kwlookup.c File Reference

#include "c.h"
#include "common/kwlookup.h"

Include dependency graph for kwlookup.c:

Go to the source code of this file.

Functions
int	ScanKeywordLookup (const char *str, const ScanKeywordList *keywords)

Function Documentation

ScanKeywordLookup()

int ScanKeywordLookup	(	const char *	str,
		const ScanKeywordList *	keywords
	)

Definition at line 38 of file kwlookup.c.

{
    size_t      len;
    int         h;
    const char *kw;
 
    /*
     * Reject immediately if too long to be any keyword.  This saves useless
     * hashing and downcasing work on long strings.
     */
    len = strlen(str);
    if (len > keywords->max_kw_len)
        return -1;
 
    /*
     * Compute the hash function.  We assume it was generated to produce
     * case-insensitive results.  Since it's a perfect hash, we need only
     * match to the specific keyword it identifies.
     */
    h = keywords->hash(str, len);
 
    /* An out-of-range result implies no match */
    if (h < 0 || h >= keywords->num_keywords)
        return -1;
 
    /*
     * Compare character-by-character to see if we have a match, applying an
     * ASCII-only downcasing to the input characters.  We must not use
     * tolower() since it may produce the wrong translation in some locales
     * (eg, Turkish).
     */
    kw = GetScanKeyword(h, keywords);
    while (*str != '\0')
    {
        char        ch = *str++;
 
        if (ch >= 'A' && ch <= 'Z')
            ch += 'a' - 'A';
        if (ch != *kw++)
            return -1;
    }
    if (*kw != '\0')
        return -1;
 
    /* Success! */
    return h;
}

References GetScanKeyword(), ScanKeywordList::hash, len, ScanKeywordList::max_kw_len, ScanKeywordList::num_keywords, and str.

Referenced by fmtId(), plpgsql_yylex(), quote_identifier(), and ScanECPGKeywordLookup().