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#include <qpdf/QPDFObject_private.hh>
#include <qpdf/QPDFObjectHandle_private.hh>
#include <qpdf/QUtil.hh>
#include <qpdf/Util.hh>
// DO NOT USE ctype -- it is locale dependent for some things, and it's not worth the risk of
// including it in case it may accidentally be used.
static bool
is_iso_latin1_printable(char ch)
{
return (ch >= 32 && ch <= 126) || static_cast<unsigned char>(ch) >= 160;
}
void
QPDF_String::writeJSON(int json_version, JSON::Writer& p)
{
if (json_version == 1) {
if (util::is_utf16(val)) {
p << "\"" << JSON::Writer::encode_string(QUtil::utf16_to_utf8(val)) << "\"";
return;
}
if (util::is_explicit_utf8(val)) {
// PDF 2.0 allows UTF-8 strings when explicitly prefixed with the three-byte
// representation of U+FEFF.
p << "\"" << JSON::Writer::encode_string(val.substr(3)) << "\"";
return;
}
p << "\"" << JSON::Writer::encode_string(QUtil::pdf_doc_to_utf8(val)) << "\"";
return;
}
// See if we can unambiguously represent as Unicode.
if (util::is_utf16(val)) {
p << "\"u:" << JSON::Writer::encode_string(QUtil::utf16_to_utf8(val)) << "\"";
return;
}
// See if we can unambiguously represent as Unicode.
if (util::is_explicit_utf8(val)) {
p << "\"u:" << JSON::Writer::encode_string(val.substr(3)) << "\"";
return;
}
if (!useHexString()) {
auto candidate = QUtil::pdf_doc_to_utf8(val);
std::string test;
if (QUtil::utf8_to_pdf_doc(candidate, test, '?') && test == val) {
// This is a PDF-doc string that can be losslessly encoded as Unicode.
p << "\"u:" << JSON::Writer::encode_string(candidate) << "\"";
return;
}
}
p << "\"b:" << QUtil::hex_encode(val) << "\"";
}
bool
QPDF_String::useHexString() const
{
// Heuristic: use the hexadecimal representation of a string if there are any non-printable (in
// PDF Doc encoding) characters or if too large of a proportion of the string consists of
// non-ASCII characters.
unsigned int non_ascii = 0;
for (auto const ch: val) {
if (ch > 126) {
++non_ascii;
} else if (ch >= 32) {
continue;
} else if (ch < 0 || ch >= 24) {
++non_ascii;
} else if (!(ch == '\n' || ch == '\r' || ch == '\t' || ch == '\b' || ch == '\f')) {
return true;
}
}
return 5 * non_ascii > val.length();
}
std::string
QPDF_String::unparse(bool force_binary)
{
bool use_hexstring = force_binary || useHexString();
std::string result;
if (use_hexstring) {
static auto constexpr hexchars = "0123456789abcdef";
result.reserve(2 * val.length() + 2);
result += '<';
for (const char c: val) {
result += hexchars[static_cast<unsigned char>(c) >> 4];
result += hexchars[c & 0x0f];
}
result += '>';
} else {
result += "(";
for (unsigned int i = 0; i < val.length(); ++i) {
char ch = val.at(i);
switch (ch) {
case '\n':
result += "\\n";
break;
case '\r':
result += "\\r";
break;
case '\t':
result += "\\t";
break;
case '\b':
result += "\\b";
break;
case '\f':
result += "\\f";
break;
case '(':
result += "\\(";
break;
case ')':
result += "\\)";
break;
case '\\':
result += "\\\\";
break;
default:
if (is_iso_latin1_printable(ch)) {
result += val.at(i);
} else {
result += "\\" +
QUtil::int_to_string_base(
static_cast<int>(static_cast<unsigned char>(ch)), 8, 3);
}
break;
}
}
result += ")";
}
return result;
}
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