FEAT: Bincode - added padding command PAD

Author: Oldes

src/core/u-bincode.c

@@ -506,6 +506,13 @@ static REBCNT EncodedU32_Size(u32 value) {
 							continue;
 						}
 						goto error;
+					case SYM_PAD:
+						if (IS_INTEGER(next)) {
+							i = count % VAL_INT32(next);
+							count += (i > 0) ? VAL_INT32(next) - i : 0;
+							continue;
+						}
+						goto error;
 					case SYM_BYTES:
 						if (IS_BINARY(next)) {
 							count += VAL_LEN(next);
@@ -902,6 +909,14 @@ static REBCNT EncodedU32_Size(u32 value) {
 						n = 0;
 						break;
 
+					case SYM_PAD:
+						n = VAL_INDEX(buffer_write) % VAL_INT32(next);
+						if (n > 0) {
+							n = VAL_INT32(next) - n;
+							memset(cp, 0, n);
+						}
+						break;
+
 					case SYM_ENCODEDU32:
 						ASSERT_U32_RANGE(next);
 						ulong = VAL_UNT32(next);
@@ -1476,6 +1491,18 @@ static REBCNT EncodedU32_Size(u32 value) {
 							VAL_INDEX(buffer_read) = i; //TODO: range test
 							cp = BIN_DATA(bin) + VAL_INDEX(buffer_read);
 							continue;
+						case SYM_PAD:
+							next = ++value;
+							if (IS_GET_WORD(next)) next = Get_Var(next);
+							if (!IS_INTEGER(next)) Trap1(RE_INVALID_SPEC, value);
+							i = VAL_INDEX(buffer_read) % VAL_INT32(next);
+							if (i > 0) {
+								i = VAL_INT32(next) - i;
+								ASSERT_INDEX_RANGE(buffer_read, i, value);
+								VAL_INDEX(buffer_read) += i;
+								cp = BIN_DATA(bin) + VAL_INDEX(buffer_read);
+							}
+							continue;
 						case SYM_SKIPBITS:
 							next = ++value;
 							if (IS_GET_WORD(next)) next = Get_Var(next);

src/tests/units/bincode-test.r3

@@ -230,6 +230,11 @@ is-protected-error?: func[code][
 		--assert is-range-error? [binary/read b [AT 1 SKIP  5 UI8]]
 		--assert is-range-error? [binary/read b [AT 1 SKIP -1 UI8]]
 
+	--test-- "BinCode - PAD"
+		binary/write b: #{} [UI8 255 PAD 4 UI8 255]
+		--assert b = #{FF000000FF}
+		--assert [255 255] = binary/read b [UI8 PAD 4 UI8]
+
 	--test-- "BinCode - LENGTH?"
 		;LENGTH? returns number of bytes remaining in the buffer
 		b: binary #{01020304}