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| author | Veikka Tuominen <git@vexu.eu> | 2021-06-12 21:30:36 +0300 |
|---|---|---|
| committer | Veikka Tuominen <git@vexu.eu> | 2021-06-14 20:13:34 +0300 |
| commit | 699b6cdf01babd86d56206667a35491d2c4d00f1 (patch) | |
| tree | ddf70f0d6282034497707a579197428740cb3b30 /lib/std/meta.zig | |
| parent | ec36b82d058b7e20101a2f55a7ec123077ce9b70 (diff) | |
| download | zig-699b6cdf01babd86d56206667a35491d2c4d00f1.tar.gz zig-699b6cdf01babd86d56206667a35491d2c4d00f1.zip | |
translate-c: move utility functions to a separate namespace
Diffstat (limited to 'lib/std/meta.zig')
| -rw-r--r-- | lib/std/meta.zig | 376 |
1 files changed, 0 insertions, 376 deletions
diff --git a/lib/std/meta.zig b/lib/std/meta.zig index e738ad6efb..e19208cd84 100644 --- a/lib/std/meta.zig +++ b/lib/std/meta.zig @@ -884,319 +884,6 @@ pub fn Vector(comptime len: u32, comptime child: type) type { }); } -/// Given a type and value, cast the value to the type as c would. -/// This is for translate-c and is not intended for general use. -pub fn cast(comptime DestType: type, target: anytype) DestType { - // this function should behave like transCCast in translate-c, except it's for macros and enums - const SourceType = @TypeOf(target); - switch (@typeInfo(DestType)) { - .Pointer => return castToPtr(DestType, SourceType, target), - .Optional => |dest_opt| { - if (@typeInfo(dest_opt.child) == .Pointer) { - return castToPtr(DestType, SourceType, target); - } - }, - .Enum => |enum_type| { - if (@typeInfo(SourceType) == .Int or @typeInfo(SourceType) == .ComptimeInt) { - const intermediate = cast(enum_type.tag_type, target); - return @intToEnum(DestType, intermediate); - } - }, - .Int => { - switch (@typeInfo(SourceType)) { - .Pointer => { - return castInt(DestType, @ptrToInt(target)); - }, - .Optional => |opt| { - if (@typeInfo(opt.child) == .Pointer) { - return castInt(DestType, @ptrToInt(target)); - } - }, - .Enum => { - return castInt(DestType, @enumToInt(target)); - }, - .Int => { - return castInt(DestType, target); - }, - else => {}, - } - }, - else => {}, - } - return @as(DestType, target); -} - -fn castInt(comptime DestType: type, target: anytype) DestType { - const dest = @typeInfo(DestType).Int; - const source = @typeInfo(@TypeOf(target)).Int; - - if (dest.bits < source.bits) - return @bitCast(DestType, @truncate(Int(source.signedness, dest.bits), target)) - else - return @bitCast(DestType, @as(Int(source.signedness, dest.bits), target)); -} - -fn castPtr(comptime DestType: type, target: anytype) DestType { - const dest = ptrInfo(DestType); - const source = ptrInfo(@TypeOf(target)); - - if (source.is_const and !dest.is_const or source.is_volatile and !dest.is_volatile) - return @intToPtr(DestType, @ptrToInt(target)) - else if (@typeInfo(dest.child) == .Opaque) - // dest.alignment would error out - return @ptrCast(DestType, target) - else - return @ptrCast(DestType, @alignCast(dest.alignment, target)); -} - -fn castToPtr(comptime DestType: type, comptime SourceType: type, target: anytype) DestType { - switch (@typeInfo(SourceType)) { - .Int => { - return @intToPtr(DestType, castInt(usize, target)); - }, - .ComptimeInt => { - if (target < 0) - return @intToPtr(DestType, @bitCast(usize, @intCast(isize, target))) - else - return @intToPtr(DestType, @intCast(usize, target)); - }, - .Pointer => { - return castPtr(DestType, target); - }, - .Optional => |target_opt| { - if (@typeInfo(target_opt.child) == .Pointer) { - return castPtr(DestType, target); - } - }, - else => {}, - } - return @as(DestType, target); -} - -fn ptrInfo(comptime PtrType: type) TypeInfo.Pointer { - return switch (@typeInfo(PtrType)) { - .Optional => |opt_info| @typeInfo(opt_info.child).Pointer, - .Pointer => |ptr_info| ptr_info, - else => unreachable, - }; -} - -test "std.meta.cast" { - const E = enum(u2) { - Zero, - One, - Two, - }; - - var i = @as(i64, 10); - - try testing.expect(cast(*u8, 16) == @intToPtr(*u8, 16)); - try testing.expect(cast(*u64, &i).* == @as(u64, 10)); - try testing.expect(cast(*i64, @as(?*align(1) i64, &i)) == &i); - - try testing.expect(cast(?*u8, 2) == @intToPtr(*u8, 2)); - try testing.expect(cast(?*i64, @as(*align(1) i64, &i)) == &i); - try testing.expect(cast(?*i64, @as(?*align(1) i64, &i)) == &i); - - try testing.expect(cast(E, 1) == .One); - - try testing.expectEqual(@as(u32, 4), cast(u32, @intToPtr(*u32, 4))); - try testing.expectEqual(@as(u32, 4), cast(u32, @intToPtr(?*u32, 4))); - try testing.expectEqual(@as(u32, 10), cast(u32, @as(u64, 10))); - try testing.expectEqual(@as(u8, 2), cast(u8, E.Two)); - - try testing.expectEqual(@bitCast(i32, @as(u32, 0x8000_0000)), cast(i32, @as(u32, 0x8000_0000))); - - try testing.expectEqual(@intToPtr(*u8, 2), cast(*u8, @intToPtr(*const u8, 2))); - try testing.expectEqual(@intToPtr(*u8, 2), cast(*u8, @intToPtr(*volatile u8, 2))); - - try testing.expectEqual(@intToPtr(?*c_void, 2), cast(?*c_void, @intToPtr(*u8, 2))); - - const C_ENUM = enum(c_int) { - A = 0, - B, - C, - _, - }; - try testing.expectEqual(cast(C_ENUM, @as(i64, -1)), @intToEnum(C_ENUM, -1)); - try testing.expectEqual(cast(C_ENUM, @as(i8, 1)), .B); - try testing.expectEqual(cast(C_ENUM, @as(u64, 1)), .B); - try testing.expectEqual(cast(C_ENUM, @as(u64, 42)), @intToEnum(C_ENUM, 42)); - - var foo: c_int = -1; - try testing.expect(cast(*c_void, -1) == @intToPtr(*c_void, @bitCast(usize, @as(isize, -1)))); - try testing.expect(cast(*c_void, foo) == @intToPtr(*c_void, @bitCast(usize, @as(isize, -1)))); - try testing.expect(cast(?*c_void, -1) == @intToPtr(?*c_void, @bitCast(usize, @as(isize, -1)))); - try testing.expect(cast(?*c_void, foo) == @intToPtr(?*c_void, @bitCast(usize, @as(isize, -1)))); -} - -/// Given a value returns its size as C's sizeof operator would. -/// This is for translate-c and is not intended for general use. -pub fn sizeof(target: anytype) usize { - const T: type = if (@TypeOf(target) == type) target else @TypeOf(target); - switch (@typeInfo(T)) { - .Float, .Int, .Struct, .Union, .Enum, .Array, .Bool, .Vector => return @sizeOf(T), - .Fn => { - // sizeof(main) returns 1, sizeof(&main) returns pointer size. - // We cannot distinguish those types in Zig, so use pointer size. - return @sizeOf(T); - }, - .Null => return @sizeOf(*c_void), - .Void => { - // Note: sizeof(void) is 1 on clang/gcc and 0 on MSVC. - return 1; - }, - .Opaque => { - if (T == c_void) { - // Note: sizeof(void) is 1 on clang/gcc and 0 on MSVC. - return 1; - } else { - @compileError("Cannot use C sizeof on opaque type " ++ @typeName(T)); - } - }, - .Optional => |opt| { - if (@typeInfo(opt.child) == .Pointer) { - return sizeof(opt.child); - } else { - @compileError("Cannot use C sizeof on non-pointer optional " ++ @typeName(T)); - } - }, - .Pointer => |ptr| { - if (ptr.size == .Slice) { - @compileError("Cannot use C sizeof on slice type " ++ @typeName(T)); - } - // for strings, sizeof("a") returns 2. - // normal pointer decay scenarios from C are handled - // in the .Array case above, but strings remain literals - // and are therefore always pointers, so they need to be - // specially handled here. - if (ptr.size == .One and ptr.is_const and @typeInfo(ptr.child) == .Array) { - const array_info = @typeInfo(ptr.child).Array; - if ((array_info.child == u8 or array_info.child == u16) and - array_info.sentinel != null and - array_info.sentinel.? == 0) - { - // length of the string plus one for the null terminator. - return (array_info.len + 1) * @sizeOf(array_info.child); - } - } - // When zero sized pointers are removed, this case will no - // longer be reachable and can be deleted. - if (@sizeOf(T) == 0) { - return @sizeOf(*c_void); - } - return @sizeOf(T); - }, - .ComptimeFloat => return @sizeOf(f64), // TODO c_double #3999 - .ComptimeInt => { - // TODO to get the correct result we have to translate - // `1073741824 * 4` as `int(1073741824) *% int(4)` since - // sizeof(1073741824 * 4) != sizeof(4294967296). - - // TODO test if target fits in int, long or long long - return @sizeOf(c_int); - }, - else => @compileError("std.meta.sizeof does not support type " ++ @typeName(T)), - } -} - -test "sizeof" { - const E = enum(c_int) { One, _ }; - const S = extern struct { a: u32 }; - - const ptr_size = @sizeOf(*c_void); - - try testing.expect(sizeof(u32) == 4); - try testing.expect(sizeof(@as(u32, 2)) == 4); - try testing.expect(sizeof(2) == @sizeOf(c_int)); - - try testing.expect(sizeof(2.0) == @sizeOf(f64)); - - try testing.expect(sizeof(E) == @sizeOf(c_int)); - try testing.expect(sizeof(E.One) == @sizeOf(c_int)); - - try testing.expect(sizeof(S) == 4); - - try testing.expect(sizeof([_]u32{ 4, 5, 6 }) == 12); - try testing.expect(sizeof([3]u32) == 12); - try testing.expect(sizeof([3:0]u32) == 16); - try testing.expect(sizeof(&[_]u32{ 4, 5, 6 }) == ptr_size); - - try testing.expect(sizeof(*u32) == ptr_size); - try testing.expect(sizeof([*]u32) == ptr_size); - try testing.expect(sizeof([*c]u32) == ptr_size); - try testing.expect(sizeof(?*u32) == ptr_size); - try testing.expect(sizeof(?[*]u32) == ptr_size); - try testing.expect(sizeof(*c_void) == ptr_size); - try testing.expect(sizeof(*void) == ptr_size); - try testing.expect(sizeof(null) == ptr_size); - - try testing.expect(sizeof("foobar") == 7); - try testing.expect(sizeof(&[_:0]u16{ 'f', 'o', 'o', 'b', 'a', 'r' }) == 14); - try testing.expect(sizeof(*const [4:0]u8) == 5); - try testing.expect(sizeof(*[4:0]u8) == ptr_size); - try testing.expect(sizeof([*]const [4:0]u8) == ptr_size); - try testing.expect(sizeof(*const *const [4:0]u8) == ptr_size); - try testing.expect(sizeof(*const [4]u8) == ptr_size); - - try testing.expect(sizeof(sizeof) == @sizeOf(@TypeOf(sizeof))); - - try testing.expect(sizeof(void) == 1); - try testing.expect(sizeof(c_void) == 1); -} - -pub const CIntLiteralRadix = enum { decimal, octal, hexadecimal }; - -fn PromoteIntLiteralReturnType(comptime SuffixType: type, comptime number: comptime_int, comptime radix: CIntLiteralRadix) type { - const signed_decimal = [_]type{ c_int, c_long, c_longlong }; - const signed_oct_hex = [_]type{ c_int, c_uint, c_long, c_ulong, c_longlong, c_ulonglong }; - const unsigned = [_]type{ c_uint, c_ulong, c_ulonglong }; - - const list: []const type = if (@typeInfo(SuffixType).Int.signedness == .unsigned) - &unsigned - else if (radix == .decimal) - &signed_decimal - else - &signed_oct_hex; - - var pos = mem.indexOfScalar(type, list, SuffixType).?; - - while (pos < list.len) : (pos += 1) { - if (number >= math.minInt(list[pos]) and number <= math.maxInt(list[pos])) { - return list[pos]; - } - } - @compileError("Integer literal is too large"); -} - -/// Promote the type of an integer literal until it fits as C would. -/// This is for translate-c and is not intended for general use. -pub fn promoteIntLiteral( - comptime SuffixType: type, - comptime number: comptime_int, - comptime radix: CIntLiteralRadix, -) PromoteIntLiteralReturnType(SuffixType, number, radix) { - return number; -} - -test "promoteIntLiteral" { - const signed_hex = promoteIntLiteral(c_int, math.maxInt(c_int) + 1, .hexadecimal); - try testing.expectEqual(c_uint, @TypeOf(signed_hex)); - - if (math.maxInt(c_longlong) == math.maxInt(c_int)) return; - - const signed_decimal = promoteIntLiteral(c_int, math.maxInt(c_int) + 1, .decimal); - const unsigned = promoteIntLiteral(c_uint, math.maxInt(c_uint) + 1, .hexadecimal); - - if (math.maxInt(c_long) > math.maxInt(c_int)) { - try testing.expectEqual(c_long, @TypeOf(signed_decimal)); - try testing.expectEqual(c_ulong, @TypeOf(unsigned)); - } else { - try testing.expectEqual(c_longlong, @TypeOf(signed_decimal)); - try testing.expectEqual(c_ulonglong, @TypeOf(unsigned)); - } -} - /// For a given function type, returns a tuple type which fields will /// correspond to the argument types. /// @@ -1316,38 +1003,6 @@ pub fn globalOption(comptime name: []const u8, comptime T: type) ?T { return @as(T, @field(root, name)); } -/// This function is for translate-c and is not intended for general use. -/// Convert from clang __builtin_shufflevector index to Zig @shuffle index -/// clang requires __builtin_shufflevector index arguments to be integer constants. -/// negative values for `this_index` indicate "don't care" so we arbitrarily choose 0 -/// clang enforces that `this_index` is less than the total number of vector elements -/// See https://ziglang.org/documentation/master/#shuffle -/// See https://clang.llvm.org/docs/LanguageExtensions.html#langext-builtin-shufflevector -pub fn shuffleVectorIndex(comptime this_index: c_int, comptime source_vector_len: usize) i32 { - if (this_index <= 0) return 0; - - const positive_index = @intCast(usize, this_index); - if (positive_index < source_vector_len) return @intCast(i32, this_index); - const b_index = positive_index - source_vector_len; - return ~@intCast(i32, b_index); -} - -test "shuffleVectorIndex" { - const vector_len: usize = 4; - - try testing.expect(shuffleVectorIndex(-1, vector_len) == 0); - - try testing.expect(shuffleVectorIndex(0, vector_len) == 0); - try testing.expect(shuffleVectorIndex(1, vector_len) == 1); - try testing.expect(shuffleVectorIndex(2, vector_len) == 2); - try testing.expect(shuffleVectorIndex(3, vector_len) == 3); - - try testing.expect(shuffleVectorIndex(4, vector_len) == -1); - try testing.expect(shuffleVectorIndex(5, vector_len) == -2); - try testing.expect(shuffleVectorIndex(6, vector_len) == -3); - try testing.expect(shuffleVectorIndex(7, vector_len) == -4); -} - /// Returns whether `error_union` contains an error. pub fn isError(error_union: anytype) bool { return if (error_union) |_| false else |_| true; @@ -1357,34 +1012,3 @@ test "isError" { try std.testing.expect(isError(math.absInt(@as(i8, -128)))); try std.testing.expect(!isError(math.absInt(@as(i8, -127)))); } - -/// This function is for translate-c and is not intended for general use. -/// Constructs a [*c] pointer with the const and volatile annotations -/// from SelfType for pointing to a C flexible array of ElementType. -pub fn FlexibleArrayType(comptime SelfType: type, ElementType: type) type { - switch (@typeInfo(SelfType)) { - .Pointer => |ptr| { - return @Type(TypeInfo{ .Pointer = .{ - .size = .C, - .is_const = ptr.is_const, - .is_volatile = ptr.is_volatile, - .alignment = @alignOf(ElementType), - .child = ElementType, - .is_allowzero = true, - .sentinel = null, - } }); - }, - else => |info| @compileError("Invalid self type \"" ++ @tagName(info) ++ "\" for flexible array getter: " ++ @typeName(SelfType)), - } -} - -test "Flexible Array Type" { - const Container = extern struct { - size: usize, - }; - - try testing.expectEqual(FlexibleArrayType(*Container, c_int), [*c]c_int); - try testing.expectEqual(FlexibleArrayType(*const Container, c_int), [*c]const c_int); - try testing.expectEqual(FlexibleArrayType(*volatile Container, c_int), [*c]volatile c_int); - try testing.expectEqual(FlexibleArrayType(*const volatile Container, c_int), [*c]const volatile c_int); -} |
