initial

1 files changed, 59 insertions, 0 deletions

diff --git a/src/commands/dd.c b/src/commands/dd.c
new file mode 100644
index 0000000..278dee3
--- /dev/null
+++ b/src/commands/dd.c
@@ -0,0 +1,59 @@
+#include "../command.h"
+#include <stdio.h>
+
+static void help() {
+    printf("Usage: dd [if=FILE] [of=FILE] [bs=N] [count=N]\n\n");
+    printf("Copy a file with converting and formatting\n\n");
+    printf("if=FILE\t\tRead from FILE instead of stdin\n");
+	printf("of=FILE\t\tWrite to FILE instead of stdout\n");
+	printf("bs=N\t\tRead and write N bytes at a time\n");
+	printf("count=N\t\tCopy only N input blocks\n");
+    exit(EXIT_SUCCESS);
+}
+
+COMMAND(dd) {
+
+    FILE* in_file = stdin;
+    FILE* out_file = stdout;
+    int bs = 1024;
+    int count = -1;
+
+    for (int i = 0; i < argc; i++) {
+        if (prefix("if=", argv[i])) {
+            char* path = argv[i] + 3;
+            in_file = get_file(path, "rb");
+        } else if (prefix("of=", argv[i])) {
+            char* path = argv[i] + 3;
+            out_file = get_file(path, "wb");
+        } else if (prefix("bs=", argv[i])) {
+            char* str = argv[i] + 3;
+            bs = get_number(str);
+            if (bs < 1) {
+                error("error: block size must be greater than 0");
+            }
+        } else if (prefix("count=", argv[i])) {
+            char* str = argv[i] + 6;
+            count = get_number(str);
+            if (count < 1) {
+                error("error: count must be greather than 0");
+            }
+        } else if (streql("--help", argv[i])) {
+            help();
+        } else {
+            error("error: unkown option %s", argv[i]);
+        }
+    }
+ 
+    char* buffer = malloc(bs);
+    size_t read;
+    while ((read = fread(buffer, 1, bs, in_file)) != 0) {
+        fwrite(buffer, 1, read, out_file);
+        if (--count, count == 0) break;
+    }
+
+    free(buffer);
+    fclose(in_file);
+    fclose(out_file);
+
+    return EXIT_SUCCESS;
+}