1 files changed, 118 insertions, 0 deletions
diff --git a/src/options.c b/src/options.c
new file mode 100644
index 0000000..2017ba5
--- /dev/null
+++ b/src/options.c
@@ -0,0 +1,118 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "options.h"
+#include "print.h"
+
+#define OPTIONS_DEFAULT_SECTOR_SIZE 512
+#define OPTIONS_DEFAULT_BUFFER_SIZE (4 * 1024 * 1024)
+
+void options_init(options_t *const opts);
+int options_parse_unsigned(const char *const arg, uint32_t *const value);
+
+int
+options_parse(int argc, char **argv, options_t *const opts)
+{
+    options_init(opts);
+
+    int ch;
+    char *arg_sector_size = NULL;
+    char *arg_buffer_size = NULL;
+
+    while ((ch = getopt(argc, argv, ":s:b:h")) != -1) {
+        switch (ch) {
+        case 's':
+            arg_sector_size = optarg;
+            break;
+
+        case 'b':
+            arg_buffer_size = optarg;
+            break;
+
+        case 'h':
+            opts->help = true;
+            break;
+
+        case ':':
+            print_error("missing argument for option '-%c'", optopt);
+            return 1;
+
+        default:
+            print_error("unknown option '-%c'", optopt);
+            return 1;
+        }
+    }
+
+    argc -= optind;
+    argv += optind;
+
+    if (opts->help) {
+        return 0;
+    } else if (argc < 2) {
+        print_error("missing arguments");
+        return 1;
+    } else if (argc > 3) {
+        print_error("too many arguments");
+        return 1;
+    }
+
+    /* Convert numbers in the arguments */
+    if ((arg_sector_size != NULL) &&
+        options_parse_unsigned(arg_sector_size, &(opts->sector_size))) {
+        print_error("incorrect sector size");
+        return 1;
+    } else if ((arg_buffer_size != NULL) &&
+               options_parse_unsigned(arg_buffer_size, &(opts->buffer_size))) {
+        print_error("incorrect buffer size");
+        return 1;
+    } else if (opts->sector_size == 0) {
+        print_error("sector size cannot be 0");
+        return 1;
+    } else if (opts->buffer_size == 0) {
+        print_error("buffer size cannot be 0");
+        return 1;
+    } else if (opts->sector_size > opts->buffer_size) {
+        print_error("sector size cannot larger than buffer size");
+        return 1;
+    } else if ((opts->buffer_size % opts->sector_size) != 0) {
+        print_error("buffer size is not multiple of sector size");
+        return 1;
+    }
+
+    /* Pick the file paths */
+    int last_path_index = argc - 1;
+    opts->out_file_path = argv[last_path_index--];
+    opts->ref_file_path = argv[last_path_index--];
+    if (last_path_index >= 0) {
+        opts->in_file_path = argv[last_path_index];
+    }
+
+    return 0;
+}
+
+void
+options_init(options_t *const opts)
+{
+    opts->help = false;
+    opts->sector_size = OPTIONS_DEFAULT_SECTOR_SIZE;
+    opts->buffer_size = OPTIONS_DEFAULT_BUFFER_SIZE;
+
+    opts->in_file_path = NULL;
+    opts->ref_file_path = NULL;
+    opts->out_file_path = NULL;
+}
+
+int
+options_parse_unsigned(const char *const arg, uint32_t *const value)
+{
+    char *end;
+
+    errno = 0;
+
+    *value = strtoul(arg, &end, 0);
+
+    return ((*end != '\0') || (errno != 0)) ? -1 : 0;
+}