frontend: json: parse negative values

Signed-off-by: Karol Gugala <kgugala@antmicro.com>

diff --git a/frontends/json/jsonparse.cc b/frontends/json/jsonparse.cc
index 1b34aaf3af7421bc841cab59d74749e116ba5653..312f6d3be505069021b7039258746b5077b2d4dc 100644 (file)
--- a/frontends/json/jsonparse.cc
+++ b/frontends/json/jsonparse.cc
@@ -72,10 +72,17 @@ struct JsonNode
                                break;
                        }
 
-                       if ('0' <= ch && ch <= '9')
+                       if (('0' <= ch && ch <= '9') || ch == '-')
                        {
+                               bool negative = false;
                                type = 'N';
-                               data_number = ch - '0';
+                               if (ch == '-') {
+                                       data_number = 0;
+                                       negative = true;
+                               } else {
+                                       data_number = ch - '0';
+                               }
+
                                data_string += ch;
 
                                while (1)
@@ -97,6 +104,7 @@ struct JsonNode
                                        data_string += ch;
                                }
 
+                               data_number = negative ? -data_number : data_number;
                                data_string = "";
                                break;