cfg.c

/* =======================================================================
    CFG.c       Generic configuration file handler.

                A. Reitsma, Delft, The Netherlands.
                v1.00  94-07-09  Public Domain.
 ---------------------------------------------------------------------- */

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include "cfg.h"

#define LINE_LEN_MAX    128                  /* actual max line length  */
#define BUFFERSIZE      LINE_LEN_MAX +2      /* ... including \n and \0 */

enum RetVal
{
    NO_PROBLEMS,
    ERR_FOPEN,
    ERR_MEM,
};

int CfgRead( char * Filename, struct CfgStrings * CfgInfo )
{
    char Buffer[ BUFFERSIZE ];
    char * WorkPtr ;
    char * CfgName ;
    char * CfgData ;
    struct CfgStrings * Cfg ;
    FILE * CfgFile ;

    CfgFile = fopen( Filename, "r" );
    if( NULL == CfgFile )
    {
        return ERR_FOPEN ;
    }

    while( NULL != fgets( Buffer, BUFFERSIZE, CfgFile ))
    {
        /* clip off optional comment tail indicated by a semi-colon
        */
        if( NULL != (WorkPtr = strchr( Buffer, ';' )))
            *WorkPtr = '\0';
        else
            WorkPtr = Buffer + strlen( Buffer );

        /* clip off trailing and leading white space
        */
        WorkPtr--;
        while( isspace( *WorkPtr ) && WorkPtr >= Buffer )
            *WorkPtr-- = '\0';
        WorkPtr = Buffer;
        while( isspace( *WorkPtr ))
            WorkPtr++;
        if( 0 == strlen( WorkPtr ))
            continue;

        CfgName = strtok( WorkPtr, " =" );
        if( NULL != CfgName )
        {
            /* Condition the name (lower case required),
               and strip leading white and a 'late' = from data part.
            */
            strlwr( CfgName );
            CfgData = strtok( NULL, "" );
            while( isspace( *CfgData ))
                CfgData++;
            if( '=' == *CfgData )
                CfgData++;
            while( isspace( *CfgData ))
                CfgData++;

            /* look for matching 'name'
            */
            Cfg = CfgInfo ;
            while( NULL != Cfg->name && 0 != strcmp( Cfg->name, CfgName ))
                Cfg++;

            /* duplicate the data if the name is found.
            */
            if( NULL != Cfg->name )
            {
                Cfg->data = strdup( CfgData ); /* strdup is not ANSI    */
                                           /* memory leaks if Cfg->data */
                                           /* is malloc'ed already      */
                if( NULL == Cfg->data )
                {
                    fclose( CfgFile );
                    return ERR_MEM;
                }
            }   /* undetected error on failure should not be a problem  */
                /* as configuration reading should be done early.       */
        }       /* but test and handle it anyway ...                    */
    }
    fclose( CfgFile );
    return NO_PROBLEMS ;
}

#ifdef TEST

struct CfgStrings CfgDemoData[] =
{
    { "workpath", NULL },
    { "archiver", NULL },
    { "splitter", NULL },
    { NULL, NULL }         /* array terminator. REQUIRED !!! */
};

main( int argc, char * argv[] )
{
    int ix ;

    if( argc > 1 )
        CfgRead( argv[ 1 ], CfgDemoData );
    else
        return ERR_FOPEN ;

    printf( "%s\n", argv[ 0 ]);
    for( ix = 0; ix < 4 ; ix++ ) /* intentionally one too much */
       printf( "CfgItem \"%s\" is \"%s\"\n", CfgDemoData[ ix ].name,
                                             CfgDemoData[ ix ].data );
    return NO_PROBLEMS;
}
#endif

/* ==== CFG.c end ===================================================== */