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

 *

 * quote.c

 *    Functions for quoting identifiers and literals

 *

 * Portions Copyright (c) 2000-2026, PostgreSQL Global Development Group

 *

 *

 * IDENTIFICATION

 *    src/backend/utils/adt/quote.c

 *

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

 */

#include "postgres.h"

#include "utils/builtins.h"

#include "varatt.h"

/*

 * quote_ident -

 *    returns a properly quoted identifier

 */

Datum

quote_ident(PG_FUNCTION_ARGS)

{

  text     *t = PG_GETARG_TEXT_PP(0);

  const char *qstr;

  char     *str;

  str = text_to_cstring(t);

  qstr = quote_identifier(str);

  PG_RETURN_TEXT_P(cstring_to_text(qstr));

}

/*

 * quote_literal_internal -

 *    helper function for quote_literal and quote_literal_cstr

 *

 * NOTE: This must produce output that will work in old servers with

 * standard_conforming_strings = off.  It's used for example by

 * dblink, which may send the result to another server.

 */

static size_t

quote_literal_internal(char *dst, const char *src, size_t len)

{

  const char *s;

  char     *savedst = dst;

  for (s = src; s < src + len; s++)

  {

    if (*s == '\\')

    {

      *dst++ = ESCAPE_STRING_SYNTAX;

      break;

    }

  }

  *dst++ = '\'';

  while (len-- > 0)

  {

    if (SQL_STR_DOUBLE(*src, true))

      *dst++ = *src;

    *dst++ = *src++;

  }

  *dst++ = '\'';

  return dst - savedst;

}

/*

 * quote_literal -

 *    returns a properly quoted literal

 */

Datum

quote_literal(PG_FUNCTION_ARGS)

{

  text     *t = PG_GETARG_TEXT_PP(0);

  text     *result;

  char     *cp1;

  char     *cp2;

  int     len;

  len = VARSIZE_ANY_EXHDR(t);

  /* We make a worst-case result area; wasting a little space is OK */

  result = (text *) palloc(len * 2 + 3 + VARHDRSZ);

  cp1 = VARDATA_ANY(t);

  cp2 = VARDATA(result);

  SET_VARSIZE(result, VARHDRSZ + quote_literal_internal(cp2, cp1, len));

  PG_RETURN_TEXT_P(result);

}

/*

 * quote_literal_cstr -

 *    returns a properly quoted literal

 */

char *

quote_literal_cstr(const char *rawstr)

{

  char     *result;

  int     len;

  int     newlen;

  len = strlen(rawstr);

  /* We make a worst-case result area; wasting a little space is OK */

  result = palloc(

          (len * 2) /* doubling for every character if each one is

                 * a quote */

          + 3     /* two outer quotes + possibly 'E' if needed */

          + 1     /* null terminator */

    );

  newlen = quote_literal_internal(result, rawstr, len);

  result[newlen] = '\0';

  return result;

}

/*

 * quote_nullable -

 *    Returns a properly quoted literal, with null values returned

 *    as the text string 'NULL'.

 */

Datum

quote_nullable(PG_FUNCTION_ARGS)

{

  if (PG_ARGISNULL(0))

    PG_RETURN_TEXT_P(cstring_to_text("NULL"));

  else

    PG_RETURN_DATUM(DirectFunctionCall1(quote_literal,

                      PG_GETARG_DATUM(0)));

}