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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include <cstdint>
namespace document {
// Sets the value of a variable for the duration of this object's lifetime.
// The original value is restored when this object is destroyed.
template <typename T>
class VarScope {
T &_ptr;
T _old;
public:
VarScope (T &ptr, T new_val) :
_ptr(ptr),
_old(_ptr) {
_ptr = new_val;
}
~VarScope() { _ptr = _old; }
};
template <typename T, typename Input>
T readValue(Input &input) {
T val;
input >> val;
return val;
}
template <typename Input>
uint32_t getInt1_4Bytes(Input &input) {
char first_byte = *input.peek();
if (!(first_byte & 0x80)) {
return readValue<uint8_t>(input);
} else {
return readValue<uint32_t>(input) & 0x7fffffff;
}
}
template <typename Input>
uint32_t getInt1_2_4Bytes(Input &input) {
char first_byte = *input.peek();
if (!(first_byte & 0x80)) {
return readValue<uint8_t>(input);
} else if (!(first_byte & 0x40)) {
return readValue<uint16_t>(input) & 0x3fff;
} else {
return readValue<uint32_t>(input) & 0x3fffffff;
}
}
template <typename Input>
uint64_t getInt2_4_8Bytes(Input &input) {
char first_byte = *input.peek();
if (!(first_byte & 0x80)) {
return readValue<uint16_t>(input);
} else if (!(first_byte & 0x40)) {
return readValue<uint32_t>(input) & 0x3fffffff;
} else {
return readValue<uint64_t>(input) & 0x3fffffffffffffff;
}
}
template <typename Output>
void putInt1_4Bytes(Output &out, uint32_t val) {
if (val < 0x80) {
out << static_cast<uint8_t>(val);
} else {
out << (val | 0x80000000);
}
}
template <typename Output>
void putInt1_2_4Bytes(Output &out, uint32_t val) {
if (val < 0x80) {
out << static_cast<uint8_t>(val);
} else if (val < 0x4000) {
out << static_cast<uint16_t>(val | 0x8000);
} else {
out << (val | 0xc0000000);
}
}
template <typename Output>
void putInt1_2_4BytesAs4(Output &out, uint32_t val) {
out << (val | 0xc0000000);
}
template <typename Output>
void putInt2_4_8Bytes(Output &out, uint64_t val) {
if (val < 0x8000) {
out << static_cast<uint16_t>(val);
} else if (val < 0x40000000) {
out << static_cast<uint32_t>(val | 0x80000000);
} else {
out << (val | 0xc000000000000000);
}
}
} // namespace document
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