| // Copyright 2018 PDFium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com |
| |
| #include "core/fxcrt/fx_number.h" |
| |
| #include <limits> |
| |
| #include "core/fxcrt/fx_extension.h" |
| #include "core/fxcrt/fx_string.h" |
| |
| FX_Number::FX_Number() |
| : m_bInteger(true), m_bSigned(false), m_UnsignedValue(0) {} |
| |
| FX_Number::FX_Number(uint32_t value) |
| : m_bInteger(true), m_bSigned(false), m_UnsignedValue(value) {} |
| |
| FX_Number::FX_Number(int32_t value) |
| : m_bInteger(true), m_bSigned(true), m_SignedValue(value) {} |
| |
| FX_Number::FX_Number(float value) |
| : m_bInteger(false), m_bSigned(true), m_FloatValue(value) {} |
| |
| FX_Number::FX_Number(const ByteStringView& strc) |
| : m_bInteger(true), m_bSigned(false), m_UnsignedValue(0) { |
| if (strc.IsEmpty()) |
| return; |
| |
| if (strc.Contains('.')) { |
| m_bInteger = false; |
| m_bSigned = true; |
| m_FloatValue = FX_atof(strc); |
| return; |
| } |
| |
| // Note, numbers in PDF are typically of the form 123, -123, etc. But, |
| // for things like the Permissions on the encryption hash the number is |
| // actually an unsigned value. We use a uint32_t so we can deal with the |
| // unsigned and then check for overflow if the user actually signed the value. |
| // The Permissions flag is listed in Table 3.20 PDF 1.7 spec. |
| pdfium::base::CheckedNumeric<uint32_t> unsigned_val = 0; |
| bool bNegative = false; |
| size_t cc = 0; |
| if (strc[0] == '+') { |
| cc++; |
| m_bSigned = true; |
| } else if (strc[0] == '-') { |
| bNegative = true; |
| m_bSigned = true; |
| cc++; |
| } |
| |
| while (cc < strc.GetLength() && std::isdigit(strc[cc])) { |
| unsigned_val = unsigned_val * 10 + FXSYS_DecimalCharToInt(strc.CharAt(cc)); |
| if (!unsigned_val.IsValid()) |
| break; |
| cc++; |
| } |
| |
| uint32_t uValue = unsigned_val.ValueOrDefault(0); |
| if (!m_bSigned) { |
| m_UnsignedValue = uValue; |
| return; |
| } |
| |
| // We have a sign, so if the value was greater then the signed integer |
| // limits, then we've overflowed and must reset to the default value. |
| constexpr uint32_t uLimit = |
| static_cast<uint32_t>(std::numeric_limits<int>::max()); |
| |
| if (uValue > (bNegative ? uLimit + 1 : uLimit)) |
| uValue = 0; |
| |
| // Switch back to the int space so we can flip to a negative if we need. |
| int32_t value = static_cast<int32_t>(uValue); |
| if (bNegative) { |
| // |value| is usually positive, except in the corner case of "-2147483648", |
| // where |uValue| is 2147483648. When it gets casted to an int, |value| |
| // becomes -2147483648. For this case, avoid undefined behavior, because |
| // an int32_t cannot represent 2147483648. |
| static constexpr int kMinInt = std::numeric_limits<int>::min(); |
| m_SignedValue = LIKELY(value != kMinInt) ? -value : kMinInt; |
| } else { |
| m_SignedValue = value; |
| } |
| } |
| |
| uint32_t FX_Number::GetUnsigned() const { |
| return m_bInteger ? m_UnsignedValue : static_cast<uint32_t>(m_FloatValue); |
| } |
| |
| int32_t FX_Number::GetSigned() const { |
| return m_bInteger ? m_SignedValue : static_cast<int32_t>(m_FloatValue); |
| } |
| |
| float FX_Number::GetFloat() const { |
| if (!m_bInteger) |
| return m_FloatValue; |
| |
| return m_bSigned ? static_cast<float>(m_SignedValue) |
| : static_cast<float>(m_UnsignedValue); |
| } |