Keskustelu: Ohjelmointikysymykset: C++: Tiedoston käpistely yms

/**************************************************
 *  Program to convert txt-file to binary file
 *  If conversion fails for some reason it will write
 *  a error.txt file which you can edit and try to run this
 *  program again to convert the fixed file  to a binary file.
 *  Usage: convert_file <input file> <output file>
 *  	   More info with -h flag
 *
 **************************************************/

/*
  TODO:
  -Change the perror to use stderror -DONE
  -Add proper error handling
  -Add error procedure if txt file has errors
  -Is assert truly needed, can it be removed
  -Fix getline before sscanf | getline seems to work, sscanf doesn't
  -Remove the debug lines (##) from final version

  CURRENT STATUS:
  -Compiles but causes segmentation fault

*/
#include <stdio.h>       /* fprintf */
#include <string.h>      /* strerror */
#include <stdlib.h>      /* malloc, free, exit */
#include <assert.h>      /* assert for debugging */
#include <errno.h>       /* errno */
#include <sys/types.h>   /* getline */

/**********************/
/* MACROS             */

#define BUFFER 512       /* Define default buffer size                */
#define DEBUG 1          /* Verbose output, enables the DEBUG lines   */

/*********************/
/* GLOBAL VARIABLES  */
extern int errno;        /* Error handling */

/**********************/
/* STRUCTS            */

struct Data {
  char license[6];              /* Car license */
  char manufacturer[BUFFER];    /* Manufacturer of the car */
  char model[BUFFER];           /* Model of the car */
  int year;                     /* Year the car was made */
  float driven;                 /* How much the car is driven for in km */
  char notice[BUFFER];          /* Other info, has the car been checked etc. */
  struct Data *next;            /* Pointer to next struct on the list  */
  };

struct Data *temp, *info, *head, *tptr;   /* Pointers needed by linked list */

/**********************/
/* FUNCTIONS          */

int print_help()
{
  printf("\tConvert_file <input file> <output file>\n \
        Program to convert txt-file to binary file\n \
        If conversion fails for some reason it will write\n \
        a error.txt file which you can edit and try to run this\n \
        program again to convert the error to a binary file.\n\n \
        Usage: convert_file -c <input file> <output file>\n\n \
        Available command line switchs:\n");

        printf("\n\t-c (C)onvert <file1> to <file2>: Converts ASCII file to binary file\n \
        \t-f (F)ix <file>: Reads error.txt and writes it to output file if OK\n\n");
	return 0;
}

char * fix_buffer(char *buffer)         /* Function that tries to fix the buffer input */
{
  /* Check the buffer string and try to figure what is the problem in it */
  /* Case 1: Too few arguments */
  /* Case 2: Too much arguments*/
  /* Case 3: Wrong type of arguments */
  /* Case 4: Missing delimiter on line */
  /* Case 5: Empty line on middle of file */
  /* Case 6: */
  return buffer;
}
/**********************/
/* MAIN */

int main(int argc, char *argv[])
{
 int i;               /* Index variable for loops */
 FILE *file1,*file2;  /* Define input file (fp) and output file (fp2) */
 char *buffer;        /* Buffer string where to check and modify data */
  int return_value;   /* Variable to hold our return values */
 size_t len = 0;
 ssize_t read;

 /* Run through command arguments and */
 /* check if some switches were given */
 for(i=1;i<argc;i++)
        {
                if(argv[i][0] == '-')
                {
                        switch(argv[i][1])
                        {
                        case 'h' :
                                print_help();
				exit(0);
                        case 'f' :
			        break;
                        default :
                                printf("Unknown parameter %s given\n",argv[i]);
				exit(1);
                        }
                }
        }

 /* If no switches found check that */
 /* there's enough parametres given to program */
 if(argc<3) { printf("%s -hf <file1> <file2>\n",argv[0]); exit(1); }

 /* Try to open txt file for reading and if not succesfull print error */
 if (DEBUG) {
   assert((file1=fopen(argv[1],"r")));
 }
 else {
   if ((file1=fopen(argv[1],"r"))==NULL) {
     fprintf( stderr, strerror( errno ) );
     exit(EXIT_FAILURE);
   }
 }

 /* Set pointer values to NULL */
 printf("\n##Setting temp->next to NULL");
 //temp->next = NULL;
 printf("\n##Setting info->next to NULL");
 //info->next = NULL;
 printf("\n##Setting head->next to NULL");
 //head->next = NULL;
 printf("\n##Setting tptr->next to NULL");
 //tptr->next = NULL;

 /* <<<< READING OF FILE1 BEGINS >>>>*/
 read = 0;
 return_value = 0;

 /* Start looping the file until EOF is reached */
 while(!feof(file1)) {
   /* Read line from file to buffer */
   read = getline(&buffer, &len, file1); /* returns -1 if fails */
   printf("## Buffer is: %s\nlen is: %d\n",buffer,len);
   if (read == -1) {
     printf("Couldn't read line from file to buffer!\nRead = %d",read);
     exit(EXIT_FAILURE);
   }
   /* Try to get 6 parameters from the buffer or try to cope with error*/
   return_value == sscanf(buffer, "%5s,%511s,%511s,%d,%f,%511s",temp->license, temp->manufacturer, temp->model, &temp->year, &temp->driven, temp->notice);
   printf("##Returnvalue before if-statement: %d\n",return_value);
   printf("##Temp values: %s %s %s %d %f %s",temp->license, temp->manufacturer, temp->model, temp->year, temp->driven, temp->notice);
   printf("##Give temp return value instead of %d: ", return_value);
   scanf("%d",&return_value);
   if (return_value == 6) {   /* Change to switch-case structure? */
     info = malloc(sizeof *info);

     /* Is following correct? */
     if (info == NULL) {
       fprintf(stderr, strerror (errno) );
       exit(EXIT_FAILURE);
     }

     printf("##Temp values before moving: %s,%s,%s,%d,%f,%s\n", temp->license,temp->manufacturer,temp->model,temp->year,temp->driven,temp->notice);

     /* Copy values from temp to info */
     info = temp;

     printf("##Info values after moving: %s,%s,%s,%d,%f,%s\n", info->license,info->manufacturer,info->model,info->year,info->driven,info->notice);


     /* If this is the first info struct point head pointer to it... */
     if(!head) {
       head = info;
       tptr = info;
     }
     /* ...otherwise put the struct after */
     /* the last element in the list */
     else {
       tptr->next = info;
       tptr = info;
     }

     /* If error occures in file, print it and exit ??? IS THIS NEEDED?*/
     if(ferror(file1)) {
       fprintf(stderr, strerror(errno) );
       exit(EXIT_FAILURE);
     }
   }
   /* <<<< IF FSCANF FAILS  >>>>*/
   else {
     /* Try to fix things, try to read values and put empty values instead */
     printf("Sscanf return value is %d", return_value);
     printf("Error while reading data from %s .\nTrying to fix it...", argv[1]);
     //char *new_buffer[BUFFER];
     //new_buffer = fix_me(buffer);
     /* Read line and write it in ASCII to error file for inspection */
   }
 }

 /* Close file1 after use*/
 fclose(file1);

 /* <<<< WRITING TO FILE2 BEGING >>>>*/

 /* Try to open file2 for binary write. */
 /* If error is found, print it and exit */
 if (DEBUG) {
   assert((file2=fopen(argv[1],"wb")));
 }
 else {
   if ((file2=fopen(argv[1],"wb"))==NULL) {
     fprintf(stderr,strerror(errno));
     exit(EXIT_FAILURE);
   }
 }

 /* Set temp pointer to head so */
 /* following list manipulations will succeed */
 tptr = head;

 /* Write info structs from the linked list to file and free unused structs */
 /* Do while not in last item (Will it work for last item?) */
 while (head->next) {
   if(DEBUG) {
     assert(fwrite(&info, sizeof info, 1, file2));
   }
   else {
     fwrite(&info, sizeof info, 1, file2); /* Check return value for success */
   }
   /* Move head pointer to next item and then free the old head item*/
   head = head->next;
   free(tptr);
   tptr = head;

   printf("##Writing following to file: %s,%s,%s,%d,%f,%s\n", info->license,info->manufacturer,info->model,info->year,info->driven,info->notice);

   if(ferror(file1)) {
     fprintf(stderr,strerror(errno));
     exit(EXIT_FAILURE);
   }
 }
 /* Closing both files after use*/
 fclose(file2);

 return (EXIT_SUCCESS);  /* End main */
}