4162

1 files changed, 25 insertions, 0 deletions

diff --git a/010vm.cc b/010vm.cc
index 09348f2d..f5138329 100644
--- a/010vm.cc
+++ b/010vm.cc
@@ -806,6 +806,31 @@ void dump_names_without_quotes(const type_tree* x, ostream& out) {
   out << ')';
 }
 
+bool is_integer(const string& s) {
+  return s.find_first_not_of("0123456789-") == string::npos  // no other characters
+      && s.find_first_of("0123456789") != string::npos  // at least one digit
+      && s.find('-', 1) == string::npos;  // '-' only at first position
+}
+
+int to_integer(string n) {
+  char* end = NULL;
+  // safe because string.c_str() is guaranteed to be null-terminated
+  int result = strtoll(n.c_str(), &end, /*any base*/0);
+  if (*end != '\0') cerr << "tried to convert " << n << " to number\n";
+  assert(*end == '\0');
+  return result;
+}
+
+void test_is_integer() {
+  CHECK(is_integer("1234"));
+  CHECK(is_integer("-1"));
+  CHECK(!is_integer("234.0"));
+  CHECK(is_integer("-567"));
+  CHECK(!is_integer("89-0"));
+  CHECK(!is_integer("-"));
+  CHECK(!is_integer("1e3"));  // not supported
+}
+
 //: helper to print numbers without excessive precision
 
 :(before "End Types")