mirror of
https://github.com/qpdf/qpdf.git
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297 lines
8.6 KiB
C++
297 lines
8.6 KiB
C++
#include <qpdf/Pl_Flate.hh>
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#include <limits.h>
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#include <string.h>
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#include <zlib.h>
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#include <qpdf/QIntC.hh>
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#include <qpdf/QUtil.hh>
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int Pl_Flate::compression_level = Z_DEFAULT_COMPRESSION;
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Pl_Flate::Members::Members(size_t out_bufsize, action_e action) :
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out_bufsize(out_bufsize),
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action(action),
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initialized(false),
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zdata(nullptr)
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{
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this->outbuf = QUtil::make_shared_array<unsigned char>(out_bufsize);
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// Indirect through zdata to reach the z_stream so we don't have
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// to include zlib.h in Pl_Flate.hh. This means people using
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// shared library versions of qpdf don't have to have zlib
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// development files available, which particularly helps in a
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// Windows environment.
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this->zdata = new z_stream;
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if (out_bufsize > UINT_MAX) {
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throw std::runtime_error("Pl_Flate: zlib doesn't support buffer"
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" sizes larger than unsigned int");
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}
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z_stream& zstream = *(static_cast<z_stream*>(this->zdata));
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zstream.zalloc = nullptr;
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zstream.zfree = nullptr;
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zstream.opaque = nullptr;
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zstream.next_in = nullptr;
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zstream.avail_in = 0;
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zstream.next_out = this->outbuf.get();
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zstream.avail_out = QIntC::to_uint(out_bufsize);
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}
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Pl_Flate::Members::~Members()
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{
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if (this->initialized) {
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z_stream& zstream = *(static_cast<z_stream*>(this->zdata));
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if (action == a_deflate) {
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deflateEnd(&zstream);
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} else {
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inflateEnd(&zstream);
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}
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}
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delete static_cast<z_stream*>(this->zdata);
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this->zdata = nullptr;
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}
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Pl_Flate::Pl_Flate(
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char const* identifier,
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Pipeline* next,
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action_e action,
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unsigned int out_bufsize_int) :
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Pipeline(identifier, next),
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m(new Members(QIntC::to_size(out_bufsize_int), action))
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{
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}
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Pl_Flate::~Pl_Flate()
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{
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// Must be explicit and not inline -- see QPDF_DLL_CLASS in
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// README-maintainer
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}
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void
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Pl_Flate::setWarnCallback(std::function<void(char const*, int)> callback)
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{
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this->m->callback = callback;
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}
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void
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Pl_Flate::warn(char const* msg, int code)
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{
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if (this->m->callback != nullptr) {
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this->m->callback(msg, code);
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}
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}
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void
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Pl_Flate::write(unsigned char const* data, size_t len)
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{
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if (this->m->outbuf == nullptr) {
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throw std::logic_error(
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this->identifier +
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": Pl_Flate: write() called after finish() called");
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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 const* buf = data;
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while (bytes_left > 0) {
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size_t bytes = (bytes_left >= max_bytes ? max_bytes : bytes_left);
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handleData(
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buf,
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bytes,
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(this->m->action == a_inflate ? Z_SYNC_FLUSH : Z_NO_FLUSH));
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bytes_left -= bytes;
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buf += bytes;
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}
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}
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void
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Pl_Flate::handleData(unsigned char const* data, size_t len, int flush)
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{
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if (len > UINT_MAX) {
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throw std::runtime_error("Pl_Flate: zlib doesn't support data"
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" blocks larger than int");
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}
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z_stream& zstream = *(static_cast<z_stream*>(this->m->zdata));
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// zlib is known not to modify the data pointed to by next_in but
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// doesn't declare the field value const unless compiled to do so.
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zstream.next_in = const_cast<unsigned char*>(data);
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zstream.avail_in = QIntC::to_uint(len);
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if (!this->m->initialized) {
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int err = Z_OK;
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// deflateInit and inflateInit are macros that use old-style
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// casts.
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#if ( \
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(defined(__GNUC__) && ((__GNUC__ * 100) + __GNUC_MINOR__) >= 406) || \
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defined(__clang__))
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# pragma GCC diagnostic push
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# pragma GCC diagnostic ignored "-Wold-style-cast"
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#endif
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if (this->m->action == a_deflate) {
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err = deflateInit(&zstream, compression_level);
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} else {
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err = inflateInit(&zstream);
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}
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#if ( \
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(defined(__GNUC__) && ((__GNUC__ * 100) + __GNUC_MINOR__) >= 406) || \
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defined(__clang__))
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# pragma GCC diagnostic pop
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#endif
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checkError("Init", err);
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this->m->initialized = true;
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}
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int err = Z_OK;
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bool done = false;
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while (!done) {
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if (this->m->action == a_deflate) {
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err = deflate(&zstream, flush);
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} else {
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err = inflate(&zstream, flush);
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}
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if ((this->m->action == a_inflate) && (err != Z_OK) && zstream.msg &&
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(strcmp(zstream.msg, "incorrect data check") == 0)) {
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// Other PDF readers ignore this specific error. Combining
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// this with Z_SYNC_FLUSH enables qpdf to handle some
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// broken zlib streams without losing data.
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err = Z_STREAM_END;
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}
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switch (err) {
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case Z_BUF_ERROR:
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// Probably shouldn't be able to happen, but possible as a
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// boundary condition: if the last call to inflate exactly
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// filled the output buffer, it's possible that the next
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// call to inflate could have nothing to do. There are PDF
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// files in the wild that have this error (including at
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// least one in qpdf's test suite). In some cases, we want
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// to know about this, because it indicates incorrect
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// compression, so call a callback if provided.
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this->warn(
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"input stream is complete but output may still be valid", err);
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done = true;
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break;
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case Z_STREAM_END:
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done = true;
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// fall through
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case Z_OK:
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{
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if ((zstream.avail_in == 0) && (zstream.avail_out > 0)) {
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// There is nothing left to read, and there was
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// sufficient buffer space to write everything we
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// needed, so we're done for now.
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done = true;
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}
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uLong ready =
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QIntC::to_ulong(this->m->out_bufsize - zstream.avail_out);
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if (ready > 0) {
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this->getNext()->write(this->m->outbuf.get(), ready);
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zstream.next_out = this->m->outbuf.get();
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zstream.avail_out = QIntC::to_uint(this->m->out_bufsize);
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}
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}
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break;
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default:
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this->checkError("data", err);
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break;
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}
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}
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}
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void
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Pl_Flate::finish()
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{
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try {
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if (this->m->outbuf.get()) {
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if (this->m->initialized) {
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z_stream& zstream = *(static_cast<z_stream*>(this->m->zdata));
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unsigned char buf[1];
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buf[0] = '\0';
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handleData(buf, 0, Z_FINISH);
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int err = Z_OK;
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if (this->m->action == a_deflate) {
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err = deflateEnd(&zstream);
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} else {
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err = inflateEnd(&zstream);
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}
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this->m->initialized = false;
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checkError("End", err);
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}
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this->m->outbuf = nullptr;
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}
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} catch (std::exception& e) {
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try {
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this->getNext()->finish();
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} catch (...) {
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// ignore secondary exception
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}
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throw std::runtime_error(e.what());
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}
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this->getNext()->finish();
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}
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void
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Pl_Flate::setCompressionLevel(int level)
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{
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compression_level = level;
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}
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void
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Pl_Flate::checkError(char const* prefix, int error_code)
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{
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z_stream& zstream = *(static_cast<z_stream*>(this->m->zdata));
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if (error_code != Z_OK) {
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char const* action_str =
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(this->m->action == a_deflate ? "deflate" : "inflate");
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std::string msg =
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this->identifier + ": " + action_str + ": " + prefix + ": ";
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if (zstream.msg) {
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msg += zstream.msg;
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} else {
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switch (error_code) {
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case Z_ERRNO:
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msg += "zlib system error";
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break;
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case Z_STREAM_ERROR:
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msg += "zlib stream error";
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break;
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case Z_DATA_ERROR:
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msg += "zlib data error";
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break;
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case Z_MEM_ERROR:
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msg += "zlib memory error";
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break;
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case Z_BUF_ERROR:
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msg += "zlib buffer error";
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break;
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case Z_VERSION_ERROR:
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msg += "zlib version error";
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break;
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default:
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msg += std::string("zlib unknown error (") +
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QUtil::int_to_string(error_code) + ")";
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break;
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}
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}
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throw std::runtime_error(msg);
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}
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}
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