string: allocate a real java object for strings

incl. fieldtable, array, ...

also see:
http://www.javamex.com/tutorials/memory/string_memory_usage.shtml

diff --git a/Mate/Strings.hs b/Mate/Strings.hs
index f1762b0a5ae1e9790639b69857ebf9bc5e9f9e82..2ebda14e4861da078d754c6730999c6fc8e8e56e 100644 (file)
--- a/Mate/Strings.hs
+++ b/Mate/Strings.hs
@@ -15,11 +15,11 @@ import Text.Printf
 
 import JVM.ClassFile
 
-import Foreign.Ptr
-import Foreign.Marshal.Utils
-import Foreign.Marshal.Array
+import Foreign
+import Foreign.C.Types
 
 import Mate.Types
+import Mate.ClassPool
 import Mate.Debug
 import Mate.GarbageAlloc
 
@@ -36,13 +36,50 @@ getUniqueStringAddr str = do
 
 allocateJavaString :: B.ByteString -> IO Word32
 allocateJavaString str = do
-  -- TODO(bernhard): is this also true for UTF8 stuff?
-  let strlen = fromIntegral $ B.length str
+  {- we have to build a java object layout here, where String object looks like
+   -
+   -  this -+
+   -        |
+   -        v
+   -  +-------------+-------+-------+----------------+--------+
+   -  | MethodTable | value | count | cachedhashcode | offset |
+   -  +-------------+-------+-------+----------------+--------+
+   -        |           |
+   -        |           +------------+
+   -        v                        v
+   -  java/lang/String           +--------+--------+--------+-----+------------------+
+   -                             | length | str[0] | str[1] | ... | str [length - 1] |
+   -                             +--------+--------+--------+-----+------------------+
+   -  all cells are 32bit wide, except str[i] of course (they're 8bit [but
+   -  should be 16bit, TODO]).
+   -}
+  -- build object layout
+  fsize <- getObjectSize "java/lang/String"
+  printfStr "string: fsize: %d (should be 4 * 5)\n" fsize
+  tblptr <- mallocObject $ fromIntegral fsize
+  let ptr = intPtrToPtr (fromIntegral tblptr) :: Ptr CUInt
+  mtbl <- getMethodTable "java/lang/String"
+  poke ptr $ fromIntegral mtbl
+
+  -- build array layout
+  let strlen = (fromIntegral $ B.length str)
+  -- (+1) for \0, (+4) for length
+  newstr <- mallocString (strlen + 5)
+  BI.memset newstr 0 (fromIntegral $ strlen + 5)
   arr <- newArray ((map fromIntegral $ B.unpack str) :: [Word8])
-  -- (+1) for \0
-  newstr <- mallocString (strlen + 1)
-  BI.memset newstr 0 (fromIntegral $ strlen + 1)
-  copyBytes newstr arr strlen
-  let w32_ptr = fromIntegral $ ptrToIntPtr newstr
-  printfStr "new str ptr: 0x%08x (%s)@%d\n" w32_ptr (toString str) strlen
-  return w32_ptr
+  copyBytes (plusPtr newstr 4) arr strlen
+  printfStr "new str ptr: (%s)@%d\n" (toString str) strlen
+
+  let newstr_length = castPtr newstr :: Ptr CUInt
+  poke newstr_length $ fromIntegral strlen
+
+  -- set value pointer
+  poke (plusPtr ptr 4) (fromIntegral (ptrToIntPtr newstr) :: CUInt)
+  -- set count field
+  poke (plusPtr ptr 8) (fromIntegral strlen :: CUInt)
+  -- set hash code (TODO)
+  poke (plusPtr ptr 12) (0 :: CUInt)
+  -- set offset
+  poke (plusPtr ptr 16) (0 :: CUInt)
+
+  return $ fromIntegral tblptr

diff --git a/ffi/native.c b/ffi/native.c
index 25e0d1ccc9c7e0542f06ba47e85b61c1e770d7a1..a3e877c0d5c8d958759cd372941e17b1606e6639 100644 (file)
--- a/ffi/native.c
+++ b/ffi/native.c
@@ -49,39 +49,56 @@ struct integer {
        int value;
 };
 
+struct string {
+       unsigned int method_table_ptr;
+       struct chararray *value;
+};
+
+struct chararray {
+       unsigned int length;
+       char str;
+};
+
 void java_io_PrintStream__printf_0___Ljava_lang_String__V
-       (const char *fmt)
+       (struct string *fmt)
 {
-       printf("%s", fmt);
+       printf("%s", &fmt->value->str);
 }
 
 void java_io_PrintStream__printf_1___Ljava_lang_String_Ljava_lang_Object__V
-       (struct integer *a1, const char *fmt)
+       (struct integer *a1, struct string *fmt)
 {
-       printf(fmt, a1->value);
+#if 0
+       printf("fmt:        0x%08x\n", (unsigned int) fmt);
+       printf("fmt->value: 0x%08x\n", (unsigned int) fmt->value);
+       printf("fmt->val.len: 0x%08x\n", (unsigned int) (*fmt->value).length);
+       printf("first: %d\n", fmt->value->length);
+       printf("*fmt: %s\n", &fmt->value->str);
+#endif
+       printf(&fmt->value->str, a1->value);
 }
 
 void java_io_PrintStream__printf_2___Ljava_lang_String_Ljava_lang_Object_Ljava_lang_Object__V
-       (struct integer *a2, struct integer *a1, const char *fmt)
+       (struct integer *a2, struct integer *a1, struct string *fmt)
 {
-       printf(fmt, a1->value, a2->value);
+       printf(&fmt->value->str, a1->value, a2->value);
 }
 
 void
 java_io_PrintStream__printf_3___Ljava_lang_String_Ljava_lang_Object_Ljava_lang_Object_Ljava_lang_Object__V
-       (struct integer *a3, struct integer *a2, struct integer *a1, const char *fmt)
+       (struct integer *a3, struct integer *a2, struct integer *a1, struct string *fmt)
 {
-       printf(fmt, a1->value, a2->value, a3->value);
+       printf(&fmt->value->str, a1->value, a2->value, a3->value);
 }
 
 void java_io_PrintStream__printf_4___Ljava_lang_String_Ljava_lang_Object_Ljava_lang_Object_Ljava_lang_Object_Ljava_lang_Object__V
-       (struct integer *a4, struct integer *a3, struct integer *a2, struct integer *a1, const char *fmt)
+       (struct integer *a4, struct integer *a3, struct integer *a2, struct integer *a1, struct string *fmt)
 {
-       printf(fmt, a1->value, a2->value, a3->value, a4->value);
+       printf(&fmt->value->str, a1->value, a2->value, a3->value, a4->value);
 }
 
 void java_io_PrintStream__printf_5___Ljava_lang_String_Ljava_lang_Object_Ljava_lang_Object_Ljava_lang_Object_Ljava_lang_Object_Ljava_lang_Object__V
-       (struct integer *a5, struct integer *a4, struct integer *a3, struct integer *a2, struct integer *a1, const char *fmt)
+       (struct integer *a5, struct integer *a4, struct integer *a3, struct integer *a2, struct integer *a1, struct string *fmt)
 {
-       printf(fmt, a1->value, a2->value, a3->value, a4->value, a5->value);
+       printf(&fmt->value->str, a1->value, a2->value, a3->value, a4->value, a5->value);
 }

diff --git a/java/lang/String.java b/java/lang/String.java
new file mode 100644 (file)
index 0000000..a12998f
--- /dev/null
+++ b/java/lang/String.java
@@ -0,0 +1,8 @@
+package java.lang;
+
+public class String {
+       public char[] value;
+       public int count;
+       public int cachedHashCode;
+       public int offset;
+}