builtin: use 0 instead of `\0` rune when setting C style terminators; use C.memcpy in `[]string{}.join("")`

vlib/builtin/array.v

@@ -533,7 +533,7 @@ pub fn (b []byte) hex() string {
 		}
 	}
 	unsafe {
-		hex[dst_i] = `\0`
+		hex[dst_i] = 0
 		return tos(hex, dst_i)
 	}
 }

vlib/builtin/int.v

@@ -30,7 +30,7 @@ pub fn (nn int) str1() string {
 		buf[max - len - 1] = `-`
 		len++
 	}
-	buf[max] = `\0`
+	buf[max] = 0
 	return tos(buf + max - len, len)
 }
 */
@@ -77,7 +77,7 @@ fn (nn int) str_l(max int) string {
 	}
 	mut index := max
 	unsafe {
-		buf[index--] = `\0`
+		buf[index--] = 0
 	}
 	for n > 0 {
 		n1 := int(n / 100)
@@ -143,7 +143,7 @@ pub fn (nn u32) str() string {
 	mut buf := unsafe { malloc(max + 1) }
 	mut index := max
 	unsafe {
-		buf[index--] = `\0`
+		buf[index--] = 0
 	}
 	for n > 0 {
 		n1 := n / u32(100)
@@ -189,7 +189,7 @@ pub fn (nn i64) str() string {
 	}
 	mut index := max
 	unsafe {
-		buf[index--] = `\0`
+		buf[index--] = 0
 	}
 	for n > 0 {
 		n1 := n / i64(100)
@@ -231,7 +231,7 @@ pub fn (nn u64) str() string {
 	mut buf := vcalloc(max + 1)
 	mut index := max
 	unsafe {
-		buf[index--] = `\0`
+		buf[index--] = 0
 	}
 	for n > 0 {
 		n1 := n / 100
@@ -279,7 +279,7 @@ pub fn (n int) hex1() string {
 fn u64_to_hex(nn u64, len byte) string {
 	mut n := nn
 	mut buf := [256]byte{}
-	buf[len] = `\0`
+	buf[len] = 0
 	mut i := 0
 	for i = len - 1; i >= 0; i-- {
 		d := byte(n & 0xF)
@@ -295,7 +295,7 @@ fn u64_to_hex(nn u64, len byte) string {
 fn u64_to_hex_no_leading_zeros(nn u64, len byte) string {
 	mut n := nn
 	mut buf := [256]byte{}
-	buf[len] = `\0`
+	buf[len] = 0
 	mut i := 0
 	for i = len - 1; i >= 0; i-- {
 		d := byte(n & 0xF)
@@ -452,7 +452,7 @@ pub fn (b byte) ascii_str() string {
 	}
 	unsafe {
 		str.str[0] = b
-		str.str[1] = `\0`
+		str.str[1] = 0
 	}
 	// println(str)
 	return str

vlib/builtin/linux_bare/string_bare.v

@@ -34,7 +34,7 @@ fn (s string) add(a string) string {
 	for j in 0 .. a.len {
 		res[s.len + j] = a[j]
 	}
-	res[new_len] = `\0` // V strings are not null terminated, but just in case
+	res[new_len] = 0 // V strings are not null terminated, but just in case
 	return res
 }
 
@@ -145,6 +145,6 @@ pub fn (a string) clone() string {
 		str: malloc(a.len + 1)
 	}
 	mem_copy(b.str, a.str, a.len)
-	b[a.len] = `\0`
+	b[a.len] = 0
 	return b
 }

vlib/builtin/string.v

@@ -257,7 +257,7 @@ pub fn (a string) clone() string {
 	}
 	unsafe {
 		C.memcpy(b.str, a.str, a.len)
-		b.str[a.len] = `\0`
+		b.str[a.len] = 0
 	}
 	return b
 }
@@ -339,7 +339,7 @@ pub fn (s string) replace(rep string, with string) string {
 		}
 	}
 	unsafe {
-		b[new_len] = `\0`
+		b[new_len] = 0
 		return tos(b, new_len)
 	}
 }
@@ -419,7 +419,7 @@ pub fn (s string) replace_each(vals []string) string {
 		return s.clone()
 	}
 	idxs.sort2()
-	mut b := unsafe { malloc(new_len + 1) } // add a \0 just in case
+	mut b := unsafe { malloc(new_len + 1) } // add space for 0 terminator
 	// Fill the new string
 	mut idx_pos := 0
 	mut cur_idx := idxs[idx_pos]
@@ -451,7 +451,7 @@ pub fn (s string) replace_each(vals []string) string {
 		}
 	}
 	unsafe {
-		b[new_len] = `\0`
+		b[new_len] = 0
 		return tos(b, new_len)
 	}
 }
@@ -576,7 +576,7 @@ pub fn (s string) add(a string) string {
 		}
 	}
 	unsafe {
-		res.str[new_len] = `\0` // V strings are not null terminated, but just in case
+		res.str[new_len] = 0 // V strings are not null terminated, but just in case
 	}
 	return res
 }
@@ -726,7 +726,7 @@ pub fn (s string) substr(start int, end int) string {
 		}
 	}
 	unsafe {
-		res.str[len] = `\0`
+		res.str[len] = 0
 	}
 	/*
 	res := string {
@@ -1644,26 +1644,21 @@ pub fn (a []string) join(del string) string {
 		len: len
 	}
 	mut idx := 0
-	// Go thru every string and copy its every char one by one
 	for i, val in a {
-		for j in 0 .. val.len {
-			unsafe {
-				res.str[idx] = val.str[j]
-			}
-			idx++
+		unsafe {
+			C.memcpy(res.str + idx, val.str, val.len)
+			idx+=val.len
 		}
 		// Add del if it's not last
-		if i != a.len - 1 {
-			for k in 0 .. del.len {
-				unsafe {
-					res.str[idx] = del.str[k]
-				}
-				idx++
+		if i != a.len-1 {
+			unsafe {
+				C.memcpy(res.str + idx, del.str, del.len)
+				idx+=del.len
 			}
 		}
 	}
 	unsafe {
-		res.str[res.len] = `\0`
+		res.str[res.len] = 0
 	}
 	return res
 }