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snix/absl/strings/internal/charconv_parse_test.cc
Abseil Team bed5bd6e18 Export of internal Abseil changes. 
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f4bb8afa9376b4120f56f3beff7b07260da4a5c2 by CJ Johnson <johnsoncj@google.com>:

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PiperOrigin-RevId: 209630262
GitOrigin-RevId: f4bb8afa9376b4120f56f3beff7b07260da4a5c2
Change-Id: I3fedf35011d805ee4a20b92e073b43523b47d15b
2018-08-22 11:02:33 -04:00

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// Copyright 2018 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/strings/internal/charconv_parse.h"
#include <string>
#include <utility>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/strings/str_cat.h"
using absl::chars_format;
using absl::strings_internal::FloatType;
using absl::strings_internal::ParsedFloat;
using absl::strings_internal::ParseFloat;
namespace {
// Check that a given string input is parsed to the expected mantissa and
// exponent.
//
// Input string `s` must contain a '$' character. It marks the end of the
// characters that should be consumed by the match. It is stripped from the
// input to ParseFloat.
//
// If input string `s` contains '[' and ']' characters, these mark the region
// of characters that should be marked as the "subrange". For NaNs, this is
// the location of the extended NaN string. For numbers, this is the location
// of the full, over-large mantissa.
template <int base>
void ExpectParsedFloat(std::string s, absl::chars_format format_flags,
FloatType expected_type, uint64_t expected_mantissa,
int expected_exponent,
int expected_literal_exponent = -999) {
SCOPED_TRACE(s);
int begin_subrange = -1;
int end_subrange = -1;
// If s contains '[' and ']', then strip these characters and set the subrange
// indices appropriately.
std::string::size_type open_bracket_pos = s.find('[');
if (open_bracket_pos != std::string::npos) {
begin_subrange = static_cast<int>(open_bracket_pos);
s.replace(open_bracket_pos, 1, "");
std::string::size_type close_bracket_pos = s.find(']');
ABSL_RAW_CHECK(close_bracket_pos != absl::string_view::npos,
"Test input contains [ without matching ]");
end_subrange = static_cast<int>(close_bracket_pos);
s.replace(close_bracket_pos, 1, "");
}
const std::string::size_type expected_characters_matched = s.find('$');
ABSL_RAW_CHECK(expected_characters_matched != std::string::npos,
"Input std::string must contain $");
s.replace(expected_characters_matched, 1, "");
ParsedFloat parsed =
ParseFloat<base>(s.data(), s.data() + s.size(), format_flags);
EXPECT_NE(parsed.end, nullptr);
if (parsed.end == nullptr) {
return; // The following tests are not useful if we fully failed to parse
}
EXPECT_EQ(parsed.type, expected_type);
if (begin_subrange == -1) {
EXPECT_EQ(parsed.subrange_begin, nullptr);
EXPECT_EQ(parsed.subrange_end, nullptr);
} else {
EXPECT_EQ(parsed.subrange_begin, s.data() + begin_subrange);
EXPECT_EQ(parsed.subrange_end, s.data() + end_subrange);
}
if (parsed.type == FloatType::kNumber) {
EXPECT_EQ(parsed.mantissa, expected_mantissa);
EXPECT_EQ(parsed.exponent, expected_exponent);
if (expected_literal_exponent != -999) {
EXPECT_EQ(parsed.literal_exponent, expected_literal_exponent);
}
}
auto characters_matched = static_cast<int>(parsed.end - s.data());
EXPECT_EQ(characters_matched, expected_characters_matched);
}
// Check that a given string input is parsed to the expected mantissa and
// exponent.
//
// Input string `s` must contain a '$' character. It marks the end of the
// characters that were consumed by the match.
template <int base>
void ExpectNumber(std::string s, absl::chars_format format_flags,
uint64_t expected_mantissa, int expected_exponent,
int expected_literal_exponent = -999) {
ExpectParsedFloat<base>(std::move(s), format_flags, FloatType::kNumber,
expected_mantissa, expected_exponent,
expected_literal_exponent);
}
// Check that a given string input is parsed to the given special value.
//
// This tests against both number bases, since infinities and NaNs have
// identical representations in both modes.
void ExpectSpecial(const std::string& s, absl::chars_format format_flags,
FloatType type) {
ExpectParsedFloat<10>(s, format_flags, type, 0, 0);
ExpectParsedFloat<16>(s, format_flags, type, 0, 0);
}
// Check that a given input string is not matched by Float.
template <int base>
void ExpectFailedParse(absl::string_view s, absl::chars_format format_flags) {
ParsedFloat parsed =
ParseFloat<base>(s.data(), s.data() + s.size(), format_flags);
EXPECT_EQ(parsed.end, nullptr);
}
TEST(ParseFloat, SimpleValue) {
// Test that various forms of floating point numbers all parse correctly.
ExpectNumber<10>("1.23456789e5$", chars_format::general, 123456789, -3);
ExpectNumber<10>("1.23456789e+5$", chars_format::general, 123456789, -3);
ExpectNumber<10>("1.23456789E5$", chars_format::general, 123456789, -3);
ExpectNumber<10>("1.23456789e05$", chars_format::general, 123456789, -3);
ExpectNumber<10>("123.456789e3$", chars_format::general, 123456789, -3);
ExpectNumber<10>("0.000123456789e9$", chars_format::general, 123456789, -3);
ExpectNumber<10>("123456.789$", chars_format::general, 123456789, -3);
ExpectNumber<10>("123456789e-3$", chars_format::general, 123456789, -3);
ExpectNumber<16>("1.234abcdefp28$", chars_format::general, 0x1234abcdef, -8);
ExpectNumber<16>("1.234abcdefp+28$", chars_format::general, 0x1234abcdef, -8);
ExpectNumber<16>("1.234ABCDEFp28$", chars_format::general, 0x1234abcdef, -8);
ExpectNumber<16>("1.234AbCdEfP0028$", chars_format::general, 0x1234abcdef,
-8);
ExpectNumber<16>("123.4abcdefp20$", chars_format::general, 0x1234abcdef, -8);
ExpectNumber<16>("0.0001234abcdefp44$", chars_format::general, 0x1234abcdef,
-8);
ExpectNumber<16>("1234abcd.ef$", chars_format::general, 0x1234abcdef, -8);
ExpectNumber<16>("1234abcdefp-8$", chars_format::general, 0x1234abcdef, -8);
// ExpectNumber does not attempt to drop trailing zeroes.
ExpectNumber<10>("0001.2345678900e005$", chars_format::general, 12345678900,
-5);
ExpectNumber<16>("0001.234abcdef000p28$", chars_format::general,
0x1234abcdef000, -20);
// Ensure non-matching characters after a number are ignored, even when they
// look like potentially matching characters.
ExpectNumber<10>("1.23456789e5$ ", chars_format::general, 123456789, -3);
ExpectNumber<10>("1.23456789e5$e5e5", chars_format::general, 123456789, -3);
ExpectNumber<10>("1.23456789e5$.25", chars_format::general, 123456789, -3);
ExpectNumber<10>("1.23456789e5$-", chars_format::general, 123456789, -3);
ExpectNumber<10>("1.23456789e5$PUPPERS!!!", chars_format::general, 123456789,
-3);
ExpectNumber<10>("123456.789$efghij", chars_format::general, 123456789, -3);
ExpectNumber<10>("123456.789$e", chars_format::general, 123456789, -3);
ExpectNumber<10>("123456.789$p5", chars_format::general, 123456789, -3);
ExpectNumber<10>("123456.789$.10", chars_format::general, 123456789, -3);
ExpectNumber<16>("1.234abcdefp28$ ", chars_format::general, 0x1234abcdef,
-8);
ExpectNumber<16>("1.234abcdefp28$p28", chars_format::general, 0x1234abcdef,
-8);
ExpectNumber<16>("1.234abcdefp28$.125", chars_format::general, 0x1234abcdef,
-8);
ExpectNumber<16>("1.234abcdefp28$-", chars_format::general, 0x1234abcdef, -8);
ExpectNumber<16>("1.234abcdefp28$KITTEHS!!!", chars_format::general,
0x1234abcdef, -8);
ExpectNumber<16>("1234abcd.ef$ghijk", chars_format::general, 0x1234abcdef,
-8);
ExpectNumber<16>("1234abcd.ef$p", chars_format::general, 0x1234abcdef, -8);
ExpectNumber<16>("1234abcd.ef$.10", chars_format::general, 0x1234abcdef, -8);
// Ensure we can read a full resolution mantissa without overflow.
ExpectNumber<10>("9999999999999999999$", chars_format::general,
9999999999999999999u, 0);
ExpectNumber<16>("fffffffffffffff$", chars_format::general,
0xfffffffffffffffu, 0);
// Check that zero is consistently read.
ExpectNumber<10>("0$", chars_format::general, 0, 0);
ExpectNumber<16>("0$", chars_format::general, 0, 0);
ExpectNumber<10>("000000000000000000000000000000000000000$",
chars_format::general, 0, 0);
ExpectNumber<16>("000000000000000000000000000000000000000$",
chars_format::general, 0, 0);
ExpectNumber<10>("0000000000000000000000.000000000000000000$",
chars_format::general, 0, 0);
ExpectNumber<16>("0000000000000000000000.000000000000000000$",
chars_format::general, 0, 0);
ExpectNumber<10>("0.00000000000000000000000000000000e123456$",
chars_format::general, 0, 0);
ExpectNumber<16>("0.00000000000000000000000000000000p123456$",
chars_format::general, 0, 0);
}
TEST(ParseFloat, LargeDecimalMantissa) {
// After 19 significant decimal digits in the mantissa, ParsedFloat will
// truncate additional digits. We need to test that:
// 1) the truncation to 19 digits happens
// 2) the returned exponent reflects the dropped significant digits
// 3) a correct literal_exponent is set
//
// If and only if a significant digit is found after 19 digits, then the
// entirety of the mantissa in case the exact value is needed to make a
// rounding decision. The [ and ] characters below denote where such a
// subregion was marked by by ParseFloat. They are not part of the input.
// Mark a capture group only if a dropped digit is significant (nonzero).
ExpectNumber<10>("100000000000000000000000000$", chars_format::general,
1000000000000000000,
/* adjusted exponent */ 8);
ExpectNumber<10>("123456789123456789100000000$", chars_format::general,
1234567891234567891,
/* adjusted exponent */ 8);
ExpectNumber<10>("[123456789123456789123456789]$", chars_format::general,
1234567891234567891,
/* adjusted exponent */ 8,
/* literal exponent */ 0);
ExpectNumber<10>("[123456789123456789100000009]$", chars_format::general,
1234567891234567891,
/* adjusted exponent */ 8,
/* literal exponent */ 0);
ExpectNumber<10>("[123456789123456789120000000]$", chars_format::general,
1234567891234567891,
/* adjusted exponent */ 8,
/* literal exponent */ 0);
// Leading zeroes should not count towards the 19 significant digit limit
ExpectNumber<10>("[00000000123456789123456789123456789]$",
chars_format::general, 1234567891234567891,
/* adjusted exponent */ 8,
/* literal exponent */ 0);
ExpectNumber<10>("00000000123456789123456789100000000$",
chars_format::general, 1234567891234567891,
/* adjusted exponent */ 8);
// Truncated digits after the decimal point should not cause a further
// exponent adjustment.
ExpectNumber<10>("1.234567891234567891e123$", chars_format::general,
1234567891234567891, 105);
ExpectNumber<10>("[1.23456789123456789123456789]e123$", chars_format::general,
1234567891234567891,
/* adjusted exponent */ 105,
/* literal exponent */ 123);
// Ensure we truncate, and not round. (The from_chars algorithm we use
// depends on our guess missing low, if it misses, so we need the rounding
// error to be downward.)
ExpectNumber<10>("[1999999999999999999999]$", chars_format::general,
1999999999999999999,
/* adjusted exponent */ 3,
/* literal exponent */ 0);
}
TEST(ParseFloat, LargeHexadecimalMantissa) {
// After 15 significant hex digits in the mantissa, ParsedFloat will treat
// additional digits as sticky, We need to test that:
// 1) The truncation to 15 digits happens
// 2) The returned exponent reflects the dropped significant digits
// 3) If a nonzero digit is dropped, the low bit of mantissa is set.
ExpectNumber<16>("123456789abcdef123456789abcdef$", chars_format::general,
0x123456789abcdef, 60);
// Leading zeroes should not count towards the 15 significant digit limit
ExpectNumber<16>("000000123456789abcdef123456789abcdef$",
chars_format::general, 0x123456789abcdef, 60);
// Truncated digits after the radix point should not cause a further
// exponent adjustment.
ExpectNumber<16>("1.23456789abcdefp100$", chars_format::general,
0x123456789abcdef, 44);
ExpectNumber<16>("1.23456789abcdef123456789abcdefp100$",
chars_format::general, 0x123456789abcdef, 44);
// test sticky digit behavior. The low bit should be set iff any dropped
// digit is nonzero.
ExpectNumber<16>("123456789abcdee123456789abcdee$", chars_format::general,
0x123456789abcdef, 60);
ExpectNumber<16>("123456789abcdee000000000000001$", chars_format::general,
0x123456789abcdef, 60);
ExpectNumber<16>("123456789abcdee000000000000000$", chars_format::general,
0x123456789abcdee, 60);
}
TEST(ParseFloat, ScientificVsFixed) {
// In fixed mode, an exponent is never matched (but the remainder of the
// number will be matched.)
ExpectNumber<10>("1.23456789$e5", chars_format::fixed, 123456789, -8);
ExpectNumber<10>("123456.789$", chars_format::fixed, 123456789, -3);
ExpectNumber<16>("1.234abcdef$p28", chars_format::fixed, 0x1234abcdef, -36);
ExpectNumber<16>("1234abcd.ef$", chars_format::fixed, 0x1234abcdef, -8);
// In scientific mode, numbers don't match *unless* they have an exponent.
ExpectNumber<10>("1.23456789e5$", chars_format::scientific, 123456789, -3);
ExpectFailedParse<10>("-123456.789$", chars_format::scientific);
ExpectNumber<16>("1.234abcdefp28$", chars_format::scientific, 0x1234abcdef,
-8);
ExpectFailedParse<16>("1234abcd.ef$", chars_format::scientific);
}
TEST(ParseFloat, Infinity) {
ExpectFailedParse<10>("in", chars_format::general);
ExpectFailedParse<16>("in", chars_format::general);
ExpectFailedParse<10>("inx", chars_format::general);
ExpectFailedParse<16>("inx", chars_format::general);
ExpectSpecial("inf$", chars_format::general, FloatType::kInfinity);
ExpectSpecial("Inf$", chars_format::general, FloatType::kInfinity);
ExpectSpecial("INF$", chars_format::general, FloatType::kInfinity);
ExpectSpecial("inf$inite", chars_format::general, FloatType::kInfinity);
ExpectSpecial("iNfInItY$", chars_format::general, FloatType::kInfinity);
ExpectSpecial("infinity$!!!", chars_format::general, FloatType::kInfinity);
}
TEST(ParseFloat, NaN) {
ExpectFailedParse<10>("na", chars_format::general);
ExpectFailedParse<16>("na", chars_format::general);
ExpectFailedParse<10>("nah", chars_format::general);
ExpectFailedParse<16>("nah", chars_format::general);
ExpectSpecial("nan$", chars_format::general, FloatType::kNan);
ExpectSpecial("NaN$", chars_format::general, FloatType::kNan);
ExpectSpecial("nAn$", chars_format::general, FloatType::kNan);
ExpectSpecial("NAN$", chars_format::general, FloatType::kNan);
ExpectSpecial("NaN$aNaNaNaNaBatman!", chars_format::general, FloatType::kNan);
// A parenthesized sequence of the characters [a-zA-Z0-9_] is allowed to
// appear after an NaN. Check that this is allowed, and that the correct
// characters are grouped.
//
// (The characters [ and ] in the pattern below delimit the expected matched
// subgroup; they are not part of the input passed to ParseFloat.)
ExpectSpecial("nan([0xabcdef])$", chars_format::general, FloatType::kNan);
ExpectSpecial("nan([0xabcdef])$...", chars_format::general, FloatType::kNan);
ExpectSpecial("nan([0xabcdef])$)...", chars_format::general, FloatType::kNan);
ExpectSpecial("nan([])$", chars_format::general, FloatType::kNan);
ExpectSpecial("nan([aAzZ09_])$", chars_format::general, FloatType::kNan);
// If the subgroup contains illegal characters, don't match it at all.
ExpectSpecial("nan$(bad-char)", chars_format::general, FloatType::kNan);
// Also cope with a missing close paren.
ExpectSpecial("nan$(0xabcdef", chars_format::general, FloatType::kNan);
}
} // namespace
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