/*-------------------------------------------------------------------------

 *

 * chklocale.c

 *    Functions for handling locale-related info

 *

 *

 * Copyright (c) 1996-2025, PostgreSQL Global Development Group

 *

 *

 * IDENTIFICATION

 *    src/port/chklocale.c

 *

 *-------------------------------------------------------------------------

 */

#ifndef FRONTEND

#include "postgres.h"

#else

#include "postgres_fe.h"

#endif

#ifndef WIN32

#include <langinfo.h>

#endif

#include "mb/pg_wchar.h"

/*

 * This table needs to recognize all the CODESET spellings for supported

 * backend encodings, as well as frontend-only encodings where possible

 * (the latter case is currently only needed for initdb to recognize

 * error situations).  On Windows, we rely on entries for codepage

 * numbers (CPnnn).

 *

 * Note that we search the table with pg_strcasecmp(), so variant

 * capitalizations don't need their own entries.

 */

struct encoding_match

{

  enum pg_enc pg_enc_code;

  const char *system_enc_name;

};

static const struct encoding_match encoding_match_list[] = {

  {PG_EUC_JP, "EUC-JP"},

  {PG_EUC_JP, "eucJP"},

  {PG_EUC_JP, "IBM-eucJP"},

  {PG_EUC_JP, "sdeckanji"},

  {PG_EUC_JP, "CP20932"},

  {PG_EUC_CN, "EUC-CN"},

  {PG_EUC_CN, "eucCN"},

  {PG_EUC_CN, "IBM-eucCN"},

  {PG_EUC_CN, "GB2312"},

  {PG_EUC_CN, "dechanzi"},

  {PG_EUC_CN, "CP20936"},

  {PG_EUC_KR, "EUC-KR"},

  {PG_EUC_KR, "eucKR"},

  {PG_EUC_KR, "IBM-eucKR"},

  {PG_EUC_KR, "deckorean"},

  {PG_EUC_KR, "5601"},

  {PG_EUC_KR, "CP51949"},

  {PG_EUC_TW, "EUC-TW"},

  {PG_EUC_TW, "eucTW"},

  {PG_EUC_TW, "IBM-eucTW"},

  {PG_EUC_TW, "cns11643"},

  /* No codepage for EUC-TW ? */

  {PG_UTF8, "UTF-8"},

  {PG_UTF8, "utf8"},

  {PG_UTF8, "CP65001"},

  {PG_LATIN1, "ISO-8859-1"},

  {PG_LATIN1, "ISO8859-1"},

  {PG_LATIN1, "iso88591"},

  {PG_LATIN1, "CP28591"},

  {PG_LATIN2, "ISO-8859-2"},

  {PG_LATIN2, "ISO8859-2"},

  {PG_LATIN2, "iso88592"},

  {PG_LATIN2, "CP28592"},

  {PG_LATIN3, "ISO-8859-3"},

  {PG_LATIN3, "ISO8859-3"},

  {PG_LATIN3, "iso88593"},

  {PG_LATIN3, "CP28593"},

  {PG_LATIN4, "ISO-8859-4"},

  {PG_LATIN4, "ISO8859-4"},

  {PG_LATIN4, "iso88594"},

  {PG_LATIN4, "CP28594"},

  {PG_LATIN5, "ISO-8859-9"},

  {PG_LATIN5, "ISO8859-9"},

  {PG_LATIN5, "iso88599"},

  {PG_LATIN5, "CP28599"},

  {PG_LATIN6, "ISO-8859-10"},

  {PG_LATIN6, "ISO8859-10"},

  {PG_LATIN6, "iso885910"},

  {PG_LATIN7, "ISO-8859-13"},

  {PG_LATIN7, "ISO8859-13"},

  {PG_LATIN7, "iso885913"},

  {PG_LATIN8, "ISO-8859-14"},

  {PG_LATIN8, "ISO8859-14"},

  {PG_LATIN8, "iso885914"},

  {PG_LATIN9, "ISO-8859-15"},

  {PG_LATIN9, "ISO8859-15"},

  {PG_LATIN9, "iso885915"},

  {PG_LATIN9, "CP28605"},

  {PG_LATIN10, "ISO-8859-16"},

  {PG_LATIN10, "ISO8859-16"},

  {PG_LATIN10, "iso885916"},

  {PG_KOI8R, "KOI8-R"},

  {PG_KOI8R, "CP20866"},

  {PG_KOI8U, "KOI8-U"},

  {PG_KOI8U, "CP21866"},

  {PG_WIN866, "CP866"},

  {PG_WIN874, "CP874"},

  {PG_WIN1250, "CP1250"},

  {PG_WIN1251, "CP1251"},

  {PG_WIN1251, "ansi-1251"},

  {PG_WIN1252, "CP1252"},

  {PG_WIN1253, "CP1253"},

  {PG_WIN1254, "CP1254"},

  {PG_WIN1255, "CP1255"},

  {PG_WIN1256, "CP1256"},

  {PG_WIN1257, "CP1257"},

  {PG_WIN1258, "CP1258"},

  {PG_ISO_8859_5, "ISO-8859-5"},

  {PG_ISO_8859_5, "ISO8859-5"},

  {PG_ISO_8859_5, "iso88595"},

  {PG_ISO_8859_5, "CP28595"},

  {PG_ISO_8859_6, "ISO-8859-6"},

  {PG_ISO_8859_6, "ISO8859-6"},

  {PG_ISO_8859_6, "iso88596"},

  {PG_ISO_8859_6, "CP28596"},

  {PG_ISO_8859_7, "ISO-8859-7"},

  {PG_ISO_8859_7, "ISO8859-7"},

  {PG_ISO_8859_7, "iso88597"},

  {PG_ISO_8859_7, "CP28597"},

  {PG_ISO_8859_8, "ISO-8859-8"},

  {PG_ISO_8859_8, "ISO8859-8"},

  {PG_ISO_8859_8, "iso88598"},

  {PG_ISO_8859_8, "CP28598"},

  {PG_SJIS, "SJIS"},

  {PG_SJIS, "PCK"},

  {PG_SJIS, "CP932"},

  {PG_SJIS, "SHIFT_JIS"},

  {PG_BIG5, "BIG5"},

  {PG_BIG5, "BIG5HKSCS"},

  {PG_BIG5, "Big5-HKSCS"},

  {PG_BIG5, "CP950"},

  {PG_GBK, "GBK"},

  {PG_GBK, "CP936"},

  {PG_UHC, "UHC"},

  {PG_UHC, "CP949"},

  {PG_JOHAB, "JOHAB"},

  {PG_JOHAB, "CP1361"},

  {PG_GB18030, "GB18030"},

  {PG_GB18030, "CP54936"},

  {PG_SHIFT_JIS_2004, "SJIS_2004"},

  {PG_SQL_ASCII, "US-ASCII"},

  {PG_SQL_ASCII, NULL}    /* end marker */

};

#ifdef WIN32

/*

 * On Windows, use CP<code page number> instead of CODESET.

 *

 * This routine uses GetLocaleInfoEx() to parse short locale names like

 * "de-DE", "fr-FR", etc.  If those cannot be parsed correctly process falls

 * back to the pre-VS-2010 manual parsing done with using

 * <Language>_<Country>.<CodePage> as a base.

 *

 * Returns a malloc()'d string for the caller to free.

 */

static char *

win32_get_codeset(const char *ctype)

{

  char     *r = NULL;

  char     *codepage;

  uint32    cp;

  WCHAR   wctype[LOCALE_NAME_MAX_LENGTH];

  memset(wctype, 0, sizeof(wctype));

  MultiByteToWideChar(CP_ACP, 0, ctype, -1, wctype, LOCALE_NAME_MAX_LENGTH);

  if (GetLocaleInfoEx(wctype,

            LOCALE_IDEFAULTANSICODEPAGE | LOCALE_RETURN_NUMBER,

            (LPWSTR) &cp, sizeof(cp) / sizeof(WCHAR)) > 0)

  {

    r = malloc(16);     /* excess */

    if (r != NULL)

    {

      /*

       * If the return value is CP_ACP that means no ANSI code page is

       * available, so only Unicode can be used for the locale.

       */

      if (cp == CP_ACP)

        strcpy(r, "utf8");

      else

        sprintf(r, "CP%u", cp);

    }

  }

  else

  {

    /*

     * Locale format on Win32 is <Language>_<Country>.<CodePage>.  For

     * example, English_United States.1252.  If we see digits after the

     * last dot, assume it's a codepage number.  Otherwise, we might be

     * dealing with a Unix-style locale string; Windows' setlocale() will

     * take those even though GetLocaleInfoEx() won't, so we end up here.

     * In that case, just return what's after the last dot and hope we can

     * find it in our table.

     */

    codepage = strrchr(ctype, '.');

    if (codepage != NULL)

    {

      size_t    ln;

      codepage++;

      ln = strlen(codepage);

      r = malloc(ln + 3);

      if (r != NULL)

      {

        if (strspn(codepage, "0123456789") == ln)

          sprintf(r, "CP%s", codepage);

        else

          strcpy(r, codepage);

      }

    }

  }

  return r;

}

#ifndef FRONTEND

/*

 * Given a Windows code page identifier, find the corresponding PostgreSQL

 * encoding.  Issue a warning and return -1 if none found.

 */

int

pg_codepage_to_encoding(UINT cp)

{

  char    sys[16];

  int     i;

  sprintf(sys, "CP%u", cp);

  /* Check the table */

  for (i = 0; encoding_match_list[i].system_enc_name; i++)

    if (pg_strcasecmp(sys, encoding_match_list[i].system_enc_name) == 0)

      return encoding_match_list[i].pg_enc_code;

  ereport(WARNING,

      (errmsg("could not determine encoding for codeset \"%s\"", sys)));

  return -1;

}

#endif

#endif              /* WIN32 */

/*

 * Given a setting for LC_CTYPE, return the Postgres ID of the associated

 * encoding, if we can determine it.  Return -1 if we can't determine it.

 *

 * Pass in NULL to get the encoding for the current locale setting.

 * Pass "" to get the encoding selected by the server's environment.

 *

 * If the result is PG_SQL_ASCII, callers should treat it as being compatible

 * with any desired encoding.

 *

 * If running in the backend and write_message is false, this function must

 * cope with the possibility that elog() and palloc() are not yet usable.

 */

int

pg_get_encoding_from_locale(const char *ctype, bool write_message)

{

  char     *sys;

  int     i;

#ifndef WIN32

  locale_t  loc;

#endif

  /* Get the CODESET property, and also LC_CTYPE if not passed in */

  if (!ctype)

    ctype = setlocale(LC_CTYPE, NULL);

  /* If locale is C or POSIX, we can allow all encodings */

  if (pg_strcasecmp(ctype, "C") == 0 ||

    pg_strcasecmp(ctype, "POSIX") == 0)

    return PG_SQL_ASCII;

#ifndef WIN32

  loc = newlocale(LC_CTYPE_MASK, ctype, (locale_t) 0);

  if (loc == (locale_t) 0)

    return -1;       /* bogus ctype passed in? */

  sys = nl_langinfo_l(CODESET, loc);

  if (sys)

    sys = strdup(sys);

  freelocale(loc);

#else

  sys = win32_get_codeset(ctype);

#endif

  if (!sys)

    return -1;       /* out of memory; unlikely */

  /* Check the table */

  for (i = 0; encoding_match_list[i].system_enc_name; i++)

  {

    if (pg_strcasecmp(sys, encoding_match_list[i].system_enc_name) == 0)

    {

      free(sys);

      return encoding_match_list[i].pg_enc_code;

    }

  }

  /* Special-case kluges for particular platforms go here */

#ifdef __darwin__

  /*

   * Current macOS has many locales that report an empty string for CODESET,

   * but they all seem to actually use UTF-8.

   */

  if (strlen(sys) == 0)

  {

    free(sys);

    return PG_UTF8;

  }

#endif

  /*

   * We print a warning if we got a CODESET string but couldn't recognize

   * it.  This means we need another entry in the table.

   */

  if (write_message)

  {

#ifdef FRONTEND

    fprintf(stderr, _("could not determine encoding for locale \"%s\": codeset is \"%s\""),

        ctype, sys);

    /* keep newline separate so there's only one translatable string */

    fputc('\n', stderr);

#else

    ereport(WARNING,

        (errmsg("could not determine encoding for locale \"%s\": codeset is \"%s\"",

            ctype, sys)));

#endif

  }

  free(sys);

  return -1;

}