YugabyteDB (2.13.1.0-b60, 21121d69985fbf76aa6958d8f04a9bfa936293b5)

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

 *

 * keywords.c

 *    lexical token lookup for key words in PostgreSQL

 *

 *

 * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group

 * Portions Copyright (c) 1994, Regents of the University of California

 *

 *

 * IDENTIFICATION

 *    src/common/keywords.c

 *

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

 */

#ifndef FRONTEND

#include "postgres.h"

#else

#include "postgres_fe.h"

#endif

#ifndef FRONTEND

#include "parser/gramparse.h"

#define PG_KEYWORD(a,b,c) {a,b,c},

#else

#include "common/keywords.h"

/*

 * We don't need the token number for frontend uses, so leave it out to avoid

 * requiring backend headers that won't compile cleanly here.

 */

#define PG_KEYWORD(a,b,c) {a,0,c},

#endif              /* FRONTEND */

const ScanKeyword ScanKeywords[] = {

#include "parser/kwlist.h"

};

const int NumScanKeywords = lengthof(ScanKeywords);

/*

 * ScanKeywordLookup - see if a given word is a keyword

 *

 * The table to be searched is passed explicitly, so that this can be used

 * to search keyword lists other than the standard list appearing above.

 *

 * Returns a pointer to the ScanKeyword table entry, or NULL if no match.

 *

 * The match is done case-insensitively.  Note that we deliberately use a

 * dumbed-down case conversion that will only translate 'A'-'Z' into 'a'-'z',

 * even if we are in a locale where tolower() would produce more or different

 * translations.  This is to conform to the SQL99 spec, which says that

 * keywords are to be matched in this way even though non-keyword identifiers

 * receive a different case-normalization mapping.

 */

const ScanKeyword *

ScanKeywordLookup(const char *text,

          const ScanKeyword *keywords,

          int num_keywords)

{

  int     len,

        i;

  char    word[NAMEDATALEN];

  const ScanKeyword *low;

  const ScanKeyword *high;

  len = strlen(text);

  /* We assume all keywords are shorter than NAMEDATALEN. */

  if (len >= NAMEDATALEN)

    return NULL;

  /*

   * Apply an ASCII-only downcasing.  We must not use tolower() since it may

   * produce the wrong translation in some locales (eg, Turkish).

   */

  
for (i = 0; 15.5M
i < len; 
i++87.6M
)

  {

    char    ch = text[i];

    if (ch >= 'A' && 
ch <= 'Z'86.3M
)

      ch += 'a' - 'A';

    word[i] = ch;

  }

  word[len] = '\0';

  /*

   * Now do a binary search using plain strcmp() comparison.

   */

  low = keywords;

  high = keywords + (num_keywords - 1);

  while (low <= high)

  {

    const ScanKeyword *middle;

    int     difference;

    middle = low + (high - low) / 2;

    difference = strcmp(middle->name, word);

    if (difference == 0)

      return middle;

    else if (difference < 0)

      low = middle + 1;

    else

      high = middle - 1;

  }

  return NULL;

}