1 files changed, 52 insertions, 0 deletions
diff --git a/lib/Strings/Character.cpp b/lib/Strings/Character.cpp
index e5274bf..823f8e3 100644
--- a/lib/Strings/Character.cpp
+++ b/lib/Strings/Character.cpp
@@ -14,6 +14,10 @@ struct CharacterValue {
   CharacterValue<T> sliceFrom(size_t Start) const {
     return CharacterValue<T>(Ptr + Start, Length - Start);
   }
+
+  T operator[] (size_t I) const {
+    return Ptr[I];
+  }
 };
 
 static inline
@@ -82,6 +86,47 @@ static int32_t lexcompare(const CharacterValue<T> LHS,
 }
 
 template<typename T>
+static size_t index(const CharacterValue<T> String,
+                    const CharacterValue<T> SubString) {
+  if(String.Length < SubString.Length)
+    return 0;
+  if(!SubString.Length) return 1;
+
+  auto Range = String.Length - SubString.Length;
+  for(size_t I = 0; I <= Range; ++I) {
+    bool Match = true;
+    for(size_t J = 0; J < SubString.Length; ++J) {
+      if(String[I+J] != SubString[J]) {
+        Match = false;
+        break;
+      }
+    }
+    if(Match) return I+1;
+  }
+  return 0;
+}
+
+template<typename T>
+static size_t index_reverse(const CharacterValue<T> String,
+                            const CharacterValue<T> SubString) {
+  if(String.Length < SubString.Length)
+    return 0;
+  if(!SubString.Length) return String.Length + 1;
+
+  for(size_t I = String.Length - SubString.Length + 1; I != 0; --I) {
+    bool Match = true;
+    for(size_t J = 0; J < SubString.Length; ++J) {
+      if(String[I-1+J] != SubString[J]) {
+        Match = false;
+        break;
+      }
+    }
+    if(Match) return I;
+  }
+  return 0;
+}
+
+template<typename T>
 static size_t lentrim(const CharacterValue<T> String) {
   for(size_t I = String.Length; I > 0; I--) {
     if(isWhitespace(String.Ptr[I-1])) return I;
@@ -115,6 +160,13 @@ LIBFLANG_ABI int32_t libflang_lexcompare_char1(const char *LHS, size_t LHSLength
   return lexcompare(generic(LHS, LHSLength), generic(RHS, RHSLength));
 }
 
+LIBFLANG_ABI size_t libflang_index_char1(const char *String, size_t Length,
+                                         const char *SubString, size_t SubLength,
+                                         int32_t Back) {
+  return Back == 0? index(generic(String, Length), generic(SubString, SubLength)) :
+                    index_reverse(generic(String, Length), generic(SubString, SubLength));
+}
+
 LIBFLANG_ABI size_t libflang_lentrim_char1(const char *String, size_t Length) {
   return lentrim(generic(String, Length));
 }