╭ truncate.zig ─────────────────────────────────────────────────╮ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ ╰───────────────────────────────────────────────────────────────╯
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╭ find file ─ ─ ─ ─ ─ ─ ─ ─ ─ ─╮ ╭────╮ ╭ clone ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╮ │ │ │http│ ssh │ │ ╰ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─╯ ╰────╯ ╰ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ╯
.. conflicting_externs/ hasdecl/ import/ namespace_depends_on_compile_var/ pub_enum/ x86_64/ zon/ abs.zig addrspace_and_linksection.zig align.zig alignof.zig array.zig asm.zig atomics.zig backing_int.zig basic.zig bit_shifting.zig bitcast.zig bitreverse.zig bool.zig builtin_functions_returning_void_ byteswap.zig byval_arg_var.zig call.zig cast.zig cast_int.zig comptime_memory.zig const_slice_child.zig decl_literals.zig decltest.zig defer.zig destructure.zig duplicated_test_names.zig enum.zig error.zig eval.zig export_builtin.zig export_c_keywords.zig export_keyword.zig export_self_referential_type_info extern.zig extern_struct_zero_size_fields.zi field_parent_ptr.zig file_to_embed.txt floatop.zig fn.zig fn_delegation.zig fn_in_struct_in_comptime.zig for.zig generics.zig globals.zig hasdecl.zig hasfield.zig if.zig import.zig import_c_keywords.zig incomplete_struct_param_tld.zig inline_switch.zig int128.zig int_comparison_elision.zig ir_block_deps.zig lower_strlit_to_vector.zig math.zig maximum_minimum.zig member_func.zig memcpy.zig memmove.zig memset.zig merge_error_sets.zig muladd.zig multiple_externs_with_conflicting namespace_depends_on_compile_var. nan.zig null.zig optional.zig overlapping_assign.zig packed-struct.zig packed-union.zig packed_struct_explicit_backing_in pointers.zig popcount.zig prefetch.zig ptrcast.zig ptrfromint.zig pub_enum.zig ref_var_in_if_after_if_2nd_switch reflection.zig return_address.zig saturating_arithmetic.zig select.zig shuffle.zig sizeof_and_typeof.zig slice.zig slice_sentinel_comptime.zig spirv.zig splat.zig src.zig string_literals.zig struct.zig struct_contains_null_ptr_itself.z struct_contains_slice_of_itself.z switch.zig switch_loop.zig switch_on_captured_error.zig switch_prong_err_enum.zig switch_prong_implicit_cast.zig this.zig threadlocal.zig ╭─────────────────────────────────╮ │truncate.zig │ ╰─────────────────────────────────╯ try.zig tuple.zig tuple_declarations.zig type.zig type_info.zig typename.zig undefined.zig underscore.zig union.zig var_args.zig vector.zig void.zig wasm.zig while.zig widening.zig wrapping_arithmetic.zig x86_64.zig zero.bin zon.zig
1 const std = @import("std"); 2 const math = std.math; 3 const maxInt = math.maxInt; 4 const minInt = math.minInt; 5 const builtin = @import("builtin"); 6 const assert = std.debug.assert; 7 const expect = std.testing.expect; 8 9 test "truncate u0 to larger integer allowed and has comptime-known result" { 10 var x: u0 = 0; 11 _ = &x; 12 const y = @as(u8, @truncate(x)); 13 comptime assert(y == 0); 14 } 15 16 test "truncate.u0.literal" { 17 const z: u0 = @truncate(0); 18 try expect(z == 0); 19 } 20 21 test "truncate.u0.const" { 22 const c0: usize = 0; 23 const z: u0 = @truncate(c0); 24 try expect(z == 0); 25 } 26 27 test "truncate.u0.var" { 28 var d: u8 = 2; 29 _ = &d; 30 const z: u0 = @truncate(d); 31 try expect(z == 0); 32 } 33 34 test "truncate on comptime integer" { 35 const x: u16 = @truncate(9999); 36 try expect(x == 9999); 37 const y: u16 = @truncate(-21555); 38 try expect(y == 0xabcd); 39 const z: i16 = @truncate(-65537); 40 try expect(z == -1); 41 const w: u1 = @truncate(1 << 100); 42 try expect(w == 0); 43 } 44 45 fn testTruncate(comptime S: type, a: S, comptime D: type, expected: D) !void { 46 const actual: D = @truncate(a); 47 try expect(actual == expected); 48 } 49 50 test "@truncate > 128 bits" { 51 if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; 52 if (builtin.zig_backend == .stage2_spirv) return error.SkipZigTest; 53 54 try testTruncate(u140, 0, u128, 0); 55 try testTruncate(u140, maxInt(u140), u128, maxInt(u128)); 56 try testTruncate(u140, 1 << 139, u128, 0); 57 try testTruncate(u140, (1 << 139) | (1 << 64) | 0x55, u128, (1 << 64) | 0x55); 58 try testTruncate(u140, (1 << 100) | (1 << 63), u128, (1 << 100) | (1 << 63)); 59 try testTruncate(u140, (1 << 130) | 0xabcd, u16, 0xabcd); 60 61 try testTruncate(u256, 1 << 200, u128, 0); 62 try testTruncate(u256, (1 << 200) | (1 << 127) | 1, u128, (1 << 127) | 1); 63 try testTruncate(u256, maxInt(u256), u128, maxInt(u128)); 64 try testTruncate(u256, (1 << 255) | (1 << 128) | 0x1234_5678_9abc_def0, u64, 0x1234_5678_9abc_def0); 65 try testTruncate(u256, (1 << 250) | (1 << 32), u32, 0); 66 try testTruncate(u256, (1 << 129) | (1 << 63), u64, 1 << 63); 67 68 try testTruncate(i140, 0, i128, 0); 69 try testTruncate(i140, -1, i128, -1); 70 try testTruncate(i140, -2, i8, -2); 71 try testTruncate(i140, -1 << 80, i64, 0); 72 try testTruncate(i140, (-1 << 80) | 0x1234, i16, 0x1234); 73 try testTruncate(i140, minInt(i140), i128, 0); 74 try testTruncate(i140, maxInt(i140), i128, -1); 75 try testTruncate(i140, (1 << 127) - 1, i128, maxInt(i128)); 76 77 try testTruncate(i256, -1, i128, -1); 78 try testTruncate(i256, minInt(i256), i128, 0); 79 try testTruncate(i256, (-1 << 128) | maxInt(i128), i128, maxInt(i128)); 80 try testTruncate(i256, (-1 << 200) | (1 << 127), i128, minInt(i128)); 81 try testTruncate(i256, -255, i8, 1); 82 try testTruncate(i256, (-1 << 64) | 0x1234_5678, i32, 0x1234_5678); 83 84 try testTruncate(i257, maxInt(i257), i256, -1); 85 try testTruncate(u257, maxInt(u257), u256, maxInt(u256)); 86 } 87 88 test "truncate on vectors" { 89 if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; 90 if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; 91 if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO 92 if (builtin.zig_backend == .stage2_riscv64) return error.SkipZigTest; 93 if (builtin.zig_backend == .stage2_spirv) return error.SkipZigTest; 94 95 const S = struct { 96 fn doTheTest() !void { 97 var v1: @Vector(4, u16) = .{ 0xaabb, 0xccdd, 0xeeff, 0x1122 }; 98 _ = &v1; 99 const v2: @Vector(4, u8) = @truncate(v1); 100 try expect(std.mem.eql(u8, &@as([4]u8, v2), &[4]u8{ 0xbb, 0xdd, 0xff, 0x22 })); 101 } 102 }; 103 try comptime S.doTheTest(); 104 try S.doTheTest(); 105 } 106