| // Copyright 2018 The PDFium Authors |
| // 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 <ctype.h> |
| |
| #include <limits> |
| |
| #include "core/fxcrt/fx_extension.h" |
| #include "core/fxcrt/fx_safe_types.h" |
| #include "core/fxcrt/fx_string.h" |
| |
| FX_Number::FX_Number() |
| : m_bIsInteger(true), m_bIsSigned(false), m_UnsignedValue(0) {} |
| |
| FX_Number::FX_Number(int32_t value) |
| : m_bIsInteger(true), m_bIsSigned(true), m_SignedValue(value) {} |
| |
| FX_Number::FX_Number(float value) |
| : m_bIsInteger(false), m_bIsSigned(true), m_FloatValue(value) {} |
| |
| FX_Number::FX_Number(ByteStringView strc) |
| : m_bIsInteger(true), m_bIsSigned(false), m_UnsignedValue(0) { |
| if (strc.IsEmpty()) |
| return; |
| |
| if (strc.Contains('.')) { |
| m_bIsInteger = false; |
| m_bIsSigned = true; |
| m_FloatValue = StringToFloat(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. |
| FX_SAFE_UINT32 unsigned_val = 0; |
| bool bNegative = false; |
| size_t cc = 0; |
| if (strc[0] == '+') { |
| cc++; |
| m_bIsSigned = true; |
| } else if (strc[0] == '-') { |
| bNegative = true; |
| m_bIsSigned = true; |
| cc++; |
| } |
| |
| for (; cc < strc.GetLength() && isdigit(strc[cc]); ++cc) { |
| // Deliberately not using FXSYS_DecimalCharToInt() in a tight loop to avoid |
| // a duplicate isdigit() call. Note that the order of operation is |
| // important to avoid unintentional overflows. |
| unsigned_val = unsigned_val * 10 + (strc[cc] - '0'); |
| } |
| |
| uint32_t uValue = unsigned_val.ValueOrDefault(0); |
| if (!m_bIsSigned) { |
| 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; |
| } |
| } |
| |
| int32_t FX_Number::GetSigned() const { |
| return m_bIsInteger ? m_SignedValue : static_cast<int32_t>(m_FloatValue); |
| } |
| |
| float FX_Number::GetFloat() const { |
| if (!m_bIsInteger) |
| return m_FloatValue; |
| |
| return m_bIsSigned ? static_cast<float>(m_SignedValue) |
| : static_cast<float>(m_UnsignedValue); |
| } |