lexicon.c

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/***************************************************************************
 *   Copyright (C) 2004, 2006 Symbian Software Ltd.                        *
 *   All rights reserved.                                                  *
 *   Copyright (C) 2007-2011 Mike Kinghan, imk@strudl.org                  *
 *   All rights reserved.                                                  *
 *                                                                         *
 *   Contributed originally by Mike Kinghan, imk@strudl.org                *
 *                                                                         *
 *   Redistribution and use in source and binary forms, with or without    *
 *   modification, are permitted provided that the following conditions    *
 *   are met:                                                              *
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 *   Redistributions of source code must retain the above copyright        *
 *   notice, this list of conditions and the following disclaimer.         *
 *                                                                         *
 *   Redistributions in binary form must reproduce the above copyright     *
 *   notice, this list of conditions and the following disclaimer in the   *
 *   documentation and/or other materials provided with the distribution.  *
 *                                                                         *
 *   Neither the name of Symbian Software Ltd. nor the names of its        *
 *   contributors may be used to endorse or promote products derived from  *
 *   this software without specific prior written permission.              *
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 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS   *
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 **************************************************************************/

#include "lexicon.h"
#include "chew.h"
#include "symbol.h"


/* Helpers */

static int
text_match(char const **ptxt, char const *match, size_t nbytes)
{
    int cmp;
    char const *txt = *ptxt;
    if (!nbytes) {
        nbytes = strlen(match);
    }
    for ( ; --nbytes && *txt && *match && *txt == *match; txt = chew_continuation(++txt),++match) {}
    if (*txt < *match) {
        cmp = -1;
    } else if (*txt > *match) {
        cmp = 1;
    } else {
        cmp = 0;
        *ptxt = chew_continuation(++txt);
    }
    return cmp;
}

/* API*/

bool
match_keyword(char const **ptxt, char const *keyword)
{
    char const *saved_txt = *ptxt;
    if (0 == text_match(ptxt,keyword,0) && !is_symbol_start_char(**ptxt)) {
        return true;
    } else {
        *ptxt = saved_txt;
        return false;
    }
}

bool
match_op(char const ** ptxt, char const *op)
{
    char const *txt = *ptxt;
    bool verdict = true;
    assert(op[1] == '\0' || op[2] =='\0');
    if (txt[0] != op[0]) {
        verdict = false;
    } else {
        if (op[1]) {
            txt = chew_continuation(++txt);
            if (txt[0] != op[1]) {
                verdict = false;
            }
        } else if (txt[1] == op[0]) {
            verdict = false;
        }
    }
    if (verdict) {
        *ptxt = txt + 1;
    }
    return verdict;
}

/* EOF*/