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/*
* crypt_args.cpp
*
* Notes: since argv[] array contains c-style char strings, I chose to use C
* functions to work on them instead of dealing with C++ class string
* conversions.
*
*/
#include "crypt_args.h"
char *fname;
char *keyfname;
char *outfname;
int crypt_args(int argc, char **argv)
{
/* flags */
int fname_f = 0;
int keyfname_f = 0;
int resultfile_f = 0;
int usage_f = 0;
int fname_args = 0;
int keyfname_args = 0;
int resultfile_args = 0;
int opt_args = 0;
int i;
for (i = 1; i < argc; i++)
{
if (argc > 7)
{
fprintf(stderr, "too many options\n");
usage_f = 1;
break;
}
/* skip non option arguments */
if (!strchr(argv[i], '-'))
{
opt_args++;
if (fname_f)
{
if (i-1 == fname_f)
fname_args++;
/* not allowed to have 2 args */
if ((i-2 == fname_f) && argv[i-1][0] != '-')
{
fprintf(stderr, "too many arguments to \"-f\" option\n");
usage_f = 1;
break;
}
}
if (keyfname_f)
{
if (i-1 == keyfname_f)
keyfname_args++;
/* not allowed to have 2 args */
if ((i-2 == keyfname_f) && argv[i-1][0] != '-')
{
fprintf(stderr, "too many arguments to \"-k\" option\n");
usage_f = 1;
break;
}
}
if (resultfile_f)
{
if (i-1 == resultfile_f)
resultfile_args++;
/* not allowed to have 2 args */
if ((i-2 == resultfile_f) && argv[i-1][0] != '-')
{
fprintf(stderr, "too many arguments to \"-o\" option\n");
usage_f = 1;
break;
}
}
continue;
}
else if (strcmp(argv[i], "-f") == 0)
fname_f = i;
else if (strcmp(argv[i], "-k") == 0)
keyfname_f = i;
else if (strcmp(argv[i], "-o") == 0)
resultfile_f = i;
else
{
fprintf(stderr, "unknown option \"%s\"\n", argv[i]);
usage_f = 1;
break;
}
}
/* error checking */
if (usage_f || opt_args > 3 || (fname_f && !fname_args) || (resultfile_f &&
!resultfile_args) || (keyfname_f && !keyfname_args) || (!fname_f &&
!keyfname_f && !resultfile_f && opt_args))
{
printf("usage: %s [-f] file [-k] key [-o ] output\n", argv[0]);
exit(EXIT_FAILURE);
}
/* used for line reading */
ssize_t amount_read = 0;
int args_parsed = 0;
size_t line_sz = 0;
char *line_ptr = NULL;
if (fname_f)
fname = strdup(argv[fname_f+1]);
else
{
/* ask user for the filename */
printf("please provide the file to be encrypted/decrypted: ");
fname = (char *) malloc(sizeof(char) * 100);
if (!fname)
{
perror("malloc");
exit(EXIT_FAILURE);
}
do
{
fflush(stdin);
amount_read = getline(&line_ptr, &line_sz, stdin);
args_parsed = sscanf(line_ptr, "%s", fname);
if (args_parsed != 1)
fprintf(stderr, "invalid input, please try again: ");
} while (args_parsed != 1);
}
if (keyfname_f)
keyfname = strdup(argv[keyfname_f+1]);
else
{
/* ask user for the filename */
printf("please provide the file that contains the key: ");
keyfname = (char *) malloc(sizeof(char) * 100);
if (!keyfname)
{
perror("malloc");
exit(EXIT_FAILURE);
}
do
{
fflush(stdin);
amount_read = getline(&line_ptr, &line_sz, stdin);
args_parsed = sscanf(line_ptr, "%s", keyfname);
if (args_parsed != 1)
fprintf(stderr, "invalid input, please try again: ");
} while (args_parsed != 1);
}
if (resultfile_f)
outfname = strdup(argv[resultfile_f+1]);
else
{
/* ask user for the filename */
printf("please specify the output file: ");
outfname = (char *) malloc(sizeof(char) * 100);
if (!outfname)
{
perror("malloc");
exit(EXIT_FAILURE);
}
do
{
fflush(stdin);
amount_read = getline(&line_ptr, &line_sz, stdin);
args_parsed = sscanf(line_ptr, "%s", outfname);
if (args_parsed != 1)
fprintf(stderr, "invalid input, please try again: ");
} while (args_parsed != 1);
}
if (line_ptr)
free(line_ptr);
return 0;
}
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