Shortening main

This is a discussion on Shortening main within the C Programming forums, part of the General Programming Boards category; I'm normally pretty good at shoretning code, Give me some ideas for shortening my main method of the following code. ...

  1. #1
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    Talking Shortening main

    I'm normally pretty good at shoretning code, Give me some ideas for shortening my main method of the following code. Which does the following commands "ls, ls -l, ls -a, ls -al"

    Code:
    #include <stdio.h>
    #include <sys/types.h>
    #include <fcntl.h>
    #include <dirent.h>
    #include <stdlib.h>
    #include <time.h>
    #include <regex.h>
    #include <errno.h>
    #include <string.h>
    #include <sys/stat.h>
    #include <pwd.h>
    #include <grp.h>
    #include <unistd.h>
    
    /*prototypes*/
    char* workdir(void);
    void printDetailsAll(char* filename,char* path);
    void printDetails(char* filename);
    int matchDetails(char* filename);
    char *get_regerror(int errcode,regex_t *compiled);
    
    int main(int argc, char **argv) {
      int count,index,result;
      char *curdir;
      struct stat sbuf;
      struct dirent **direntp;
      char path[FILENAME_MAX];
    
      if(argv[1] != '\0'){ /*If argument supplied*/
        if(strcmp(argv[1], "-al") == 0){
    	  if(argv[2] != '\0'){/*ls '-al' on an argument*/
            if(stat(argv[2], &sbuf) != -1){
              if(S_ISDIR(sbuf.st_mode)){ /* Is a directory */
                count = scandir(argv[2],&direntp,NULL,alphasort);
                if(count){
                  for(index=0; index<count; ++index){
                    strcpy(path,argv[1]);
                    printDetailsAll(direntp[index]->d_name,path);
                    free(direntp[index]);
    			  }
    			}else{
                  fprintf(stderr,"Can't open %s\n",argv[1]);
                  exit(EXIT_FAILURE);
    			}
    		  }else
                printDetailsAll(argv[2],NULL);             
    		}else
              fprintf(stderr,"Can't stat %s\n", argv[1]);
    	  }else{/*ls '-al' on curdir*/
    	    curdir = workdir(); 
            if(stat(curdir,&sbuf) !=-1){
              count = scandir(curdir,&direntp,NULL,alphasort);
              if(count){
                for(index=0; index<count; ++index){
    		      printDetailsAll(direntp[index]->d_name,NULL);
                  free(direntp[index]);
    			}
    		  }else{
                fprintf(stderr,"Can't open %s\n",curdir);
                exit(EXIT_FAILURE);
    		  }
    		}else{
              fprintf(stderr,"Can't stat %s\n",curdir);
              exit(EXIT_FAILURE);
    		}
            free(curdir);
    	  }
    	}else if(strcmp(argv[1], "-l") == 0){
    	  if(argv[2] != '\0'){/*ls -l on an argument*/
    	    if(stat(argv[2], &sbuf) != -1){
              if(S_ISDIR(sbuf.st_mode)){ /* Is a directory */
                count = scandir(argv[2],&direntp,NULL,alphasort);
                if(count){
                  for(index=0; index<count; ++index){
                    strcpy(path,argv[1]);
    				result = matchDetails(direntp[index]->d_name);
    				if(result > 0)
                      printDetailsAll(direntp[index]->d_name,path);
                    free(direntp[index]);
    			  }
    			}else{
                  fprintf(stderr,"Can't open %s\n",argv[1]);
                  exit(EXIT_FAILURE);
    			}
    		  }else
                printDetailsAll(argv[2],NULL);             
    		}else
              fprintf(stderr,"Can't stat %s\n", argv[1]);
    	  }else{/*ls -l on current dir*/
    	    curdir = workdir(); 
            if(stat(curdir,&sbuf) !=-1){
              count = scandir(curdir,&direntp,NULL,alphasort);
              if(count){
                for(index=0; index<count; ++index){
    			  result = matchDetails(direntp[index]->d_name);
    			  if(result > 0)
    		        printDetailsAll(direntp[index]->d_name,NULL);
                  free(direntp[index]);
    			}
    		  }else{
                fprintf(stderr,"Can't open %s\n",curdir);
                exit(EXIT_FAILURE);
    		  }
    		}else{
              fprintf(stderr,"Can't stat %s\n",curdir);
              exit(EXIT_FAILURE);
    		}
            free(curdir);
    	  }
    	}else if(strcmp(argv[1], "-a") == 0){
    	  if(argv[2] != '\0'){/*ls -a on an argument*/
    	    if(stat(argv[2], &sbuf) != -1){
    		  if(S_ISDIR(sbuf.st_mode)){ /* Is a directory */
                count = scandir(argv[2],&direntp,NULL,alphasort);
                if(count){
                  for(index=0; index<count; ++index){
                    printDetails(direntp[index]->d_name);
                    free(direntp[index]);
    			  }
    			}else{
                  fprintf(stderr,"Can't open %s\n",argv[1]);
                  exit(EXIT_FAILURE);
    			}
    		  }else
                printDetails(argv[2]);             
    		}else
              fprintf(stderr,"Can't stat %s\n", argv[1]);
    	  }else{
    	    curdir = workdir(); 
            if(stat(curdir,&sbuf) !=-1){
              count = scandir(curdir,&direntp,NULL,alphasort);
              if(count){
                for(index=0; index<count; ++index){
                  printDetails(direntp[index]->d_name);
                  free(direntp[index]);
    			}
    		  }else{
                fprintf(stderr,"Can't open %s\n",curdir);
                exit(EXIT_FAILURE);
    		  }
    		}else{
              fprintf(stderr,"Can't stat %s\n",curdir);
              exit(EXIT_FAILURE);
    		}
            free(curdir);
    	  }
    	}
      }else{  /*Normal ls command on curdir*/
        curdir = workdir(); 
        if(stat(curdir,&sbuf) !=-1){
          count = scandir(curdir,&direntp,NULL,alphasort);
          if(count){
            for(index=0; index<count; ++index){
    		  result = matchDetails(direntp[index]->d_name);
    		  if(result > 0)
                printDetails(direntp[index]->d_name);
              free(direntp[index]);
            }
          }else{
            fprintf(stderr,"Can't open %s\n",curdir);
            exit(EXIT_FAILURE);
          }
        }else{
          fprintf(stderr,"Can't stat %s\n",curdir);
          exit(EXIT_FAILURE);
        }
        free(curdir);
      }
      return EXIT_SUCCESS;
    }
    
    /*Get the current working directory*/
    char* workdir(){
      while(1){
        char* wdbuf = (char*)malloc(FILENAME_MAX);
        if(getcwd(wdbuf,FILENAME_MAX) == wdbuf)
          return wdbuf;
        free(wdbuf);
        if(errno != ERANGE){
          fprintf(stderr,"Out of range\n");
          return 0;
        }
      }
    }
    
    
    /*Will print all details of a file/dir. */
    void printDetailsAll(char *filename,char *path){
    
      struct passwd *my_passwd;	    /*User details*/
      struct group *my_group;	    /*Group details*/
      struct stat sbuf;		        /*File details*/
      struct tm *strtime;		    /*Time format*/
    
      int fdes;			            /*File descriptor*/
      unsigned char type ='?';	    /*File type*/
      unsigned char usr[] = "---";  /*User Permissions*/
      unsigned char grp[] = "---";  /*Group Permissions*/
      unsigned char oth[] = "---";	/*Other Permissions*/
      unsigned char uid[9], gid[9]; /*User name and Group name*/
      unsigned char mod[13];	    /*Time information*/
      mode_t mode;			        /*Used to determine type and permission bits*/
      char* curdir;			        /*Used to hold the current working directory*/
      char* buf;                    /*Used to hold a link location*/
      time_t now;			        /*Used to format the time*/
      int year;			            /*Used to format the time*/
    
      /*If path is null stat by the curdir*/
      if(path == NULL){
        curdir = workdir();
        strcat(curdir,"/");
        strcat(curdir,filename);
        if(stat(curdir,&sbuf) != -1){
          if(S_ISLNK(sbuf.st_mode)){
            if(readlink(curdir,buf,(size_t)FILENAME_MAX) != -1){
              if(lstat(buf,&sbuf) == -1){
                fprintf(stderr,"Can't stat %s\n",filename);
                return;
              }
            }else
              fprintf(stderr,"Can't readlink %s\n",filename);
          }else if(S_ISREG(sbuf.st_mode)){
            if((fdes = open(curdir,O_RDONLY)) != ENOENT){
              if(fstat(fdes,&sbuf) == -1){
                fprintf(stderr,"Can't stat %s\n",filename);
                return;
              }
              close(fdes);
            }else{
              fprintf(stderr,"Can't open %s\n",filename);
              return;
            }
          }
        }else{
          fprintf(stderr,"Can't stat %s\n",filename);
          return;
        }
        free(curdir);
      /*Otherwise stat by the path provided*/
      }else{
        strcat(path,"/");
        strcat(path,filename);
        if(stat(path,&sbuf) != -1){
          if(S_ISLNK(sbuf.st_mode)){
            if(readlink(path,buf,(size_t)FILENAME_MAX) != -1){
              if(lstat(buf,&sbuf) == -1){
                fprintf(stderr,"Can't stat %s\n",filename);
                return;
              }
            }else
              fprintf(stderr,"Can't readlink %s\n",filename);
          }else if(S_ISREG(sbuf.st_mode)){
            if((fdes = open(path,O_RDONLY)) != ENOENT){
              if(fstat(fdes,&sbuf) == -1){
                fprintf(stderr,"Can't stat %s\n",filename);
                return;
              }
              close(fdes);
            }else{
              fprintf(stderr,"Can't open %s\n",filename);
              return;
            }
          }    
        }else{
          fprintf(stderr,"Path: %s\n",path);
          fprintf(stderr,"Can't stat %s\n",curdir);
          return;
        }
      }      
    
      /*Get file types and permissions*/
      mode = sbuf.st_mode;
      if( S_ISLNK( mode ) ){ type = 'l'; /*symlink*/ printf("%c\n",type);}
      else if( S_ISDIR ( mode ) ) type = 'd'; /*directory*/
      else if( S_ISCHR ( mode ) ) type = 'c'; /*character raw device*/
      else if( S_ISBLK ( mode ) ) type = 'b'; /*block raw device*/
      else if( S_ISFIFO( mode ) ) type = 'p'; /*named pipe*/
      else if( S_ISSOCK( mode ) ) type = 's'; /*Unix domain socket*/
      else if( S_ISREG ( mode ) ) type = '-'; /*regular file*/
      if( mode & S_IRUSR ) usr[0] = 'r';
      if( mode & S_IWUSR ) usr[1] = 'w';
      if( mode & S_IXUSR ) usr[2] = 'x';
      if( mode & S_ISUID ) usr[2] = 's'; /* set UID bit*/
      if( mode & S_IRGRP ) grp[0] = 'r';
      if( mode & S_IWGRP ) grp[1] = 'w';
      if( mode & S_IXGRP ) grp[2] = 'x';
      if( mode & S_ISGID ) grp[2] = 's'; /* set GID bit*/
      if( mode & S_IROTH ) oth[0] = 'r';
      if( mode & S_IWOTH ) oth[1] = 'w';
      if( mode & S_IXOTH ) oth[2] = 'x';
    
      /*Get user information*/
      my_passwd = getpwuid(sbuf.st_uid);
      if(my_passwd != NULL){
        strncpy(uid,my_passwd->pw_name,8);
        uid[8] = '\0';
      }else
        snprintf(uid,9,"%d",sbuf.st_uid);
    
      /*Get group information*/
      my_group = getgrgid(sbuf.st_gid);
      if(my_group != NULL){
        strncpy(gid,my_group->gr_name,8);
        gid[8] = '\0';
      }else
        snprintf(gid,9,"%d",sbuf.st_gid);
    
      /*Format the time to readable form*/
      time(&now);
      year = localtime(&now)->tm_year;
      strtime = localtime(&sbuf.st_ctime);
      if(strtime->tm_year == year)
        strftime(mod,13,"%b %e %R",strtime);
      else
        strftime(mod,13,"%b %e %Y",strtime);
             
      /*print the details*/
      printf("%c%s%s%-6s%-8d%-10s%-10s%-10d%-10s%s\n",
             type,usr,grp,oth,sbuf.st_nlink,
             uid,gid,sbuf.st_size,mod,filename);
    
    }
    
    /*Used to print the filename*/
    void printDetails(char* filename){
      printf("%s\n",filename);
    
    }
    
    /*Used to find process directories*/
    int matchDetails(char* filename){
      int status,regstat;
      char *pattern = "^[^.].*$"; /*Match all strings without a begining '.'*/
      char *result;
    
      regex_t re;
      if((regstat = regcomp(&re,pattern,REG_EXTENDED | REG_NOSUB)) != 0){
        result = get_regerror(regstat,&re);
        fprintf(stderr,"%s\n",result);
        return(0);
      }
      if((status = regexec(&re,filename,(size_t) 0,NULL,0)) != 0)
        return(0);
      regfree(&re);
    	
      return(1);
    
    }
    
    /*Used to store regex errors*/
    char *get_regerror(int errcode,regex_t *compiled){
      size_t length = regerror(errcode,compiled,NULL,0);
      char *buffer = malloc(length);
      (void) regerror(errcode,compiled,buffer,length);
      return buffer;
    }
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  2. #2
    ATH0 quzah's Avatar
    Join Date
    Oct 2001
    Posts
    14,826
    > if(argv[1] != '\0'){ /*If argument supplied*/

    There is a reason they include 'argc'.

    if( argc < 2 ) /*...no argument...*/
    {

    }
    else /*...arguments...*/
    {

    }

    Furthermore, if you want to shorten main, just pass the arguments to another function.

    myfunction( argc[1] );

    Quzah.
    Hope is the first step on the road to disappointment.

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