/*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
-#define FOLLY_CONV_INTERNAL
#include <folly/Conv.h>
+#include <array>
namespace folly {
namespace detail {
namespace {
+/**
+ * Finds the first non-digit in a string. The number of digits
+ * searched depends on the precision of the Tgt integral. Assumes the
+ * string starts with NO whitespace and NO sign.
+ *
+ * The semantics of the routine is:
+ * for (;; ++b) {
+ * if (b >= e || !isdigit(*b)) return b;
+ * }
+ *
+ * Complete unrolling marks bottom-line (i.e. entire conversion)
+ * improvements of 20%.
+ */
+inline const char* findFirstNonDigit(const char* b, const char* e) {
+ for (; b < e; ++b) {
+ auto const c = static_cast<unsigned>(*b) - '0';
+ if (c >= 10) {
+ break;
+ }
+ }
+ return b;
+}
+
// Maximum value of number when represented as a string
template <class T>
struct MaxString {
"Wrong value for MaxString<unsigned long long>::value"
", please update.");
-#ifdef FOLLY_HAVE_INT128_T
+#if FOLLY_HAVE_INT128_T
template <> const char *const MaxString<__uint128_t>::value =
"340282366920938463463374607431768211455";
#endif
OOR, OOR, OOR, OOR, OOR, OOR, OOR, OOR, OOR, OOR, // 240
OOR, OOR, OOR, OOR, OOR, OOR // 250
};
+
+struct ErrorString {
+ const char* string;
+ bool quote;
+};
+
+// Keep this in sync with ConversionCode in Conv.h
+constexpr const std::array<
+ ErrorString,
+ static_cast<std::size_t>(ConversionCode::NUM_ERROR_CODES)>
+ kErrorStrings{{
+ {"Success", true},
+ {"Empty input string", true},
+ {"No digits found in input string", true},
+ {"Integer overflow when parsing bool (must be 0 or 1)", true},
+ {"Invalid value for bool", true},
+ {"Non-digit character found", true},
+ {"Invalid leading character", true},
+ {"Overflow during conversion", true},
+ {"Negative overflow during conversion", true},
+ {"Unable to convert string to floating point value", true},
+ {"Non-whitespace character found after end of conversion", true},
+ {"Overflow during arithmetic conversion", false},
+ {"Negative overflow during arithmetic conversion", false},
+ {"Loss of precision during arithmetic conversion", false},
+ }};
+
+// Check if ASCII is really ASCII
+using IsAscii = std::
+ integral_constant<bool, 'A' == 65 && 'Z' == 90 && 'a' == 97 && 'z' == 122>;
+
+// The code in this file that uses tolower() really only cares about
+// 7-bit ASCII characters, so we can take a nice shortcut here.
+inline char tolower_ascii(char in) {
+ return IsAscii::value ? in | 0x20 : char(std::tolower(in));
}
inline bool bool_str_cmp(const char** b, size_t len, const char* value) {
const char* e = *b + len;
const char* v = value;
while (*v != '\0') {
- if (p == e || tolower(*p) != *v) { // value is already lowercase
+ if (p == e || tolower_ascii(*p) != *v) { // value is already lowercase
return false;
}
++p;
return true;
}
-bool str_to_bool(StringPiece* src) {
+} // anonymous namespace
+
+Expected<bool, ConversionCode> str_to_bool(StringPiece* src) noexcept {
auto b = src->begin(), e = src->end();
for (;; ++b) {
- FOLLY_RANGE_CHECK_STRINGPIECE(
- b < e, "No non-whitespace characters found in input string", *src);
- if (!isspace(*b)) break;
+ if (b >= e) {
+ return makeUnexpected(ConversionCode::EMPTY_INPUT_STRING);
+ }
+ if (!std::isspace(*b)) {
+ break;
+ }
}
bool result;
- size_t len = e - b;
+ size_t len = size_t(e - b);
switch (*b) {
case '0':
case '1': {
result = false;
for (; b < e && isdigit(*b); ++b) {
- FOLLY_RANGE_CHECK_STRINGPIECE(
- !result && (*b == '0' || *b == '1'),
- "Integer overflow when parsing bool: must be 0 or 1", *src);
+ if (result || (*b != '0' && *b != '1')) {
+ return makeUnexpected(ConversionCode::BOOL_OVERFLOW);
+ }
result = (*b == '1');
}
break;
} else if (bool_str_cmp(&b, len, "off")) {
result = false;
} else {
- FOLLY_RANGE_CHECK_STRINGPIECE(false, "Invalid value for bool", *src);
+ return makeUnexpected(ConversionCode::BOOL_INVALID_VALUE);
}
break;
default:
- FOLLY_RANGE_CHECK_STRINGPIECE(false, "Invalid value for bool", *src);
+ return makeUnexpected(ConversionCode::BOOL_INVALID_VALUE);
}
src->assign(b, e);
+
return result;
}
-namespace {
/**
* StringPiece to double, with progress information. Alters the
* StringPiece parameter to munch the already-parsed characters.
*/
template <class Tgt>
-Tgt str_to_floating(StringPiece* src) {
+Expected<Tgt, ConversionCode> str_to_floating(StringPiece* src) noexcept {
using namespace double_conversion;
static StringToDoubleConverter
conv(StringToDoubleConverter::ALLOW_TRAILING_JUNK
std::numeric_limits<double>::quiet_NaN(),
nullptr, nullptr);
- FOLLY_RANGE_CHECK_STRINGPIECE(!src->empty(),
- "No digits found in input string", *src);
+ if (src->empty()) {
+ return makeUnexpected(ConversionCode::EMPTY_INPUT_STRING);
+ }
int length;
auto result = conv.StringToDouble(src->data(),
&length); // processed char count
if (!std::isnan(result)) {
- src->advance(length);
- return result;
+ // If we get here with length = 0, the input string is empty.
+ // If we get here with result = 0.0, it's either because the string
+ // contained only whitespace, or because we had an actual zero value
+ // (with potential trailing junk). If it was only whitespace, we
+ // want to raise an error; length will point past the last character
+ // that was processed, so we need to check if that character was
+ // whitespace or not.
+ if (length == 0 ||
+ (result == 0.0 && std::isspace((*src)[size_t(length) - 1]))) {
+ return makeUnexpected(ConversionCode::EMPTY_INPUT_STRING);
+ }
+ src->advance(size_t(length));
+ return Tgt(result);
}
- for (;; src->advance(1)) {
- if (src->empty()) {
- throw std::range_error("Unable to convert an empty string"
- " to a floating point value.");
- }
- if (!isspace(src->front())) {
+ auto* e = src->end();
+ auto* b =
+ std::find_if_not(src->begin(), e, [](char c) { return std::isspace(c); });
+
+ // There must be non-whitespace, otherwise we would have caught this above
+ assert(b < e);
+ size_t size = size_t(e - b);
+
+ bool negative = false;
+ if (*b == '-') {
+ negative = true;
+ ++b;
+ --size;
+ }
+
+ result = 0.0;
+
+ switch (tolower_ascii(*b)) {
+ case 'i':
+ if (size >= 3 && tolower_ascii(b[1]) == 'n' &&
+ tolower_ascii(b[2]) == 'f') {
+ if (size >= 8 && tolower_ascii(b[3]) == 'i' &&
+ tolower_ascii(b[4]) == 'n' && tolower_ascii(b[5]) == 'i' &&
+ tolower_ascii(b[6]) == 't' && tolower_ascii(b[7]) == 'y') {
+ b += 8;
+ } else {
+ b += 3;
+ }
+ result = std::numeric_limits<Tgt>::infinity();
+ }
+ break;
+
+ case 'n':
+ if (size >= 3 && tolower_ascii(b[1]) == 'a' &&
+ tolower_ascii(b[2]) == 'n') {
+ b += 3;
+ result = std::numeric_limits<Tgt>::quiet_NaN();
+ }
+ break;
+
+ default:
break;
- }
}
- // Was that "inf[inity]"?
- if (src->size() >= 3 && toupper((*src)[0]) == 'I'
- && toupper((*src)[1]) == 'N' && toupper((*src)[2]) == 'F') {
- if (src->size() >= 8 &&
- toupper((*src)[3]) == 'I' &&
- toupper((*src)[4]) == 'N' &&
- toupper((*src)[5]) == 'I' &&
- toupper((*src)[6]) == 'T' &&
- toupper((*src)[7]) == 'Y') {
- src->advance(8);
- } else {
- src->advance(3);
- }
- return std::numeric_limits<Tgt>::infinity();
- }
-
- // Was that "-inf[inity]"?
- if (src->size() >= 4 && toupper((*src)[0]) == '-'
- && toupper((*src)[1]) == 'I' && toupper((*src)[2]) == 'N'
- && toupper((*src)[3]) == 'F') {
- if (src->size() >= 9 &&
- toupper((*src)[4]) == 'I' &&
- toupper((*src)[5]) == 'N' &&
- toupper((*src)[6]) == 'I' &&
- toupper((*src)[7]) == 'T' &&
- toupper((*src)[8]) == 'Y') {
- src->advance(9);
- } else {
- src->advance(4);
+ if (result == 0.0) {
+ // All bets are off
+ return makeUnexpected(ConversionCode::STRING_TO_FLOAT_ERROR);
+ }
+
+ if (negative) {
+ result = -result;
+ }
+
+ src->assign(b, e);
+
+ return Tgt(result);
+}
+
+template Expected<float, ConversionCode> str_to_floating<float>(
+ StringPiece* src) noexcept;
+template Expected<double, ConversionCode> str_to_floating<double>(
+ StringPiece* src) noexcept;
+
+/**
+ * This class takes care of additional processing needed for signed values,
+ * like leading sign character and overflow checks.
+ */
+template <typename T, bool IsSigned = std::is_signed<T>::value>
+class SignedValueHandler;
+
+template <typename T>
+class SignedValueHandler<T, true> {
+ public:
+ ConversionCode init(const char*& b) {
+ negative_ = false;
+ if (!std::isdigit(*b)) {
+ if (*b == '-') {
+ negative_ = true;
+ } else if (UNLIKELY(*b != '+')) {
+ return ConversionCode::INVALID_LEADING_CHAR;
+ }
+ ++b;
}
- return -std::numeric_limits<Tgt>::infinity();
+ return ConversionCode::SUCCESS;
}
- // "nan"?
- if (src->size() >= 3 && toupper((*src)[0]) == 'N'
- && toupper((*src)[1]) == 'A' && toupper((*src)[2]) == 'N') {
- src->advance(3);
- return std::numeric_limits<Tgt>::quiet_NaN();
+ ConversionCode overflow() {
+ return negative_ ? ConversionCode::NEGATIVE_OVERFLOW
+ : ConversionCode::POSITIVE_OVERFLOW;
}
- // "-nan"?
- if (src->size() >= 4 &&
- toupper((*src)[0]) == '-' &&
- toupper((*src)[1]) == 'N' &&
- toupper((*src)[2]) == 'A' &&
- toupper((*src)[3]) == 'N') {
- src->advance(4);
- return -std::numeric_limits<Tgt>::quiet_NaN();
+ template <typename U>
+ Expected<T, ConversionCode> finalize(U value) {
+ T rv;
+ if (negative_) {
+ rv = T(-value);
+ if (UNLIKELY(rv > 0)) {
+ return makeUnexpected(ConversionCode::NEGATIVE_OVERFLOW);
+ }
+ } else {
+ rv = T(value);
+ if (UNLIKELY(rv < 0)) {
+ return makeUnexpected(ConversionCode::POSITIVE_OVERFLOW);
+ }
+ }
+ return rv;
}
- // All bets are off
- throw std::range_error("Unable to convert \"" + src->toString()
- + "\" to a floating point value.");
-}
+ private:
+ bool negative_;
+};
-}
+// For unsigned types, we don't need any extra processing
+template <typename T>
+class SignedValueHandler<T, false> {
+ public:
+ ConversionCode init(const char*&) {
+ return ConversionCode::SUCCESS;
+ }
-float str_to_float(StringPiece* src) {
- return str_to_floating<float>(src);
-}
+ ConversionCode overflow() {
+ return ConversionCode::POSITIVE_OVERFLOW;
+ }
-double str_to_double(StringPiece* src) {
- return str_to_floating<double>(src);
-}
+ Expected<T, ConversionCode> finalize(T value) {
+ return value;
+ }
+};
/**
- * String represented as a pair of pointers to char to unsigned
+ * String represented as a pair of pointers to char to signed/unsigned
* integrals. Assumes NO whitespace before or after, and also that the
- * string is composed entirely of digits. Tgt must be unsigned, and no
- * sign is allowed in the string (even it's '+'). String may be empty,
- * in which case digits_to throws.
+ * string is composed entirely of digits (and an optional sign only for
+ * signed types). String may be empty, in which case digits_to returns
+ * an appropriate error.
*/
template <class Tgt>
-Tgt digits_to(const char* b, const char* e) {
-
- static_assert(!std::is_signed<Tgt>::value, "Unsigned type expected");
+inline Expected<Tgt, ConversionCode> digits_to(
+ const char* b,
+ const char* const e) noexcept {
+ using UT = typename std::make_unsigned<Tgt>::type;
assert(b <= e);
- const size_t size = e - b;
+ SignedValueHandler<Tgt> sgn;
+
+ auto err = sgn.init(b);
+ if (UNLIKELY(err != ConversionCode::SUCCESS)) {
+ return makeUnexpected(err);
+ }
+
+ size_t size = size_t(e - b);
/* Although the string is entirely made of digits, we still need to
* check for overflow.
*/
- if (size >= std::numeric_limits<Tgt>::digits10 + 1) {
- // Leading zeros? If so, recurse to keep things simple
+ if (size > std::numeric_limits<UT>::digits10) {
+ // Leading zeros?
if (b < e && *b == '0') {
for (++b;; ++b) {
- if (b == e)
- return 0; // just zeros, e.g. "0000"
- if (*b != '0')
- return digits_to<Tgt>(b, e);
+ if (b == e) {
+ return Tgt(0); // just zeros, e.g. "0000"
+ }
+ if (*b != '0') {
+ size = size_t(e - b);
+ break;
+ }
}
}
- FOLLY_RANGE_CHECK_BEGIN_END(
- size == std::numeric_limits<Tgt>::digits10 + 1 &&
- strncmp(b, detail::MaxString<Tgt>::value, size) <= 0,
- "Numeric overflow upon conversion",
- b,
- e);
+ if (size > std::numeric_limits<UT>::digits10 &&
+ (size != std::numeric_limits<UT>::digits10 + 1 ||
+ strncmp(b, MaxString<UT>::value, size) > 0)) {
+ return makeUnexpected(sgn.overflow());
+ }
}
// Here we know that the number won't overflow when
// converted. Proceed without checks.
- Tgt result = 0;
+ UT result = 0;
for (; e - b >= 4; b += 4) {
- result *= 10000;
+ result *= static_cast<UT>(10000);
const int32_t r0 = shift1000[static_cast<size_t>(b[0])];
const int32_t r1 = shift100[static_cast<size_t>(b[1])];
const int32_t r2 = shift10[static_cast<size_t>(b[2])];
const int32_t r3 = shift1[static_cast<size_t>(b[3])];
const auto sum = r0 + r1 + r2 + r3;
- assert(sum < OOR && "Assumption: string only has digits");
- result += sum;
+ if (sum >= OOR) {
+ goto outOfRange;
+ }
+ result += UT(sum);
}
switch (e - b) {
const int32_t r1 = shift10[static_cast<size_t>(b[1])];
const int32_t r2 = shift1[static_cast<size_t>(b[2])];
const auto sum = r0 + r1 + r2;
- assert(sum < OOR && "Assumption: string only has digits");
- return result * 1000 + sum;
+ if (sum >= OOR) {
+ goto outOfRange;
+ }
+ result = UT(1000 * result + sum);
+ break;
}
case 2: {
const int32_t r0 = shift10[static_cast<size_t>(b[0])];
const int32_t r1 = shift1[static_cast<size_t>(b[1])];
const auto sum = r0 + r1;
- assert(sum < OOR && "Assumption: string only has digits");
- return result * 100 + sum;
+ if (sum >= OOR) {
+ goto outOfRange;
+ }
+ result = UT(100 * result + sum);
+ break;
}
case 1: {
const int32_t sum = shift1[static_cast<size_t>(b[0])];
- assert(sum < OOR && "Assumption: string only has digits");
- return result * 10 + sum;
+ if (sum >= OOR) {
+ goto outOfRange;
+ }
+ result = UT(10 * result + sum);
+ break;
}
+ default:
+ assert(b == e);
+ if (size == 0) {
+ return makeUnexpected(ConversionCode::NO_DIGITS);
+ }
+ break;
}
- assert(b == e);
- FOLLY_RANGE_CHECK_BEGIN_END(
- size > 0, "Found no digits to convert in input", b, e);
- return result;
+ return sgn.finalize(result);
+
+outOfRange:
+ return makeUnexpected(ConversionCode::NON_DIGIT_CHAR);
+}
+
+template Expected<char, ConversionCode> digits_to<char>(
+ const char*,
+ const char*) noexcept;
+template Expected<signed char, ConversionCode> digits_to<signed char>(
+ const char*,
+ const char*) noexcept;
+template Expected<unsigned char, ConversionCode> digits_to<unsigned char>(
+ const char*,
+ const char*) noexcept;
+
+template Expected<short, ConversionCode> digits_to<short>(
+ const char*,
+ const char*) noexcept;
+template Expected<unsigned short, ConversionCode> digits_to<unsigned short>(
+ const char*,
+ const char*) noexcept;
+
+template Expected<int, ConversionCode> digits_to<int>(
+ const char*,
+ const char*) noexcept;
+template Expected<unsigned int, ConversionCode> digits_to<unsigned int>(
+ const char*,
+ const char*) noexcept;
+
+template Expected<long, ConversionCode> digits_to<long>(
+ const char*,
+ const char*) noexcept;
+template Expected<unsigned long, ConversionCode> digits_to<unsigned long>(
+ const char*,
+ const char*) noexcept;
+
+template Expected<long long, ConversionCode> digits_to<long long>(
+ const char*,
+ const char*) noexcept;
+template Expected<unsigned long long, ConversionCode>
+digits_to<unsigned long long>(const char*, const char*) noexcept;
+
+#if FOLLY_HAVE_INT128_T
+template Expected<__int128, ConversionCode> digits_to<__int128>(
+ const char*,
+ const char*) noexcept;
+template Expected<unsigned __int128, ConversionCode>
+digits_to<unsigned __int128>(const char*, const char*) noexcept;
+#endif
+
+/**
+ * StringPiece to integrals, with progress information. Alters the
+ * StringPiece parameter to munch the already-parsed characters.
+ */
+template <class Tgt>
+Expected<Tgt, ConversionCode> str_to_integral(StringPiece* src) noexcept {
+ using UT = typename std::make_unsigned<Tgt>::type;
+
+ auto b = src->data(), past = src->data() + src->size();
+
+ for (;; ++b) {
+ if (UNLIKELY(b >= past)) {
+ return makeUnexpected(ConversionCode::EMPTY_INPUT_STRING);
+ }
+ if (!std::isspace(*b)) {
+ break;
+ }
+ }
+
+ SignedValueHandler<Tgt> sgn;
+ auto err = sgn.init(b);
+
+ if (UNLIKELY(err != ConversionCode::SUCCESS)) {
+ return makeUnexpected(err);
+ }
+ if (std::is_signed<Tgt>::value && UNLIKELY(b >= past)) {
+ return makeUnexpected(ConversionCode::NO_DIGITS);
+ }
+ if (UNLIKELY(!isdigit(*b))) {
+ return makeUnexpected(ConversionCode::NON_DIGIT_CHAR);
+ }
+
+ auto m = findFirstNonDigit(b + 1, past);
+
+ auto tmp = digits_to<UT>(b, m);
+
+ if (UNLIKELY(!tmp.hasValue())) {
+ return makeUnexpected(
+ tmp.error() == ConversionCode::POSITIVE_OVERFLOW ? sgn.overflow()
+ : tmp.error());
+ }
+
+ auto res = sgn.finalize(tmp.value());
+
+ if (res.hasValue()) {
+ src->advance(size_t(m - src->data()));
+ }
+
+ return res;
}
-template unsigned char digits_to<unsigned char>(const char* b, const char* e);
-template unsigned short digits_to<unsigned short>(const char* b, const char* e);
-template unsigned int digits_to<unsigned int>(const char* b, const char* e);
-template unsigned long digits_to<unsigned long>(const char* b, const char* e);
-template unsigned long long digits_to<unsigned long long>(const char* b,
- const char* e);
+template Expected<char, ConversionCode> str_to_integral<char>(
+ StringPiece* src) noexcept;
+template Expected<signed char, ConversionCode> str_to_integral<signed char>(
+ StringPiece* src) noexcept;
+template Expected<unsigned char, ConversionCode> str_to_integral<unsigned char>(
+ StringPiece* src) noexcept;
+
+template Expected<short, ConversionCode> str_to_integral<short>(
+ StringPiece* src) noexcept;
+template Expected<unsigned short, ConversionCode>
+str_to_integral<unsigned short>(StringPiece* src) noexcept;
+
+template Expected<int, ConversionCode> str_to_integral<int>(
+ StringPiece* src) noexcept;
+template Expected<unsigned int, ConversionCode> str_to_integral<unsigned int>(
+ StringPiece* src) noexcept;
+
+template Expected<long, ConversionCode> str_to_integral<long>(
+ StringPiece* src) noexcept;
+template Expected<unsigned long, ConversionCode> str_to_integral<unsigned long>(
+ StringPiece* src) noexcept;
+
+template Expected<long long, ConversionCode> str_to_integral<long long>(
+ StringPiece* src) noexcept;
+template Expected<unsigned long long, ConversionCode>
+str_to_integral<unsigned long long>(StringPiece* src) noexcept;
+
#if FOLLY_HAVE_INT128_T
-template unsigned __int128 digits_to<unsigned __int128>(const char* b,
- const char* e);
+template Expected<__int128, ConversionCode> str_to_integral<__int128>(
+ StringPiece* src) noexcept;
+template Expected<unsigned __int128, ConversionCode>
+str_to_integral<unsigned __int128>(StringPiece* src) noexcept;
#endif
} // namespace detail
+
+ConversionError makeConversionError(ConversionCode code, StringPiece input) {
+ using namespace detail;
+ static_assert(
+ std::is_unsigned<std::underlying_type<ConversionCode>::type>::value,
+ "ConversionCode should be unsigned");
+ assert((std::size_t)code < kErrorStrings.size());
+ const ErrorString& err = kErrorStrings[(std::size_t)code];
+ if (code == ConversionCode::EMPTY_INPUT_STRING && input.empty()) {
+ return {err.string, code};
+ }
+ std::string tmp(err.string);
+ tmp.append(": ");
+ if (err.quote) {
+ tmp.append(1, '"');
+ }
+ if (input.size() > 0) {
+ tmp.append(input.data(), input.size());
+ }
+ if (err.quote) {
+ tmp.append(1, '"');
+ }
+ return {tmp, code};
+}
+
} // namespace folly
projects / folly.git / blobdiff