LCOV - code coverage report
Current view: top level - src/include/mb - pg_wchar.h (source / functions) Hit Total Coverage
Test: PostgreSQL 17devel Lines: 45 47 95.7 %
Date: 2024-04-18 20:11:42 Functions: 7 7 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * pg_wchar.h
       4             :  *    multibyte-character support
       5             :  *
       6             :  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994, Regents of the University of California
       8             :  *
       9             :  * src/include/mb/pg_wchar.h
      10             :  *
      11             :  *  NOTES
      12             :  *      This is used both by the backend and by frontends, but should not be
      13             :  *      included by libpq client programs.  In particular, a libpq client
      14             :  *      should not assume that the encoding IDs used by the version of libpq
      15             :  *      it's linked to match up with the IDs declared here.
      16             :  *      To help prevent mistakes, relevant functions that are exported by
      17             :  *      libpq have a physically different name when being referenced
      18             :  *      statically.
      19             :  *
      20             :  *-------------------------------------------------------------------------
      21             :  */
      22             : #ifndef PG_WCHAR_H
      23             : #define PG_WCHAR_H
      24             : 
      25             : /*
      26             :  * The pg_wchar type
      27             :  */
      28             : typedef unsigned int pg_wchar;
      29             : 
      30             : /*
      31             :  * Maximum byte length of multibyte characters in any backend encoding
      32             :  */
      33             : #define MAX_MULTIBYTE_CHAR_LEN  4
      34             : 
      35             : /*
      36             :  * various definitions for EUC
      37             :  */
      38             : #define SS2 0x8e                /* single shift 2 (JIS0201) */
      39             : #define SS3 0x8f                /* single shift 3 (JIS0212) */
      40             : 
      41             : /*
      42             :  * SJIS validation macros
      43             :  */
      44             : #define ISSJISHEAD(c) (((c) >= 0x81 && (c) <= 0x9f) || ((c) >= 0xe0 && (c) <= 0xfc))
      45             : #define ISSJISTAIL(c) (((c) >= 0x40 && (c) <= 0x7e) || ((c) >= 0x80 && (c) <= 0xfc))
      46             : 
      47             : /*----------------------------------------------------
      48             :  * MULE Internal Encoding (MIC)
      49             :  *
      50             :  * This encoding follows the design used within XEmacs; it is meant to
      51             :  * subsume many externally-defined character sets.  Each character includes
      52             :  * identification of the character set it belongs to, so the encoding is
      53             :  * general but somewhat bulky.
      54             :  *
      55             :  * Currently PostgreSQL supports 5 types of MULE character sets:
      56             :  *
      57             :  * 1) 1-byte ASCII characters.  Each byte is below 0x80.
      58             :  *
      59             :  * 2) "Official" single byte charsets such as ISO-8859-1 (Latin1).
      60             :  *    Each MULE character consists of 2 bytes: LC1 + C1, where LC1 is
      61             :  *    an identifier for the charset (in the range 0x81 to 0x8d) and C1
      62             :  *    is the character code (in the range 0xa0 to 0xff).
      63             :  *
      64             :  * 3) "Private" single byte charsets such as SISHENG.  Each MULE
      65             :  *    character consists of 3 bytes: LCPRV1 + LC12 + C1, where LCPRV1
      66             :  *    is a private-charset flag, LC12 is an identifier for the charset,
      67             :  *    and C1 is the character code (in the range 0xa0 to 0xff).
      68             :  *    LCPRV1 is either 0x9a (if LC12 is in the range 0xa0 to 0xdf)
      69             :  *    or 0x9b (if LC12 is in the range 0xe0 to 0xef).
      70             :  *
      71             :  * 4) "Official" multibyte charsets such as JIS X0208.  Each MULE
      72             :  *    character consists of 3 bytes: LC2 + C1 + C2, where LC2 is
      73             :  *    an identifier for the charset (in the range 0x90 to 0x99) and C1
      74             :  *    and C2 form the character code (each in the range 0xa0 to 0xff).
      75             :  *
      76             :  * 5) "Private" multibyte charsets such as CNS 11643-1992 Plane 3.
      77             :  *    Each MULE character consists of 4 bytes: LCPRV2 + LC22 + C1 + C2,
      78             :  *    where LCPRV2 is a private-charset flag, LC22 is an identifier for
      79             :  *    the charset, and C1 and C2 form the character code (each in the range
      80             :  *    0xa0 to 0xff).  LCPRV2 is either 0x9c (if LC22 is in the range 0xf0
      81             :  *    to 0xf4) or 0x9d (if LC22 is in the range 0xf5 to 0xfe).
      82             :  *
      83             :  * "Official" encodings are those that have been assigned code numbers by
      84             :  * the XEmacs project; "private" encodings have Postgres-specific charset
      85             :  * identifiers.
      86             :  *
      87             :  * See the "XEmacs Internals Manual", available at http://www.xemacs.org,
      88             :  * for more details.  Note that for historical reasons, Postgres'
      89             :  * private-charset flag values do not match what XEmacs says they should be,
      90             :  * so this isn't really exactly MULE (not that private charsets would be
      91             :  * interoperable anyway).
      92             :  *
      93             :  * Note that XEmacs's implementation is different from what emacs does.
      94             :  * We follow emacs's implementation, rather than XEmacs's.
      95             :  *----------------------------------------------------
      96             :  */
      97             : 
      98             : /*
      99             :  * Charset identifiers (also called "leading bytes" in the MULE documentation)
     100             :  */
     101             : 
     102             : /*
     103             :  * Charset IDs for official single byte encodings (0x81-0x8e)
     104             :  */
     105             : #define LC_ISO8859_1        0x81    /* ISO8859 Latin 1 */
     106             : #define LC_ISO8859_2        0x82    /* ISO8859 Latin 2 */
     107             : #define LC_ISO8859_3        0x83    /* ISO8859 Latin 3 */
     108             : #define LC_ISO8859_4        0x84    /* ISO8859 Latin 4 */
     109             : #define LC_TIS620           0x85    /* Thai (not supported yet) */
     110             : #define LC_ISO8859_7        0x86    /* Greek (not supported yet) */
     111             : #define LC_ISO8859_6        0x87    /* Arabic (not supported yet) */
     112             : #define LC_ISO8859_8        0x88    /* Hebrew (not supported yet) */
     113             : #define LC_JISX0201K        0x89    /* Japanese 1 byte kana */
     114             : #define LC_JISX0201R        0x8a    /* Japanese 1 byte Roman */
     115             : /* Note that 0x8b seems to be unused as of Emacs 20.7.
     116             :  * However, there might be a chance that 0x8b could be used
     117             :  * in later versions of Emacs.
     118             :  */
     119             : #define LC_KOI8_R           0x8b    /* Cyrillic KOI8-R */
     120             : #define LC_ISO8859_5        0x8c    /* ISO8859 Cyrillic */
     121             : #define LC_ISO8859_9        0x8d    /* ISO8859 Latin 5 (not supported yet) */
     122             : #define LC_ISO8859_15       0x8e    /* ISO8859 Latin 15 (not supported yet) */
     123             : /* #define CONTROL_1        0x8f    control characters (unused) */
     124             : 
     125             : /* Is a leading byte for "official" single byte encodings? */
     126             : #define IS_LC1(c)   ((unsigned char)(c) >= 0x81 && (unsigned char)(c) <= 0x8d)
     127             : 
     128             : /*
     129             :  * Charset IDs for official multibyte encodings (0x90-0x99)
     130             :  * 0x9a-0x9d are free. 0x9e and 0x9f are reserved.
     131             :  */
     132             : #define LC_JISX0208_1978    0x90    /* Japanese Kanji, old JIS (not supported) */
     133             : #define LC_GB2312_80        0x91    /* Chinese */
     134             : #define LC_JISX0208         0x92    /* Japanese Kanji (JIS X 0208) */
     135             : #define LC_KS5601           0x93    /* Korean */
     136             : #define LC_JISX0212         0x94    /* Japanese Kanji (JIS X 0212) */
     137             : #define LC_CNS11643_1       0x95    /* CNS 11643-1992 Plane 1 */
     138             : #define LC_CNS11643_2       0x96    /* CNS 11643-1992 Plane 2 */
     139             : #define LC_JISX0213_1       0x97    /* Japanese Kanji (JIS X 0213 Plane 1)
     140             :                                      * (not supported) */
     141             : #define LC_BIG5_1           0x98    /* Plane 1 Chinese traditional (not
     142             :                                      * supported) */
     143             : #define LC_BIG5_2           0x99    /* Plane 1 Chinese traditional (not
     144             :                                      * supported) */
     145             : 
     146             : /* Is a leading byte for "official" multibyte encodings? */
     147             : #define IS_LC2(c)   ((unsigned char)(c) >= 0x90 && (unsigned char)(c) <= 0x99)
     148             : 
     149             : /*
     150             :  * Postgres-specific prefix bytes for "private" single byte encodings
     151             :  * (According to the MULE docs, we should be using 0x9e for this)
     152             :  */
     153             : #define LCPRV1_A        0x9a
     154             : #define LCPRV1_B        0x9b
     155             : #define IS_LCPRV1(c)    ((unsigned char)(c) == LCPRV1_A || (unsigned char)(c) == LCPRV1_B)
     156             : #define IS_LCPRV1_A_RANGE(c)    \
     157             :     ((unsigned char)(c) >= 0xa0 && (unsigned char)(c) <= 0xdf)
     158             : #define IS_LCPRV1_B_RANGE(c)    \
     159             :     ((unsigned char)(c) >= 0xe0 && (unsigned char)(c) <= 0xef)
     160             : 
     161             : /*
     162             :  * Postgres-specific prefix bytes for "private" multibyte encodings
     163             :  * (According to the MULE docs, we should be using 0x9f for this)
     164             :  */
     165             : #define LCPRV2_A        0x9c
     166             : #define LCPRV2_B        0x9d
     167             : #define IS_LCPRV2(c)    ((unsigned char)(c) == LCPRV2_A || (unsigned char)(c) == LCPRV2_B)
     168             : #define IS_LCPRV2_A_RANGE(c)    \
     169             :     ((unsigned char)(c) >= 0xf0 && (unsigned char)(c) <= 0xf4)
     170             : #define IS_LCPRV2_B_RANGE(c)    \
     171             :     ((unsigned char)(c) >= 0xf5 && (unsigned char)(c) <= 0xfe)
     172             : 
     173             : /*
     174             :  * Charset IDs for private single byte encodings (0xa0-0xef)
     175             :  */
     176             : #define LC_SISHENG          0xa0    /* Chinese SiSheng characters for
     177             :                                      * PinYin/ZhuYin (not supported) */
     178             : #define LC_IPA              0xa1    /* IPA (International Phonetic
     179             :                                      * Association) (not supported) */
     180             : #define LC_VISCII_LOWER     0xa2    /* Vietnamese VISCII1.1 lower-case (not
     181             :                                      * supported) */
     182             : #define LC_VISCII_UPPER     0xa3    /* Vietnamese VISCII1.1 upper-case (not
     183             :                                      * supported) */
     184             : #define LC_ARABIC_DIGIT     0xa4    /* Arabic digit (not supported) */
     185             : #define LC_ARABIC_1_COLUMN  0xa5    /* Arabic 1-column (not supported) */
     186             : #define LC_ASCII_RIGHT_TO_LEFT  0xa6    /* ASCII (left half of ISO8859-1) with
     187             :                                          * right-to-left direction (not
     188             :                                          * supported) */
     189             : #define LC_LAO              0xa7    /* Lao characters (ISO10646 0E80..0EDF)
     190             :                                      * (not supported) */
     191             : #define LC_ARABIC_2_COLUMN  0xa8    /* Arabic 1-column (not supported) */
     192             : 
     193             : /*
     194             :  * Charset IDs for private multibyte encodings (0xf0-0xff)
     195             :  */
     196             : #define LC_INDIAN_1_COLUMN  0xf0    /* Indian charset for 1-column width
     197             :                                      * glyphs (not supported) */
     198             : #define LC_TIBETAN_1_COLUMN 0xf1    /* Tibetan 1-column width glyphs (not
     199             :                                      * supported) */
     200             : #define LC_UNICODE_SUBSET_2 0xf2    /* Unicode characters of the range
     201             :                                      * U+2500..U+33FF. (not supported) */
     202             : #define LC_UNICODE_SUBSET_3 0xf3    /* Unicode characters of the range
     203             :                                      * U+E000..U+FFFF. (not supported) */
     204             : #define LC_UNICODE_SUBSET   0xf4    /* Unicode characters of the range
     205             :                                      * U+0100..U+24FF. (not supported) */
     206             : #define LC_ETHIOPIC         0xf5    /* Ethiopic characters (not supported) */
     207             : #define LC_CNS11643_3       0xf6    /* CNS 11643-1992 Plane 3 */
     208             : #define LC_CNS11643_4       0xf7    /* CNS 11643-1992 Plane 4 */
     209             : #define LC_CNS11643_5       0xf8    /* CNS 11643-1992 Plane 5 */
     210             : #define LC_CNS11643_6       0xf9    /* CNS 11643-1992 Plane 6 */
     211             : #define LC_CNS11643_7       0xfa    /* CNS 11643-1992 Plane 7 */
     212             : #define LC_INDIAN_2_COLUMN  0xfb    /* Indian charset for 2-column width
     213             :                                      * glyphs (not supported) */
     214             : #define LC_TIBETAN          0xfc    /* Tibetan (not supported) */
     215             : /* #define FREE             0xfd    free (unused) */
     216             : /* #define FREE             0xfe    free (unused) */
     217             : /* #define FREE             0xff    free (unused) */
     218             : 
     219             : /*----------------------------------------------------
     220             :  * end of MULE stuff
     221             :  *----------------------------------------------------
     222             :  */
     223             : 
     224             : /*
     225             :  * PostgreSQL encoding identifiers
     226             :  *
     227             :  * WARNING: If you add some encoding don't forget to update
     228             :  *          the pg_enc2name_tbl[] array (in src/common/encnames.c),
     229             :  *          the pg_enc2gettext_tbl[] array (in src/common/encnames.c) and
     230             :  *          the pg_wchar_table[] array (in src/common/wchar.c) and to check
     231             :  *          PG_ENCODING_BE_LAST macro.
     232             :  *
     233             :  * PG_SQL_ASCII is default encoding and must be = 0.
     234             :  *
     235             :  * XXX  We must avoid renumbering any backend encoding until libpq's major
     236             :  * version number is increased beyond 5; it turns out that the backend
     237             :  * encoding IDs are effectively part of libpq's ABI as far as 8.2 initdb and
     238             :  * psql are concerned.
     239             :  */
     240             : typedef enum pg_enc
     241             : {
     242             :     PG_SQL_ASCII = 0,           /* SQL/ASCII */
     243             :     PG_EUC_JP,                  /* EUC for Japanese */
     244             :     PG_EUC_CN,                  /* EUC for Chinese */
     245             :     PG_EUC_KR,                  /* EUC for Korean */
     246             :     PG_EUC_TW,                  /* EUC for Taiwan */
     247             :     PG_EUC_JIS_2004,            /* EUC-JIS-2004 */
     248             :     PG_UTF8,                    /* Unicode UTF8 */
     249             :     PG_MULE_INTERNAL,           /* Mule internal code */
     250             :     PG_LATIN1,                  /* ISO-8859-1 Latin 1 */
     251             :     PG_LATIN2,                  /* ISO-8859-2 Latin 2 */
     252             :     PG_LATIN3,                  /* ISO-8859-3 Latin 3 */
     253             :     PG_LATIN4,                  /* ISO-8859-4 Latin 4 */
     254             :     PG_LATIN5,                  /* ISO-8859-9 Latin 5 */
     255             :     PG_LATIN6,                  /* ISO-8859-10 Latin6 */
     256             :     PG_LATIN7,                  /* ISO-8859-13 Latin7 */
     257             :     PG_LATIN8,                  /* ISO-8859-14 Latin8 */
     258             :     PG_LATIN9,                  /* ISO-8859-15 Latin9 */
     259             :     PG_LATIN10,                 /* ISO-8859-16 Latin10 */
     260             :     PG_WIN1256,                 /* windows-1256 */
     261             :     PG_WIN1258,                 /* Windows-1258 */
     262             :     PG_WIN866,                  /* (MS-DOS CP866) */
     263             :     PG_WIN874,                  /* windows-874 */
     264             :     PG_KOI8R,                   /* KOI8-R */
     265             :     PG_WIN1251,                 /* windows-1251 */
     266             :     PG_WIN1252,                 /* windows-1252 */
     267             :     PG_ISO_8859_5,              /* ISO-8859-5 */
     268             :     PG_ISO_8859_6,              /* ISO-8859-6 */
     269             :     PG_ISO_8859_7,              /* ISO-8859-7 */
     270             :     PG_ISO_8859_8,              /* ISO-8859-8 */
     271             :     PG_WIN1250,                 /* windows-1250 */
     272             :     PG_WIN1253,                 /* windows-1253 */
     273             :     PG_WIN1254,                 /* windows-1254 */
     274             :     PG_WIN1255,                 /* windows-1255 */
     275             :     PG_WIN1257,                 /* windows-1257 */
     276             :     PG_KOI8U,                   /* KOI8-U */
     277             :     /* PG_ENCODING_BE_LAST points to the above entry */
     278             : 
     279             :     /* followings are for client encoding only */
     280             :     PG_SJIS,                    /* Shift JIS (Windows-932) */
     281             :     PG_BIG5,                    /* Big5 (Windows-950) */
     282             :     PG_GBK,                     /* GBK (Windows-936) */
     283             :     PG_UHC,                     /* UHC (Windows-949) */
     284             :     PG_GB18030,                 /* GB18030 */
     285             :     PG_JOHAB,                   /* EUC for Korean JOHAB */
     286             :     PG_SHIFT_JIS_2004,          /* Shift-JIS-2004 */
     287             :     _PG_LAST_ENCODING_          /* mark only */
     288             : 
     289             : } pg_enc;
     290             : 
     291             : #define PG_ENCODING_BE_LAST PG_KOI8U
     292             : 
     293             : /*
     294             :  * Please use these tests before access to pg_enc2name_tbl[]
     295             :  * or to other places...
     296             :  */
     297             : #define PG_VALID_BE_ENCODING(_enc) \
     298             :         ((_enc) >= 0 && (_enc) <= PG_ENCODING_BE_LAST)
     299             : 
     300             : #define PG_ENCODING_IS_CLIENT_ONLY(_enc) \
     301             :         ((_enc) > PG_ENCODING_BE_LAST && (_enc) < _PG_LAST_ENCODING_)
     302             : 
     303             : #define PG_VALID_ENCODING(_enc) \
     304             :         ((_enc) >= 0 && (_enc) < _PG_LAST_ENCODING_)
     305             : 
     306             : /* On FE are possible all encodings */
     307             : #define PG_VALID_FE_ENCODING(_enc)  PG_VALID_ENCODING(_enc)
     308             : 
     309             : /*
     310             :  * When converting strings between different encodings, we assume that space
     311             :  * for converted result is 4-to-1 growth in the worst case.  The rate for
     312             :  * currently supported encoding pairs are within 3 (SJIS JIS X0201 half width
     313             :  * kana -> UTF8 is the worst case).  So "4" should be enough for the moment.
     314             :  *
     315             :  * Note that this is not the same as the maximum character width in any
     316             :  * particular encoding.
     317             :  */
     318             : #define MAX_CONVERSION_GROWTH  4
     319             : 
     320             : /*
     321             :  * Maximum byte length of a string that's required in any encoding to convert
     322             :  * at least one character to any other encoding.  In other words, if you feed
     323             :  * MAX_CONVERSION_INPUT_LENGTH bytes to any encoding conversion function, it
     324             :  * is guaranteed to be able to convert something without needing more input
     325             :  * (assuming the input is valid).
     326             :  *
     327             :  * Currently, the maximum case is the conversion UTF8 -> SJIS JIS X0201 half
     328             :  * width kana, where a pair of UTF-8 characters is converted into a single
     329             :  * SHIFT_JIS_2004 character (the reverse of the worst case for
     330             :  * MAX_CONVERSION_GROWTH).  It needs 6 bytes of input.  In theory, a
     331             :  * user-defined conversion function might have more complicated cases, although
     332             :  * for the reverse mapping you would probably also need to bump up
     333             :  * MAX_CONVERSION_GROWTH.  But there is no need to be stingy here, so make it
     334             :  * generous.
     335             :  */
     336             : #define MAX_CONVERSION_INPUT_LENGTH 16
     337             : 
     338             : /*
     339             :  * Maximum byte length of the string equivalent to any one Unicode code point,
     340             :  * in any backend encoding.  The current value assumes that a 4-byte UTF-8
     341             :  * character might expand by MAX_CONVERSION_GROWTH, which is a huge
     342             :  * overestimate.  But in current usage we don't allocate large multiples of
     343             :  * this, so there's little point in being stingy.
     344             :  */
     345             : #define MAX_UNICODE_EQUIVALENT_STRING   16
     346             : 
     347             : /*
     348             :  * Table for mapping an encoding number to official encoding name and
     349             :  * possibly other subsidiary data.  Be careful to check encoding number
     350             :  * before accessing a table entry!
     351             :  *
     352             :  * if (PG_VALID_ENCODING(encoding))
     353             :  *      pg_enc2name_tbl[ encoding ];
     354             :  */
     355             : typedef struct pg_enc2name
     356             : {
     357             :     const char *name;
     358             :     pg_enc      encoding;
     359             : #ifdef WIN32
     360             :     unsigned    codepage;       /* codepage for WIN32 */
     361             : #endif
     362             : } pg_enc2name;
     363             : 
     364             : extern PGDLLIMPORT const pg_enc2name pg_enc2name_tbl[];
     365             : 
     366             : /*
     367             :  * Encoding names for gettext
     368             :  */
     369             : extern PGDLLIMPORT const char *pg_enc2gettext_tbl[];
     370             : 
     371             : /*
     372             :  * pg_wchar stuff
     373             :  */
     374             : typedef int (*mb2wchar_with_len_converter) (const unsigned char *from,
     375             :                                             pg_wchar *to,
     376             :                                             int len);
     377             : 
     378             : typedef int (*wchar2mb_with_len_converter) (const pg_wchar *from,
     379             :                                             unsigned char *to,
     380             :                                             int len);
     381             : 
     382             : typedef int (*mblen_converter) (const unsigned char *mbstr);
     383             : 
     384             : typedef int (*mbdisplaylen_converter) (const unsigned char *mbstr);
     385             : 
     386             : typedef bool (*mbcharacter_incrementer) (unsigned char *mbstr, int len);
     387             : 
     388             : typedef int (*mbchar_verifier) (const unsigned char *mbstr, int len);
     389             : 
     390             : typedef int (*mbstr_verifier) (const unsigned char *mbstr, int len);
     391             : 
     392             : typedef struct
     393             : {
     394             :     mb2wchar_with_len_converter mb2wchar_with_len;  /* convert a multibyte
     395             :                                                      * string to a wchar */
     396             :     wchar2mb_with_len_converter wchar2mb_with_len;  /* convert a wchar string
     397             :                                                      * to a multibyte */
     398             :     mblen_converter mblen;      /* get byte length of a char */
     399             :     mbdisplaylen_converter dsplen;  /* get display width of a char */
     400             :     mbchar_verifier mbverifychar;   /* verify multibyte character */
     401             :     mbstr_verifier mbverifystr; /* verify multibyte string */
     402             :     int         maxmblen;       /* max bytes for a char in this encoding */
     403             : } pg_wchar_tbl;
     404             : 
     405             : extern PGDLLIMPORT const pg_wchar_tbl pg_wchar_table[];
     406             : 
     407             : /*
     408             :  * Data structures for conversions between UTF-8 and other encodings
     409             :  * (UtfToLocal() and LocalToUtf()).  In these data structures, characters of
     410             :  * either encoding are represented by uint32 words; hence we can only support
     411             :  * characters up to 4 bytes long.  For example, the byte sequence 0xC2 0x89
     412             :  * would be represented by 0x0000C289, and 0xE8 0xA2 0xB4 by 0x00E8A2B4.
     413             :  *
     414             :  * There are three possible ways a character can be mapped:
     415             :  *
     416             :  * 1. Using a radix tree, from source to destination code.
     417             :  * 2. Using a sorted array of source -> destination code pairs. This
     418             :  *    method is used for "combining" characters. There are so few of
     419             :  *    them that building a radix tree would be wasteful.
     420             :  * 3. Using a conversion function.
     421             :  */
     422             : 
     423             : /*
     424             :  * Radix tree for character conversion.
     425             :  *
     426             :  * Logically, this is actually four different radix trees, for 1-byte,
     427             :  * 2-byte, 3-byte and 4-byte inputs. The 1-byte tree is a simple lookup
     428             :  * table from source to target code. The 2-byte tree consists of two levels:
     429             :  * one lookup table for the first byte, where the value in the lookup table
     430             :  * points to a lookup table for the second byte. And so on.
     431             :  *
     432             :  * Physically, all the trees are stored in one big array, in 'chars16' or
     433             :  * 'chars32', depending on the maximum value that needs to be represented. For
     434             :  * each level in each tree, we also store lower and upper bound of allowed
     435             :  * values - values outside those bounds are considered invalid, and are left
     436             :  * out of the tables.
     437             :  *
     438             :  * In the intermediate levels of the trees, the values stored are offsets
     439             :  * into the chars[16|32] array.
     440             :  *
     441             :  * In the beginning of the chars[16|32] array, there is always a number of
     442             :  * zeros, so that you safely follow an index from an intermediate table
     443             :  * without explicitly checking for a zero. Following a zero any number of
     444             :  * times will always bring you to the dummy, all-zeros table in the
     445             :  * beginning. This helps to shave some cycles when looking up values.
     446             :  */
     447             : typedef struct
     448             : {
     449             :     /*
     450             :      * Array containing all the values. Only one of chars16 or chars32 is
     451             :      * used, depending on how wide the values we need to represent are.
     452             :      */
     453             :     const uint16 *chars16;
     454             :     const uint32 *chars32;
     455             : 
     456             :     /* Radix tree for 1-byte inputs */
     457             :     uint32      b1root;         /* offset of table in the chars[16|32] array */
     458             :     uint8       b1_lower;       /* min allowed value for a single byte input */
     459             :     uint8       b1_upper;       /* max allowed value for a single byte input */
     460             : 
     461             :     /* Radix tree for 2-byte inputs */
     462             :     uint32      b2root;         /* offset of 1st byte's table */
     463             :     uint8       b2_1_lower;     /* min/max allowed value for 1st input byte */
     464             :     uint8       b2_1_upper;
     465             :     uint8       b2_2_lower;     /* min/max allowed value for 2nd input byte */
     466             :     uint8       b2_2_upper;
     467             : 
     468             :     /* Radix tree for 3-byte inputs */
     469             :     uint32      b3root;         /* offset of 1st byte's table */
     470             :     uint8       b3_1_lower;     /* min/max allowed value for 1st input byte */
     471             :     uint8       b3_1_upper;
     472             :     uint8       b3_2_lower;     /* min/max allowed value for 2nd input byte */
     473             :     uint8       b3_2_upper;
     474             :     uint8       b3_3_lower;     /* min/max allowed value for 3rd input byte */
     475             :     uint8       b3_3_upper;
     476             : 
     477             :     /* Radix tree for 4-byte inputs */
     478             :     uint32      b4root;         /* offset of 1st byte's table */
     479             :     uint8       b4_1_lower;     /* min/max allowed value for 1st input byte */
     480             :     uint8       b4_1_upper;
     481             :     uint8       b4_2_lower;     /* min/max allowed value for 2nd input byte */
     482             :     uint8       b4_2_upper;
     483             :     uint8       b4_3_lower;     /* min/max allowed value for 3rd input byte */
     484             :     uint8       b4_3_upper;
     485             :     uint8       b4_4_lower;     /* min/max allowed value for 4th input byte */
     486             :     uint8       b4_4_upper;
     487             : 
     488             : } pg_mb_radix_tree;
     489             : 
     490             : /*
     491             :  * UTF-8 to local code conversion map (for combined characters)
     492             :  */
     493             : typedef struct
     494             : {
     495             :     uint32      utf1;           /* UTF-8 code 1 */
     496             :     uint32      utf2;           /* UTF-8 code 2 */
     497             :     uint32      code;           /* local code */
     498             : } pg_utf_to_local_combined;
     499             : 
     500             : /*
     501             :  * local code to UTF-8 conversion map (for combined characters)
     502             :  */
     503             : typedef struct
     504             : {
     505             :     uint32      code;           /* local code */
     506             :     uint32      utf1;           /* UTF-8 code 1 */
     507             :     uint32      utf2;           /* UTF-8 code 2 */
     508             : } pg_local_to_utf_combined;
     509             : 
     510             : /*
     511             :  * callback function for algorithmic encoding conversions (in either direction)
     512             :  *
     513             :  * if function returns zero, it does not know how to convert the code
     514             :  */
     515             : typedef uint32 (*utf_local_conversion_func) (uint32 code);
     516             : 
     517             : /*
     518             :  * Support macro for encoding conversion functions to validate their
     519             :  * arguments.  (This could be made more compact if we included fmgr.h
     520             :  * here, but we don't want to do that because this header file is also
     521             :  * used by frontends.)
     522             :  */
     523             : #define CHECK_ENCODING_CONVERSION_ARGS(srcencoding,destencoding) \
     524             :     check_encoding_conversion_args(PG_GETARG_INT32(0), \
     525             :                                    PG_GETARG_INT32(1), \
     526             :                                    PG_GETARG_INT32(4), \
     527             :                                    (srcencoding), \
     528             :                                    (destencoding))
     529             : 
     530             : 
     531             : /*
     532             :  * Some handy functions for Unicode-specific tests.
     533             :  */
     534             : static inline bool
     535        1344 : is_valid_unicode_codepoint(pg_wchar c)
     536             : {
     537        1344 :     return (c > 0 && c <= 0x10FFFF);
     538             : }
     539             : 
     540             : static inline bool
     541        1028 : is_utf16_surrogate_first(pg_wchar c)
     542             : {
     543        1028 :     return (c >= 0xD800 && c <= 0xDBFF);
     544             : }
     545             : 
     546             : static inline bool
     547         914 : is_utf16_surrogate_second(pg_wchar c)
     548             : {
     549         914 :     return (c >= 0xDC00 && c <= 0xDFFF);
     550             : }
     551             : 
     552             : static inline pg_wchar
     553          60 : surrogate_pair_to_codepoint(pg_wchar first, pg_wchar second)
     554             : {
     555          60 :     return ((first & 0x3FF) << 10) + 0x10000 + (second & 0x3FF);
     556             : }
     557             : 
     558             : /*
     559             :  * Convert a UTF-8 character to a Unicode code point.
     560             :  * This is a one-character version of pg_utf2wchar_with_len.
     561             :  *
     562             :  * No error checks here, c must point to a long-enough string.
     563             :  */
     564             : static inline pg_wchar
     565    51403492 : utf8_to_unicode(const unsigned char *c)
     566             : {
     567    51403492 :     if ((*c & 0x80) == 0)
     568    51396846 :         return (pg_wchar) c[0];
     569        6646 :     else if ((*c & 0xe0) == 0xc0)
     570        5624 :         return (pg_wchar) (((c[0] & 0x1f) << 6) |
     571        5624 :                            (c[1] & 0x3f));
     572        1022 :     else if ((*c & 0xf0) == 0xe0)
     573         920 :         return (pg_wchar) (((c[0] & 0x0f) << 12) |
     574         920 :                            ((c[1] & 0x3f) << 6) |
     575         920 :                            (c[2] & 0x3f));
     576         102 :     else if ((*c & 0xf8) == 0xf0)
     577         102 :         return (pg_wchar) (((c[0] & 0x07) << 18) |
     578         102 :                            ((c[1] & 0x3f) << 12) |
     579         102 :                            ((c[2] & 0x3f) << 6) |
     580         102 :                            (c[3] & 0x3f));
     581             :     else
     582             :         /* that is an invalid code on purpose */
     583           0 :         return 0xffffffff;
     584             : }
     585             : 
     586             : /*
     587             :  * Map a Unicode code point to UTF-8.  utf8string must have at least
     588             :  * unicode_utf8len(c) bytes available.
     589             :  */
     590             : static inline unsigned char *
     591    16253784 : unicode_to_utf8(pg_wchar c, unsigned char *utf8string)
     592             : {
     593    16253784 :     if (c <= 0x7F)
     594             :     {
     595    16252512 :         utf8string[0] = c;
     596             :     }
     597        1272 :     else if (c <= 0x7FF)
     598             :     {
     599         746 :         utf8string[0] = 0xC0 | ((c >> 6) & 0x1F);
     600         746 :         utf8string[1] = 0x80 | (c & 0x3F);
     601             :     }
     602         526 :     else if (c <= 0xFFFF)
     603             :     {
     604         460 :         utf8string[0] = 0xE0 | ((c >> 12) & 0x0F);
     605         460 :         utf8string[1] = 0x80 | ((c >> 6) & 0x3F);
     606         460 :         utf8string[2] = 0x80 | (c & 0x3F);
     607             :     }
     608             :     else
     609             :     {
     610          66 :         utf8string[0] = 0xF0 | ((c >> 18) & 0x07);
     611          66 :         utf8string[1] = 0x80 | ((c >> 12) & 0x3F);
     612          66 :         utf8string[2] = 0x80 | ((c >> 6) & 0x3F);
     613          66 :         utf8string[3] = 0x80 | (c & 0x3F);
     614             :     }
     615             : 
     616    16253784 :     return utf8string;
     617             : }
     618             : 
     619             : /*
     620             :  * Number of bytes needed to represent the given char in UTF8.
     621             :  */
     622             : static inline int
     623     1200058 : unicode_utf8len(pg_wchar c)
     624             : {
     625     1200058 :     if (c <= 0x7F)
     626     1198294 :         return 1;
     627        1764 :     else if (c <= 0x7FF)
     628        1320 :         return 2;
     629         444 :     else if (c <= 0xFFFF)
     630         444 :         return 3;
     631             :     else
     632           0 :         return 4;
     633             : }
     634             : 
     635             : /*
     636             :  * The functions in this list are exported by libpq, and we need to be sure
     637             :  * that we know which calls are satisfied by libpq and which are satisfied
     638             :  * by static linkage to libpgcommon.  (This is because we might be using a
     639             :  * libpq.so that's of a different major version and has encoding IDs that
     640             :  * differ from the current version's.)  The nominal function names are what
     641             :  * are actually used in and exported by libpq, while the names exported by
     642             :  * libpgcommon.a and libpgcommon_srv.a end in "_private".
     643             :  */
     644             : #if defined(USE_PRIVATE_ENCODING_FUNCS) || !defined(FRONTEND)
     645             : #define pg_char_to_encoding         pg_char_to_encoding_private
     646             : #define pg_encoding_to_char         pg_encoding_to_char_private
     647             : #define pg_valid_server_encoding    pg_valid_server_encoding_private
     648             : #define pg_valid_server_encoding_id pg_valid_server_encoding_id_private
     649             : #define pg_utf_mblen                pg_utf_mblen_private
     650             : #endif
     651             : 
     652             : /*
     653             :  * These functions are considered part of libpq's exported API and
     654             :  * are also declared in libpq-fe.h.
     655             :  */
     656             : extern int  pg_char_to_encoding(const char *name);
     657             : extern const char *pg_encoding_to_char(int encoding);
     658             : extern int  pg_valid_server_encoding_id(int encoding);
     659             : 
     660             : /*
     661             :  * These functions are available to frontend code that links with libpgcommon
     662             :  * (in addition to the ones just above).  The constant tables declared
     663             :  * earlier in this file are also available from libpgcommon.
     664             :  */
     665             : extern int  pg_encoding_mblen(int encoding, const char *mbstr);
     666             : extern int  pg_encoding_mblen_bounded(int encoding, const char *mbstr);
     667             : extern int  pg_encoding_dsplen(int encoding, const char *mbstr);
     668             : extern int  pg_encoding_verifymbchar(int encoding, const char *mbstr, int len);
     669             : extern int  pg_encoding_verifymbstr(int encoding, const char *mbstr, int len);
     670             : extern int  pg_encoding_max_length(int encoding);
     671             : extern int  pg_valid_client_encoding(const char *name);
     672             : extern int  pg_valid_server_encoding(const char *name);
     673             : extern bool is_encoding_supported_by_icu(int encoding);
     674             : extern const char *get_encoding_name_for_icu(int encoding);
     675             : 
     676             : extern unsigned char *unicode_to_utf8(pg_wchar c, unsigned char *utf8string);
     677             : extern pg_wchar utf8_to_unicode(const unsigned char *c);
     678             : extern bool pg_utf8_islegal(const unsigned char *source, int length);
     679             : extern int  pg_utf_mblen(const unsigned char *s);
     680             : extern int  pg_mule_mblen(const unsigned char *s);
     681             : 
     682             : /*
     683             :  * The remaining functions are backend-only.
     684             :  */
     685             : extern int  pg_mb2wchar(const char *from, pg_wchar *to);
     686             : extern int  pg_mb2wchar_with_len(const char *from, pg_wchar *to, int len);
     687             : extern int  pg_encoding_mb2wchar_with_len(int encoding,
     688             :                                           const char *from, pg_wchar *to, int len);
     689             : extern int  pg_wchar2mb(const pg_wchar *from, char *to);
     690             : extern int  pg_wchar2mb_with_len(const pg_wchar *from, char *to, int len);
     691             : extern int  pg_encoding_wchar2mb_with_len(int encoding,
     692             :                                           const pg_wchar *from, char *to, int len);
     693             : extern int  pg_char_and_wchar_strcmp(const char *s1, const pg_wchar *s2);
     694             : extern int  pg_wchar_strncmp(const pg_wchar *s1, const pg_wchar *s2, size_t n);
     695             : extern int  pg_char_and_wchar_strncmp(const char *s1, const pg_wchar *s2, size_t n);
     696             : extern size_t pg_wchar_strlen(const pg_wchar *str);
     697             : extern int  pg_mblen(const char *mbstr);
     698             : extern int  pg_dsplen(const char *mbstr);
     699             : extern int  pg_mbstrlen(const char *mbstr);
     700             : extern int  pg_mbstrlen_with_len(const char *mbstr, int limit);
     701             : extern int  pg_mbcliplen(const char *mbstr, int len, int limit);
     702             : extern int  pg_encoding_mbcliplen(int encoding, const char *mbstr,
     703             :                                   int len, int limit);
     704             : extern int  pg_mbcharcliplen(const char *mbstr, int len, int limit);
     705             : extern int  pg_database_encoding_max_length(void);
     706             : extern mbcharacter_incrementer pg_database_encoding_character_incrementer(void);
     707             : 
     708             : extern int  PrepareClientEncoding(int encoding);
     709             : extern int  SetClientEncoding(int encoding);
     710             : extern void InitializeClientEncoding(void);
     711             : extern int  pg_get_client_encoding(void);
     712             : extern const char *pg_get_client_encoding_name(void);
     713             : 
     714             : extern void SetDatabaseEncoding(int encoding);
     715             : extern int  GetDatabaseEncoding(void);
     716             : extern const char *GetDatabaseEncodingName(void);
     717             : extern void SetMessageEncoding(int encoding);
     718             : extern int  GetMessageEncoding(void);
     719             : 
     720             : #ifdef ENABLE_NLS
     721             : extern int  pg_bind_textdomain_codeset(const char *domainname);
     722             : #endif
     723             : 
     724             : extern unsigned char *pg_do_encoding_conversion(unsigned char *src, int len,
     725             :                                                 int src_encoding,
     726             :                                                 int dest_encoding);
     727             : extern int  pg_do_encoding_conversion_buf(Oid proc,
     728             :                                           int src_encoding,
     729             :                                           int dest_encoding,
     730             :                                           unsigned char *src, int srclen,
     731             :                                           unsigned char *dest, int destlen,
     732             :                                           bool noError);
     733             : 
     734             : extern char *pg_client_to_server(const char *s, int len);
     735             : extern char *pg_server_to_client(const char *s, int len);
     736             : extern char *pg_any_to_server(const char *s, int len, int encoding);
     737             : extern char *pg_server_to_any(const char *s, int len, int encoding);
     738             : 
     739             : extern void pg_unicode_to_server(pg_wchar c, unsigned char *s);
     740             : extern bool pg_unicode_to_server_noerror(pg_wchar c, unsigned char *s);
     741             : 
     742             : extern unsigned short BIG5toCNS(unsigned short big5, unsigned char *lc);
     743             : extern unsigned short CNStoBIG5(unsigned short cns, unsigned char lc);
     744             : 
     745             : extern int  UtfToLocal(const unsigned char *utf, int len,
     746             :                        unsigned char *iso,
     747             :                        const pg_mb_radix_tree *map,
     748             :                        const pg_utf_to_local_combined *cmap, int cmapsize,
     749             :                        utf_local_conversion_func conv_func,
     750             :                        int encoding, bool noError);
     751             : extern int  LocalToUtf(const unsigned char *iso, int len,
     752             :                        unsigned char *utf,
     753             :                        const pg_mb_radix_tree *map,
     754             :                        const pg_local_to_utf_combined *cmap, int cmapsize,
     755             :                        utf_local_conversion_func conv_func,
     756             :                        int encoding, bool noError);
     757             : 
     758             : extern bool pg_verifymbstr(const char *mbstr, int len, bool noError);
     759             : extern bool pg_verify_mbstr(int encoding, const char *mbstr, int len,
     760             :                             bool noError);
     761             : extern int  pg_verify_mbstr_len(int encoding, const char *mbstr, int len,
     762             :                                 bool noError);
     763             : 
     764             : extern void check_encoding_conversion_args(int src_encoding,
     765             :                                            int dest_encoding,
     766             :                                            int len,
     767             :                                            int expected_src_encoding,
     768             :                                            int expected_dest_encoding);
     769             : 
     770             : extern void report_invalid_encoding(int encoding, const char *mbstr, int len) pg_attribute_noreturn();
     771             : extern void report_untranslatable_char(int src_encoding, int dest_encoding,
     772             :                                        const char *mbstr, int len) pg_attribute_noreturn();
     773             : 
     774             : extern int  local2local(const unsigned char *l, unsigned char *p, int len,
     775             :                         int src_encoding, int dest_encoding,
     776             :                         const unsigned char *tab, bool noError);
     777             : extern int  latin2mic(const unsigned char *l, unsigned char *p, int len,
     778             :                       int lc, int encoding, bool noError);
     779             : extern int  mic2latin(const unsigned char *mic, unsigned char *p, int len,
     780             :                       int lc, int encoding, bool noError);
     781             : extern int  latin2mic_with_table(const unsigned char *l, unsigned char *p,
     782             :                                  int len, int lc, int encoding,
     783             :                                  const unsigned char *tab, bool noError);
     784             : extern int  mic2latin_with_table(const unsigned char *mic, unsigned char *p,
     785             :                                  int len, int lc, int encoding,
     786             :                                  const unsigned char *tab, bool noError);
     787             : 
     788             : #ifdef WIN32
     789             : extern WCHAR *pgwin32_message_to_UTF16(const char *str, int len, int *utf16len);
     790             : #endif
     791             : 
     792             : #endif                          /* PG_WCHAR_H */

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