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3d6615b276
Rather than keeping a list of buffers for every write, accumulate bytes in a single buffer, doubling the size of the buffer when needed to accommodate new data. This is not the best possible implementation, but the change was implemented in this way to avoid changing the shape of Pl_Buffer and thus breaking backward compatibility.
84 lines
1.7 KiB
C++
84 lines
1.7 KiB
C++
#include <qpdf/Pl_Buffer.hh>
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#include <stdexcept>
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#include <assert.h>
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#include <string.h>
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Pl_Buffer::Pl_Buffer(char const* identifier, Pipeline* next) :
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Pipeline(identifier, next),
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ready(true),
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total_size(0)
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{
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}
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Pl_Buffer::~Pl_Buffer()
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{
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}
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void
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Pl_Buffer::write(unsigned char* buf, size_t len)
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{
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PointerHolder<Buffer> cur_buf;
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size_t cur_size = 0;
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if (! this->data.empty())
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{
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cur_buf = this->data.back();
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cur_size = cur_buf->getSize();
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}
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size_t left = cur_size - this->total_size;
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if (left < len)
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{
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size_t new_size = std::max(this->total_size + len, 2 * cur_size);
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Buffer* b = new Buffer(new_size);
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if (cur_buf.getPointer())
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{
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memcpy(b->getBuffer(), cur_buf->getBuffer(), this->total_size);
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}
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this->data.clear();
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cur_buf = b;
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this->data.push_back(cur_buf);
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}
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if (len)
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{
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memcpy(cur_buf->getBuffer() + this->total_size, buf, len);
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this->total_size += len;
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}
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this->ready = false;
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if (getNext(true))
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{
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getNext()->write(buf, len);
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}
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}
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void
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Pl_Buffer::finish()
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{
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this->ready = true;
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if (getNext(true))
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{
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getNext()->finish();
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}
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}
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Buffer*
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Pl_Buffer::getBuffer()
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{
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if (! this->ready)
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{
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throw std::logic_error("Pl_Buffer::getBuffer() called when not ready");
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}
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Buffer* b = new Buffer(this->total_size);
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unsigned char* p = b->getBuffer();
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if (! this->data.empty())
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{
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PointerHolder<Buffer> bp = this->data.back();
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this->data.clear();
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memcpy(p, bp->getBuffer(), this->total_size);
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}
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this->total_size = 0;
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this->ready = false;
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return b;
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}
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