remove Prefix.fromSlice from prefix*()

* to workaround too aggressive compiler in
    ReleaseSmall

Author: thislight

src/Prefix.zig

@@ -22,7 +22,6 @@ pub fn unusedCapacitySlice(self: *Prefix) []u8 {
 }
 
 pub fn checkedAppend(self: *Prefix, item: u8) error{BufOverflow}!void {
-    @setRuntimeSafety(false);
     if (self.len > std.math.maxInt(u3) - 1) {
         return error.BufOverflow;
     }
@@ -35,20 +34,18 @@ pub fn append(self: *Prefix, item: u8) void {
 }
 
 pub fn checkedAppendSlice(self: *Prefix, items: []const u8) error{BufOverflow}!void {
-    @setRuntimeSafety(false);
     if (std.math.maxInt(u3) - self.len < items.len) {
         return error.BufOverflow;
     }
     std.mem.copyForwards(u8, self.unusedCapacitySlice(), items);
-    self.len += @intCast(items.len);
+    self.len += @truncate(items.len);
 }
 
 pub fn appendSlice(self: *Prefix, items: []const u8) void {
     return self.checkedAppendSlice(items) catch unreachable;
 }
 
 pub fn checkedWriteInt(self: *Prefix, T: type, value: T, endian: std.builtin.Endian) error{BufOverflow}!void {
-    @setRuntimeSafety(false);
     const intsz = @divExact(@bitSizeOf(T), 8);
     if (std.math.maxInt(u3) - self.len < intsz) {
         return error.BufOverflow;
@@ -62,9 +59,10 @@ pub fn writeInt(self: *Prefix, T: type, value: T, endian: std.builtin.Endian) vo
 }
 
 pub fn fromSlice(value: []const u8) Prefix {
-    var result: Prefix = .{};
+    var result: Prefix = .{
+        .len = @intCast(value.len),
+    };
     std.mem.copyForwards(u8, &result.buffer, value);
-    result.len = @intCast(value.len);
     return result;
 }
 

src/root.zig

@@ -371,10 +371,10 @@ pub fn prefixString(len: u32) Prefix {
     var result: Prefix = .{};
     switch (len) {
         0...0b00011111 => {
-            return Prefix.fromSlice(&.{0b10100000 | (0b00011111 & @as(u8, @intCast(len)))});
+            result.append(0b10100000 | (0b00011111 & @as(u8, @intCast(len))));
         },
         0b00011111 + 1...maxInt(u8) => {
-            return Prefix.fromSlice(&.{
+            result.appendSlice(&.{
                 0xd9,
                 @truncate(len),
             });
@@ -396,7 +396,7 @@ pub fn prefixBinary(len: u32) Prefix {
     var result: Prefix = .{};
     switch (len) {
         0...maxInt(u8) => {
-            return Prefix.fromSlice(&.{
+            result.appendSlice(&.{
                 @intFromEnum(ContainerType.bin8),
                 @as(u8, @truncate(len)),
             });
@@ -418,7 +418,7 @@ pub fn prefixArray(len: u32) Prefix {
     var result: Prefix = .{};
     switch (len) {
         0...0b00001111 => {
-            return Prefix.fromSlice(&.{0b10010000 | (0b00001111 & @as(u8, @truncate(len)))});
+            result.append(0b10010000 | (0b00001111 & @as(u8, @truncate(len))));
         },
         (0b00001111 + 1)...maxInt(u16) => {
             result.append(0xdc);
@@ -441,7 +441,7 @@ pub fn prefixMap(len: u32) Prefix {
     var result: Prefix = .{};
     switch (len) {
         0...0b00001111 => {
-            return Prefix.fromSlice(&.{0b10000000 | (0b00001111 & @as(u8, @truncate(len)))});
+            result.append(0b10000000 | (0b00001111 & @as(u8, @truncate(len))));
         },
         (0b00001111 + 1)...maxInt(u16) => {
             result.append(0xde);