bitfield: fix bit order

vlib/bitfield/bitfield.v

@@ -13,7 +13,7 @@ Bit arrays are stored in data structures called 'BitField'. The structure is
 provides API (functions and methods) for accessing and modifying bit arrays.
 */
 
-struct BitField {
+pub struct BitField {
 mut:
 	size int
 	//field *u32
@@ -77,36 +77,19 @@ fn cleartail(instance mut BitField) {
 
 // public functions
 
-// from_bytes() converts a byte arry into a bitfield.
-// Be aware of possible trailing zeroes being added
-// due to the underlying 32bit int containers.
+// from_bytes() converts a byte array into a bitfield.
 pub fn from_bytes(input []byte) BitField {
 	mut output := new(input.len * 8)
 	for i, b in input {
-		pos := i / 4
-		match i % 4 {
-			0 {
-				output.field[pos] = output.field[pos] | (u32(b) << 24)
+		output.field[i / 4] |= u32(b) << ((i % 4) * 8)
 	}
-			1 {
-				output.field[pos] = output.field[pos] | (u32(b) << 16)
-			}
-			2 {
-				output.field[pos] = output.field[pos] | (u32(b) << 8)
-			}
-			3 {
-				output.field[pos] = output.field[pos] | u32(b)
-			}
-		}
-	}
-
 	return output
 }
 
-// str2bf() converts a string of characters ('0' and '1') to a bit
+// from_string() converts a string of characters ('0' and '1') to a bit
 // array. Any character different from '0' is treated as '1'.
 
-pub fn str2bf(input string) BitField {
+pub fn from_string(input string) BitField {
 	mut output := new(input.len)
 	for i := 0; i < input.len; i++ {
 		if input[i] != 48 {

vlib/bitfield/bitfield_test.v

@@ -127,16 +127,14 @@ fn test_bf_from_bytes() {
 	output := bitfield.from_bytes(input)
 	mut result := 1
 	for i := 0; i < input.len * 8; i++ {
-		expected := input[input.len - 1 - i / 8] >> i % 8 & 1
-		actual := output.getbit(i)
-		if expected != actual {
+		if (input[i / 8] >> (i % 8)) & 1 != output.getbit(i) {
 			result = 0
 		}
 	}
 	assert result == 1
 }
 
-fn test_bf_str2bf() {
+fn test_bf_from_string() {
 	rand.seed(time.now().uni)
 	len := 80
 	mut input := ''
@@ -148,7 +146,7 @@ fn test_bf_str2bf() {
 			input = input + '0'
 		}
 	}
-	output := bitfield.str2bf(input)
+	output := bitfield.from_string(input)
 	mut result := 1
 	for i := 0; i < len; i++ {
 		if input[i] != output.getbit(i) + 48 {