/src/postgres/src/include/mb/pg_wchar.h

Source (jump to first uncovered line)
/*-------------------------------------------------------------------------
 *
 * pg_wchar.h
 *    multibyte-character support
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/mb/pg_wchar.h
 *
 *  NOTES
 *    This is used both by the backend and by frontends, but should not be
 *    included by libpq client programs.  In particular, a libpq client
 *    should not assume that the encoding IDs used by the version of libpq
 *    it's linked to match up with the IDs declared here.
 *    To help prevent mistakes, relevant functions that are exported by
 *    libpq have a physically different name when being referenced
 *    statically.
 *
 *-------------------------------------------------------------------------
 */
#ifndef PG_WCHAR_H
#define PG_WCHAR_H

/*
 * The pg_wchar type
 */
typedef unsigned int pg_wchar;

/*
 * Maximum byte length of multibyte characters in any backend encoding
 */
#define MAX_MULTIBYTE_CHAR_LEN  4

/*
 * various definitions for EUC
 */
#define SS2 0x8e        /* single shift 2 (JIS0201) */
#define SS3 0x8f        /* single shift 3 (JIS0212) */

/*
 * SJIS validation macros
 */
#define ISSJISHEAD(c) (((c) >= 0x81 && (c) <= 0x9f) || ((c) >= 0xe0 && (c) <= 0xfc))
#define ISSJISTAIL(c) (((c) >= 0x40 && (c) <= 0x7e) || ((c) >= 0x80 && (c) <= 0xfc))

/*----------------------------------------------------
 * MULE Internal Encoding (MIC)
 *
 * This encoding follows the design used within XEmacs; it is meant to
 * subsume many externally-defined character sets.  Each character includes
 * identification of the character set it belongs to, so the encoding is
 * general but somewhat bulky.
 *
 * Currently PostgreSQL supports 5 types of MULE character sets:
 *
 * 1) 1-byte ASCII characters.  Each byte is below 0x80.
 *
 * 2) "Official" single byte charsets such as ISO-8859-1 (Latin1).
 *    Each MULE character consists of 2 bytes: LC1 + C1, where LC1 is
 *    an identifier for the charset (in the range 0x81 to 0x8d) and C1
 *    is the character code (in the range 0xa0 to 0xff).
 *
 * 3) "Private" single byte charsets such as SISHENG.  Each MULE
 *    character consists of 3 bytes: LCPRV1 + LC12 + C1, where LCPRV1
 *    is a private-charset flag, LC12 is an identifier for the charset,
 *    and C1 is the character code (in the range 0xa0 to 0xff).
 *    LCPRV1 is either 0x9a (if LC12 is in the range 0xa0 to 0xdf)
 *    or 0x9b (if LC12 is in the range 0xe0 to 0xef).
 *
 * 4) "Official" multibyte charsets such as JIS X0208.  Each MULE
 *    character consists of 3 bytes: LC2 + C1 + C2, where LC2 is
 *    an identifier for the charset (in the range 0x90 to 0x99) and C1
 *    and C2 form the character code (each in the range 0xa0 to 0xff).
 *
 * 5) "Private" multibyte charsets such as CNS 11643-1992 Plane 3.
 *    Each MULE character consists of 4 bytes: LCPRV2 + LC22 + C1 + C2,
 *    where LCPRV2 is a private-charset flag, LC22 is an identifier for
 *    the charset, and C1 and C2 form the character code (each in the range
 *    0xa0 to 0xff).  LCPRV2 is either 0x9c (if LC22 is in the range 0xf0
 *    to 0xf4) or 0x9d (if LC22 is in the range 0xf5 to 0xfe).
 *
 * "Official" encodings are those that have been assigned code numbers by
 * the XEmacs project; "private" encodings have Postgres-specific charset
 * identifiers.
 *
 * See the "XEmacs Internals Manual", available at http://www.xemacs.org,
 * for more details.  Note that for historical reasons, Postgres'
 * private-charset flag values do not match what XEmacs says they should be,
 * so this isn't really exactly MULE (not that private charsets would be
 * interoperable anyway).
 *
 * Note that XEmacs's implementation is different from what emacs does.
 * We follow emacs's implementation, rather than XEmacs's.
 *----------------------------------------------------
 */

/*
 * Charset identifiers (also called "leading bytes" in the MULE documentation)
 */

/*
 * Charset IDs for official single byte encodings (0x81-0x8e)
 */
#define LC_ISO8859_1    0x81  /* ISO8859 Latin 1 */
#define LC_ISO8859_2    0x82  /* ISO8859 Latin 2 */
#define LC_ISO8859_3    0x83  /* ISO8859 Latin 3 */
#define LC_ISO8859_4    0x84  /* ISO8859 Latin 4 */
#define LC_TIS620     0x85  /* Thai (not supported yet) */
#define LC_ISO8859_7    0x86  /* Greek (not supported yet) */
#define LC_ISO8859_6    0x87  /* Arabic (not supported yet) */
#define LC_ISO8859_8    0x88  /* Hebrew (not supported yet) */
#define LC_JISX0201K    0x89  /* Japanese 1 byte kana */
#define LC_JISX0201R    0x8a  /* Japanese 1 byte Roman */
/* Note that 0x8b seems to be unused as of Emacs 20.7.
 * However, there might be a chance that 0x8b could be used
 * in later versions of Emacs.
 */
#define LC_KOI8_R     0x8b  /* Cyrillic KOI8-R */
#define LC_ISO8859_5    0x8c  /* ISO8859 Cyrillic */
#define LC_ISO8859_9    0x8d  /* ISO8859 Latin 5 (not supported yet) */
#define LC_ISO8859_15   0x8e  /* ISO8859 Latin 15 (not supported yet) */
/* #define CONTROL_1    0x8f  control characters (unused) */

/* Is a leading byte for "official" single byte encodings? */
#define IS_LC1(c) ((unsigned char)(c) >= 0x81 && (unsigned char)(c) <= 0x8d)

/*
 * Charset IDs for official multibyte encodings (0x90-0x99)
 * 0x9a-0x9d are free. 0x9e and 0x9f are reserved.
 */
#define LC_JISX0208_1978  0x90  /* Japanese Kanji, old JIS (not supported) */
#define LC_GB2312_80    0x91  /* Chinese */
#define LC_JISX0208     0x92  /* Japanese Kanji (JIS X 0208) */
#define LC_KS5601     0x93  /* Korean */
#define LC_JISX0212     0x94  /* Japanese Kanji (JIS X 0212) */
#define LC_CNS11643_1   0x95  /* CNS 11643-1992 Plane 1 */
#define LC_CNS11643_2   0x96  /* CNS 11643-1992 Plane 2 */
#define LC_JISX0213_1   0x97  /* Japanese Kanji (JIS X 0213 Plane 1)
                   * (not supported) */
#define LC_BIG5_1     0x98  /* Plane 1 Chinese traditional (not
                   * supported) */
#define LC_BIG5_2     0x99  /* Plane 1 Chinese traditional (not
                   * supported) */

/* Is a leading byte for "official" multibyte encodings? */
#define IS_LC2(c) ((unsigned char)(c) >= 0x90 && (unsigned char)(c) <= 0x99)

/*
 * Postgres-specific prefix bytes for "private" single byte encodings
 * (According to the MULE docs, we should be using 0x9e for this)
 */
#define LCPRV1_A    0x9a
#define LCPRV1_B    0x9b
#define IS_LCPRV1(c)  ((unsigned char)(c) == LCPRV1_A || (unsigned char)(c) == LCPRV1_B)
#define IS_LCPRV1_A_RANGE(c)  \
  ((unsigned char)(c) >= 0xa0 && (unsigned char)(c) <= 0xdf)
#define IS_LCPRV1_B_RANGE(c)  \
  ((unsigned char)(c) >= 0xe0 && (unsigned char)(c) <= 0xef)

/*
 * Postgres-specific prefix bytes for "private" multibyte encodings
 * (According to the MULE docs, we should be using 0x9f for this)
 */
#define LCPRV2_A    0x9c
#define LCPRV2_B    0x9d
#define IS_LCPRV2(c)  ((unsigned char)(c) == LCPRV2_A || (unsigned char)(c) == LCPRV2_B)
#define IS_LCPRV2_A_RANGE(c)  \
  ((unsigned char)(c) >= 0xf0 && (unsigned char)(c) <= 0xf4)
#define IS_LCPRV2_B_RANGE(c)  \
  ((unsigned char)(c) >= 0xf5 && (unsigned char)(c) <= 0xfe)

/*
 * Charset IDs for private single byte encodings (0xa0-0xef)
 */
#define LC_SISHENG      0xa0  /* Chinese SiSheng characters for
                   * PinYin/ZhuYin (not supported) */
#define LC_IPA        0xa1  /* IPA (International Phonetic
                   * Association) (not supported) */
#define LC_VISCII_LOWER   0xa2  /* Vietnamese VISCII1.1 lower-case (not
                   * supported) */
#define LC_VISCII_UPPER   0xa3  /* Vietnamese VISCII1.1 upper-case (not
                   * supported) */
#define LC_ARABIC_DIGIT   0xa4  /* Arabic digit (not supported) */
#define LC_ARABIC_1_COLUMN  0xa5  /* Arabic 1-column (not supported) */
#define LC_ASCII_RIGHT_TO_LEFT  0xa6  /* ASCII (left half of ISO8859-1) with
                     * right-to-left direction (not
                     * supported) */
#define LC_LAO        0xa7  /* Lao characters (ISO10646 0E80..0EDF)
                   * (not supported) */
#define LC_ARABIC_2_COLUMN  0xa8  /* Arabic 1-column (not supported) */

/*
 * Charset IDs for private multibyte encodings (0xf0-0xff)
 */
#define LC_INDIAN_1_COLUMN  0xf0  /* Indian charset for 1-column width
                   * glyphs (not supported) */
#define LC_TIBETAN_1_COLUMN 0xf1  /* Tibetan 1-column width glyphs (not
                   * supported) */
#define LC_UNICODE_SUBSET_2 0xf2  /* Unicode characters of the range
                   * U+2500..U+33FF. (not supported) */
#define LC_UNICODE_SUBSET_3 0xf3  /* Unicode characters of the range
                   * U+E000..U+FFFF. (not supported) */
#define LC_UNICODE_SUBSET 0xf4  /* Unicode characters of the range
                   * U+0100..U+24FF. (not supported) */
#define LC_ETHIOPIC     0xf5  /* Ethiopic characters (not supported) */
#define LC_CNS11643_3   0xf6  /* CNS 11643-1992 Plane 3 */
#define LC_CNS11643_4   0xf7  /* CNS 11643-1992 Plane 4 */
#define LC_CNS11643_5   0xf8  /* CNS 11643-1992 Plane 5 */
#define LC_CNS11643_6   0xf9  /* CNS 11643-1992 Plane 6 */
#define LC_CNS11643_7   0xfa  /* CNS 11643-1992 Plane 7 */
#define LC_INDIAN_2_COLUMN  0xfb  /* Indian charset for 2-column width
                   * glyphs (not supported) */
#define LC_TIBETAN      0xfc  /* Tibetan (not supported) */
/* #define FREE       0xfd  free (unused) */
/* #define FREE       0xfe  free (unused) */
/* #define FREE       0xff  free (unused) */

/*----------------------------------------------------
 * end of MULE stuff
 *----------------------------------------------------
 */

/*
 * PostgreSQL encoding identifiers
 *
 * WARNING: If you add some encoding don't forget to update
 *      the pg_enc2name_tbl[] array (in src/common/encnames.c),
 *      the pg_enc2gettext_tbl[] array (in src/common/encnames.c) and
 *      the pg_wchar_table[] array (in src/common/wchar.c) and to check
 *      PG_ENCODING_BE_LAST macro.
 *
 * PG_SQL_ASCII is default encoding and must be = 0.
 *
 * XXX  We must avoid renumbering any backend encoding until libpq's major
 * version number is increased beyond 5; it turns out that the backend
 * encoding IDs are effectively part of libpq's ABI as far as 8.2 initdb and
 * psql are concerned.
 */
typedef enum pg_enc
{
  PG_SQL_ASCII = 0,     /* SQL/ASCII */
  PG_EUC_JP,          /* EUC for Japanese */
  PG_EUC_CN,          /* EUC for Chinese */
  PG_EUC_KR,          /* EUC for Korean */
  PG_EUC_TW,          /* EUC for Taiwan */
  PG_EUC_JIS_2004,      /* EUC-JIS-2004 */
  PG_UTF8,          /* Unicode UTF8 */
  PG_MULE_INTERNAL,     /* Mule internal code */
  PG_LATIN1,          /* ISO-8859-1 Latin 1 */
  PG_LATIN2,          /* ISO-8859-2 Latin 2 */
  PG_LATIN3,          /* ISO-8859-3 Latin 3 */
  PG_LATIN4,          /* ISO-8859-4 Latin 4 */
  PG_LATIN5,          /* ISO-8859-9 Latin 5 */
  PG_LATIN6,          /* ISO-8859-10 Latin6 */
  PG_LATIN7,          /* ISO-8859-13 Latin7 */
  PG_LATIN8,          /* ISO-8859-14 Latin8 */
  PG_LATIN9,          /* ISO-8859-15 Latin9 */
  PG_LATIN10,         /* ISO-8859-16 Latin10 */
  PG_WIN1256,         /* windows-1256 */
  PG_WIN1258,         /* Windows-1258 */
  PG_WIN866,          /* (MS-DOS CP866) */
  PG_WIN874,          /* windows-874 */
  PG_KOI8R,         /* KOI8-R */
  PG_WIN1251,         /* windows-1251 */
  PG_WIN1252,         /* windows-1252 */
  PG_ISO_8859_5,        /* ISO-8859-5 */
  PG_ISO_8859_6,        /* ISO-8859-6 */
  PG_ISO_8859_7,        /* ISO-8859-7 */
  PG_ISO_8859_8,        /* ISO-8859-8 */
  PG_WIN1250,         /* windows-1250 */
  PG_WIN1253,         /* windows-1253 */
  PG_WIN1254,         /* windows-1254 */
  PG_WIN1255,         /* windows-1255 */
  PG_WIN1257,         /* windows-1257 */
  PG_KOI8U,         /* KOI8-U */
  /* PG_ENCODING_BE_LAST points to the above entry */

  /* followings are for client encoding only */
  PG_SJIS,          /* Shift JIS (Windows-932) */
  PG_BIG5,          /* Big5 (Windows-950) */
  PG_GBK,           /* GBK (Windows-936) */
  PG_UHC,           /* UHC (Windows-949) */
  PG_GB18030,         /* GB18030 */
  PG_JOHAB,         /* EUC for Korean JOHAB */
  PG_SHIFT_JIS_2004,      /* Shift-JIS-2004 */
  _PG_LAST_ENCODING_      /* mark only */

} pg_enc;

#define PG_ENCODING_BE_LAST PG_KOI8U

/*
 * Please use these tests before access to pg_enc2name_tbl[]
 * or to other places...
 */
#define PG_VALID_BE_ENCODING(_enc) \
    ((_enc) >= 0 && (_enc) <= PG_ENCODING_BE_LAST)

#define PG_ENCODING_IS_CLIENT_ONLY(_enc) \
    ((_enc) > PG_ENCODING_BE_LAST && (_enc) < _PG_LAST_ENCODING_)

#define PG_VALID_ENCODING(_enc) \
    ((_enc) >= 0 && (_enc) < _PG_LAST_ENCODING_)

/* On FE are possible all encodings */
#define PG_VALID_FE_ENCODING(_enc)  PG_VALID_ENCODING(_enc)

/*
 * When converting strings between different encodings, we assume that space
 * for converted result is 4-to-1 growth in the worst case.  The rate for
 * currently supported encoding pairs are within 3 (SJIS JIS X0201 half width
 * kana -> UTF8 is the worst case).  So "4" should be enough for the moment.
 *
 * Note that this is not the same as the maximum character width in any
 * particular encoding.
 */
#define MAX_CONVERSION_GROWTH  4

/*
 * Maximum byte length of a string that's required in any encoding to convert
 * at least one character to any other encoding.  In other words, if you feed
 * MAX_CONVERSION_INPUT_LENGTH bytes to any encoding conversion function, it
 * is guaranteed to be able to convert something without needing more input
 * (assuming the input is valid).
 *
 * Currently, the maximum case is the conversion UTF8 -> SJIS JIS X0201 half
 * width kana, where a pair of UTF-8 characters is converted into a single
 * SHIFT_JIS_2004 character (the reverse of the worst case for
 * MAX_CONVERSION_GROWTH).  It needs 6 bytes of input.  In theory, a
 * user-defined conversion function might have more complicated cases, although
 * for the reverse mapping you would probably also need to bump up
 * MAX_CONVERSION_GROWTH.  But there is no need to be stingy here, so make it
 * generous.
 */
#define MAX_CONVERSION_INPUT_LENGTH 16

/*
 * Maximum byte length of the string equivalent to any one Unicode code point,
 * in any backend encoding.  The current value assumes that a 4-byte UTF-8
 * character might expand by MAX_CONVERSION_GROWTH, which is a huge
 * overestimate.  But in current usage we don't allocate large multiples of
 * this, so there's little point in being stingy.
 */
#define MAX_UNICODE_EQUIVALENT_STRING 16

/*
 * Table for mapping an encoding number to official encoding name and
 * possibly other subsidiary data.  Be careful to check encoding number
 * before accessing a table entry!
 *
 * if (PG_VALID_ENCODING(encoding))
 *    pg_enc2name_tbl[ encoding ];
 */
typedef struct pg_enc2name
{
  const char *name;
  pg_enc    encoding;
#ifdef WIN32
  unsigned  codepage;   /* codepage for WIN32 */
#endif
} pg_enc2name;

extern PGDLLIMPORT const pg_enc2name pg_enc2name_tbl[];

/*
 * Encoding names for gettext
 */
extern PGDLLIMPORT const char *pg_enc2gettext_tbl[];

/*
 * pg_wchar stuff
 */
typedef int (*mb2wchar_with_len_converter) (const unsigned char *from,
                      pg_wchar *to,
                      int len);

typedef int (*wchar2mb_with_len_converter) (const pg_wchar *from,
                      unsigned char *to,
                      int len);

typedef int (*mblen_converter) (const unsigned char *mbstr);

typedef int (*mbdisplaylen_converter) (const unsigned char *mbstr);

typedef bool (*mbcharacter_incrementer) (unsigned char *mbstr, int len);

typedef int (*mbchar_verifier) (const unsigned char *mbstr, int len);

typedef int (*mbstr_verifier) (const unsigned char *mbstr, int len);

typedef struct
{
  mb2wchar_with_len_converter mb2wchar_with_len;  /* convert a multibyte
                           * string to a wchar */
  wchar2mb_with_len_converter wchar2mb_with_len;  /* convert a wchar string
                           * to a multibyte */
  mblen_converter mblen;    /* get byte length of a char */
  mbdisplaylen_converter dsplen;  /* get display width of a char */
  mbchar_verifier mbverifychar; /* verify multibyte character */
  mbstr_verifier mbverifystr; /* verify multibyte string */
  int     maxmblen;   /* max bytes for a char in this encoding */
} pg_wchar_tbl;

extern PGDLLIMPORT const pg_wchar_tbl pg_wchar_table[];

/*
 * Data structures for conversions between UTF-8 and other encodings
 * (UtfToLocal() and LocalToUtf()).  In these data structures, characters of
 * either encoding are represented by uint32 words; hence we can only support
 * characters up to 4 bytes long.  For example, the byte sequence 0xC2 0x89
 * would be represented by 0x0000C289, and 0xE8 0xA2 0xB4 by 0x00E8A2B4.
 *
 * There are three possible ways a character can be mapped:
 *
 * 1. Using a radix tree, from source to destination code.
 * 2. Using a sorted array of source -> destination code pairs. This
 *    method is used for "combining" characters. There are so few of
 *    them that building a radix tree would be wasteful.
 * 3. Using a conversion function.
 */

/*
 * Radix tree for character conversion.
 *
 * Logically, this is actually four different radix trees, for 1-byte,
 * 2-byte, 3-byte and 4-byte inputs. The 1-byte tree is a simple lookup
 * table from source to target code. The 2-byte tree consists of two levels:
 * one lookup table for the first byte, where the value in the lookup table
 * points to a lookup table for the second byte. And so on.
 *
 * Physically, all the trees are stored in one big array, in 'chars16' or
 * 'chars32', depending on the maximum value that needs to be represented. For
 * each level in each tree, we also store lower and upper bound of allowed
 * values - values outside those bounds are considered invalid, and are left
 * out of the tables.
 *
 * In the intermediate levels of the trees, the values stored are offsets
 * into the chars[16|32] array.
 *
 * In the beginning of the chars[16|32] array, there is always a number of
 * zeros, so that you safely follow an index from an intermediate table
 * without explicitly checking for a zero. Following a zero any number of
 * times will always bring you to the dummy, all-zeros table in the
 * beginning. This helps to shave some cycles when looking up values.
 */
typedef struct
{
  /*
   * Array containing all the values. Only one of chars16 or chars32 is
   * used, depending on how wide the values we need to represent are.
   */
  const uint16 *chars16;
  const uint32 *chars32;

  /* Radix tree for 1-byte inputs */
  uint32    b1root;     /* offset of table in the chars[16|32] array */
  uint8   b1_lower;   /* min allowed value for a single byte input */
  uint8   b1_upper;   /* max allowed value for a single byte input */

  /* Radix tree for 2-byte inputs */
  uint32    b2root;     /* offset of 1st byte's table */
  uint8   b2_1_lower;   /* min/max allowed value for 1st input byte */
  uint8   b2_1_upper;
  uint8   b2_2_lower;   /* min/max allowed value for 2nd input byte */
  uint8   b2_2_upper;

  /* Radix tree for 3-byte inputs */
  uint32    b3root;     /* offset of 1st byte's table */
  uint8   b3_1_lower;   /* min/max allowed value for 1st input byte */
  uint8   b3_1_upper;
  uint8   b3_2_lower;   /* min/max allowed value for 2nd input byte */
  uint8   b3_2_upper;
  uint8   b3_3_lower;   /* min/max allowed value for 3rd input byte */
  uint8   b3_3_upper;

  /* Radix tree for 4-byte inputs */
  uint32    b4root;     /* offset of 1st byte's table */
  uint8   b4_1_lower;   /* min/max allowed value for 1st input byte */
  uint8   b4_1_upper;
  uint8   b4_2_lower;   /* min/max allowed value for 2nd input byte */
  uint8   b4_2_upper;
  uint8   b4_3_lower;   /* min/max allowed value for 3rd input byte */
  uint8   b4_3_upper;
  uint8   b4_4_lower;   /* min/max allowed value for 4th input byte */
  uint8   b4_4_upper;

} pg_mb_radix_tree;

/*
 * UTF-8 to local code conversion map (for combined characters)
 */
typedef struct
{
  uint32    utf1;     /* UTF-8 code 1 */
  uint32    utf2;     /* UTF-8 code 2 */
  uint32    code;     /* local code */
} pg_utf_to_local_combined;

/*
 * local code to UTF-8 conversion map (for combined characters)
 */
typedef struct
{
  uint32    code;     /* local code */
  uint32    utf1;     /* UTF-8 code 1 */
  uint32    utf2;     /* UTF-8 code 2 */
} pg_local_to_utf_combined;

/*
 * callback function for algorithmic encoding conversions (in either direction)
 *
 * if function returns zero, it does not know how to convert the code
 */
typedef uint32 (*utf_local_conversion_func) (uint32 code);

/*
 * Support macro for encoding conversion functions to validate their
 * arguments.  (This could be made more compact if we included fmgr.h
 * here, but we don't want to do that because this header file is also
 * used by frontends.)
 */
#define CHECK_ENCODING_CONVERSION_ARGS(srcencoding,destencoding) \
  check_encoding_conversion_args(PG_GETARG_INT32(0), \
                   PG_GETARG_INT32(1), \
                   PG_GETARG_INT32(4), \
                   (srcencoding), \
                   (destencoding))


/*
 * Some handy functions for Unicode-specific tests.
 */
static inline bool
is_valid_unicode_codepoint(pg_wchar c)
{
  return (c > 0 && c <= 0x10FFFF);
}

static inline bool
is_utf16_surrogate_first(pg_wchar c)
{
  return (c >= 0xD800 && c <= 0xDBFF);
}

static inline bool
is_utf16_surrogate_second(pg_wchar c)
{
  return (c >= 0xDC00 && c <= 0xDFFF);
}

static inline pg_wchar
surrogate_pair_to_codepoint(pg_wchar first, pg_wchar second)
{
  return ((first & 0x3FF) << 10) + 0x10000 + (second & 0x3FF);
}

/*
 * Convert a UTF-8 character to a Unicode code point.
 * This is a one-character version of pg_utf2wchar_with_len.
 *
 * No error checks here, c must point to a long-enough string.
 */
static inline pg_wchar
utf8_to_unicode(const unsigned char *c)
{
  if ((*c & 0x80) == 0)
    return (pg_wchar) c[0];
  else if ((*c & 0xe0) == 0xc0)
    return (pg_wchar) (((c[0] & 0x1f) << 6) |
               (c[1] & 0x3f));
  else if ((*c & 0xf0) == 0xe0)
    return (pg_wchar) (((c[0] & 0x0f) << 12) |
               ((c[1] & 0x3f) << 6) |
               (c[2] & 0x3f));
  else if ((*c & 0xf8) == 0xf0)
    return (pg_wchar) (((c[0] & 0x07) << 18) |
               ((c[1] & 0x3f) << 12) |
               ((c[2] & 0x3f) << 6) |
               (c[3] & 0x3f));
  else
    /* that is an invalid code on purpose */
    return 0xffffffff;
}

/*
 * Map a Unicode code point to UTF-8.  utf8string must have at least
 * unicode_utf8len(c) bytes available.
 */
static inline unsigned char *
unicode_to_utf8(pg_wchar c, unsigned char *utf8string)
{
  if (c <= 0x7F)
  {
    utf8string[0] = c;
  }
  else if (c <= 0x7FF)
  {
    utf8string[0] = 0xC0 | ((c >> 6) & 0x1F);
    utf8string[1] = 0x80 | (c & 0x3F);
  }
  else if (c <= 0xFFFF)
  {
    utf8string[0] = 0xE0 | ((c >> 12) & 0x0F);
    utf8string[1] = 0x80 | ((c >> 6) & 0x3F);
    utf8string[2] = 0x80 | (c & 0x3F);
  }
  else
  {
    utf8string[0] = 0xF0 | ((c >> 18) & 0x07);
    utf8string[1] = 0x80 | ((c >> 12) & 0x3F);
    utf8string[2] = 0x80 | ((c >> 6) & 0x3F);
    utf8string[3] = 0x80 | (c & 0x3F);
  }

  return utf8string;
}

/*
 * Number of bytes needed to represent the given char in UTF8.
 */
static inline int
unicode_utf8len(pg_wchar c)
{
  if (c <= 0x7F)
    return 1;
  else if (c <= 0x7FF)
    return 2;
  else if (c <= 0xFFFF)
    return 3;
  else
    return 4;
}

/*
 * The functions in this list are exported by libpq, and we need to be sure
 * that we know which calls are satisfied by libpq and which are satisfied
 * by static linkage to libpgcommon.  (This is because we might be using a
 * libpq.so that's of a different major version and has encoding IDs that
 * differ from the current version's.)  The nominal function names are what
 * are actually used in and exported by libpq, while the names exported by
 * libpgcommon.a and libpgcommon_srv.a end in "_private".
 */
#if defined(USE_PRIVATE_ENCODING_FUNCS) || !defined(FRONTEND)
#define pg_char_to_encoding     pg_char_to_encoding_private
#define pg_encoding_to_char     pg_encoding_to_char_private
#define pg_valid_server_encoding  pg_valid_server_encoding_private
#define pg_valid_server_encoding_id pg_valid_server_encoding_id_private
#define pg_utf_mblen        pg_utf_mblen_private
#endif

/*
 * These functions are considered part of libpq's exported API and
 * are also declared in libpq-fe.h.
 */
extern int  pg_char_to_encoding(const char *name);
extern const char *pg_encoding_to_char(int encoding);
extern int  pg_valid_server_encoding_id(int encoding);

/*
 * These functions are available to frontend code that links with libpgcommon
 * (in addition to the ones just above).  The constant tables declared
 * earlier in this file are also available from libpgcommon.
 */
extern void pg_encoding_set_invalid(int encoding, char *dst);
extern int  pg_encoding_mblen(int encoding, const char *mbstr);
extern int  pg_encoding_mblen_or_incomplete(int encoding, const char *mbstr,
                      size_t remaining);
extern int  pg_encoding_mblen_bounded(int encoding, const char *mbstr);
extern int  pg_encoding_dsplen(int encoding, const char *mbstr);
extern int  pg_encoding_verifymbchar(int encoding, const char *mbstr, int len);
extern int  pg_encoding_verifymbstr(int encoding, const char *mbstr, int len);
extern int  pg_encoding_max_length(int encoding);
extern int  pg_valid_client_encoding(const char *name);
extern int  pg_valid_server_encoding(const char *name);
extern bool is_encoding_supported_by_icu(int encoding);
extern const char *get_encoding_name_for_icu(int encoding);

extern unsigned char *unicode_to_utf8(pg_wchar c, unsigned char *utf8string);
extern pg_wchar utf8_to_unicode(const unsigned char *c);
extern bool pg_utf8_islegal(const unsigned char *source, int length);
extern int  pg_utf_mblen(const unsigned char *s);
extern int  pg_mule_mblen(const unsigned char *s);

/*
 * The remaining functions are backend-only.
 */
extern int  pg_mb2wchar(const char *from, pg_wchar *to);
extern int  pg_mb2wchar_with_len(const char *from, pg_wchar *to, int len);
extern int  pg_encoding_mb2wchar_with_len(int encoding,
                      const char *from, pg_wchar *to, int len);
extern int  pg_wchar2mb(const pg_wchar *from, char *to);
extern int  pg_wchar2mb_with_len(const pg_wchar *from, char *to, int len);
extern int  pg_encoding_wchar2mb_with_len(int encoding,
                      const pg_wchar *from, char *to, int len);
extern int  pg_char_and_wchar_strcmp(const char *s1, const pg_wchar *s2);
extern int  pg_wchar_strncmp(const pg_wchar *s1, const pg_wchar *s2, size_t n);
extern int  pg_char_and_wchar_strncmp(const char *s1, const pg_wchar *s2, size_t n);
extern size_t pg_wchar_strlen(const pg_wchar *str);
extern int  pg_mblen(const char *mbstr);
extern int  pg_dsplen(const char *mbstr);
extern int  pg_mbstrlen(const char *mbstr);
extern int  pg_mbstrlen_with_len(const char *mbstr, int limit);
extern int  pg_mbcliplen(const char *mbstr, int len, int limit);
extern int  pg_encoding_mbcliplen(int encoding, const char *mbstr,
                  int len, int limit);
extern int  pg_mbcharcliplen(const char *mbstr, int len, int limit);
extern int  pg_database_encoding_max_length(void);
extern mbcharacter_incrementer pg_database_encoding_character_incrementer(void);

extern int  PrepareClientEncoding(int encoding);
extern int  SetClientEncoding(int encoding);
extern void InitializeClientEncoding(void);
extern int  pg_get_client_encoding(void);
extern const char *pg_get_client_encoding_name(void);

extern void SetDatabaseEncoding(int encoding);
extern int  GetDatabaseEncoding(void);
extern const char *GetDatabaseEncodingName(void);
extern void SetMessageEncoding(int encoding);
extern int  GetMessageEncoding(void);

#ifdef ENABLE_NLS
extern int  pg_bind_textdomain_codeset(const char *domainname);
#endif

extern unsigned char *pg_do_encoding_conversion(unsigned char *src, int len,
                        int src_encoding,
                        int dest_encoding);
extern int  pg_do_encoding_conversion_buf(Oid proc,
                      int src_encoding,
                      int dest_encoding,
                      unsigned char *src, int srclen,
                      unsigned char *dest, int destlen,
                      bool noError);

extern char *pg_client_to_server(const char *s, int len);
extern char *pg_server_to_client(const char *s, int len);
extern char *pg_any_to_server(const char *s, int len, int encoding);
extern char *pg_server_to_any(const char *s, int len, int encoding);

extern void pg_unicode_to_server(pg_wchar c, unsigned char *s);
extern bool pg_unicode_to_server_noerror(pg_wchar c, unsigned char *s);

extern unsigned short BIG5toCNS(unsigned short big5, unsigned char *lc);
extern unsigned short CNStoBIG5(unsigned short cns, unsigned char lc);

extern int  UtfToLocal(const unsigned char *utf, int len,
             unsigned char *iso,
             const pg_mb_radix_tree *map,
             const pg_utf_to_local_combined *cmap, int cmapsize,
             utf_local_conversion_func conv_func,
             int encoding, bool noError);
extern int  LocalToUtf(const unsigned char *iso, int len,
             unsigned char *utf,
             const pg_mb_radix_tree *map,
             const pg_local_to_utf_combined *cmap, int cmapsize,
             utf_local_conversion_func conv_func,
             int encoding, bool noError);

extern bool pg_verifymbstr(const char *mbstr, int len, bool noError);
extern bool pg_verify_mbstr(int encoding, const char *mbstr, int len,
              bool noError);
extern int  pg_verify_mbstr_len(int encoding, const char *mbstr, int len,
                bool noError);

extern void check_encoding_conversion_args(int src_encoding,
                       int dest_encoding,
                       int len,
                       int expected_src_encoding,
                       int expected_dest_encoding);

pg_noreturn extern void report_invalid_encoding(int encoding, const char *mbstr, int len);
pg_noreturn extern void report_untranslatable_char(int src_encoding, int dest_encoding,
                           const char *mbstr, int len);

extern int  local2local(const unsigned char *l, unsigned char *p, int len,
            int src_encoding, int dest_encoding,
            const unsigned char *tab, bool noError);
extern int  latin2mic(const unsigned char *l, unsigned char *p, int len,
            int lc, int encoding, bool noError);
extern int  mic2latin(const unsigned char *mic, unsigned char *p, int len,
            int lc, int encoding, bool noError);
extern int  latin2mic_with_table(const unsigned char *l, unsigned char *p,
                 int len, int lc, int encoding,
                 const unsigned char *tab, bool noError);
extern int  mic2latin_with_table(const unsigned char *mic, unsigned char *p,
                 int len, int lc, int encoding,
                 const unsigned char *tab, bool noError);

#ifdef WIN32
extern WCHAR *pgwin32_message_to_UTF16(const char *str, int len, int *utf16len);
#endif

#endif              /* PG_WCHAR_H */

Coverage Report

Created: 2025-06-13 06:06