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b8bdef0ad1
For non-encrypted files, determinstic ID generation uses file contents instead of timestamp and file name. At a small runtime cost, this enables generation of the same /ID if the same inputs are converted in the same way multiple times.
78 lines
1.5 KiB
C++
78 lines
1.5 KiB
C++
#include <qpdf/Pl_MD5.hh>
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#include <stdexcept>
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Pl_MD5::Pl_MD5(char const* identifier, Pipeline* next) :
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Pipeline(identifier, next),
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in_progress(false),
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enabled(true),
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persist_across_finish(false)
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{
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}
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Pl_MD5::~Pl_MD5()
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{
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}
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void
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Pl_MD5::write(unsigned char* buf, size_t len)
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{
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if (this->enabled)
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{
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if (! this->in_progress)
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{
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this->md5.reset();
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this->in_progress = true;
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}
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// Write in chunks in case len is too big to fit in an int.
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// Assume int is at least 32 bits.
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static size_t const max_bytes = 1 << 30;
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size_t bytes_left = len;
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unsigned char* data = buf;
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while (bytes_left > 0)
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{
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size_t bytes = (bytes_left >= max_bytes ? max_bytes : bytes_left);
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this->md5.encodeDataIncrementally(
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reinterpret_cast<char*>(data), bytes);
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bytes_left -= bytes;
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data += bytes;
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}
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}
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this->getNext()->write(buf, len);
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}
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void
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Pl_MD5::finish()
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{
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this->getNext()->finish();
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if (! this->persist_across_finish)
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{
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this->in_progress = false;
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}
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}
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void
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Pl_MD5::enable(bool enabled)
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{
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this->enabled = enabled;
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}
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void
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Pl_MD5::persistAcrossFinish(bool persist)
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{
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this->persist_across_finish = persist;
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}
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std::string
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Pl_MD5::getHexDigest()
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{
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if (! this->enabled)
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{
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throw std::logic_error(
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"digest requested for a disabled MD5 Pipeline");
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}
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this->in_progress = false;
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return this->md5.unparse();
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}
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