Revert "Delete and re-add libpqxx-7.7.3 due to weird corruption."

This reverts commit e96515433d.

ext/libpqxx-7.7.3/include/pqxx/internal/sql_cursor.hxx

@@ -0,0 +1,118 @@
+/** Internal wrapper for SQL cursors.  Supports higher-level cursor classes.
+ *
+ * DO NOT INCLUDE THIS FILE DIRECTLY.  Other headers include it for you.
+ *
+ * Copyright (c) 2000-2022, Jeroen T. Vermeulen.
+ *
+ * See COPYING for copyright license.  If you did not receive a file called
+ * COPYING with this source code, please notify the distributor of this
+ * mistake, or contact the author.
+ */
+#ifndef PQXX_H_SQL_CURSOR
+#define PQXX_H_SQL_CURSOR
+
+namespace pqxx::internal
+{
+/// Cursor with SQL positioning semantics.
+/** Thin wrapper around an SQL cursor, with SQL's ideas of positioning.
+ *
+ * SQL cursors have pre-increment/pre-decrement semantics, with on either end
+ * of the result set a special position that does not repesent a row.  This
+ * class models SQL cursors for the purpose of implementing more C++-like
+ * semantics on top.
+ *
+ * Positions of actual rows are numbered starting at 1.  Position 0 exists but
+ * does not refer to a row.  There is a similar non-row position at the end of
+ * the result set.
+ *
+ * Don't use this at home.  You deserve better.  Use the stateles_cursor
+ * instead.
+ */
+class PQXX_LIBEXPORT sql_cursor : public cursor_base
+{
+public:
+  sql_cursor(
+    transaction_base &t, std::string_view query, std::string_view cname,
+    cursor_base::access_policy ap, cursor_base::update_policy up,
+    cursor_base::ownership_policy op, bool hold);
+
+  sql_cursor(
+    transaction_base &t, std::string_view cname,
+    cursor_base::ownership_policy op);
+
+  ~sql_cursor() noexcept { close(); }
+
+  result fetch(difference_type rows, difference_type &displacement);
+  result fetch(difference_type rows)
+  {
+    difference_type d = 0;
+    return fetch(rows, d);
+  }
+  difference_type move(difference_type rows, difference_type &displacement);
+  difference_type move(difference_type rows)
+  {
+    difference_type d = 0;
+    return move(rows, d);
+  }
+
+  /// Current position, or -1 for unknown
+  /**
+   * The starting position, just before the first row, counts as position zero.
+   *
+   * Position may be unknown if (and only if) this cursor was adopted, and has
+   * never hit its starting position (position zero).
+   */
+  difference_type pos() const noexcept { return m_pos; }
+
+  /// End position, or -1 for unknown
+  /**
+   * Returns the final position, just after the last row in the result set. The
+   * starting position, just before the first row, counts as position zero.
+   *
+   * End position is unknown until it is encountered during use.
+   */
+  difference_type endpos() const noexcept { return m_endpos; }
+
+  /// Return zero-row result for this cursor.
+  result const &empty_result() const noexcept { return m_empty_result; }
+
+  void close() noexcept;
+
+private:
+  difference_type adjust(difference_type hoped, difference_type actual);
+  static std::string stridestring(difference_type);
+  /// Initialize cached empty result.  Call only at beginning or end!
+  void init_empty_result(transaction_base &);
+
+  /// Connection in which this cursor lives.
+  connection &m_home;
+
+  /// Zero-row result from this cursor (or plain empty one if cursor is
+  /// adopted)
+  result m_empty_result;
+
+  result m_cached_current_row;
+
+  /// Is this cursor adopted (as opposed to created by this cursor object)?
+  bool m_adopted;
+
+  /// Will this cursor object destroy its SQL cursor when it dies?
+  cursor_base::ownership_policy m_ownership;
+
+  /// At starting position (-1), somewhere in the middle (0), or past end (1)
+  int m_at_end;
+
+  /// Position, or -1 for unknown
+  difference_type m_pos;
+
+  /// End position, or -1 for unknown
+  difference_type m_endpos = -1;
+};
+
+
+PQXX_LIBEXPORT result_size_type obtain_stateless_cursor_size(sql_cursor &);
+PQXX_LIBEXPORT result stateless_cursor_retrieve(
+  sql_cursor &, result::difference_type size,
+  result::difference_type begin_pos, result::difference_type end_pos);
+} // namespace pqxx::internal
+#endif