Changeset 83886 in vbox for trunk/src/VBox/Runtime/common/string

Timestamp:

Apr 21, 2020 11:14:20 AM (5 years ago)

Author:

vboxsync

Message:

IPRT: Implement RTStrEnd in assembly & C++, drop the inlining. memchr from VC++ 14.1 cannot deal wtih RTSTR_MAX on unaligned string, it may step into an electric fence page after the end of the string. bugref:8489

Location:

trunk/src/VBox/Runtime/common/string

Files:

• RTStrEnd.asm (copied) (copied from trunk/src/VBox/Runtime/common/string/memchr.asm ) (3 diffs)
• RTStrEnd.cpp (copied) (copied from trunk/src/VBox/Runtime/common/string/memchr.cpp ) (2 diffs)

trunk/src/VBox/Runtime/common/string/RTStrEnd.asm

@@ -1 +1 @@
 ; $Id$
 ;; @file
-; IPRT - No-CRT memchr - AMD64 & X86.
+; IPRT - RTStrEnd - AMD64 & X86.
 ;
 
@@ -30 +30 @@
 
 ;;
-; @param    pv      gcc: rdi  msc: ecx  x86:[esp+4]   wcall: eax
-; @param    ch      gcc: esi  msc: edx  x86:[esp+8]   wcall: edx
-; @param    cb      gcc: rdx  msc: r8   x86:[esp+0ch] wcall: ebx
-RT_NOCRT_BEGINPROC memchr
+; @param    pszString   gcc: rdi  msc: rcx  x86:[esp+4]   wcall: eax
+; @param    cchMax      gcc: rsi  msc: rdx  x86:[esp+8]   wcall: edx
+;
+BEGINPROC_EXPORTED RTStrEnd
         cld
 %ifdef RT_ARCH_AMD64
  %ifdef ASM_CALL64_MSC
-        or      r8, r8
+        or      rdx, rdx
         jz      .not_found_early
 
         mov     r9, rdi                 ; save rdi
-        mov     eax, edx
         mov     rdi, rcx
-        mov     rcx, r8
+        mov     rcx, rdx
  %else
-        mov     rcx, rdx
+        mov     rcx, rsi
         jrcxz   .not_found_early
-
-        mov     eax, esi
  %endif
 
 %else
  %ifdef ASM_CALL32_WATCOM
-        mov     ecx, ebx
+        mov     ecx, edx
         jecxz   .not_found_early
-        xchg    eax, edx
-        xchg    edi, edx                ; load and save edi.
+        mov     edx, edi                ; save rdi
+        mov     edi, eax
  %else
-        mov     ecx, [esp + 0ch]
+        mov     ecx, [esp + 8]
         jecxz   .not_found_early
         mov     edx, edi                ; save edi
-        mov     eax, [esp + 8]
         mov     edi, [esp + 4]
  %endif
 %endif
+        xor     eax, eax                ; we're searching for zero
 
         ; do the search
@@ -90 +87 @@
         xor     eax, eax
         ret
-ENDPROC RT_NOCRT(memchr)
+ENDPROC RTStrEnd
 

trunk/src/VBox/Runtime/common/string/RTStrEnd.cpp

@@ -1 +1 @@
 /* $Id$ */
 /** @file
- * IPRT - CRT Strings, memcpy().
+ * IPRT - RTStrEnd, C++ version.
  */
 
@@ -32 +32 @@
 
 
-/**
- * Search a memory block for a character.
- *
- * @returns Pointer to the first instance of ch in pv.
- * @returns NULL if ch wasn't found.
- * @param   pv          Pointer to the block to search.
- * @param   ch          The character to search for.
- * @param   cb          The size of the block.
- */
-#ifdef _MSC_VER /* Silly 'safeness' from MS. */
-# if _MSC_VER >= 1400
-_CRTIMP __checkReturn _CONST_RETURN void *  __cdecl memchr( __in_bcount_opt(_MaxCount) const void * pv, __in int ch, __in size_t cb)
-# else
-void *memchr(const void *pv, int ch, size_t cb)
-# endif
-#else
-void *memchr(const void *pv, int ch, size_t cb)
-#endif
+RTDECL(char *) RTStrEnd(const char *pszString, size_t cchMax)
 {
-    register uint8_t const *pu8 = (uint8_t const *)pv;
-    register size_t cb2 = cb;
-    while (cb2-- > 0)
+    while (cchMax-- > 0)
     {
-        if (*pu8 == ch)
-            return (void *)pu8;
-        pu8++;
+        if (*pszString)
+        { }
+        else
+            return pszString;
+        pszString++;
     }
     return NULL;
 }
-
+RT_EXPORT_SYMBOL(RTStrEnd);