oleaut32: Use a struct for internal BSTR representation to avoid pointer magic.

oldstable
Jacek Caban 2012-05-02 16:24:57 +02:00 committed by Alexandre Julliard
parent e0fab0d39c
commit 4eebe0bcf0
1 changed files with 56 additions and 40 deletions

View File

@ -80,10 +80,19 @@ static CRITICAL_SECTION_DEBUG cs_bstr_cache_dbg =
};
static CRITICAL_SECTION cs_bstr_cache = { &cs_bstr_cache_dbg, -1, 0, 0, 0, 0 };
typedef struct {
DWORD size;
union {
char ptr[1];
WCHAR str[1];
DWORD dwptr[1];
} u;
} bstr_t;
typedef struct {
unsigned short head;
unsigned short cnt;
DWORD *buf[6];
bstr_t *buf[6];
} bstr_cache_entry_t;
#define BUCKET_SIZE 16
@ -92,28 +101,32 @@ static bstr_cache_entry_t bstr_cache[0x10000/BUCKET_SIZE];
static inline size_t bstr_alloc_size(size_t size)
{
return (size+sizeof(DWORD)+BUCKET_SIZE) & ~(BUCKET_SIZE-1);
return (FIELD_OFFSET(bstr_t, u.ptr[size]) + sizeof(WCHAR) + BUCKET_SIZE-1) & ~(BUCKET_SIZE-1);
}
static inline bstr_t *bstr_from_str(BSTR str)
{
return CONTAINING_RECORD(str, bstr_t, u.str);
}
static inline bstr_cache_entry_t *get_cache_entry(size_t size)
{
unsigned cache_idx = (size+sizeof(DWORD)-1)/BUCKET_SIZE;
unsigned cache_idx = FIELD_OFFSET(bstr_t, u.ptr[size-1])/BUCKET_SIZE;
return bstr_cache_enabled && cache_idx < sizeof(bstr_cache)/sizeof(*bstr_cache)
? bstr_cache + cache_idx
: NULL;
}
static DWORD *alloc_bstr(size_t size)
static bstr_t *alloc_bstr(size_t size)
{
bstr_cache_entry_t *cache_entry = get_cache_entry(size);
bstr_cache_entry_t *cache_entry = get_cache_entry(size+sizeof(WCHAR));
bstr_t *ret;
if(cache_entry) {
DWORD *ret = NULL;
EnterCriticalSection(&cs_bstr_cache);
if(!cache_entry->cnt) {
cache_entry = get_cache_entry(size+BUCKET_SIZE);
cache_entry = get_cache_entry(size+sizeof(WCHAR)+BUCKET_SIZE);
if(cache_entry && !cache_entry->cnt)
cache_entry = NULL;
}
@ -126,11 +139,16 @@ static DWORD *alloc_bstr(size_t size)
LeaveCriticalSection(&cs_bstr_cache);
if(ret)
if(cache_entry) {
ret->size = size;
return ret;
}
}
return HeapAlloc(GetProcessHeap(), 0, bstr_alloc_size(size));
ret = HeapAlloc(GetProcessHeap(), 0, bstr_alloc_size(size));
if(ret)
ret->size = size;
return ret;
}
/******************************************************************************
@ -152,7 +170,7 @@ static DWORD *alloc_bstr(size_t size)
*/
UINT WINAPI SysStringLen(BSTR str)
{
return str ? *((DWORD*)str-1)/sizeof(WCHAR) : 0;
return str ? bstr_from_str(str)->size/sizeof(WCHAR) : 0;
}
/******************************************************************************
@ -171,7 +189,7 @@ UINT WINAPI SysStringLen(BSTR str)
*/
UINT WINAPI SysStringByteLen(BSTR str)
{
return str ? *((DWORD*)str-1) : 0;
return str ? bstr_from_str(str)->size : 0;
}
/******************************************************************************
@ -218,19 +236,20 @@ BSTR WINAPI SysAllocString(LPCOLESTR str)
void WINAPI SysFreeString(BSTR str)
{
bstr_cache_entry_t *cache_entry;
DWORD *ptr;
bstr_t *bstr;
if(!str)
return;
ptr = (DWORD*)str-1;
cache_entry = get_cache_entry(*ptr+sizeof(WCHAR));
bstr = bstr_from_str(str);
cache_entry = get_cache_entry(bstr->size+sizeof(WCHAR));
if(cache_entry) {
EnterCriticalSection(&cs_bstr_cache);
if(cache_entry->cnt < sizeof(cache_entry->buf)/sizeof(*cache_entry->buf)) {
cache_entry->buf[(cache_entry->head+cache_entry->cnt)%((sizeof(cache_entry->buf)/sizeof(*cache_entry->buf)))] = ptr;
cache_entry->buf[(cache_entry->head+cache_entry->cnt)%((sizeof(cache_entry->buf)/sizeof(*cache_entry->buf)))] = bstr;
cache_entry->cnt++;
LeaveCriticalSection(&cs_bstr_cache);
return;
}
@ -238,7 +257,7 @@ void WINAPI SysFreeString(BSTR str)
LeaveCriticalSection(&cs_bstr_cache);
}
HeapFree(GetProcessHeap(), 0, ptr);
HeapFree(GetProcessHeap(), 0, bstr);
}
/******************************************************************************
@ -259,28 +278,28 @@ void WINAPI SysFreeString(BSTR str)
*/
BSTR WINAPI SysAllocStringLen(const OLECHAR *str, unsigned int len)
{
DWORD size, *ptr;
BSTR ret;
bstr_t *bstr;
DWORD size;
/* Detect integer overflow. */
if (len >= ((UINT_MAX-sizeof(WCHAR)-sizeof(DWORD))/sizeof(WCHAR)))
return NULL;
TRACE("%s\n", debugstr_wn(str, len));
size = len*sizeof(WCHAR);
ptr = alloc_bstr(size + sizeof(WCHAR));
if(!ptr)
bstr = alloc_bstr(size);
if(!bstr)
return NULL;
*ptr = size;
ret = (BSTR)(ptr+1);
if(str) {
memcpy(ret, str, size);
ret[len] = 0;
memcpy(bstr->u.str, str, size);
bstr->u.str[len] = 0;
}else {
memset(ret, 0, size+sizeof(WCHAR));
memset(bstr->u.str, 0, size+sizeof(WCHAR));
}
return ret;
return bstr->u.str;
}
/******************************************************************************
@ -310,9 +329,9 @@ int WINAPI SysReAllocStringLen(BSTR* old, const OLECHAR* str, unsigned int len)
if (*old!=NULL) {
BSTR old_copy = *old;
DWORD newbytelen = len*sizeof(WCHAR);
DWORD *ptr = HeapReAlloc(GetProcessHeap(),0,((DWORD*)*old)-1,bstr_alloc_size(newbytelen+sizeof(WCHAR)));
*old = (BSTR)(ptr+1);
*ptr = newbytelen;
bstr_t *bstr = HeapReAlloc(GetProcessHeap(),0,((DWORD*)*old)-1,bstr_alloc_size(newbytelen));
*old = bstr->u.str;
bstr->size = newbytelen;
/* Subtle hidden feature: The old string data is still there
* when 'in' is NULL!
* Some Microsoft program needs it.
@ -352,27 +371,24 @@ int WINAPI SysReAllocStringLen(BSTR* old, const OLECHAR* str, unsigned int len)
*/
BSTR WINAPI SysAllocStringByteLen(LPCSTR str, UINT len)
{
DWORD *ptr;
char *ret;
bstr_t *bstr;
/* Detect integer overflow. */
if (len >= (UINT_MAX-sizeof(WCHAR)-sizeof(DWORD)))
return NULL;
ptr = alloc_bstr(len + sizeof(WCHAR));
if(!ptr)
bstr = alloc_bstr(len);
if(!bstr)
return NULL;
*ptr = len;
ret = (char*)(ptr+1);
if(str) {
memcpy(ret, str, len);
ret[len] = ret[len+1] = 0;
memcpy(bstr->u.ptr, str, len);
bstr->u.ptr[len] = bstr->u.ptr[len+1] = 0;
}else {
memset(ret, 0, len+sizeof(WCHAR));
memset(bstr->u.ptr, 0, len+sizeof(WCHAR));
}
return (BSTR)ret;
return bstr->u.str;
}
/******************************************************************************