cfg.c

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/*
 *  Copyright (C) 2006  Baris Simsek, http://www.enderunix.org/simsek
 *  
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *  
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *  
 *  $Id: cfg_8c-source.html,v 1.4 2006/08/26 09:35:02 simsek Exp $
 *  
 *  Common Config Parser
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#include "../include/cupl.h"
#include "../include/cfg.h"

extern int errno;

static int parse_config_file(cfg_data *cfg);
static void add_cfg_array(cfg_data *cfg, char *var, char *val);
static void release_cfg_array(cfg_array *head);

/* To alloc cfg_data object and open config file. */
extern cfg_data *cupl_init_cfg(char *path)
{
    cfg_data *cfg;

    if ((cfg = (cfg_data *) malloc(sizeof(cfg_data))) == NULL) {
        fprintf(stderr, "%s: %d: malloc(): %s.\n", __FILE__, __LINE__,
                strerror(errno));
        return NULL;
    }

    if ((cfg->cfd = fopen(path, "r")) == NULL) {
        fprintf(stderr, "%s: %d: fopen(): %s.\n", __FILE__, __LINE__,
                strerror(errno));
        return NULL;
    }

    cfg->vars = NULL;
    cfg->nov = 0;

    if (parse_config_file(cfg) == -1)
        return NULL;
    
    return cfg;
}

/* To free cfg_data object and close config file. */
extern int cupl_release_cfg(cfg_data *cfg)
{
    if (cfg == NULL) return 0;

    fclose(cfg->cfd);

    if (cfg->vars) release_cfg_array(cfg->vars);

    free(cfg);

    return 1;
}

/* To release cfg_array linked list. */
static void release_cfg_array(cfg_array *head)
{
    cfg_array *prev = head;
    cfg_array *next = head->next;

    while (prev != NULL) {
        /* Save coming chain */
        next = prev->next;

        free(prev);

        /* Move next */
        prev = next;
        if (prev) next = prev->next;
    }
    
    return;
}

/* Parse the config file. */
static int parse_config_file(cfg_data *cfg)
{
    int i, j;
    int lcnt = 0;
    int blen;
    char buf[CFG_VAL_LEN];
    char val[CFG_VAL_LEN];
    char var[CFG_VAR_LEN];
    char ch;

    memset(buf, 0, CFG_VAL_LEN);

    while (fgets(buf, CFG_VAL_LEN, cfg->cfd)) {
        lcnt++;
        ch = buf[0];
        blen = strlen(buf) - 1;

        /* Comments or spaces. Skip. */
        if (USELESS_LINE) {
            goto loop_end;
        }

        /* Invalid chars. Report and skip. */
        if (INVALID) {
            fprintf(stderr, "parse_config_file: Invalid character at line %d.\n", lcnt);
            goto loop_end;
        }

        if (IDENTIFIER) {
            fprintf(stderr, "parse_config_file: Variables must start with a char, line: %d.\n", lcnt);
            goto loop_end;
        }

        /* Valid identifier. */

        /* Get variable */
        memset(var, 0, CFG_VAR_LEN);
        for (i=0;i<blen;i++) {
            ch = buf[i];
            if (END_OF_LINE) {
                fprintf(stderr, "parse_config_file: Syntax error at line %d.\n", lcnt);
                goto loop_end;
            }
            if (INVALID) {
                fprintf(stderr, "parse_config_file: Invalid character at line %d.\n", lcnt);
                goto loop_end;
            }
            if (SEPERATOR) {
                break;
            }
            if (i < CFG_VAR_LEN - 1)
                var[i] = ch;
            else {
                fprintf(stderr, "parse_config_file: Too long variable name at line %d.\n", lcnt);
                goto loop_end;
            }
        }

        i++;

        /* Skip extra seperators. */
        for(j=i;j<blen;j++) {
            ch = buf[j];
            if (SEPERATOR)
                continue;
            else
                break;
        }

        i = j;

        /* Get value */
        memset(val, 0, CFG_VAL_LEN);
        for (j=i;j<blen;j++) {
            ch = buf[j];
            if (END_OF_LINE) {
                break;
            }
            if (INVALID) {
                fprintf(stderr, "parse_config_file: Invalid character at line %d.\n", lcnt);
                goto loop_end;
            }
            if ((j - i) < (CFG_VAL_LEN - 1))
                val[j-i] = ch;
            else {
                fprintf(stderr, "parse_config_file: Too long value at line %d.\n", lcnt);
                goto loop_end;
            }
        }

        add_cfg_array(cfg, var, val);

        cfg->nov = cfg->nov + 1;

loop_end:
        memset(buf, 0, CFG_VAL_LEN);
    }

    return 1;
}

/* Add new item to cfg_array linked list. */
static void add_cfg_array(cfg_data *cfg, char *var, char *val)
{
    cfg_array *tail;
    cfg_array *cfgp;

    tail = cfg->vars;

    if (tail != NULL)
        while (tail->next != NULL)
            tail = tail->next;

    if ((cfgp = (cfg_array *) malloc(sizeof(cfg_array))) == NULL) {
        fprintf(stderr, "%s: %d: malloc(): %s.\n", __FILE__, __LINE__, strerror(errno));
        return;
    }

    strncpy(cfgp->var, var, CFG_VAR_LEN-1);
    strncpy(cfgp->val, val, CFG_VAL_LEN-1);
    cfgp->next = NULL;

    if (cfg->vars == NULL) {
        cfg->vars = cfgp;
    }
    else {
        tail->next = cfgp;
    }


    return;
}

/* To print all the parsed items */
extern void cupl_print_items(cfg_data *cfg)
{
    cfg_array *tmp;

    if (cfg == NULL) return;

    printf("Number of items parsed: %d\n\n", cfg->nov);
    printf("Items:\n");

    tmp = cfg->vars;

    while (tmp != NULL) {
        printf("%s: %s\n", tmp->var, tmp->val);
        tmp = tmp->next;
    }

    return;
}

/* To get a variable from cfg_data object */
extern char *cupl_get_var(char *var, cfg_data *cfg)
{
    cfg_array *tmp = cfg->vars;

    if (cfg == NULL) return NULL;

    while (tmp != NULL) {
        if (strncmp(tmp->var, var, sizeof(tmp->var)) == 0) 
            return tmp->val;
        tmp = tmp->next;
    }

    return NULL;
}

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