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stage1: detect underflow in bigint_fits_in_bits

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xackus 2020-05-11 14:06:37 +02:00
parent d4d509090b
commit 204f8daeed
2 changed files with 9 additions and 0 deletions
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1
src/bigint.cpp
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@ -243,6 +243,7 @@ bool bigint_fits_in_bits(const BigInt *bn, size_t bit_count, bool is_signed) {
} }
if (!is_signed) { if (!is_signed) {
if(bn->is_negative) return false;
size_t full_bits = bn->digit_count * 64; size_t full_bits = bn->digit_count * 64;
size_t leading_zero_count = bigint_clz(bn, full_bits); size_t leading_zero_count = bigint_clz(bn, full_bits);
return bit_count >= full_bits - leading_zero_count; return bit_count >= full_bits - leading_zero_count;

8
test/compile_errors.zig
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@ -7411,4 +7411,12 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
, &[_][]const u8{ , &[_][]const u8{
":5:28: error: expected type '[]u8', found '*const [3:0]u8'", ":5:28: error: expected type '[]u8', found '*const [3:0]u8'",
}); });
cases.add("integer underflow error",
\\export fn entry() void {
\\ _ = @intToPtr(*c_void, ~@as(usize, @import("std").math.maxInt(usize)) - 1);
\\}
, &[_][]const u8{
":2:75: error: operation caused overflow",
});
} }