jsutil.h
/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
* PR assertion checker.
*/
#ifndef jsutil_h___
#define jsutil_h___
#include "mozilla/Attributes.h"
#include "js/Utility.h"
/* Forward declarations. */
struct JSContext;
static JS_ALWAYS_INLINE void *
js_memcpy(void *dst_, const void *src_, size_t len)
{
char *dst = (char *) dst_;
const char *src = (const char *) src_;
JS_ASSERT_IF(dst >= src, (size_t) (dst - src) >= len);
JS_ASSERT_IF(src >= dst, (size_t) (src - dst) >= len);
return memcpy(dst, src, len);
}
#ifdef __cplusplus
namespace js {
template <class T>
class AlignedPtrAndFlag
{
uintptr_t bits;
public:
AlignedPtrAndFlag(T *t, bool flag) {
JS_ASSERT((uintptr_t(t) & 1) == 0);
bits = uintptr_t(t) | uintptr_t(flag);
}
T *ptr() const {
return (T *)(bits & ~uintptr_t(1));
}
bool flag() const {
return (bits & 1) != 0;
}
void setPtr(T *t) {
JS_ASSERT((uintptr_t(t) & 1) == 0);
bits = uintptr_t(t) | uintptr_t(flag());
}
void setFlag() {
bits |= 1;
}
void unsetFlag() {
bits &= ~uintptr_t(1);
}
void set(T *t, bool flag) {
JS_ASSERT((uintptr_t(t) & 1) == 0);
bits = uintptr_t(t) | flag;
}
};
template <class T>
static inline void
Reverse(T *beg, T *end)
{
while (beg != end) {
if (--end == beg)
return;
T tmp = *beg;
*beg = *end;
*end = tmp;
++beg;
}
}
template <class T>
static inline T *
Find(T *beg, T *end, const T &v)
{
for (T *p = beg; p != end; ++p) {
if (*p == v)
return p;
}
return end;
}
template <class Container>
static inline typename Container::ElementType *
Find(Container &c, const typename Container::ElementType &v)
{
return Find(c.begin(), c.end(), v);
}
template <typename InputIterT, typename CallableT>
void
ForEach(InputIterT begin, InputIterT end, CallableT f)
{
for (; begin != end; ++begin)
f(*begin);
}
template <class T>
static inline T
Min(T t1, T t2)
{
return t1 < t2 ? t1 : t2;
}
template <class T>
static inline T
Max(T t1, T t2)
{
return t1 > t2 ? t1 : t2;
}
/* Allows a const variable to be initialized after its declaration. */
template <class T>
static T&
InitConst(const T &t)
{
return const_cast<T &>(t);
}
template <class T, class U>
JS_ALWAYS_INLINE T &
ImplicitCast(U &u)
{
T &t = u;
return t;
}
template<typename T>
class AutoScopedAssign
{
private:
JS_DECL_USE_GUARD_OBJECT_NOTIFIER
T *addr;
T old;
public:
AutoScopedAssign(T *addr, const T &value JS_GUARD_OBJECT_NOTIFIER_PARAM)
: addr(addr), old(*addr)
{
JS_GUARD_OBJECT_NOTIFIER_INIT;
*addr = value;
}
~AutoScopedAssign() { *addr = old; }
};
template <class RefCountable>
class AlreadyIncRefed
{
typedef RefCountable *****ConvertibleToBool;
RefCountable *obj;
public:
explicit AlreadyIncRefed(RefCountable *obj = NULL) : obj(obj) {}
bool null() const { return obj == NULL; }
operator ConvertibleToBool() const { return (ConvertibleToBool)obj; }
RefCountable *operator->() const { JS_ASSERT(!null()); return obj; }
RefCountable &operator*() const { JS_ASSERT(!null()); return *obj; }
RefCountable *get() const { return obj; }
};
template <class RefCountable>
class NeedsIncRef
{
typedef RefCountable *****ConvertibleToBool;
RefCountable *obj;
public:
explicit NeedsIncRef(RefCountable *obj = NULL) : obj(obj) {}
bool null() const { return obj == NULL; }
operator ConvertibleToBool() const { return (ConvertibleToBool)obj; }
RefCountable *operator->() const { JS_ASSERT(!null()); return obj; }
RefCountable &operator*() const { JS_ASSERT(!null()); return *obj; }
RefCountable *get() const { return obj; }
};
template <class RefCountable>
class AutoRefCount
{
typedef RefCountable *****ConvertibleToBool;
JSContext *const cx;
RefCountable *obj;
AutoRefCount(const AutoRefCount &other) MOZ_DELETE;
void operator=(const AutoRefCount &other) MOZ_DELETE;
public:
explicit AutoRefCount(JSContext *cx)
: cx(cx), obj(NULL)
{}
AutoRefCount(JSContext *cx, NeedsIncRef<RefCountable> aobj)
: cx(cx), obj(aobj.get())
{
if (obj)
obj->incref(cx);
}
AutoRefCount(JSContext *cx, AlreadyIncRefed<RefCountable> aobj)
: cx(cx), obj(aobj.get())
{}
~AutoRefCount() {
if (obj)
obj->decref(cx);
}
void reset(NeedsIncRef<RefCountable> aobj) {
if (obj)
obj->decref(cx);
obj = aobj.get();
if (obj)
obj->incref(cx);
}
void reset(AlreadyIncRefed<RefCountable> aobj) {
if (obj)
obj->decref(cx);
obj = aobj.get();
}
bool null() const { return obj == NULL; }
operator ConvertibleToBool() const { return (ConvertibleToBool)obj; }
RefCountable *operator->() const { JS_ASSERT(!null()); return obj; }
RefCountable &operator*() const { JS_ASSERT(!null()); return *obj; }
RefCountable *get() const { return obj; }
};
template <class T>
JS_ALWAYS_INLINE static void
PodZero(T *t)
{
memset(t, 0, sizeof(T));
}
template <class T>
JS_ALWAYS_INLINE static void
PodZero(T *t, size_t nelem)
{
/*
* This function is often called with 'nelem' small; we use an
* inline loop instead of calling 'memset' with a non-constant
* length. The compiler should inline the memset call with constant
* size, though.
*/
for (T *end = t + nelem; t != end; ++t)
memset(t, 0, sizeof(T));
}
/*
* Arrays implicitly convert to pointers to their first element, which is
* dangerous when combined with the above PodZero definitions. Adding an
* overload for arrays is ambiguous, so we need another identifier. The
* ambiguous overload is left to catch mistaken uses of PodZero; if you get a
* compile error involving PodZero and array types, use PodArrayZero instead.
*/
template <class T, size_t N> static void PodZero(T (&)[N]); /* undefined */
template <class T, size_t N> static void PodZero(T (&)[N], size_t); /* undefined */
template <class T, size_t N>
JS_ALWAYS_INLINE static void
PodArrayZero(T (&t)[N])
{
memset(t, 0, N * sizeof(T));
}
template <class T>
JS_ALWAYS_INLINE static void
PodAssign(T *dst, const T *src)
{
js_memcpy((char *) dst, (const char *) src, sizeof(T));
}
template <class T>
JS_ALWAYS_INLINE static void
PodCopy(T *dst, const T *src, size_t nelem)
{
/* Cannot find portable word-sized abs(). */
JS_ASSERT_IF(dst >= src, size_t(dst - src) >= nelem);
JS_ASSERT_IF(src >= dst, size_t(src - dst) >= nelem);
if (nelem < 128) {
/*
* Avoid using operator= in this loop, as it may have been
* intentionally deleted by the POD type.
*/
for (const T *srcend = src + nelem; src != srcend; ++src, ++dst)
PodAssign(dst, src);
} else {
memcpy(dst, src, nelem * sizeof(T));
}
}
template <class T>
JS_ALWAYS_INLINE static bool
PodEqual(T *one, T *two, size_t len)
{
if (len < 128) {
T *p1end = one + len;
for (T *p1 = one, *p2 = two; p1 != p1end; ++p1, ++p2) {
if (*p1 != *p2)
return false;
}
return true;
}
return !memcmp(one, two, len * sizeof(T));
}
JS_ALWAYS_INLINE static size_t
UnsignedPtrDiff(const void *bigger, const void *smaller)
{
return size_t(bigger) - size_t(smaller);
}
/*
* Ordinarily, a function taking a JSContext* 'cx' parameter reports errors on
* the context. In some cases, functions optionally report and indicate this by
* taking a nullable 'maybecx' parameter. In some cases, though, a function
* always needs a 'cx', but optionally reports. This option is presented by the
* MaybeReportError.
*/
enum MaybeReportError { REPORT_ERROR = true, DONT_REPORT_ERROR = false };
} /* namespace js */
#endif /* __cplusplus */
/*
* JS_ROTATE_LEFT32
*
* There is no rotate operation in the C Language so the construct (a << 4) |
* (a >> 28) is used instead. Most compilers convert this to a rotate
* instruction but some versions of MSVC don't without a little help. To get
* MSVC to generate a rotate instruction, we have to use the _rotl intrinsic
* and use a pragma to make _rotl inline.
*
* MSVC in VS2005 will do an inline rotate instruction on the above construct.
*/
#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64) || \
defined(_M_X64))
#include <stdlib.h>
#pragma intrinsic(_rotl)
#define JS_ROTATE_LEFT32(a, bits) _rotl(a, bits)
#else
#define JS_ROTATE_LEFT32(a, bits) (((a) << (bits)) | ((a) >> (32 - (bits))))
#endif
/* Static control-flow checks. */
#ifdef NS_STATIC_CHECKING
/* Trigger a control flow check to make sure that code flows through label */
inline __attribute__ ((unused)) void MUST_FLOW_THROUGH(const char *label) {}
/* Avoid unused goto-label warnings. */
# define MUST_FLOW_LABEL(label) goto label; label:
#else
# define MUST_FLOW_THROUGH(label) ((void) 0)
# define MUST_FLOW_LABEL(label)
#endif
/* Crash diagnostics */
#ifdef DEBUG
# define JS_CRASH_DIAGNOSTICS 1
#endif
#ifdef JS_CRASH_DIAGNOSTICS
# define JS_POISON(p, val, size) memset((p), (val), (size))
# define JS_OPT_ASSERT(expr) \
((expr) ? (void)0 : JS_Assert(#expr, __FILE__, __LINE__))
# define JS_OPT_ASSERT_IF(cond, expr) \
((!(cond) || (expr)) ? (void)0 : JS_Assert(#expr, __FILE__, __LINE__))
#else
# define JS_POISON(p, val, size) ((void) 0)
# define JS_OPT_ASSERT(expr) ((void) 0)
# define JS_OPT_ASSERT_IF(cond, expr) ((void) 0)
#endif
/* Basic stats */
#ifdef DEBUG
# define JS_BASIC_STATS 1
#endif
#ifdef JS_BASIC_STATS
# include <stdio.h>
typedef struct JSBasicStats {
uint32_t num;
uint32_t max;
double sum;
double sqsum;
uint32_t logscale; /* logarithmic scale: 0 (linear), 2, 10 */
uint32_t hist[11];
} JSBasicStats;
# define JS_INIT_STATIC_BASIC_STATS {0,0,0,0,0,{0,0,0,0,0,0,0,0,0,0,0}}
# define JS_BASIC_STATS_INIT(bs) memset((bs), 0, sizeof(JSBasicStats))
# define JS_BASIC_STATS_ACCUM(bs,val) \
JS_BasicStatsAccum(bs, val)
# define JS_MeanAndStdDevBS(bs,sigma) \
JS_MeanAndStdDev((bs)->num, (bs)->sum, (bs)->sqsum, sigma)
extern void
JS_BasicStatsAccum(JSBasicStats *bs, uint32_t val);
extern double
JS_MeanAndStdDev(uint32_t num, double sum, double sqsum, double *sigma);
extern void
JS_DumpBasicStats(JSBasicStats *bs, const char *title, FILE *fp);
extern void
JS_DumpHistogram(JSBasicStats *bs, FILE *fp);
#else
# define JS_BASIC_STATS_ACCUM(bs,val)
#endif
/* A jsbitmap_t is a long integer that can be used for bitmaps. */
typedef size_t jsbitmap;
#define JS_TEST_BIT(_map,_bit) ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] & \
((jsbitmap)1<<((_bit)&(JS_BITS_PER_WORD-1))))
#define JS_SET_BIT(_map,_bit) ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] |= \
((jsbitmap)1<<((_bit)&(JS_BITS_PER_WORD-1))))
#define JS_CLEAR_BIT(_map,_bit) ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] &= \
~((jsbitmap)1<<((_bit)&(JS_BITS_PER_WORD-1))))
/* Wrapper for various macros to stop warnings coming from their expansions. */
#if defined(__clang__)
# define JS_SILENCE_UNUSED_VALUE_IN_EXPR(expr) \
JS_BEGIN_MACRO \
_Pragma("clang diagnostic push") \
_Pragma("clang diagnostic ignored \"-Wunused-value\"") \
expr; \
_Pragma("clang diagnostic pop") \
JS_END_MACRO
#elif (__GNUC__ >= 5) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
# define JS_SILENCE_UNUSED_VALUE_IN_EXPR(expr) \
JS_BEGIN_MACRO \
_Pragma("GCC diagnostic push") \
_Pragma("GCC diagnostic ignored \"-Wunused-but-set-variable\"") \
expr; \
_Pragma("GCC diagnostic pop") \
JS_END_MACRO
#else
# define JS_SILENCE_UNUSED_VALUE_IN_EXPR(expr) \
JS_BEGIN_MACRO \
expr; \
JS_END_MACRO
#endif
#endif /* jsutil_h___ */
