1 files changed, 63 insertions, 0 deletions
diff --git a/command/dd.c b/command/dd.c
new file mode 100644
index 0000000..67f8be3
--- /dev/null
+++ b/command/dd.c
@@ -0,0 +1,63 @@
+#include "command.h"
+#include "lslib.h"
+
+#include <stdlib.h>
+
+static void help(void) {
+    printf("Usage: dd [if=FILE] [of=FILE] [bs=N] [count=N]\n\n");
+    printf("Copy a file with converting and formatting\n\n");
+    printf("\tif=FILE\t\tRead from FILE instead of stdin\n");
+    printf("\tof=FILE\t\tWrite to FILE instead of stdout\n");
+    printf("\tbs=N\t\tRead and write N bytes at a time\n");
+    printf("\tcount=N\t\tCopy only N input blocks\n");
+}
+
+COMMAND(dd) {
+
+    FILE* in_file = stdin;
+    FILE* out_file = stdout;
+    int bs = 1024;
+    int count = -1;
+    int i;
+    char* buffer;
+    size_t read;
+
+    parse_help(argc, argv, help);
+
+    for (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("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("count must be greather than 0");
+            }
+        } else {
+            error("unkown option %s", argv[i]);
+        }
+    }
+ 
+    buffer = malloc(bs);
+    
+    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;
+}