msvcrt: Test and fix _mbsinc/_mbsninc.

dlls/msvcrt/mbcs.c

@@ -27,6 +27,7 @@
 #include "wine/unicode.h"
 #include "wine/debug.h"
 #include "msvcrt/mbctype.h"
+#include "msvcrt/mbstring.h"
 
 WINE_DEFAULT_DEBUG_CHANNEL(msvcrt);
 
@@ -335,10 +336,7 @@ unsigned char* CDECL _mbsdec(const unsigned char* start, const unsigned char* cu
  */
 unsigned char* CDECL _mbsinc(const unsigned char* str)
 {
-  if(MSVCRT___mb_cur_max > 1 && MSVCRT_isleadbyte(*str))
-    return (unsigned char*)str + 2; /* MB char */
-
-  return (unsigned char*)str + 1; /* ASCII CP or SB char */
+  return (unsigned char *)(str + _mbclen(str));
 }
 
 /*********************************************************************
@@ -346,15 +344,22 @@ unsigned char* CDECL _mbsinc(const unsigned char* str)
  */
 unsigned char* CDECL _mbsninc(const unsigned char* str, MSVCRT_size_t num)
 {
-  if(!str || num < 1)
+  if(!str)
     return NULL;
-  if(MSVCRT___mb_cur_max > 1)
+
+  while (num > 0 && *str)
   {
-    while(num--)
-      str = _mbsinc(str);
-    return (unsigned char*)str;
+    if (_ismbblead(*str))
+    {
+      if (!*(str+1))
+         break;
+      str++;
+    }
+    str++;
+    num--;
   }
-  return (unsigned char*)str + num; /* ASCII CP */
+
+  return (unsigned char*)str;
 }
 
 /*********************************************************************
@@ -1348,7 +1353,7 @@ MSVCRT_size_t CDECL _mbsspn(const unsigned char* string, const unsigned char* se
 /*********************************************************************
  *              _mbsspnp (MSVCRT.@)
  */
-const unsigned char* CDECL _mbsspnp(const unsigned char* string, const unsigned char* set)
+unsigned char* CDECL _mbsspnp(const unsigned char* string, const unsigned char* set)
 {
     const unsigned char *p, *q;
 
@@ -1376,7 +1381,7 @@ const unsigned char* CDECL _mbsspnp(const unsigned char* string, const unsigned
     }
     if (*p == '\0')
         return NULL;
-    return p;
+    return (unsigned char *)p;
 }
 
 /*********************************************************************

dlls/msvcrt/tests/string.c

@@ -185,6 +185,7 @@ static void test_mbcp(void)
     unsigned char *mbstring2 = (unsigned char *)"\xb0\xb1\xb2\xb3Q\xb4\xb5"; /* correct string */
     unsigned char *mbsonlylead = (unsigned char *)"\xb0\0\xb1\xb2";
     unsigned char buf[16];
+    int step;
 
     /* some two single-byte code pages*/
     test_codepage(1252);
@@ -252,6 +253,31 @@ static void test_mbcp(void)
     _mbsnbcpy(buf, mbsonlylead, 5);
     expect_bin(buf, "\0\0\0\0\0\xff", 6);
 
+    /* _mbsinc/mbsdec */
+    step = _mbsinc(mbstring) - mbstring;
+    ok(step == 2, "_mbsinc adds %d (exp. 2)\n", step);
+    step = _mbsinc(&mbstring[2]) - &mbstring[2];  /* lead + invalid tail */
+    ok(step == 2, "_mbsinc adds %d (exp. 2)\n", step);
+
+    step = _mbsninc(mbsonlylead, 1) - mbsonlylead;
+    ok(step == 0, "_mbsninc adds %d (exp. 0)\n", step);
+    step = _mbsninc(mbsonlylead, 2) - mbsonlylead;  /* lead + NUL byte + lead + char */
+    ok(step == 0, "_mbsninc adds %d (exp. 0)\n", step);
+    step = _mbsninc(mbstring2, 0) - mbstring2;
+    ok(step == 0, "_mbsninc adds %d (exp. 2)\n", step);
+    step = _mbsninc(mbstring2, 1) - mbstring2;
+    ok(step == 2, "_mbsninc adds %d (exp. 2)\n", step);
+    step = _mbsninc(mbstring2, 2) - mbstring2;
+    ok(step == 4, "_mbsninc adds %d (exp. 4)\n", step);
+    step = _mbsninc(mbstring2, 3) - mbstring2;
+    ok(step == 5, "_mbsninc adds %d (exp. 5)\n", step);
+    step = _mbsninc(mbstring2, 4) - mbstring2;
+    ok(step == 7, "_mbsninc adds %d (exp. 7)\n", step);
+    step = _mbsninc(mbstring2, 5) - mbstring2;
+    ok(step == 7, "_mbsninc adds %d (exp. 7)\n", step);
+    step = _mbsninc(mbstring2, 17) - mbstring2;
+    ok(step == 7, "_mbsninc adds %d (exp. 7)\n", step);
+
     /* functions that depend on locale codepage, not mbcp.
      * we hope the current locale to be SBCS because setlocale(LC_ALL, ".1252") seems not to work yet
      * (as of Wine 0.9.43)