1 files changed, 257 insertions, 0 deletions
diff --git a/src/pal/src/cruntime/mbstring.cpp b/src/pal/src/cruntime/mbstring.cpp
new file mode 100644
index 0000000000..dd4bcbbdce
--- /dev/null
+++ b/src/pal/src/cruntime/mbstring.cpp
@@ -0,0 +1,257 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+/*++
+
+
+
+Module Name:
+
+    mbstring.c
+
+Abstract:
+
+    Implementation of the multi-byte string functions in the C runtime library that 
+    are Windows specific.
+
+Implementation Notes:
+
+    Assuming it is not possible to change multi-byte code page using
+    the PAL (_setmbcp does not seem to be required), these functions
+    should have a trivial implementation (treat as single-byte). If it
+    is possible, then support for multi-byte code pages will have to
+    be implemented before these functions can behave correctly for
+    multi-byte strings.
+
+
+
+--*/
+
+#include "pal/palinternal.h"
+#include "pal/dbgmsg.h"
+
+
+SET_DEFAULT_DEBUG_CHANNEL(CRT);
+
+
+/*++
+Function:
+  _mbslen
+
+Determines the number of characters (code points) in a multibyte
+character string.
+
+Parameters
+
+string  Points to a multibyte character string.
+
+Return Values
+
+The mbslen subroutine returns the number of multibyte characters in a
+multibyte character string. It returns 0 if the string parameter
+points to a null character or if a character cannot be formed from the
+string pointed to by this parameter.
+
+--*/
+size_t 
+__cdecl
+_mbslen(
+        const unsigned char *string)
+{
+    size_t ret = 0;
+    CPINFO cpinfo;
+    PERF_ENTRY(_mbslen);
+    ENTRY("_mbslen (string=%p (%s))\n", string, string);
+
+    if (string)
+    {
+        if (GetCPInfo(CP_ACP, &cpinfo) && cpinfo.MaxCharSize == 1)
+        {
+            ret = strlen((const char*)string);
+        }
+        else
+        {
+            while (*string)
+            {
+                if (IsDBCSLeadByteEx(CP_ACP, *string))
+                {
+                    ++string;
+                }
+                ++string;
+                ++ret;
+            }
+        }
+    }
+
+    LOGEXIT("_mbslen returning size_t %u\n", ret);
+    PERF_EXIT(_mbslen);
+    return ret;
+}
+
+/*++
+Function:
+  _mbsinc
+
+Return Value
+
+Returns a pointer to the character that immediately follows string.
+
+Parameter
+
+string  Character pointer
+
+Remarks
+
+The _mbsinc function returns a pointer to the first byte of the
+multibyte character that immediately follows string.
+
+--*/
+unsigned char *
+__cdecl
+_mbsinc(
+        const unsigned char *string)
+{
+    unsigned char *ret;
+
+    PERF_ENTRY(_mbsinc);
+    ENTRY("_mbsinc (string=%p)\n", string);
+
+    if (string == NULL)
+    {
+        ret = NULL;
+    }
+    else
+    {
+        ret = (unsigned char *) string;
+        if (IsDBCSLeadByteEx(CP_ACP, *ret))
+        {
+            ++ret;
+        }
+        ++ret;
+    }
+
+    LOGEXIT("_mbsinc returning unsigned char* %p (%s)\n", ret, ret);
+    PERF_EXIT(_mbsinc);
+    return ret;
+}
+
+
+/*++
+Function:
+  _mbsninc
+
+Return Value
+
+Returns a pointer to string after string has been incremented by count
+characters, or NULL if the supplied pointer is NULL. If count is
+greater than or equal to the number of characters in string, the
+result is undefined.
+
+Parameters
+
+string  Source string
+count   Number of characters to increment string pointer
+
+Remarks
+
+The _mbsninc function increments string by count multibyte
+characters. _mbsninc recognizes multibyte-character sequences
+according to the multibyte code page currently in use.
+
+--*/
+unsigned char *
+__cdecl
+_mbsninc(
+         const unsigned char *string, size_t count)
+{
+    unsigned char *ret;
+    CPINFO cpinfo;
+
+    PERF_ENTRY(_mbsninc);
+    ENTRY("_mbsninc (string=%p, count=%lu)\n", string, count);
+    if (string == NULL)
+    {
+        ret = NULL;
+    }
+    else
+    {
+        ret = (unsigned char *) string;
+        if (GetCPInfo(CP_ACP, &cpinfo) && cpinfo.MaxCharSize == 1)
+        {
+            ret += min(count, strlen((const char*)string));
+        }
+        else
+        {
+            while (count-- && (*ret != 0))
+            {
+                if (IsDBCSLeadByteEx(CP_ACP, *ret))
+                {
+                    ++ret;
+                }
+                ++ret;
+            }
+        }
+    }
+    LOGEXIT("_mbsninc returning unsigned char* %p (%s)\n", ret, ret);
+    PERF_EXIT(_mbsninc);
+    return ret;
+}
+
+/*++
+Function:
+  _mbsdec
+
+Return Value
+
+_mbsdec returns a pointer to the character that immediately precedes
+current; _mbsdec returns NULL if the value of start is greater than or
+equal to that of current.
+
+Parameters
+
+start    Pointer to first byte of any multibyte character in the source
+         string; start must precede current in the source string
+
+current  Pointer to first byte of any multibyte character in the source
+         string; current must follow start in the source string
+
+--*/
+unsigned char * 
+__cdecl
+_mbsdec(
+        const unsigned char *start, 
+        const unsigned char *current)
+{
+    unsigned char *ret;
+    unsigned char *strPtr;
+    CPINFO cpinfo;
+
+    PERF_ENTRY(_mbsdec);
+    ENTRY("_mbsdec (start=%p, current=%p)\n", start, current);
+
+    if (current <= start)
+    {
+        ret = NULL;
+    }
+    else if (GetCPInfo(CP_ACP, &cpinfo) && cpinfo.MaxCharSize == 1)
+    {
+        ret = (unsigned char *) current - 1;
+    }
+    else
+    {
+        ret = strPtr = (unsigned char *) start;
+        while (strPtr < current)
+        {
+            ret = strPtr;
+            if (IsDBCSLeadByteEx(CP_ACP, *strPtr))
+            {
+                ++strPtr;
+            }
+            ++strPtr;
+        }
+    }
+    LOGEXIT("_mbsdec returning unsigned int %p (%s)\n", ret, ret);
+    PERF_EXIT(_mbsdec);
+    return ret;
+}