mirror of
https://github.com/tumic0/GPXSee.git
synced 2024-10-07 07:13:21 +02:00
101 lines
1.8 KiB
C++
101 lines
1.8 KiB
C++
#include <QFile>
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#include "img.h"
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#include "subfile.h"
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bool SubFile::seek(Handle &handle, quint32 pos) const
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{
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if (handle._file) {
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int blockNum = pos / BLOCK_SIZE;
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if (handle._blockNum != blockNum) {
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if (!handle._file->seek((qint64)blockNum * BLOCK_SIZE))
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return false;
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if (handle._file->read(handle._data.data(), BLOCK_SIZE) < 0)
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return false;
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handle._blockNum = blockNum;
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}
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handle._blockPos = pos % BLOCK_SIZE;
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handle._pos = pos;
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return true;
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} else {
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quint32 blockSize = _img->blockSize();
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int blockNum = pos / blockSize;
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if (handle._blockNum != blockNum) {
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if (blockNum >= _blocks->size())
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return false;
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if (!_img->readBlock(_blocks->at(blockNum), handle._data.data()))
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return false;
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handle._blockNum = blockNum;
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}
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handle._blockPos = pos % blockSize;
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handle._pos = pos;
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return true;
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}
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}
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bool SubFile::readVUInt32(Handle &hdl, quint32 &val) const
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{
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quint8 bytes, shift, b;
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if (!readByte(hdl, b))
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return false;
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if ((b & 1) == 0) {
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if ((b & 2) == 0) {
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bytes = ((b >> 2) & 1) ^ 3;
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shift = 5;
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} else {
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shift = 6;
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bytes = 1;
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}
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} else {
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shift = 7;
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bytes = 0;
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}
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val = b >> (8 - shift);
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for (int i = 1; i <= bytes; i++) {
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if (!readByte(hdl, b))
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return false;
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val |= (((quint32)b) << (i * 8)) >> (8 - shift);
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}
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return true;
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}
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bool SubFile::readVBitfield32(Handle &hdl, quint32 &bitfield) const
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{
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quint8 bits;
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if (!readUInt8(hdl, bits))
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return false;
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if (!(bits & 1)) {
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seek(hdl, hdl._pos - 1);
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if (!((bits>>1) & 1)) {
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if (!((bits>>2) & 1)) {
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if (!readUInt32(hdl, bitfield))
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return false;
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} else {
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if (!readUInt24(hdl, bitfield))
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return false;
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}
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bitfield >>= 3;
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} else {
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if (!readUInt16(hdl, bitfield))
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return false;
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bitfield >>= 2;
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}
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} else
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bitfield = bits>>1;
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return true;
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}
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