Add some fixes to enable build on msys2 under Windows

Makefile.am

@@ -1,9 +1,9 @@
 bin_PROGRAMS=bitwise
-bitwise_SOURCES= src/main.c src/misc.c \
+bitwise_SOURCES= src/main.c src/misc.c src/compat.c\
 				 src/interactive.c src/cmd.c \
 				 src/stack.c src/shunting-yard.c \
-				 src/help.c inc/bitwise.h inc/stack.h \
-				 inc/shunting-yard.h
+				 src/help.c inc/bitwise.h \
+				 inc/stack.h inc/shunting-yard.h
 
 dist_man_MANS=bitwise.1
 
@@ -24,7 +24,7 @@ AM_CFLAGS = $(MAYBE_COVERAGE) $(MAYBE_DEBUG) $(MAYBE_TRACE)
 check_PROGRAMS = tests/test-shunting-yard
 tests_test_shunting_yard_SOURCES = src/shunting-yard.c inc/shunting-yard.h \
                                    src/stack.c inc/stack.h inc/bitwise.h \
-								   src/misc.c \
+				   src/misc.c src/compat.c \
                                    tests/test-shunting-yard.c
 tests_test_shunting_yard_LDADD = -lcunit
 

README.md

@@ -156,7 +156,7 @@ brew install bitwise
 ```
 
 ### Windows
-NCurses doesn't support Windows. You can use the Windows Subsystem for Linux as a workaround.
+Bitwise is possible to compile on Windows under mingw or msys2
 
 ### Nix
 ```

configure.ac

@@ -25,13 +25,17 @@ if test "$ac_cv_have_readline" = no; then
     AC_MSG_ERROR([requires readline library])
 fi
 
+# Checks for header files. Ncurses is a bit of a mess in windows/mingw, has form in separate include location
+AC_CHECK_HEADERS([fcntl.h inttypes.h stdint.h stdlib.h string.h curses.h form.h ncursesw/ncurses.h ncursesw/form.h])
+
 # Checks for libraries.
 AC_CHECK_LIB([form], [form_driver])
+AC_CHECK_LIB([formw], [form_driver])
 AC_CHECK_LIB([ncurses], [newwin])
+AC_CHECK_LIB([ncursesw], [newwin])
 AC_SEARCH_LIBS([sqrt], [m])
 
-# Checks for header files.
-AC_CHECK_HEADERS([fcntl.h inttypes.h stdint.h stdlib.h string.h curses.h form.h])
+
 
 AC_CHECK_DECLS([bswap_32], [], [], [[#include <byteswap.h>]])
 AM_CONDITIONAL(HAVE_BYTESWAP_H, [test "x$ac_cv_have_decl_bswap_32" = "xyes"])
@@ -42,7 +46,7 @@ AC_TYPE_UINT64_T
 
 # Checks for library functions.
 AC_FUNC_STRCOLL
-AC_CHECK_FUNCS([memchr memmove memset stpcpy strchr strcspn strdup strerror strpbrk strrchr strspn strstr])
+AC_CHECK_FUNCS([memchr memmove memset stpcpy strchr strcspn strdup strndup strerror strpbrk strrchr strspn strstr l64a])
 
 # Then check for the variable considering both possible locations
 AC_CHECK_DECL([rl_change_environment],

inc/bitwise.h

@@ -9,11 +9,15 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdbool.h>
-#include <form.h>
 #include <string.h>
 #include "config.h"
+#include "compat.h"
+#if defined(HAVE_NCURSESW_FORM_H)
+#include <ncursesw/form.h>
+#else
+#include <form.h>
+#endif
 /* Readine checks */
-
 #ifdef HAVE_LIBREADLINE
 #  if defined(HAVE_READLINE_READLINE_H)
 #    include <readline/readline.h>
@@ -68,6 +72,7 @@ int sprintf_type(uint64_t val, char *buf, output_type type);
 
 void init_terminal(void);
 void deinit_terminal(void);
+const char *ipv4_to_str(uint32_t ip, char out[static 16]);
 
 /* Interactive */
 extern FORM *form;

inc/compat.h

@@ -0,0 +1,14 @@
+#ifndef COMPAT_H
+#define COMPAT_H
+// Functions needed to substitute some POSIX extensions on Windows/MinGW
+
+#ifndef HAVE_STRNDUP
+char *strndup(const char *s, size_t n);
+#endif
+
+#ifndef HAVE_L64A
+char *l64a(long value);
+#endif
+
+#endif
+

src/compat.c

@@ -0,0 +1,56 @@
+#include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <stdint.h>
+
+#ifndef HAVE_STRNDUP
+char *strndup(const char *s, size_t n)
+{
+    char *copy;
+    size_t len;
+
+    if (!s) {
+        return NULL;  // Handle NULL input safely
+    }
+
+    // Determine the number of characters to copy (up to n or up to '\0')
+    len = 0;
+    while (len < n && s[len] != '\0') {
+        len++;
+    }
+
+    // Prevent overflow: len + 1 must not overflow size_t
+    if (len == SIZE_MAX) {
+        return NULL; // extremely unlikely but technically correct
+    }
+
+    copy = (char *)malloc(len + 1);
+    if (!copy) {
+        return NULL;
+    }
+
+    memcpy(copy, s, len);
+    copy[len] = '\0';
+    return copy;
+}
+#endif
+
+
+#ifndef HAVE_L64A
+char *l64a(long value)
+{
+    static char buf[7];
+    static const char tbl[] =
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+    int i = 0;
+    if (value == 0) {
+        buf[i++] = '.';
+    } else {        while (value && i < 6) {
+            buf[i++] = tbl[value & 0x3F];
+            value >>= 6;
+        }
+    }
+    buf[i] = '\0';
+    return buf;
+}
+#endif

src/interactive.c

@@ -3,7 +3,6 @@
  */
 
 #include <stdlib.h>
-#include <form.h>
 #include <ctype.h>
 #include <stdint.h>
 #include <inttypes.h>
@@ -14,6 +13,11 @@
 #include <sys/stat.h>
 #include <math.h>
 #include "bitwise.h"
+#if defined(HAVE_NCURSESW_FORM_H)
+#include <ncursesw/form.h>
+#else
+#include <form.h>
+#endif
 
 #define MAX_DEC_DIGITS_64 20
 #define MAX_HEX_DIGITS_64 16

src/main.c

@@ -8,7 +8,6 @@
 #include <stdint.h>
 #include <getopt.h>
 #include <locale.h>
-#include <arpa/inet.h>
 #include <limits.h>
 
 #ifdef HAVE_DECL_BSWAP_32
@@ -23,14 +22,12 @@
 #include "bitwise.h"
 #include "shunting-yard.h"
 
-
 int print_conversions(uint64_t val, bool si)
 {
 	char buf_size[16];
 	char binary[512];
 	int pos = 0;
 	int i, j;
-	struct in_addr ip_addr;
 
 	buf_size[0] = '\0';
 	sprintf_size(val, buf_size, si);
@@ -69,10 +66,10 @@ int print_conversions(uint64_t val, bool si)
 	if (val > UINT_MAX) {
 		printf("%sIPv4: %s%s\n", color_green, color_blue, "Value too big to be a valid IPv4 address");
 	} else {
-		ip_addr.s_addr = val;
-		printf("%sIPv4 (Network byte order - Big): %s %s\n", color_green, color_blue, inet_ntoa(ip_addr));
-		ip_addr.s_addr = bswap_32(val);
-		printf("%sIPv4 (Reversed byte order - Little): %s %s\n", color_green, color_blue, inet_ntoa(ip_addr));
+		char ipstrbuf[16];
+		printf("%sIPv4 (Network byte order - Big): %s %s\n", color_green, color_blue, ipv4_to_str(val, ipstrbuf));
+		const uint64_t reversedval = bswap_32(val);
+		printf("%sIPv4 (Reversed byte order - Little): %s %s\n", color_green, color_blue, ipv4_to_str(reversedval, ipstrbuf));
 	}
 
 	printf("%sASCII: %s", color_green, color_blue);

src/misc.c

@@ -360,3 +360,17 @@ int set_width(char width)
 
 	return 0;
 }
+
+
+const char *
+ipv4_to_str(uint32_t ip, char out[static 16])
+{
+    const unsigned char b0 = (ip >> 24) & 0xFF;
+    const unsigned char b1 = (ip >> 16) & 0xFF;
+    const unsigned char b2 = (ip >> 8)  & 0xFF;
+    const unsigned char b3 = ip & 0xFF;
+
+    snprintf(out, 16, "%u.%u.%u.%u", b0, b1, b2, b3);
+    return out;
+}
+