Add some missing JNI string functions, GetObjectArrayElement, and all the primitive array region functions.

This also pulls the UTF-8/UTF-16 functions out of class String.

Change-Id: I75936b84fd619c9cf91f6e6a6037488220b05781
diff --git a/src/utf.cc b/src/utf.cc
new file mode 100644
index 0000000..81c93ca
--- /dev/null
+++ b/src/utf.cc
@@ -0,0 +1,76 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+
+#include "utf.h"
+
+namespace art {
+
+size_t CountModifiedUtf8Chars(const char* utf8) {
+  size_t len = 0;
+  int ic;
+  while ((ic = *utf8++) != '\0') {
+    len++;
+    if ((ic & 0x80) == 0) {
+      // one-byte encoding
+      continue;
+    }
+    // two- or three-byte encoding
+    utf8++;
+    if ((ic & 0x20) == 0) {
+      // two-byte encoding
+      continue;
+    }
+    // three-byte encoding
+    utf8++;
+  }
+  return len;
+}
+
+void ConvertModifiedUtf8ToUtf16(uint16_t* utf16_data_out, const char* utf8_data_in) {
+  while (*utf8_data_in != '\0') {
+    *utf16_data_out++ = GetUtf16FromUtf8(&utf8_data_in);
+  }
+}
+
+int32_t ComputeUtf16Hash(const uint16_t* chars, size_t char_count) {
+  int32_t hash = 0;
+  while (char_count--) {
+    hash = hash * 31 + *chars++;
+  }
+  return hash;
+}
+
+uint16_t GetUtf16FromUtf8(const char** utf8_data_in) {
+  uint8_t one = *(*utf8_data_in)++;
+  if ((one & 0x80) == 0) {
+    // one-byte encoding
+    return one;
+  }
+  // two- or three-byte encoding
+  uint8_t two = *(*utf8_data_in)++;
+  if ((one & 0x20) == 0) {
+    // two-byte encoding
+    return ((one & 0x1f) << 6) | (two & 0x3f);
+  }
+  // three-byte encoding
+  uint8_t three = *(*utf8_data_in)++;
+  return ((one & 0x0f) << 12) | ((two & 0x3f) << 6) | (three & 0x3f);
+}
+
+size_t CountUtf8Bytes(const uint16_t* chars, size_t char_count) {
+  size_t result = 0;
+  while (char_count--) {
+    uint16_t ch = *chars++;
+    if (ch > 0 && ch <= 0x7f) {
+      ++result;
+    } else {
+      if (ch > 0x7ff) {
+        result += 3;
+      } else {
+        result += 2;
+      }
+    }
+  }
+  return result;
+}
+
+}  // namespace art