crt: Add _(v)scwprintf emulation for msvcrt.dll

__ms_vsnwprintf() function now calls _vscwprintf() funcion. _vscwprintf()
is not available in older msvcrt.dll version, so provide emulation of
_scwprintf() and _vscwprintf() functions.

This emulation is similar to existing _scprintf and _vscprintf emulation.

Signed-off-by: Martin Storsjö <martin@martin.st>

mingw-w64-crt/Makefile.am

@@ -489,7 +489,9 @@ src_msvcrt32=\
   misc/wctob.c \
   stdio/_fstat64i32.c \
   stdio/_scprintf.c \
+  stdio/_scwprintf.c \
   stdio/_vscprintf.c \
+  stdio/_vscwprintf.c \
   string/wcstok.c
 
 # Files included in libmsvcrt-os.a (for msvcrt.dll) on x86_64
@@ -732,7 +734,9 @@ src_pre_msvcr70=\
   misc/wcstoimax.c \
   misc/wcstoumax.c \
   stdio/_scprintf.c \
-  stdio/_vscprintf.c
+  stdio/_scwprintf.c \
+  stdio/_vscprintf.c \
+  stdio/_vscwprintf.c
 
 src_pre_msvcr71=\
   misc/_set_purecall_handler.c

mingw-w64-crt/lib-common/msvcrt.def.in

@@ -1214,7 +1214,7 @@ _getwche
 _putwch
 _resetstkoflw
 F_NON_I386(_scprintf) ; i386 _scprintf replaced by emu
-_scwprintf
+F_NON_I386(_scwprintf) ; i386 _scwprintf replaced by emu
 F_I386(_set_SSE2_enable)
 _snscanf
 _snwscanf
@@ -1222,7 +1222,7 @@ F_NON_I386(_strtoi64) ; i386 _strtoi64 replaced by emu
 F_NON_I386(_strtoui64) ; i386 _strtoui64 replaced by emu
 _ungetwch
 F_NON_I386(_vscprintf) ; i386 _vscprintf replaced by emu
-_vscwprintf
+F_NON_I386(_vscwprintf) ; i386 _vscwprintf replaced by emu
 _wcserror
 F_NON_I386(_wcstoi64) ; i386 _wcstoi64 replaced by emu
 F_NON_I386(_wcstoui64) ; i386 _wcstoui64 replaced by emu

mingw-w64-crt/stdio/_scwprintf.c

@@ -0,0 +1,67 @@
+/**
+ * This file has no copyright assigned and is placed in the Public Domain.
+ * This file is part of the mingw-w64 runtime package.
+ * No warranty is given; refer to the file DISCLAIMER.PD within this package.
+ */
+#include <windows.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <wchar.h>
+
+/* mingw-w64 always provides _vscwprintf() implementation, so use it */
+static int __cdecl emu_scwprintf(const wchar_t * __restrict__ format, ...)
+{
+    va_list arglist;
+    int ret;
+
+    va_start(arglist, format);
+    ret = _vscwprintf(format, arglist);
+    va_end(arglist);
+    return ret;
+}
+
+#ifndef __LIBMSVCRT_OS__
+
+int __attribute__ ((alias ("emu_scwprintf"))) __cdecl _scwprintf(const wchar_t * __restrict__, ...);
+int (__cdecl *__MINGW_IMP_SYMBOL(_scwprintf))(const wchar_t * __restrict__, ...) = _scwprintf;
+
+#else
+
+#include <msvcrt.h>
+
+static int __cdecl init_scwprintf(const wchar_t * __restrict__ format, ...);
+
+int (__cdecl *__MINGW_IMP_SYMBOL(_scwprintf))(const wchar_t * __restrict__, ...) = init_scwprintf;
+
+__attribute__((used))
+static void resolve_scwprintf(void)
+{
+    HMODULE msvcrt = __mingw_get_msvcrt_handle();
+    int (__cdecl *func)(const wchar_t * __restrict__, ...) = NULL;
+
+    if (msvcrt)
+        func = (int (__cdecl *)(const wchar_t * __restrict__, ...))GetProcAddress(msvcrt, "_scwprintf");
+
+    if (!func)
+        func = emu_scwprintf;
+
+    __MINGW_IMP_SYMBOL(_scwprintf) = func;
+}
+
+/* gcc does not provide an easy way to call another variadic function with reusing current arguments
+ * this source file is used only on i386, so do this function redirect via inline i386 assembly */
+#define ASM_SYM(sym) __MINGW64_STRINGIFY(__MINGW_USYMBOL(sym))
+asm (
+".def\t" ASM_SYM(init_scwprintf) ";\t.scl\t3;\t.type\t32;\t.endef\n"
+ASM_SYM(init_scwprintf) ":\n\t"
+    "pushal\n\t"
+    "call\t" ASM_SYM(resolve_scwprintf) "\n\t"
+    "popal\n\t"
+    /* fallthrough */
+".globl\t" ASM_SYM(_scwprintf) "\n\t"
+".def\t" ASM_SYM(_scwprintf) ";\t.scl\t2;\t.type\t32;\t.endef\n"
+ASM_SYM(_scwprintf) ":\n\t"
+    "jmp\t*" ASM_SYM(__MINGW_IMP_SYMBOL(_scwprintf))
+);
+
+#endif

mingw-w64-crt/stdio/_vscwprintf.c

@@ -0,0 +1,87 @@
+/**
+ * This file has no copyright assigned and is placed in the Public Domain.
+ * This file is part of the mingw-w64 runtime package.
+ * No warranty is given; refer to the file DISCLAIMER.PD within this package.
+ */
+#include <windows.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <wchar.h>
+#include <errno.h>
+
+/* emulation of _vscwprintf() via _vsnwprintf() */
+static int __cdecl emu_vscwprintf(const wchar_t * __restrict__ format, va_list arglist)
+{
+    wchar_t *buffer, *new_buffer;
+    size_t size;
+    int ret = -1;
+
+    /* if format is a null pointer, _vscwprintf() returns -1 and sets errno to EINVAL */
+    if (!format) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    /* size for _vsnwprintf() must be non-zero and buffer must have place for terminating null character */
+    size = (wcslen(format) * 2 + 1) * sizeof(wchar_t);
+    buffer = malloc(size);
+
+    if (!buffer) {
+        errno = ENOMEM;
+        return -1;
+    }
+
+    /* if the number of characters to write is greater than size, _vsnwprintf() returns -1 */
+    while (size < SIZE_MAX/2 && (ret = _vsnwprintf(buffer, size, format, arglist)) < 0) {
+        /* in this case try with larger buffer */
+        size *= 2;
+        new_buffer = realloc(buffer, size);
+        if (!new_buffer)
+            break;
+        buffer = new_buffer;
+    }
+
+    free(buffer);
+
+    if (ret < 0) {
+        errno = ENOMEM;
+        return -1;
+    }
+
+    return ret;
+}
+
+#ifndef __LIBMSVCRT_OS__
+
+int __attribute__ ((alias ("emu_vscwprintf"))) __cdecl _vscwprintf(const wchar_t * __restrict__, va_list);
+int (__cdecl *__MINGW_IMP_SYMBOL(_vscwprintf))(const wchar_t * __restrict__, va_list) = _vscwprintf;
+
+#else
+
+#include <msvcrt.h>
+
+static int __cdecl init_vscwprintf(const wchar_t * __restrict__ format, va_list arglist);
+
+int (__cdecl *__MINGW_IMP_SYMBOL(_vscwprintf))(const wchar_t * __restrict__, va_list) = init_vscwprintf;
+
+static int __cdecl init_vscwprintf(const wchar_t * __restrict__ format, va_list arglist)
+{
+    HMODULE msvcrt = __mingw_get_msvcrt_handle();
+    int (__cdecl *func)(const wchar_t * __restrict__, va_list) = NULL;
+
+    if (msvcrt)
+        func = (int (__cdecl *)(const wchar_t * __restrict__, va_list))GetProcAddress(msvcrt, "_vscwprintf");
+
+    if (!func)
+        func = emu_vscwprintf;
+
+    return (__MINGW_IMP_SYMBOL(_vscwprintf) = func)(format, arglist);
+}
+
+int __cdecl _vscwprintf(const wchar_t * __restrict__ format, va_list arglist)
+{
+    return __MINGW_IMP_SYMBOL(_vscwprintf)(format, arglist);
+}
+
+#endif