/*
**  OSSP cfg - Configuration Parsing
**  Copyright (c) 1999-2002 Ralf S. Engelschall <rse@engelschall.com>
**  Copyright (c) 1999-2002 The OSSP Project (http://www.ossp.org/)
**  Copyright (c) 2001-2002 Cable & Wireless Deutschland (http://www.cw.com/de/)
**
**  This file is part of OSSP cfg, a configuration parsing
**  library which can be found at http://www.ossp.org/pkg/lib/cfg/.
**
**  Permission to use, copy, modify, and distribute this software for
**  any purpose with or without fee is hereby granted, provided that
**  the above copyright notice and this permission notice appear in all
**  copies.
**
**  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
**  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
**  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
**  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
**  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
**  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
**  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
**  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
**  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
**  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
**  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
**  SUCH DAMAGE.
**
**  cfg_syn.c: syntax parsing
*/

#include "cfg.h"
#include "cfg_grid.h"
#include "cfg_node.h"
#include "cfg_fmt.h"
#include "cfg_syn.h"

/* prototypes for Flex-generated scanner */
extern int  cfg_syn_lex_init(void *);
extern int  cfg_syn_lex_destroy(void *);
extern void cfg_syn_set_extra(void *, void *);

/* prototypes for Bison-generated parser */
extern int  cfg_syn_parse(void *);

/* build a node tree according to a textual specification */
cfg_rc_t cfg_syn(cfg_t *cfg, cfg_node_t **node, char *err_buf, size_t err_len, const char *input)
{
    cfg_syn_ctx_t ctx;
    void *yyscan;

    /* initialize scanner */
    cfg_syn_lex_init(&yyscan);
    cfg_syn_set_extra(&ctx, yyscan);

    /* establish our own context which is passed 
       through the parser and scanner */
    ctx.inputptr = input;
    ctx.inputbuf = input;
    ctx.inputlen = strlen(input);
    ctx.cfg      = cfg;
    ctx.node     = NULL;
    ctx.rv       = CFG_OK;
    ctx.err_buf  = err_buf;
    ctx.err_len  = err_len;
    ctx.yyscan   = yyscan;

    /* start the parser loop */
    if (cfg_syn_parse(&ctx))
        ctx.rv = (ctx.rv == CFG_OK ? CFG_ERR_INT : ctx.rv);

    /* destroy scanner */
    cfg_syn_lex_destroy(yyscan);

    /* provide root/top-level node as result */
    *node = ctx.node;

    return ctx.rv;
}

/* remember a parsing error (used internally) */
void cfg_syn_error(cfg_syn_ctx_t *ctx, cfg_rc_t rv, YYLTYPE *loc, const char *fmt, ...)
{
    va_list ap;
    const char *cpF, *cpL;
    const char *cpP, *cpE;
    int line, column;
    char *cpBuf;
    char *cp;
    size_t n;

    /* remember error code */
    ctx->rv = rv;

    /* short circuit processing if no error buffer exists */
    if (ctx->err_buf == NULL || ctx->err_len <= 0)
        return;

    /* determine first and last positions of token */
    cpF = ctx->inputbuf+loc->first;
    cpL = ctx->inputbuf+loc->last;

    /* determine epilog and prolog of token */
    cpP = cpF-4;
    if (cpP < ctx->inputbuf)
        cpP = ctx->inputbuf;
    cpE = cpL+4;
    if (cpE > ctx->inputbuf+ctx->inputlen)
        cpE = ctx->inputbuf+ctx->inputlen;

    /* calculate line and column of token */
    line   = 1;
    column = 1;
    for (cp = (char *)ctx->inputbuf; cp < (ctx->inputbuf+ctx->inputlen) && cp != cpF; cp++) {
        column++;
        if (*cp == '\n') {
            column = 1;
            line++;
        }
    }

    /* extract token context with mark token borders */
    if ((cpBuf = malloc((size_t)((cpE-cpP)+2+1))) == NULL)
        return;
    cp = cpBuf;
    n = cpF-cpP;
    memcpy(cp, cpP, n); cp += n;
    *cp++ = '<';
    n = cpL-cpF;
    memcpy(cp, cpF, n); cp += n;
    *cp++ = '>';
    n = cpE-cpL;
    memcpy(cp, cpL, n); cp += n;
    *cp++ = '\0';

    /* remember parsing error: part I (context part) */
    cfg_fmt_sprintf(ctx->err_buf, sizeof(ctx->err_len), 
                    "line %d, column %d: `%s'; %s",
                    line, column, cpBuf);
    free(cpBuf);

    /* remember parsing error: part II (parsing part) */
    n = strlen(ctx->err_buf);
    va_start(ap, fmt);
    cfg_fmt_vsprintf(ctx->err_buf+n, sizeof(ctx->err_len)-n, fmt, ap);
    va_end(ap);

    return;
}