Added initial check for buffer space [skip ci]

Author: ankane

include/pgvector/pqxx.hpp

@@ -47,6 +47,11 @@ template<> struct string_traits<pgvector::Vector> {
     }
 
     static std::string_view to_buf(std::span<char> buf, const pgvector::Vector& value, ctx c = {}) {
+        // confirm caller provided estimated buffer space
+        if (buf.size() < size_buffer(value)) {
+            throw conversion_overrun{"Not enough space in buffer for vector"};
+        }
+
         const std::vector<float>& values = value.values();
 
         // important! size_buffer cannot throw an exception on overflow
@@ -115,6 +120,11 @@ template<> struct string_traits<pgvector::HalfVector> {
     }
 
     static std::string_view to_buf(std::span<char> buf, const pgvector::HalfVector& value, ctx c = {}) {
+        // confirm caller provided estimated buffer space
+        if (buf.size() < size_buffer(value)) {
+            throw conversion_overrun{"Not enough space in buffer for halfvec"};
+        }
+
         const std::vector<pgvector::Half>& values = value.values();
 
         // important! size_buffer cannot throw an exception on overflow
@@ -213,6 +223,11 @@ template<> struct string_traits<pgvector::SparseVector> {
     }
 
     static std::string_view to_buf(std::span<char> buf, const pgvector::SparseVector& value, ctx c = {}) {
+        // confirm caller provided estimated buffer space
+        if (buf.size() < size_buffer(value)) {
+            throw conversion_overrun{"Not enough space in buffer for sparsevec"};
+        }
+
         int dimensions = value.dimensions();
         const std::vector<int>& indices = value.indices();
         const std::vector<float>& values = value.values();

test/pqxx_test.cpp

@@ -281,63 +281,63 @@ void test_sparsevec_from_string() {
 }
 
 void test_vector_to_buf() {
-    char buf[10];
+    char buf[60];
     assert_equal(pqxx::to_buf(std::span<char>{buf}, pgvector::Vector{{1, 2, 3}}), "[1,2,3]");
 
     assert_exception<pqxx::conversion_overrun>([] {
         return pqxx::to_buf(std::span<char>{}, pgvector::Vector{{1, 2, 3}});
-    });
+    }, "Not enough space in buffer for vector");
 }
 
 void test_vector_into_buf() {
-    char buf[10];
+    char buf[60];
     size_t size = pqxx::into_buf(std::span<char>{buf}, pgvector::Vector{{1, 2, 3}});
     assert_equal(size, 7u);
     assert_equal(std::string_view{buf, size}, "[1,2,3]");
 
     assert_exception<pqxx::conversion_overrun>([] {
         return pqxx::into_buf(std::span<char>{}, pgvector::Vector{{1, 2, 3}});
-    });
+    }, "Not enough space in buffer for vector");
 }
 
 void test_halfvec_to_buf() {
-    char buf[10];
+    char buf[60];
     assert_equal(pqxx::to_buf(std::span<char>{buf}, pgvector::HalfVector{{1, 2, 3}}), "[1,2,3]");
 
     assert_exception<pqxx::conversion_overrun>([] {
         return pqxx::to_buf(std::span<char>{}, pgvector::HalfVector{{1, 2, 3}});
-    });
+    }, "Not enough space in buffer for halfvec");
 }
 
 void test_halfvec_into_buf() {
-    char buf[10];
+    char buf[60];
     size_t size = pqxx::into_buf(std::span<char>{buf}, pgvector::HalfVector{{1, 2, 3}});
     assert_equal(size, 7u);
     assert_equal(std::string_view{buf, size}, "[1,2,3]");
 
     assert_exception<pqxx::conversion_overrun>([] {
         return pqxx::into_buf(std::span<char>{}, pgvector::HalfVector{{1, 2, 3}});
-    });
+    }, "Not enough space in buffer for halfvec");
 }
 
 void test_sparsevec_to_buf() {
-    char buf[40];
+    char buf[120];
     assert_equal(pqxx::to_buf(std::span<char>{buf}, pgvector::SparseVector{{1, 2, 3}}), "{1:1,2:2,3:3}/3");
 
     assert_exception<pqxx::conversion_overrun>([] {
         return pqxx::to_buf(std::span<char>{}, pgvector::SparseVector{{1, 2, 3}});
-    });
+    }, "Not enough space in buffer for sparsevec");
 }
 
 void test_sparsevec_into_buf() {
-    char buf[40];
+    char buf[120];
     size_t size = pqxx::into_buf(std::span<char>{buf}, pgvector::SparseVector{{1, 2, 3}});
     assert_equal(size, 15u);
     assert_equal(std::string_view{buf, size}, "{1:1,2:2,3:3}/3");
 
     assert_exception<pqxx::conversion_overrun>([] {
         return pqxx::into_buf(std::span<char>{}, pgvector::SparseVector{{1, 2, 3}});
-    });
+    }, "Not enough space in buffer for sparsevec");
 }
 
 void test_vector_size_buffer() {