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// 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);
}
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