Remove use of non-standard `char_traits<unsigned char>` from Pl_Buffer

`basic_string<unsigned char>` implies use of
`char_traits<unsigned char>`.

This char_traits specialization is not standard C++, and will be
removed from LibC++ as of LLVM 18. To ensure continued LibC++
compatibility it needs to be removed.

There are two possible replacements here: `std::string` (e.g.
`std::basic_string<char>`), or `std::vector<unsigned char>`.

I have opted for vector since this code is dealing with a binary
buffer; though probably either way is fine (why does C++ even have
strings anyway??).

https://github.com/qpdf/qpdf/issues/1024

1 files changed, 2 insertions, 1 deletions

diff --git a/include/qpdf/Pl_Buffer.hh b/include/qpdf/Pl_Buffer.hh
index 39ef0746..5030e10e 100644
--- a/include/qpdf/Pl_Buffer.hh
+++ b/include/qpdf/Pl_Buffer.hh
@@ -33,6 +33,7 @@
 #include <qpdf/PointerHolder.hh> // unused -- remove in qpdf 12 (see #785)
 
 #include <memory>
+#include <vector>
 
 class QPDF_DLL_CLASS Pl_Buffer: public Pipeline
 {
@@ -77,7 +78,7 @@ class QPDF_DLL_CLASS Pl_Buffer: public Pipeline
         Members(Members const&) = delete;
 
         bool ready{true};
-        std::basic_string<unsigned char> data;
+        std::vector<unsigned char> data;
     };
 
     std::shared_ptr<Members> m;