windows: do console output using WriteConsole

4 files changed, 128 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 3862de1..7826677 100644
--- a/Makefile
+++ b/Makefile
@@ -23,7 +23,7 @@ endif
 
 ifneq ($(BUILD_WIN32),)
 E = .exe
-SOURCES += randgen_win32.c
+SOURCES += randgen_win32.c winconsole.c
 else
 E =
 SOURCES += randgen_unix.c
diff --git a/main.c b/main.c
index cab4586..a565a05 100644
--- a/main.c
+++ b/main.c
@@ -6,6 +6,10 @@
 #include <errno.h>
 #include <string.h>
 
+#ifdef _WIN32
+#include "winconsole.h"
+#endif
+
 /*
     Generates a random id of length `size-1` consisting of characters in the set
     [1-6] and places it in the buffer pointed to by `id`. The buffer is NULL
diff --git a/winconsole.c b/winconsole.c
new file mode 100644
index 0000000..4eded13
--- /dev/null
+++ b/winconsole.c
@@ -0,0 +1,104 @@
+#define WINCONSOLE_NO_DEF
+#include "winconsole.h"
+
+#include <windows.h>
+#include <io.h>
+
+/*
+
+    To correctly make console output on Windows, we need to check if the
+    output stream we are writing to is a console. If it is, we use
+    WriteConsoleW() to directly write to the console. Otherwise we use the
+    fprintf() function. This dance makes us correctly output whatever codepage
+    the console is in (we assume that our internal strings and dictionary are
+    UTF-8).
+
+*/
+
+static int is_console(HANDLE h)
+{
+    DWORD mode;
+
+    if (h == INVALID_HANDLE_VALUE)
+        return 0;
+
+    return !!(GetConsoleMode(h, &mode));
+}
+
+int winconsole_vfprintf(FILE *fp, const char *fmt, va_list ap)
+{
+    wchar_t *wbuf;
+    va_list aq;
+    DWORD nwritten;
+    char *buf;
+    int bufsz, wbufsz;
+    HANDLE h = (HANDLE) _get_osfhandle(_fileno(fp));
+
+    /* WriteConsoleW works only with the console */
+    if (!is_console(h))
+        return vfprintf(fp, fmt, ap);
+
+    /* get the length of the buffer */
+    va_copy(aq, ap);
+    bufsz = vsnprintf(NULL, 0, fmt, aq);
+    if (bufsz < 0)
+        return bufsz;
+    va_end(aq);
+
+    if (bufsz == 0)
+        return 0;
+
+    buf = malloc(bufsz+1);
+    if (!buf)
+        return -1;
+
+    /* now really print to the buffer */
+    bufsz = vsnprintf(buf, bufsz+1, fmt, ap);
+    if (bufsz < 0)
+        return bufsz;
+
+    /* get the length of the wide buf */
+    wbufsz = MultiByteToWideChar(CP_UTF8, 0, buf, bufsz+1, NULL, 0);
+    if (wbufsz == 0xFFFD || wbufsz == 0)
+    {
+        free(buf);
+        return -1;
+    }
+
+    wbuf = malloc(sizeof(wchar_t) * wbufsz);
+    if (!wbuf)
+    {
+        free(buf);
+        return -1;
+    }
+
+    MultiByteToWideChar(CP_UTF8, 0, buf, bufsz+1, wbuf, wbufsz);
+
+    if (!WriteConsoleW(h, wbuf, wbufsz-1, &nwritten, NULL))
+        return -1;
+
+    return nwritten;
+}
+
+int winconsole_fprintf(FILE *fp, const char *fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    int ret = winconsole_vfprintf(fp, fmt, ap);
+    va_end(ap);
+    return ret;
+}
+
+int winconsole_vprintf(const char *fmt, va_list ap)
+{
+    return winconsole_vfprintf(stdout, fmt, ap);
+}
+
+int winconsole_printf(const char *fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    int ret = winconsole_vprintf(fmt, ap);
+    va_end(ap);
+    return ret;
+}
diff --git a/winconsole.h b/winconsole.h
new file mode 100644
index 0000000..195dac4
--- /dev/null
+++ b/winconsole.h
@@ -0,0 +1,19 @@
+#ifndef WINCONSOLE_H
+#define WINCONSOLE_H
+
+#include <stdio.h>
+
+#ifndef WINCONSOLE_NO_DEF
+#define vfprintf(FILE, FMT, AP) winconsole_vfprintf((FILE), (FMT), (AP))
+#define fprintf(FILE, FMT, ...) winconsole_fprintf((FILE), (FMT), ##__VA_ARGS__)
+#define vprintf(FMT, AP) winconsole_vprintf((FMT), (AP))
+#define printf(FMT, ...) winconsole_printf((FMT), ##__VA_ARGS__)
+#endif
+
+int winconsole_vfprintf(FILE *fp, const char *fmt, va_list ap);
+int winconsole_fprintf(FILE *fp, const char *fmt, ...);
+
+int winconsole_vprintf(const char *fmt, va_list ap);
+int winconsole_printf(const char *fmt, ...);
+
+#endif