Use symbols for type, charset

We want to set some of these values as symbols instead of ints
on the Column to make it easier to work with. In this commit, we
created loopups for int to string using macros, then changed the
type to a symbol via `rb_intern` + `rb_id2sym`. It's possible there's
a single function to do this, but we couldn't find one.

I also added a downcase function to make sure we get the values in
lower instead of uppercase. I'm sure there is a better way to do this.
I have no idea how to write C.

Co-authored-by: Daniel Colson <composerinteralia@github.com>

contrib/ruby/ext/trilogy-ruby/cext.c

@@ -1144,16 +1144,40 @@ static VALUE rb_trilogy_write_timeout_set(VALUE self, VALUE write_timeout)
     return write_timeout;
 }
 
+const char *const trilogy_type_names[] = {
+#define XX(name, code) [name] = (char *)#name + strlen("TRILOGY_TYPE_"),
+    TRILOGY_TYPES(XX)
+#undef XX
+};
+
+const char *const trilogy_charset_names[] = {
+#define XX(name, code) [name] = (char *)#name + strlen("TRILOGY_CHARSET_"),
+    TRILOGY_CHARSETS(XX)
+#undef XX
+};
+
+static char *downcase(const char *str)
+{
+    char *new_str = ALLOC_N(char, strlen(str) + 1);
+    char *p = new_str;
+    while (*str) {
+        *p++ = tolower(*str++);
+    }
+    *p = '\0';
+    return new_str;
+}
+
 static VALUE rb_trilogy_result_columns(VALUE self)
 {
     struct trilogy_result_ctx *trilogy_result_ctx = get_trilogy_result_ctx(self);
     VALUE cols = rb_ary_new();
     for (uint64_t i = 0; i < trilogy_result_ctx->column_count; i++) {
         VALUE obj = rb_funcall(
             Trilogy_Result_Column, rb_intern("new"), 6, trilogy_result_ctx->column_info[i].name,
-            rb_int_new(trilogy_result_ctx->column_info[i].type), rb_int_new(trilogy_result_ctx->column_info[i].len),
-            rb_int_new(trilogy_result_ctx->column_info[i].flags),
-            rb_int_new(trilogy_result_ctx->column_info[i].charset), rb_int_new(trilogy_result_ctx->column_info[i].decimals));
+            rb_id2sym(rb_intern(downcase(trilogy_type_names[trilogy_result_ctx->column_info[i].type]))),
+            rb_int_new(trilogy_result_ctx->column_info[i].len), rb_int_new(trilogy_result_ctx->column_info[i].flags),
+            rb_id2sym(rb_intern(downcase(trilogy_charset_names[trilogy_result_ctx->column_info[i].charset]))),
+            rb_int_new(trilogy_result_ctx->column_info[i].decimals));
         rb_ary_push(cols, obj);
     }
     return cols;    

contrib/ruby/test/client_test.rb

@@ -256,6 +256,8 @@ def test_trilogy_query_values
     assert_equal ["id", "int_test"], result.fields
     assert_equal 2, result.columns.count
     assert_equal ["id", "int_test"], result.columns.map(&:name)
+    assert_equal :long, result.columns.first.type
+    assert_equal :binary, result.columns.first.charset
     assert_equal [1, 4, 2, 3, 3, 1], result.rows
   end