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safe_integer.cpp
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safe_integer.cpp
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/*
* Copyright 2016 WebAssembly Community Group participants
*
* 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 <cassert>
#include <cmath>
#include <limits>
#include "support/safe_integer.h"
using namespace wasm;
bool wasm::isInteger(double x) { return fmod(x, 1) == 0; }
bool wasm::isUInteger32(double x) {
return !std::signbit(x) && isInteger(x) &&
x <= std::numeric_limits<uint32_t>::max();
}
bool wasm::isSInteger32(double x) {
return isInteger(x) && x >= std::numeric_limits<int32_t>::min() &&
x <= std::numeric_limits<int32_t>::max();
}
uint32_t wasm::toUInteger32(double x) {
return std::signbit(x) ? 0
: (x < std::numeric_limits<uint32_t>::max()
? (uint32_t)x
: std::numeric_limits<uint32_t>::max());
}
int32_t wasm::toSInteger32(double x) {
return (x > std::numeric_limits<int32_t>::min() &&
x < std::numeric_limits<int32_t>::max())
? (int32_t)x
: (std::signbit(x) ? std::numeric_limits<int32_t>::min()
: std::numeric_limits<int32_t>::max());
}
bool wasm::isUInteger64(double x) {
return !std::signbit(x) && isInteger(x) &&
x <= std::numeric_limits<uint64_t>::max();
}
bool wasm::isSInteger64(double x) {
return isInteger(x) && x >= std::numeric_limits<int64_t>::min() &&
x <= std::numeric_limits<int64_t>::max();
}
uint64_t wasm::toUInteger64(double x) {
return std::signbit(x) ? 0
: (x < (double)std::numeric_limits<uint64_t>::max()
? (uint64_t)x
: std::numeric_limits<uint64_t>::max());
}
int64_t wasm::toSInteger64(double x) {
return (x > (double)std::numeric_limits<int64_t>::min() &&
x < (double)std::numeric_limits<int64_t>::max())
? (int64_t)x
: (std::signbit(x) ? std::numeric_limits<int64_t>::min()
: std::numeric_limits<int64_t>::max());
}
/* 3 32222222 222...00
* 1 09876543 210...10
* -------------------
* 0 00000000 000...00 => 0x00000000 => 0
* 0 10011101 111...11 => 0x4effffff => 2147483520 (~INT32_MAX)
* 0 10011110 000...00 => 0x4f000000 => 2147483648
* 0 10011110 111...11 => 0x4f7fffff => 4294967040 (~UINT32_MAX)
* 0 10111110 111...11 => 0x5effffff => 9223371487098961920 (~INT64_MAX)
* 0 10111110 000...00 => 0x5f000000 => 9223372036854775808
* 0 10111111 111...11 => 0x5f7fffff => 18446742974197923840 (~UINT64_MAX)
* 0 10111111 000...00 => 0x5f800000 => 18446744073709551616
* 0 11111111 000...00 => 0x7f800000 => inf
* 0 11111111 000...01 => 0x7f800001 => nan(0x1)
* 0 11111111 111...11 => 0x7fffffff => nan(0x7fffff)
* 1 00000000 000...00 => 0x80000000 => -0
* 1 01111110 111...11 => 0xbf7fffff => -1 + ulp (~UINT32_MIN, ~UINT64_MIN)
* 1 01111111 000...00 => 0xbf800000 => -1
* 1 10011110 000...00 => 0xcf000000 => -2147483648 (INT32_MIN)
* 1 10111110 000...00 => 0xdf000000 => -9223372036854775808 (INT64_MIN)
* 1 11111111 000...00 => 0xff800000 => -inf
* 1 11111111 000...01 => 0xff800001 => -nan(0x1)
* 1 11111111 111...11 => 0xffffffff => -nan(0x7fffff)
*/
bool wasm::isInRangeI32TruncS(int32_t i) {
uint32_t u = i;
return (u < 0x4f000000U) || (u >= 0x80000000U && u <= 0xcf000000U);
}
bool wasm::isInRangeI64TruncS(int32_t i) {
uint32_t u = i;
return (u < 0x5f000000U) || (u >= 0x80000000U && u <= 0xdf000000U);
}
bool wasm::isInRangeI32TruncU(int32_t i) {
uint32_t u = i;
return (u < 0x4f800000U) || (u >= 0x80000000U && u < 0xbf800000U);
}
bool wasm::isInRangeI64TruncU(int32_t i) {
uint32_t u = i;
return (u < 0x5f800000U) || (u >= 0x80000000U && u < 0xbf800000U);
}
/* clang-format off */
/*
* 6 66655555555 5544...222221...000
* 3 21098765432 1098...432109...210
* ---------------------------------
* 0 00000000000 0000...000000...000 0x0000000000000000 => 0
* 0 10000011101 1111...111000...000 0x41dfffffffc00000 => 2147483647 (INT32_MAX)
* 0 10000011110 1111...111100...000 0x41efffffffe00000 => 4294967295 (UINT32_MAX)
* 0 10000111101 1111...111111...111 0x43dfffffffffffff => 9223372036854774784 (~INT64_MAX)
* 0 10000111110 0000...000000...000 0x43e0000000000000 => 9223372036854775808
* 0 10000111110 1111...111111...111 0x43efffffffffffff => 18446744073709549568 (~UINT64_MAX)
* 0 10000111111 0000...000000...000 0x43f0000000000000 => 18446744073709551616
* 0 11111111111 0000...000000...000 0x7ff0000000000000 => inf
* 0 11111111111 0000...000000...001 0x7ff0000000000001 => nan(0x1)
* 0 11111111111 1111...111111...111 0x7fffffffffffffff => nan(0xfff...)
* 1 00000000000 0000...000000...000 0x8000000000000000 => -0
* 1 01111111110 1111...111111...111 0xbfefffffffffffff => -1 + ulp (~UINT32_MIN, ~UINT64_MIN)
* 1 01111111111 0000...000000...000 0xbff0000000000000 => -1
* 1 10000011110 0000...000000...000 0xc1e0000000000000 => -2147483648 (INT32_MIN)
* 1 10000111110 0000...000000...000 0xc3e0000000000000 => -9223372036854775808 (INT64_MIN)
* 1 11111111111 0000...000000...000 0xfff0000000000000 => -inf
* 1 11111111111 0000...000000...001 0xfff0000000000001 => -nan(0x1)
* 1 11111111111 1111...111111...111 0xffffffffffffffff => -nan(0xfff...)
*/
/* clang-format on */
bool wasm::isInRangeI32TruncS(int64_t i) {
uint64_t u = i;
return (u <= 0x41dfffffffc00000ULL) ||
(u >= 0x8000000000000000ULL && u <= 0xc1e0000000000000ULL);
}
bool wasm::isInRangeI32TruncU(int64_t i) {
uint64_t u = i;
return (u <= 0x41efffffffe00000ULL) ||
(u >= 0x8000000000000000ULL && u <= 0xbfefffffffffffffULL);
}
bool wasm::isInRangeI64TruncS(int64_t i) {
uint64_t u = i;
return (u < 0x43e0000000000000ULL) ||
(u >= 0x8000000000000000ULL && u <= 0xc3e0000000000000ULL);
}
bool wasm::isInRangeI64TruncU(int64_t i) {
uint64_t u = i;
return (u < 0x43f0000000000000ULL) ||
(u >= 0x8000000000000000ULL && u <= 0xbfefffffffffffffULL);
}