Modify runtime to reduce dependencies on other packages

core/runtime/internal.odin

@@ -1,9 +1,22 @@
 package runtime
 
-import "core:mem"
 import "core:os"
-import "core:unicode/utf8"
 
+mem_copy :: proc "contextless" (dst, src: rawptr, len: int) -> rawptr {
+	if src == nil do return dst;
+	// NOTE(bill): This _must_ be implemented like C's memmove
+	foreign _ {
+		when size_of(rawptr) == 8 {
+			@(link_name="llvm.memmove.p0i8.p0i8.i64")
+			llvm_memmove :: proc(dst, src: rawptr, len: int, align: i32, is_volatile: bool) ---;
+		} else {
+			@(link_name="llvm.memmove.p0i8.p0i8.i32")
+			llvm_memmove :: proc(dst, src: rawptr, len: int, align: i32, is_volatile: bool) ---;
+		}
+	}
+	llvm_memmove(dst, src, len, 1, false);
+	return dst;
+}
 
 print_u64 :: proc(fd: os.Handle, x: u64) {
 	digits := "0123456789";
@@ -336,17 +349,22 @@ string_ge :: inline proc "contextless" (a, b: string) -> bool { return string_cm
 
 cstring_len :: proc "contextless" (s: cstring) -> int {
 	n := 0;
-	for p := (^byte)(s); p != nil && p^ != 0; p = mem.ptr_offset(p, 1) {
-		n += 1;
+	p := uintptr((^byte)(s));
+	for p != 0 && (^byte)(p)^ != 0 {
+		p += 1;
 	}
 	return n;
 }
 
 cstring_to_string :: proc "contextless" (s: cstring) -> string {
+	Raw_String :: struct {
+		data: ^byte,
+		len: int,
+	};
 	if s == nil do return "";
 	ptr := (^byte)(s);
 	n := cstring_len(s);
-	return transmute(string)mem.Raw_String{ptr, n};
+	return transmute(string)Raw_String{ptr, n};
 }
 
 
@@ -435,8 +453,84 @@ type_assertion_check :: proc "contextless" (ok: bool, file: string, line, column
 	handle_error(file, line, column, from, to);
 }
 
+
 string_decode_rune :: inline proc "contextless" (s: string) -> (rune, int) {
-	return utf8.decode_rune_in_string(s);
+	// NOTE(bill): Duplicated here to remove dependency on package unicode/utf8
+
+	@static accept_sizes := [256]u8{
+		0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, // 0x00-0x0f
+		0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, // 0x10-0x1f
+		0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, // 0x20-0x2f
+		0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, // 0x30-0x3f
+		0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, // 0x40-0x4f
+		0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, // 0x50-0x5f
+		0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, // 0x60-0x6f
+		0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, // 0x70-0x7f
+
+		0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, // 0x80-0x8f
+		0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, // 0x90-0x9f
+		0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, // 0xa0-0xaf
+		0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, // 0xb0-0xbf
+		0xf1, 0xf1, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, // 0xc0-0xcf
+		0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, // 0xd0-0xdf
+		0x13, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x23, 0x03, 0x03, // 0xe0-0xef
+		0x34, 0x04, 0x04, 0x04, 0x44, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, 0xf1, // 0xf0-0xff
+	};
+	Accept_Range :: struct {lo, hi: u8};
+
+	@static accept_ranges := [5]Accept_Range{
+		{0x80, 0xbf},
+		{0xa0, 0xbf},
+		{0x80, 0x9f},
+		{0x90, 0xbf},
+		{0x80, 0x8f},
+	};
+
+	MASKX :: 0b0011_1111;
+	MASK2 :: 0b0001_1111;
+	MASK3 :: 0b0000_1111;
+	MASK4 :: 0b0000_0111;
+
+	LOCB :: 0b1000_0000;
+	HICB :: 0b1011_1111;
+
+
+	RUNE_ERROR :: '\ufffd';
+
+	n := len(s);
+	if n < 1 {
+		return RUNE_ERROR, 0;
+	}
+	s0 := s[0];
+	x := accept_sizes[s0];
+	if x >= 0xF0 {
+		mask := rune(x) << 31 >> 31; // NOTE(bill): Create 0x0000 or 0xffff.
+		return rune(s[0])&~mask | RUNE_ERROR&mask, 1;
+	}
+	sz := x & 7;
+	accept := accept_ranges[x>>4];
+	if n < int(sz) {
+		return RUNE_ERROR, 1;
+	}
+	b1 := s[1];
+	if b1 < accept.lo || accept.hi < b1 {
+		return RUNE_ERROR, 1;
+	}
+	if sz == 2 {
+		return rune(s0&MASK2)<<6 | rune(b1&MASKX), 2;
+	}
+	b2 := s[2];
+	if b2 < LOCB || HICB < b2 {
+		return RUNE_ERROR, 1;
+	}
+	if sz == 3 {
+		return rune(s0&MASK3)<<12 | rune(b1&MASKX)<<6 | rune(b2&MASKX), 3;
+	}
+	b3 := s[3];
+	if b3 < LOCB || HICB < b3 {
+		return RUNE_ERROR, 1;
+	}
+	return rune(s0&MASK4)<<18 | rune(b1&MASKX)<<12 | rune(b2&MASKX)<<6 | rune(b3&MASKX), 4;
 }
 
 bounds_check_error_loc :: inline proc "contextless" (using loc := #caller_location, index, count: int) {