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mem: add byteswap array support (#17959)

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also make byteswap work with enums
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Tristan Ross 2024-01-14 18:06:31 -08:00 committed by GitHub
parent f9d8176e94
commit 9fce1d1ab1
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1 changed files with 34 additions and 7 deletions
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41
lib/std/mem.zig
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@ -1965,13 +1965,34 @@ pub fn writeVarPackedInt(bytes: []u8, bit_offset: usize, bit_count: usize, value
/// Swap the byte order of all the members of the fields of a struct
/// (Changing their endianness)
pub fn byteSwapAllFields(comptime S: type, ptr: *S) void {
if (@typeInfo(S) != .Struct) @compileError("byteSwapAllFields expects a struct as the first argument");
inline for (std.meta.fields(S)) |f| {
if (@typeInfo(f.type) == .Struct) {
byteSwapAllFields(f.type, &@field(ptr, f.name));
} else {
@field(ptr, f.name) = @byteSwap(@field(ptr, f.name));
}
switch (@typeInfo(S)) {
.Struct => {
inline for (std.meta.fields(S)) |f| {
switch (@typeInfo(f.type)) {
.Struct, .Array => byteSwapAllFields(f.type, &@field(ptr, f.name)),
.Enum => {
@field(ptr, f.name) = @enumFromInt(@byteSwap(@intFromEnum(@field(ptr, f.name))));
},
else => {
@field(ptr, f.name) = @byteSwap(@field(ptr, f.name));
},
}
}
},
.Array => {
for (ptr) |*item| {
switch (@typeInfo(@TypeOf(item.*))) {
.Struct, .Array => byteSwapAllFields(@TypeOf(item.*), item),
.Enum => {
item.* = @enumFromInt(@byteSwap(@intFromEnum(item.*)));
},
else => {
item.* = @byteSwap(item.*);
},
}
}
},
else => @compileError("byteSwapAllFields expects a struct or array as the first argument"),
}
}
@ -1980,21 +2001,25 @@ test "byteSwapAllFields" {
f0: u8,
f1: u16,
f2: u32,
f3: [1]u8,
};
const K = extern struct {
f0: u8,
f1: T,
f2: u16,
f3: [1]u8,
};
var s = T{
.f0 = 0x12,
.f1 = 0x1234,
.f2 = 0x12345678,
.f3 = .{0x12},
};
var k = K{
.f0 = 0x12,
.f1 = s,
.f2 = 0x1234,
.f3 = .{0x12},
};
byteSwapAllFields(T, &s);
byteSwapAllFields(K, &k);
@ -2002,11 +2027,13 @@ test "byteSwapAllFields" {
.f0 = 0x12,
.f1 = 0x3412,
.f2 = 0x78563412,
.f3 = .{0x12},
}, s);
try std.testing.expectEqual(K{
.f0 = 0x12,
.f1 = s,
.f2 = 0x3412,
.f3 = .{0x12},
}, k);
}