTBraaaalccceeeeiiddnnoooo/ruuuuyt ";
  70                 range = RANGE_128;
  71         }
  72         else
  73         {
  74                 ereport(ERROR,
  75                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
  76                                  errmsg("encoding conversion from %s to ASCII not supported",
  77                                                 pg_encoding_to_char(enc))));
  78                 return;                                 /* keep compiler quiet */
  79         }
  80
  81         /*
  82          * Encode
  83          */
  84         for (x = src; x < src_end; x++)
  85         {
  86                 if (*x < 128)
  87                         *dest++ = *x;
  88                 else if (*x < range)
  89                         *dest++ = ' ';          /* bogus 128 to 'range' */
  90                 else
  91                         *dest++ = ascii[*x - range];
  92         }
  93 }
  94
  95 /* ----------
  96  * encode text
  97  *
  98  * The text datum is overwritten in-place, therefore this coding method
  99  * cannot support conversions that change the string length!
 100  * ----------
 101  */
 102 static text *
 103 encode_to_ascii(text *data, int enc)
 104 {
 105         pg_to_ascii((unsigned char *) VARDATA(data),    /* src */
 106                                 (unsigned char *) (data) + VARSIZE(data),       /* src end */
 107                                 (unsigned char *) VARDATA(data),        /* dest */
 108                                 enc);                   /* encoding */
 109
 110         return data;
 111 }
 112
 113 /* ----------
 114  * convert to ASCII - enc is set as 'name' arg.
 115  * ----------
 116  */
 117 Datum
 118 to_ascii_encname(PG_FUNCTION_ARGS)
 119 {
 120         text       *data = PG_GETARG_TEXT_P_COPY(0);
 121         char       *encname = NameStr(*PG_GETARG_NAME(1));
 122         int                     enc = pg_char_to_encoding(encname);
 123
 124         if (enc < 0)
 125                 ereport(ERROR,
 126                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
 127                                  errmsg("%s is not a valid encoding name", encname)));
 128
 129         PG_RETURN_TEXT_P(encode_to_ascii(data, enc));
 130 }
 131
 132 /* ----------
 133  * convert to ASCII - enc is set as int4
 134  * ----------
 135  */
 136 Datum
 137 to_ascii_enc(PG_FUNCTION_ARGS)
 138 {
 139         text       *data = PG_GETARG_TEXT_P_COPY(0);
 140         int                     enc = PG_GETARG_INT32(1);
 141
 142         if (!PG_VALID_ENCODING(enc))
 143                 ereport(ERROR,
 144                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
 145                                  errmsg("%d is not a valid encoding code", enc)));
 146
 147         PG_RETURN_TEXT_P(encode_to_ascii(data, enc));
 148 }
 149
 150 /* ----------
 151  * convert to ASCII - current enc is DatabaseEncoding
 152  * ----------
 153  */
 154 Datum
 155 to_ascii_default(PG_FUNCTION_ARGS)
 156 {
 157         text       *data = PG_GETARG_TEXT_P_COPY(0);
 158         int                     enc = GetDatabaseEncoding();
 159
 160         PG_RETURN_TEXT_P(encode_to_ascii(data, enc));
 161 }
 162
 163 /* ----------
 164  * Copy a string in an arbitrary backend-safe encoding, converting it to a
 165  * valid ASCII string by replacing non-ASCII bytes with '?'.  Otherwise the
 166  * behavior is identical to strlcpy(), except that we don't bother with a
 167  * return value.
 168  *
 169  * This must not trigger ereport(ERROR), as it is called in postmaster.
 170  * ----------
 171  */
 172 void
 173 ascii_safe_strlcpy(char *dest, const char *src, size_t destsiz)
 174 {
 175         if (destsiz == 0)                       /* corner case: no room for trailing nul */
 176                 return;
 177
 178         while (--destsiz > 0)
 179         {
 180                 /* use unsigned char here to avoid compiler warning */
 181                 unsigned char ch = *src++;
 182
 183                 if (ch == '\0')
 184                         break;
 185                 /* Keep printable ASCII characters */
 186                 if (32 <= ch && ch <= 127)
 187                         *dest = ch;
 188                 /* White-space is also OK */
 189                 else if (ch == '\n' || ch == '\r' || ch == '\t')
 190                         *dest = ch;
 191                 /* Everything else is replaced with '?' */
 192                 else
 193                         *dest = '?';
 194                 dest++;
 195         }
 196
 197         *dest = '\0';
 198 }