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/*
* Copyright (c) 2010,
* Gavriloaie Eugen-Andrei (shiretu@gmail.com)
*
* This file is part of crtmpserver.
* crtmpserver is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* crtmpserver is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with crtmpserver. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _BITARRAY_H
#define _BITARRAY_H
#include "utils/buffering/iobuffer.h"
class BitArray
: public IOBuffer {
private:
uint32_t _cursor;
public:
BitArray() : IOBuffer() {
_cursor = 0;
}
virtual ~BitArray() {
}
public:
template<typename T>
bool PutBits(T data, uint8_t count) {
if (!EnsureSize(sizeof (T)))
return false;
uint8_t *pBuffer = GETIBPOINTER(*this);
for (uint8_t i = 0; i < count; i++) {
uint8_t srcBitIndex = sizeof (T)*8 - count + i;
uint8_t dstByteIndex = (uint8_t) ((_cursor + i) / 8);
uint8_t dstBitIndex = (_cursor + i) % 8;
if (dstBitIndex == 0) {
pBuffer[dstByteIndex] = 0;
}
T flag = (data << srcBitIndex);
flag = (flag >> (sizeof (T)*8 - 1));
pBuffer[dstByteIndex] |= (flag << (7 - dstBitIndex));
}
_cursor += count;
_published = (_cursor / 8)+(((_cursor % 8) == 0) ? 0 : 1);
return true;
}
template<typename T>
T ReadBits(uint8_t count) {
T result = PeekBits<T > (count);
IgnoreBits(count);
return result;
}
template<typename T>
T PeekBits(uint8_t count) {
T result = 0;
if (GETAVAILABLEBYTESCOUNT(*this) == 0) {
assert(false);
}
if (GETAVAILABLEBYTESCOUNT(*this) < (_cursor + count) / 8) {
assert(false);
}
if (count>sizeof (T)*8) {
assert(false);
}
for (uint8_t i = 0; i < count; i++) {
uint32_t currentCursor = _cursor + i;
uint8_t currentByteIndex = (uint8_t) (currentCursor / 8);
uint8_t currentBitIndex = currentCursor % 8;
uint8_t currentByte = GETIBPOINTER(*this)[currentByteIndex];
result = (result << 1) | ((currentByte >> (7 - currentBitIndex))&0x01);
}
return result;
}
void IgnoreBits(uint32_t count) {
if (GETAVAILABLEBYTESCOUNT(*this) == 0) {
assert(false);
}
if (GETAVAILABLEBYTESCOUNT(*this) < (_cursor + count) / 8) {
assert(false);
}
_cursor += count;
}
uint32_t AvailableBits() {
return GETAVAILABLEBYTESCOUNT(*this)*8 - _cursor;
}
bool ReadExpGolomb(uint64_t &value) {
value = 1;
uint32_t zeroBitsCount = 0;
while (true) {
if (AvailableBits() == 0) {
return false;
}
if (ReadBits<bool>(1)) {
break;
}
zeroBitsCount++;
}
if (AvailableBits() < zeroBitsCount) {
return false;
}
for (uint32_t i = 0; i < zeroBitsCount; i++) {
value = ((value << 1) | (ReadBits<uint8_t > (1)));
}
value = value - 1;
return true;
}
};
#endif /* _BITARRAY_H */
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