mirror of https://github.com/qpdf/qpdf.git
75 lines
1.8 KiB
C++
75 lines
1.8 KiB
C++
#include <qpdf/OffsetInputSource.hh>
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#include <limits>
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#include <sstream>
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#include <stdexcept>
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OffsetInputSource::OffsetInputSource(
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std::shared_ptr<InputSource> proxied, qpdf_offset_t global_offset) :
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proxied(proxied),
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global_offset(global_offset)
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{
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if (global_offset < 0) {
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throw std::logic_error("OffsetInputSource constructed with negative offset");
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}
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this->max_safe_offset = std::numeric_limits<qpdf_offset_t>::max() - global_offset;
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}
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qpdf_offset_t
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OffsetInputSource::findAndSkipNextEOL()
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{
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return this->proxied->findAndSkipNextEOL() - this->global_offset;
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}
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std::string const&
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OffsetInputSource::getName() const
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{
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return this->proxied->getName();
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}
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qpdf_offset_t
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OffsetInputSource::tell()
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{
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return this->proxied->tell() - this->global_offset;
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}
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void
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OffsetInputSource::seek(qpdf_offset_t offset, int whence)
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{
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if (whence == SEEK_SET) {
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if (offset > this->max_safe_offset) {
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std::ostringstream msg;
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msg.imbue(std::locale::classic());
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msg << "seeking to " << offset << " offset by " << global_offset
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<< " would cause an overflow of the offset type";
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throw std::range_error(msg.str());
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}
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this->proxied->seek(offset + global_offset, whence);
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} else {
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this->proxied->seek(offset, whence);
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}
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if (tell() < 0) {
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throw std::runtime_error("offset input source: seek before beginning of file");
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}
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}
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void
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OffsetInputSource::rewind()
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{
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seek(0, SEEK_SET);
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}
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size_t
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OffsetInputSource::read(char* buffer, size_t length)
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{
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size_t result = this->proxied->read(buffer, length);
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this->setLastOffset(this->proxied->getLastOffset() - global_offset);
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return result;
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}
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void
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OffsetInputSource::unreadCh(char ch)
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{
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this->proxied->unreadCh(ch);
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}
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