From b5e6fb6c4f7587fef873ae86a22b3bf024a749b0 Mon Sep 17 00:00:00 2001
From: Ali Chraghi <alichraghi@pm.me>
Date: Mon, 29 Aug 2022 15:44:24 +0430
Subject: [PATCH] basisu: use @bitCast for casting bit fields

---
 libs/basisu/src/encoder.zig    | 42 ++++------------------------------
 libs/basisu/src/transcoder.zig | 34 ++++-----------------------
 2 files changed, 8 insertions(+), 68 deletions(-)

diff --git a/libs/basisu/src/encoder.zig b/libs/basisu/src/encoder.zig
index 825f467d..428585cd 100644
--- a/libs/basisu/src/encoder.zig
+++ b/libs/basisu/src/encoder.zig
@@ -94,11 +94,11 @@ pub const CompressorParams = struct {
     }
 
     pub fn getPackUASTCFlags(self: CompressorParams) PackUASTCFlags {
-        return PackUASTCFlags.from(b.compressor_params_get_pack_uastc_flags(self.handle));
+        return @bitCast(PackUASTCFlags, b.compressor_params_get_pack_uastc_flags(self.handle));
     }
 
     pub fn setPackUASTCFlags(self: CompressorParams, flags: PackUASTCFlags) void {
-        b.compressor_params_set_pack_uastc_flags(self.handle, flags.cast());
+        b.compressor_params_set_pack_uastc_flags(self.handle, @bitCast(u32, flags));
     }
 
     pub fn setBasisFormat(self: CompressorParams, format: BasisTextureFormat) void {
@@ -209,48 +209,14 @@ pub const PackUASTCFlags = packed struct {
     default: bool = false,
     slower: bool = false,
     verySlow: bool = false,
-    mask: bool = false,
     favor_uastc_error: bool = false,
     favor_bc7_error: bool = false,
+    _padding: u1 = 0,
     etc1_faster_hints: bool = false,
     etc1_fastest_hints: bool = false,
     etc1_disable_flip_and_individual: bool = false,
     favor_simpler_modes: bool = false,
-
-    pub const Flag = enum(u32) {
-        fastest = 0,
-        faster = 1,
-        default = 2,
-        slower = 3,
-        verySlow = 4,
-        mask = 0xF,
-        favor_uastc_error = 8,
-        favor_bc7_error = 16,
-        etc1_faster_hints = 64,
-        etc1_fastest_hints = 128,
-        etc1_disable_flip_and_individual = 256,
-        favor_simpler_modes = 512,
-    };
-
-    pub fn from(bits: u32) PackUASTCFlags {
-        var value = PackUASTCFlags{};
-        inline for (comptime std.meta.fieldNames(Flag)) |field_name| {
-            if (bits & (@enumToInt(@field(Flag, field_name))) != 0) {
-                @field(value, field_name) = true;
-            }
-        }
-        return value;
-    }
-
-    pub fn cast(self: PackUASTCFlags) u32 {
-        var value: u32 = 0;
-        inline for (comptime std.meta.fieldNames(Flag)) |field_name| {
-            if (@field(self, field_name)) {
-                value |= @enumToInt(@field(Flag, field_name));
-            }
-        }
-        return value;
-    }
+    _padding0: u20 = 0,
 };
 
 pub const ColorSpace = enum {
diff --git a/libs/basisu/src/transcoder.zig b/libs/basisu/src/transcoder.zig
index aaa2f55d..2869d775 100644
--- a/libs/basisu/src/transcoder.zig
+++ b/libs/basisu/src/transcoder.zig
@@ -68,7 +68,7 @@ pub const Transcoder = struct {
     }
 
     pub const TranscodeParams = struct {
-        decode_flags: ?DecodeFlags = null,
+        decode_flags: DecodeFlags = .{},
         /// Output row pitch in blocks or pixels.
         /// Should be at least the image level's total_blocks (num_blocks_x * num_blocks_y),
         /// or the total number of output pixels if fmt==cTFRGBA32.
@@ -104,7 +104,7 @@ pub const Transcoder = struct {
             image_index,
             level_index,
             @enumToInt(format),
-            if (params.decode_flags) |f| f.cast() else 0,
+            @bitCast(u32, params.decode_flags),
             params.output_row_pitch orelse 0,
             params.output_rows orelse 0,
         )) return error.Unknown;
@@ -117,39 +117,13 @@ pub const Transcoder = struct {
     };
 
     pub const DecodeFlags = packed struct {
+        _padding: u1 = 0,
         pvrtc_decode_to_next_pow_2: bool = false,
         transcode_alpha_data_to_opaque_formats: bool = false,
         bc1_forbid_three_color_blocks: bool = false,
         output_has_alpha_indices: bool = false,
         high_quality: bool = false,
-
-        pub const Flag = enum(u32) {
-            pvrtc_decode_to_next_pow_2 = 2,
-            transcode_alpha_data_to_opaque_formats = 4,
-            bc1_forbid_three_color_blocks = 8,
-            output_has_alpha_indices = 16,
-            high_quality = 32,
-        };
-
-        pub fn from(bits: u32) DecodeFlags {
-            var value = DecodeFlags{};
-            inline for (comptime std.meta.fieldNames(Flag)) |field_name| {
-                if (bits & (@enumToInt(@field(Flag, field_name))) != 0) {
-                    @field(value, field_name) = true;
-                }
-            }
-            return value;
-        }
-
-        pub fn cast(self: DecodeFlags) u32 {
-            var value: u32 = 0;
-            inline for (comptime std.meta.fieldNames(Flag)) |field_name| {
-                if (@field(self, field_name)) {
-                    value |= @enumToInt(@field(Flag, field_name));
-                }
-            }
-            return value;
-        }
+        _padding0: u26 = 0,
     };
 
     pub const TextureFormat = enum(u5) {