c_keywords.c

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/*-------------------------------------------------------------------------
 *
 * c_keywords.c
 *    lexical token lookup for reserved words in postgres embedded SQL
 *
 * src/interfaces/ecpg/preproc/c_keywords.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres_fe.h"

#include <ctype.h>

#include "extern.h"
#include "preproc.h"

/*
 * List of (keyword-name, keyword-token-value) pairs.
 *
 * !!WARNING!!: This list must be sorted, because binary
 *       search is used to locate entries.
 */
static const ScanKeyword ScanCKeywords[] = {
    /* name, value, category */

    /*
     * category is not needed in ecpg, it is only here so we can share the
     * data structure with the backend
     */
    {"VARCHAR", VARCHAR, 0},
    {"auto", S_AUTO, 0},
    {"bool", SQL_BOOL, 0},
    {"char", CHAR_P, 0},
    {"const", S_CONST, 0},
    {"enum", ENUM_P, 0},
    {"extern", S_EXTERN, 0},
    {"float", FLOAT_P, 0},
    {"hour", HOUR_P, 0},
    {"int", INT_P, 0},
    {"long", SQL_LONG, 0},
    {"minute", MINUTE_P, 0},
    {"month", MONTH_P, 0},
    {"register", S_REGISTER, 0},
    {"second", SECOND_P, 0},
    {"short", SQL_SHORT, 0},
    {"signed", SQL_SIGNED, 0},
    {"static", S_STATIC, 0},
    {"struct", SQL_STRUCT, 0},
    {"to", TO, 0},
    {"typedef", S_TYPEDEF, 0},
    {"union", UNION, 0},
    {"unsigned", SQL_UNSIGNED, 0},
    {"varchar", VARCHAR, 0},
    {"volatile", S_VOLATILE, 0},
    {"year", YEAR_P, 0},
};


/*
 * Do a binary search using plain strcmp() comparison.  This is much like
 * ScanKeywordLookup(), except we want case-sensitive matching.
 */
const ScanKeyword *
ScanCKeywordLookup(const char *text)
{
    const ScanKeyword *low = &ScanCKeywords[0];
    const ScanKeyword *high = &ScanCKeywords[lengthof(ScanCKeywords) - 1];

    while (low <= high)
    {
        const ScanKeyword *middle;
        int         difference;

        middle = low + (high - low) / 2;
        difference = strcmp(middle->name, text);
        if (difference == 0)
            return middle;
        else if (difference < 0)
            low = middle + 1;
        else
            high = middle - 1;
    }

    return NULL;
}