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/*
* Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
// A symbolOop is a canonicalized string.
// All symbolOops reside in global symbolTable.
// See oopFactory::new_symbol for how to allocate a symbolOop
class symbolOopDesc : public oopDesc {
friend class VMStructs;
private:
unsigned short _length; // number of UTF8 characters in the symbol
jbyte _body[1];
enum {
// max_symbol_length is constrained by type of _length
max_symbol_length = (1 << 16) -1
};
public:
// Low-level access (used with care, since not GC-safe)
jbyte* base() { return &_body[0]; }
// Returns the largest size symbol we can safely hold.
static int max_length() {
return max_symbol_length;
}
static int object_size(int length) {
int size = header_size() + (sizeof(unsigned short) + length + HeapWordSize - 1) / HeapWordSize;
return align_object_size(size);
}
int object_size() { return object_size(utf8_length()); }
int byte_at(int index) const {
assert(index >=0 && index < _length, "symbol index overflow");
return ((symbolOopDesc*)this)->base()[index];
}
void byte_at_put(int index, int value) {
assert(index >=0 && index < _length, "symbol index overflow");
((symbolOopDesc*)this)->base()[index] = value;
}
jbyte* bytes() { return base(); }
int utf8_length() const { return _length; }
void set_utf8_length(int len) { _length = len; }
// Compares the symbol with a string.
bool equals(const char* str, int len) const;
bool equals(const char* str) const { return equals(str, (int) strlen(str)); }
// Tests if the symbol starts with the given prefix.
bool starts_with(const char* prefix, int len) const;
bool starts_with(const char* prefix) const {
return starts_with(prefix, (int) strlen(prefix));
}
// Tests if the symbol starts with the given prefix.
int index_of_at(int i, const char* str, int len) const;
int index_of_at(int i, const char* str) const {
return index_of_at(i, str, (int) strlen(str));
}
// Three-way compare for sorting; returns -1/0/1 if receiver is </==/> than arg
// note that the ordering is not alfabetical
inline int fast_compare(symbolOop other) const;
// Returns receiver converted to null-terminated UTF-8 string; string is
// allocated in resource area, or in the char buffer provided by caller.
char* as_C_string() const;
char* as_C_string(char* buf, int size) const;
// Use buf if needed buffer length is <= size.
char* as_C_string_flexible_buffer(Thread* t, char* buf, int size) const;
// Returns a null terminated utf8 string in a resource array
char* as_utf8() const { return as_C_string(); }
char* as_utf8_flexible_buffer(Thread* t, char* buf, int size) const {
return as_C_string_flexible_buffer(t, buf, size);
}
jchar* as_unicode(int& length) const;
// Treating this symbol as a class name, returns the Java name for the class.
// String is allocated in resource area if buffer is not provided.
// See Klass::external_name()
const char* as_klass_external_name() const;
const char* as_klass_external_name(char* buf, int size) const;
bool object_is_parsable() const {
return (utf8_length() > 0 || (oop)this == Universe::emptySymbol());
}
// Printing
void print_symbol_on(outputStream* st = NULL);
};
// Note: this comparison is used for vtable sorting only; it doesn't matter
// what order it defines, as long as it is a total, time-invariant order
// Since symbolOops are in permSpace, their relative order in memory never changes,
// so use address comparison for speed
int symbolOopDesc::fast_compare(symbolOop other) const {
return (((uintptr_t)this < (uintptr_t)other) ? -1
: ((uintptr_t)this == (uintptr_t) other) ? 0 : 1);
}
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