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carbon-lang/toolchain/lex/helpers.cpp
T
Jon Ross-Perkins 0db63ff17a Abbreviate Integer and FloatingPoint (#3435)
I was suggesting this because `FloatingPoint` is pretty long. `int` and
`float` should be familiar abbreviations. `unsigned` should be familiar
to developers too, but `UnsignedInt` still feels usefully clearer for
the additional chars.
2023-11-29 23:29:48 +00:00

33 lines
1.2 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "toolchain/lex/helpers.h"
namespace Carbon::Lex {
auto CanLexInt(DiagnosticEmitter<const char*>& emitter, llvm::StringRef text)
-> bool {
// llvm::getAsInteger is used for parsing, but it's quadratic and visibly slow
// on large integer values. This limit exists to avoid hitting those limits.
// Per https://github.com/carbon-language/carbon-lang/issues/980, it may be
// feasible to optimize integer parsing in order to address performance if
// this limit becomes an issue.
//
// 2^128 would be 39 decimal digits or 128 binary. In either case, this limit
// is far above the threshold for normal ints.
constexpr size_t DigitLimit = 1000;
if (text.size() > DigitLimit) {
CARBON_DIAGNOSTIC(
TooManyDigits, Error,
"Found a sequence of {0} digits, which is greater than the "
"limit of {1}.",
size_t, size_t);
emitter.Emit(text.begin(), TooManyDigits, text.size(), DigitLimit);
return false;
}
return true;
}
} // namespace Carbon::Lex