add check for mem_map(size=0) (#14)

uc.c

@@ -126,6 +126,8 @@ const char *uc_strerror(uc_err code)
             return "Invalid instruction (UC_ERR_INSN_INVALID)";
         case UC_ERR_HOOK:
             return "Invalid hook type (UC_ERR_HOOK)";
+        case UC_ERR_MAP:
+            return "Invalid memory mapping (UC_ERR_MAP)";
     }
 }
 
@@ -552,6 +554,10 @@ uc_err uc_mem_map(uch handle, uint64_t address, size_t size)
         // invalid handle
         return UC_ERR_UCH;
 
+    if (size == 0)
+        // invalid memory mapping
+        return UC_ERR_MAP;
+
     // align to 8KB boundary
     map_begin[map_count] = address & (~ (8*1024 - 1));
     s = (size + 8*1024 - 1) & (~ (8*1024 - 1));