From fa2712d89b1cb6451946a52bf055f6bb19b43b4f Mon Sep 17 00:00:00 2001
From: Tianyi Chen <TianyiChen@users.noreply.github.com>
Date: Fri, 7 Jun 2024 22:25:20 -0700
Subject: [PATCH] wide_string_input_adapter fallback to get_character

---
 include/nlohmann/detail/input/input_adapters.hpp | 12 ++++++++----
 single_include/nlohmann/json.hpp                 | 10 +++++++---
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/include/nlohmann/detail/input/input_adapters.hpp b/include/nlohmann/detail/input/input_adapters.hpp
index d19425f3a4..a68d7019ca 100644
--- a/include/nlohmann/detail/input/input_adapters.hpp
+++ b/include/nlohmann/detail/input/input_adapters.hpp
@@ -136,7 +136,7 @@ class input_stream_adapter
     template<class T>
     std::size_t get_elements(T* dest, std::size_t count = 1)
     {
-        auto res = sb->sgetn(reinterpret_cast<char*>(dest), count * sizeof(T));
+        auto res = sb->sgetn(reinterpret_cast<char*>(dest), static_cast<std::streamsize>(count * sizeof(T)));
         if (JSON_HEDLEY_UNLIKELY(res < count * sizeof(T)))
         {
             is->clear(is->rdstate() | std::ios::eofbit);
@@ -359,10 +359,14 @@ class wide_string_input_adapter
     }
 
     template<class T>
-    std::size_t get_elements(T*, std::size_t = 1)
+    std::size_t get_elements(T* dest, std::size_t count = 1)
     {
-        JSON_THROW(other_error::create(500, "Unexpected get_elements call to wchar input adapter", nullptr));
-        return 0;
+        auto ptr = reinterpret_cast<char*>(dest);
+        for (std::size_t read_index = 0; read_index < count * sizeof(T); ++read_index)
+        {
+            ptr[read_index] = get_character();
+        }
+        return count * sizeof(T);
     }
 
   private:
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index dfa1d30056..e9890ea0e9 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -6281,7 +6281,7 @@ class input_stream_adapter
     template<class T>
     std::size_t get_elements(T* dest, std::size_t count = 1)
     {
-        auto res = sb->sgetn(reinterpret_cast<char*>(dest), count * sizeof(T));
+        auto res = sb->sgetn(reinterpret_cast<char*>(dest), static_cast<std::streamsize>(count * sizeof(T)));
         if (JSON_HEDLEY_UNLIKELY(res < count * sizeof(T)))
         {
             is->clear(is->rdstate() | std::ios::eofbit);
@@ -6506,8 +6506,12 @@ class wide_string_input_adapter
     template<class T>
     std::size_t get_elements(T* dest, std::size_t count = 1)
     {
-        JSON_THROW(other_error::create(500, "Unexpected get_elements call to wchar input adapter", nullptr));
-        return 0;
+        auto ptr = reinterpret_cast<char*>(dest);
+        for (std::size_t read_index = 0; read_index < count * sizeof(T); ++read_index)
+        {
+            ptr[read_index] = get_character();
+        }
+        return count * sizeof(T);
     }
 
   private: