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Refactor QPDF::isLinearized

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This commit is contained in:
m-holger 2024-11-02 14:18:41 +00:00
parent b21973618b
commit f92368f44f
1 changed files with 11 additions and 13 deletions
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24
libqpdf/QPDF_linearization.cc
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@ -18,6 +18,8 @@
#include <cmath>
#include <cstring>
using namespace std::literals;
template <class T, class int_type>
static void
load_vector_int(
@ -95,25 +97,17 @@ QPDF::isLinearized()
// The PDF spec says the linearization dictionary must be completely contained within the first
// 1024 bytes of the file. Add a byte for a null terminator.
auto buffer = m->file->read(1024, 0);
auto buf = buffer.data();
auto tbuf_size = buffer.size();
int lindict_obj = -1;
char* p = buf;
size_t pos = 0;
while (lindict_obj == -1) {
// Find a digit or end of buffer
while (((p - buf) < tbuf_size) && (!QUtil::is_digit(*p))) {
++p;
}
if (p - buf == tbuf_size) {
break;
pos = buffer.find_first_of("0123456789"sv, pos);
if (pos == std::string::npos) {
return false;
}
// Seek to the digit. Then skip over digits for a potential
// next iteration.
m->file->seek(p - buf, SEEK_SET);
while (((p - buf) < tbuf_size) && QUtil::is_digit(*p)) {
++p;
}
m->file->seek(toO(pos), SEEK_SET);
QPDFTokenizer::Token t1 = readToken(*m->file);
if (t1.isInteger() && readToken(*m->file).isInteger() &&
@ -121,6 +115,10 @@ QPDF::isLinearized()
readToken(*m->file).getType() == QPDFTokenizer::tt_dict_open) {
lindict_obj = toI(QUtil::string_to_ll(t1.getValue().c_str()));
}
pos = buffer.find_first_not_of("0123456789"sv, pos);
if (pos == std::string::npos) {
return false;
}
}
if (lindict_obj <= 0) {