Implement rb_enc_strlen.

Author: nirvdrum

CHANGELOG.md

@@ -25,6 +25,7 @@ Compatibility:
 * Fix exception message when there are missing or extra keyword arguments - it contains all the missing/extra keywords now (#1522, @andrykonchin).
 * Always terminate native strings with enough `\0` bytes (#2704, @eregon).
 * Support `#dup` and `#clone` on foreign strings (@eregon).
+* Implement the `rb_enc_strlen` function for use by native extensions (@nirvdrum).
 
 Performance:
 

src/main/c/cext/encoding.c

@@ -246,6 +246,16 @@ int rb_enc_precise_mbclen(const char *p, const char *e, rb_encoding *enc) {
   return polyglot_as_i32(RUBY_CEXT_INVOKE_NO_WRAP("rb_enc_precise_mbclen", rb_tr_temporary_native_string(p, length, enc)));
 }
 
+long rb_enc_strlen(const char *p, const char *e, rb_encoding *enc) {
+  long length = e - p;
+
+  if (rb_enc_mbminlen(enc) == rb_enc_mbmaxlen(enc)) {
+    return length / rb_enc_mbminlen(enc) + !!(length % rb_enc_mbminlen(enc));
+  }
+
+  return polyglot_as_i64(RUBY_CEXT_INVOKE_NO_WRAP("rb_enc_strlen", rb_tr_temporary_native_string(p, length, enc)));
+}
+
 int rb_enc_dummy_p(rb_encoding *enc) {
   return polyglot_as_i32(RUBY_INVOKE_NO_WRAP(rb_enc_from_encoding(enc), "dummy?"));
 }
@@ -433,5 +443,3 @@ int enc_is_unicode(const OnigEncodingType *enc) {
   const char *name = rb_enc_name(enc);
   return !strncmp(name,"UTF", 3);
 }
-
-

src/main/java/org/truffleruby/cext/CExtNodes.java

@@ -1481,6 +1481,21 @@ protected int rbEncPreciseMbclen(Object string,
         }
     }
 
+    @CoreMethod(names = "rb_enc_strlen", onSingleton = true, required = 1)
+    public abstract static class RbEncStrlen extends CoreMethodArrayArgumentsNode {
+
+        @Specialization(guards = "strings.isRubyString(string)", limit = "1")
+        protected int rbEncStrlen(Object string,
+                @Cached RubyStringLibrary strings,
+                @Cached TruffleString.CodePointLengthNode codePointLengthNode) {
+            var tstring = strings.getTString(string);
+            var tencoding = strings.getTEncoding(string);
+
+            return codePointLengthNode.execute(tstring, tencoding);
+        }
+
+    }
+
     @CoreMethod(names = "rb_enc_left_char_head", onSingleton = true, required = 3, lowerFixnum = 3)
     public abstract static class RbEncLeftCharHeadNode extends CoreMethodArrayArgumentsNode {