diff options
Diffstat (limited to 'crypt_args.cpp')
| -rw-r--r-- | crypt_args.cpp | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/crypt_args.cpp b/crypt_args.cpp new file mode 100644 index 0000000..7c1dc67 --- /dev/null +++ b/crypt_args.cpp @@ -0,0 +1,195 @@ +/* + * 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 = 80; + char *line_ptr = (char *) malloc(sizeof(char) * line_sz); + if (!line_ptr) + { + perror("malloc"); + exit(EXIT_FAILURE); + } + + 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; +} + |