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InfoType for pointers #3103

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171 changes: 171 additions & 0 deletions std/meta.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -115,6 +115,177 @@ test "std.meta.Child" {
testing.expect(Child(?u8) == u8);
}


/// Returns the type for the given TypeInfo
pub fn infoType(comptime typeInfo: TypeInfo) type {
return switch (typeInfo) {
.Pointer => |ptr| infoTypePointer(ptr),
else => @compileError("infoType does not handle TypeInfo with TypeID '" ++ @tagName(typeInfo) ++ "'"),
};
}

/// Returns the type for the given TypeInfo.Pointer
pub fn infoTypePointer(comptime ptrTypeInfo: TypeInfo.Pointer) type {
switch (ptrTypeInfo.size) {
.One => {
if (ptrTypeInfo.is_const) {
if (ptrTypeInfo.is_volatile) {
if (ptrTypeInfo.is_allowzero) {
return *const volatile align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return *const volatile align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
} else {
if (ptrTypeInfo.is_allowzero) {
return *const align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return *const align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
}
} else {
if (ptrTypeInfo.is_volatile) {
if (ptrTypeInfo.is_allowzero) {
return *volatile align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return *volatile align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
} else {
if (ptrTypeInfo.is_allowzero) {
return *align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return *align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
}
}
},
.Many => {
if (ptrTypeInfo.is_const) {
if (ptrTypeInfo.is_volatile) {
if (ptrTypeInfo.is_allowzero) {
return [*]const volatile align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return [*]const volatile align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
} else {
if (ptrTypeInfo.is_allowzero) {
return [*]const align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return [*]const align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
}
} else {
if (ptrTypeInfo.is_volatile) {
if (ptrTypeInfo.is_allowzero) {
return [*]volatile align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return [*]volatile align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
} else {
if (ptrTypeInfo.is_allowzero) {
return [*]align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return [*]align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
}
}
},
.Slice => {
if (ptrTypeInfo.is_const) {
if (ptrTypeInfo.is_volatile) {
if (ptrTypeInfo.is_allowzero) {
return []const volatile align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return []const volatile align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
} else {
if (ptrTypeInfo.is_allowzero) {
return []const align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return []const align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
}
} else {
if (ptrTypeInfo.is_volatile) {
if (ptrTypeInfo.is_allowzero) {
return []volatile align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return []volatile align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
} else {
if (ptrTypeInfo.is_allowzero) {
return []align(ptrTypeInfo.alignment) allowzero ptrTypeInfo.child;
} else {
return []align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
}
}
},
.C => {
if (ptrTypeInfo.is_const) {
if (ptrTypeInfo.is_volatile) {
return [*c]const volatile align(ptrTypeInfo.alignment) ptrTypeInfo.child;
} else {
return [*c]const align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
} else {
if (ptrTypeInfo.is_volatile) {
return [*c]volatile align(ptrTypeInfo.alignment) ptrTypeInfo.child;
} else {
return [*c]align(ptrTypeInfo.alignment) ptrTypeInfo.child;
}
}
},
}
}

test "std.meta.infoType" {
const testTypes = [_]type {
// One Value Pointer Types
*u8, *const u8,
*volatile u8, *const volatile u8,
*align(4) u8, *const align(4) u8,
*volatile align(4) u8, *const volatile align(4) u8,
*align(8) u8, *const align(8) u8,
*volatile align(8) u8, *const volatile align(8) u8,
*allowzero u8, *const allowzero u8,
*volatile allowzero u8, *const volatile allowzero u8,
*align(4) allowzero u8, *const align(4) allowzero u8,
*volatile align(4) allowzero u8, *const volatile align(4) allowzero u8,
// Many Values Pointer Types
[*]u8, [*]const u8,
[*]volatile u8, [*]const volatile u8,
[*]align(4) u8, [*]const align(4) u8,
[*]volatile align(4) u8, [*]const volatile align(4) u8,
[*]align(8) u8, [*]const align(8) u8,
[*]volatile align(8) u8, [*]const volatile align(8) u8,
[*]allowzero u8, [*]const allowzero u8,
[*]volatile allowzero u8, [*]const volatile allowzero u8,
[*]align(4) allowzero u8, [*]const align(4) allowzero u8,
[*]volatile align(4) allowzero u8, [*]const volatile align(4) allowzero u8,
// Slice Types
[]u8, []const u8,
[]volatile u8, []const volatile u8,
[]align(4) u8, []const align(4) u8,
[]volatile align(4) u8, []const volatile align(4) u8,
[]align(8) u8, []const align(8) u8,
[]volatile align(8) u8, []const volatile align(8) u8,
[]allowzero u8, []const allowzero u8,
[]volatile allowzero u8, []const volatile allowzero u8,
[]align(4) allowzero u8, []const align(4) allowzero u8,
[]volatile align(4) allowzero u8, []const volatile align(4) allowzero u8,
// C Pointer Types
[*c]u8, [*c]const u8,
[*c]volatile u8, [*c]const volatile u8,
[*c]align(4) u8, [*c]const align(4) u8,
[*c]volatile align(4) u8, [*c]const volatile align(4) u8,
[*c]align(8) u8, [*c]const align(8) u8,
[*c]volatile align(8) u8, [*c]const volatile align(8) u8,
};
inline for (testTypes) |testType| {
testing.expect(testType == infoType(@typeInfo(testType)));
}
}

pub fn containerLayout(comptime T: type) TypeInfo.ContainerLayout {
return switch (@typeInfo(T)) {
TypeId.Struct => |info| info.layout,
Expand Down