Add qpdf private API methods InputSource::read_line

m-holger
1 parent 8768387c
Showing 2 changed files with 33 additions and 14 deletions
include/qpdf/InputSource.hh
libqpdf/InputSource.cc
@@ -78,6 +78,8 @@ class QPDF_DLL_CLASS InputSource
     // The following methods are for internal use by qpdf only.
     inline size_t read(std::string& str, size_t count, qpdf_offset_t at = -1);
     inline std::string read(size_t count, qpdf_offset_t at = -1);
+    size_t read_line(std::string& str, size_t count, qpdf_offset_t at = -1);
+    std::string read_line(size_t count, qpdf_offset_t at = -1);
     inline qpdf_offset_t fastTell();
     inline bool fastRead(char&);
     inline void fastUnread(bool);
@@ -5,6 +5,8 @@
 #include <cstring>
 #include <stdexcept>
  
+using namespace std::literals;
+
 void
 InputSource::setLastOffset(qpdf_offset_t offset)
 {
@@ -17,27 +19,42 @@ InputSource::getLastOffset() const
     return this->last_offset;
 }
  
-std::string
-InputSource::readLine(size_t max_line_length)
+size_t
+InputSource::read_line(std::string& str, size_t count, qpdf_offset_t at)
 {
     // Return at most max_line_length characters from the next line. Lines are terminated by one or
     // more \r or \n characters. Consume the trailing newline characters but don't return them.
     // After this is called, the file will be positioned after a line terminator or at the end of
     // the file, and last_offset will point to position the file had when this method was called.
  
-    qpdf_offset_t offset = this->tell();
-    auto bp = std::make_unique<char[]>(max_line_length + 1);
-    char* buf = bp.get();
-    memset(buf, '\0', max_line_length + 1);
-    this->read(buf, max_line_length);
-    this->seek(offset, SEEK_SET);
-    qpdf_offset_t eol = this->findAndSkipNextEOL();
-    this->last_offset = offset;
-    size_t line_length = QIntC::to_size(eol - offset);
-    if (line_length < max_line_length) {
-        buf[line_length] = '\0';
+    read(str, count, at);
+    auto eol = str.find_first_of("\n\r"sv);
+    if (eol != std::string::npos) {
+        auto next_line = str.find_first_not_of("\n\r"sv, eol);
+        str.resize(eol);
+        if (eol != std::string::npos) {
+            seek(last_offset + static_cast<qpdf_offset_t>(next_line), SEEK_SET);
+            return eol;
+        }
     }
-    return {buf};
+    // We did not necessarily find the end of the trailing newline sequence.
+    seek(last_offset, SEEK_SET);
+    findAndSkipNextEOL();
+    return eol;
+}
+
+std::string
+InputSource::readLine(size_t max_line_length)
+{
+    return read_line(max_line_length);
+}
+
+inline std::string
+InputSource::read_line(size_t count, qpdf_offset_t at)
+{
+    std::string result(count, '\0');
+    read_line(result, count, at);
+    return result;
 }
  
 bool