kwlookup.c File Reference

#include "c.h"
#include <ctype.h>
#include "parser/keywords.h"

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Functions
const ScanKeyword *	ScanKeywordLookup (const char *text, const ScanKeyword *keywords, int num_keywords)

---

Function Documentation

const ScanKeyword* ScanKeywordLookup	(	const char *	text,
		const ScanKeyword *	keywords,
		int	num_keywords
	)

Definition at line 39 of file kwlookup.c.

References i, ScanKeyword::name, NAMEDATALEN, and word().

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

{
    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; i < len; i++)
    {
        char        ch = text[i];

        if (ch >= 'A' && ch <= 'Z')
            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;
}