Split reading/writing preferences into OS specific files

This adds tested code for Linux and Mac OS, implementing the api that
Linus suggested.

The Windows code was moved into its own file, but hasn't even been compile
tested, yet.

In order to have just one interface to set or get a preference value we
encode TRUE as (void *) 1 and FALSE as NULL. This works consistently on
all platforms and regardless of whether we have 32 or 64 bit.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

6 files changed, 285 insertions, 187 deletions

diff --git a/Makefile b/Makefile
index edad32ce4..0b0dd2f5f 100644
--- a/Makefile
+++ b/Makefile
@@ -80,11 +80,39 @@ LIBGTK = $(shell $(PKGCONFIG) --libs gtk+-2.0 glib-2.0 gconf-2.0)
 LIBDIVECOMPUTERCFLAGS = $(LIBDIVECOMPUTERINCLUDES)
 LIBDIVECOMPUTER = $(LIBDIVECOMPUTERARCHIVE) $(LIBUSB)
 
+LIBXML2 = $(shell $(XML2CONFIG) --libs)
+LIBXSLT = $(shell $(XSLCONFIG) --libs)
+XML2CFLAGS = $(shell $(XML2CONFIG) --cflags)
+GLIB2CFLAGS = $(shell $(PKGCONFIG) --cflags glib-2.0)
+GCONF2CFLAGS =  $(shell $(PKGCONFIG) --cflags gconf-2.0)
+GTK2CFLAGS = $(shell $(PKGCONFIG) --cflags gtk+-2.0)
+CFLAGS += $(shell $(XSLCONFIG) --cflags)
+
+UNAME := $(shell uname)
+
+ifeq ($(UNAME), Linux)
+	OSSUPPORT = linux
+	OSSUPPORT_CFLAGS = $(GTK2CFLAGS) $(GCONF2CFLAGS)
+else ifeq ($(UNAME), Darwin)
+	OSSUPPORT = macos
+	OSSUPPORT_CFLAGS = $(GTK2CFLAGS)
+else
+	OSSUPPORT = windows
+	OSSUPPORT_CFLAGS = $(GTK2CFLAGS)
+endif
+
+ifneq ($(strip $(LIBXSLT)),)
+	# We still need proper paths and install options for OSX and Windows
+	ifeq ($(shell sh -c 'uname -s 2>/dev/null || echo not'),Linux)
+		XSLT=-DXSLT='"$(XSLTDIR)"'
+	endif
+endif
+
 LIBS = $(LIBXML2) $(LIBXSLT) $(LIBGTK) $(LIBDIVECOMPUTER) -lpthread
 
 OBJS =	main.o dive.o profile.o info.o equipment.o divelist.o \
 	parse-xml.o save-xml.o libdivecomputer.o print.o uemis.o \
-	gtk-gui.o statistics.o $(RESFILE)
+	gtk-gui.o statistics.o $(OSSUPPORT).o $(RESFILE)
 
 $(NAME): $(OBJS)
 	$(CC) $(LDFLAGS) -o $(NAME) $(OBJS) $(LIBS)
@@ -107,21 +135,6 @@ install: $(NAME)
 		$(INSTALL) -m 644 $(XSLTFILES) $(XSLTDIR); \
 	fi
 
-LIBXML2 = $(shell $(XML2CONFIG) --libs)
-LIBXSLT = $(shell $(XSLCONFIG) --libs)
-XML2CFLAGS = $(shell $(XML2CONFIG) --cflags)
-GLIB2CFLAGS = $(shell $(PKGCONFIG) --cflags glib-2.0)
-GCONF2CFLAGS =  $(shell $(PKGCONFIG) --cflags gconf-2.0)
-GTK2CFLAGS = $(shell $(PKGCONFIG) --cflags gtk+-2.0)
-CFLAGS += $(shell $(XSLCONFIG) --cflags)
-
-ifneq ($(strip $(LIBXSLT)),)
-	# We still need proper paths and install options for OSX and Windows
-	ifeq ($(shell sh -c 'uname -s 2>/dev/null || echo not'),Linux)
-		XSLT=-DXSLT='"$(XSLTDIR)"'
-	endif
-endif
-
 install-macosx: $(NAME)
 	$(INSTALL) -d -m 755 $(MACOSXINSTALL)/Contents/Resources
 	$(INSTALL) -d -m 755 $(MACOSXINSTALL)/Contents/MacOS
@@ -176,5 +189,8 @@ gtk-gui.o: gtk-gui.c dive.h display.h divelist.h display-gtk.h libdivecomputer.h
 uemis.o: uemis.c dive.h uemis.h
 	$(CC) $(CFLAGS) $(GTK2CFLAGS) $(GLIB2CFLAGS) $(XML2CFLAGS) -c uemis.c
 
+$(OSSUPPORT).o: $(OSSUPPORT).c display-gtk.h
+	$(CC) $(CFLAGS) $(OSSUPPORT_CFLAGS) -c $(OSSUPPORT).c
+
 clean:
 	rm -f $(OBJS) *~ $(NAME)
diff --git a/display-gtk.h b/display-gtk.h
index 56fd5c4d9..9e5093d40 100644
--- a/display-gtk.h
+++ b/display-gtk.h
@@ -19,6 +19,19 @@ typedef struct {
 	gboolean otu;
 } visible_cols_t;
 
+typedef enum {
+	PREF_BOOL,
+	PREF_STRING
+} pref_type_t;
+
+#define BOOL_TO_PTR(_cond) ((_cond) ? (void *)1 : NULL)
+#define PTR_TO_BOOL(_ptr) ((_ptr) != NULL)
+
+extern void subsurface_open_conf(void);
+extern void subsurface_set_conf(char *name, pref_type_t type, const void *value);
+extern const void *subsurface_get_conf(char *name, pref_type_t type);
+extern void subsurface_close_conf(void);
+
 extern visible_cols_t visible_cols;
 
 extern const char *divelist_font;
diff --git a/gtk-gui.c b/gtk-gui.c
index e740357cd..22f6870dd 100644
--- a/gtk-gui.c
+++ b/gtk-gui.c
@@ -8,15 +8,6 @@
 #include <stdlib.h>
 #include <time.h>
 
-#if defined __linux__
-#include <gconf/gconf-client.h>
-#elif defined WIN32
-#include <windows.h>
-#elif defined __APPLE__
-#include <CoreFoundation/CoreFoundation.h>
-static CFURLRef fileURL;
-#endif
-
 #include "dive.h"
 #include "divelist.h"
 #include "display.h"
@@ -33,11 +24,6 @@ int        error_count;
 #define DIVELIST_DEFAULT_FONT "Sans 8"
 const char *divelist_font;
 
-#ifdef __linux__
-GConfClient *gconf;
-#define GCONF_NAME(x) "/apps/subsurface/" #x
-#endif
-
 struct units output_units;
 
 static GtkWidget *dive_profile;
@@ -409,74 +395,18 @@ static void preferences_dialog(GtkWidget *w, gpointer data)
 		update_dive_list_units();
 		repaint_dive();
 		update_dive_list_col_visibility();
-#ifdef __linux__
-		gconf_client_set_bool(gconf, GCONF_NAME(feet), output_units.length == FEET, NULL);
-		gconf_client_set_bool(gconf, GCONF_NAME(psi), output_units.pressure == PSI, NULL);
-		gconf_client_set_bool(gconf, GCONF_NAME(cuft), output_units.volume == CUFT, NULL);
-		gconf_client_set_bool(gconf, GCONF_NAME(fahrenheit), output_units.temperature == FAHRENHEIT, NULL);
-		gconf_client_set_bool(gconf, GCONF_NAME(TEMPERATURE), visible_cols.temperature, NULL);
-		gconf_client_set_bool(gconf, GCONF_NAME(CYLINDER), visible_cols.cylinder, NULL);
-		gconf_client_set_bool(gconf, GCONF_NAME(NITROX), visible_cols.nitrox, NULL);
-		gconf_client_set_bool(gconf, GCONF_NAME(SAC), visible_cols.sac, NULL);
-		gconf_client_set_bool(gconf, GCONF_NAME(OTU), visible_cols.otu, NULL);
-		gconf_client_set_string(gconf, GCONF_NAME(divelist_font), divelist_font, NULL);
-#elif defined __APPLE__
-#define STRING_BOOL(_cond) (_cond) ? CFSTR("1") : CFSTR("0")
-
-		CFPropertyListRef propertyList;
-		CFMutableDictionaryRef dict;
-		CFDataRef xmlData;
-		CFStringRef cf_divelist_font;
-		Boolean status;
-		SInt32 errorCode;
-
-		dict = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks,
-						&kCFTypeDictionaryValueCallBacks);
-		CFDictionarySetValue(dict, CFSTR("feet"), STRING_BOOL(output_units.length == FEET));
-		CFDictionarySetValue(dict, CFSTR("psi"), STRING_BOOL(output_units.pressure == PSI));
-		CFDictionarySetValue(dict, CFSTR("cuft"), STRING_BOOL(output_units.volume == CUFT));
-		CFDictionarySetValue(dict, CFSTR("fahrenheit"), STRING_BOOL(output_units.temperature == FAHRENHEIT));
-		CFDictionarySetValue(dict, CFSTR("TEMPERATURE"), STRING_BOOL(visible_cols.temperature));
-		CFDictionarySetValue(dict, CFSTR("CYLINDER"), STRING_BOOL(visible_cols.cylinder));
-		CFDictionarySetValue(dict, CFSTR("NITROX"), STRING_BOOL(visible_cols.nitrox));
-		CFDictionarySetValue(dict, CFSTR("SAC"), STRING_BOOL(visible_cols.sac));
-		CFDictionarySetValue(dict, CFSTR("OTU"), STRING_BOOL(visible_cols.otu));
-		cf_divelist_font = CFStringCreateWithCString(kCFAllocatorDefault, divelist_font, 1);
-		CFDictionarySetValue(dict, CFSTR("divelist_font"), cf_divelist_font);
-		propertyList = dict;
-		xmlData = CFPropertyListCreateXMLData(kCFAllocatorDefault, propertyList);
-		status = CFURLWriteDataAndPropertiesToResource (fileURL, xmlData, NULL, &errorCode);
-		// some error handling
-		CFRelease(xmlData);
-		CFRelease(propertyList);
-#elif defined WIN32
-		HKEY hkey;
-		LONG success = RegCreateKeyEx(HKEY_CURRENT_USER, TEXT("Software\\subsurface"),
-					0L, NULL, REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS,
-					NULL, &hkey, NULL);
-		if (success != ERROR_SUCCESS)
-			printf("CreateKey Software\\subsurface failed %ld\n", success);
-		DWORD value;
-
-#define StoreInReg(_key, _val) { \
-			value = (_val) ;				\
-			RegSetValueEx(hkey, TEXT(_key), 0, REG_DWORD, &value, 4); \
-		}
 
-		StoreInReg("feet", output_units.length == FEET);
-		StoreInReg("psi",  output_units.pressure == PSI);
-		StoreInReg("cuft", output_units.volume == CUFT);
-		StoreInReg("fahrenheit", output_units.temperature == FAHRENHEIT);
-		StoreInReg("temperature", visible_cols.temperature);
-		StoreInReg("cylinder", visible_cols.cylinder);
-		StoreInReg("nitrox", visible_cols.nitrox);
-		StoreInReg("sac", visible_cols.sac);
-		StoreInReg("otu", visible_cols.otu);
-		RegSetValueEx(hkey, TEXT("divelist_font"), 0, REG_SZ, divelist_font, strlen(divelist_font));
-		if (RegFlushKey(hkey) != ERROR_SUCCESS)
-			printf("RegFlushKey failed %ld\n");
-		RegCloseKey(hkey);
-#endif
+		subsurface_set_conf("feet", PREF_BOOL, BOOL_TO_PTR(output_units.length == FEET));
+		subsurface_set_conf("psi", PREF_BOOL, BOOL_TO_PTR(output_units.pressure == PSI));
+		subsurface_set_conf("cuft", PREF_BOOL, BOOL_TO_PTR(output_units.volume == CUFT));
+		subsurface_set_conf("fahrenheit", PREF_BOOL, BOOL_TO_PTR(output_units.temperature == FAHRENHEIT));
+		subsurface_set_conf("TEMPERATURE", PREF_BOOL, BOOL_TO_PTR(visible_cols.temperature));
+		subsurface_set_conf("CYLINDER", PREF_BOOL, BOOL_TO_PTR(visible_cols.cylinder));
+		subsurface_set_conf("NITROX", PREF_BOOL, BOOL_TO_PTR(visible_cols.nitrox));
+		subsurface_set_conf("SAC", PREF_BOOL, BOOL_TO_PTR(visible_cols.sac));
+		subsurface_set_conf("OTU", PREF_BOOL, BOOL_TO_PTR(visible_cols.otu));
+		subsurface_set_conf("divelist_font", PREF_STRING, divelist_font);
+		subsurface_close_conf();
 	}
 	gtk_widget_destroy(dialog);
 }
@@ -756,21 +686,6 @@ static gboolean drag_cb(GtkWidget *widget, GdkDragContext *context,
 	return TRUE;
 }
 
-#if defined WIN32
-static int get_from_registry(HKEY hkey, const char *key)
-{
-	DWORD value;
-	DWORD len = 4;
-	LONG success;
-
-	success = RegQueryValueEx(hkey, TEXT(key), NULL, NULL,
-				(LPBYTE) &value, &len );
-	if (success != ERROR_SUCCESS)
-		return FALSE; /* that's what happens the first time we start */
-	return value;
-}
-#endif
-
 void init_ui(int *argcp, char ***argvp)
 {
 	GtkWidget *win;
@@ -795,86 +710,24 @@ void init_ui(int *argcp, char ***argvp)
 
 	g_type_init();
 
-#ifdef __linux__
-	gconf = gconf_client_get_default();
-
-	if (gconf_client_get_bool(gconf, GCONF_NAME(feet), NULL))
+	subsurface_open_conf();
+	if (subsurface_get_conf("feet", PREF_BOOL))
 		output_units.length = FEET;
-	if (gconf_client_get_bool(gconf, GCONF_NAME(psi), NULL))
+	if (subsurface_get_conf("psi", PREF_BOOL))
 		output_units.pressure = PSI;
-	if (gconf_client_get_bool(gconf, GCONF_NAME(cuft), NULL))
+	if (subsurface_get_conf("cuft", PREF_BOOL))
 		output_units.volume = CUFT;
-	if (gconf_client_get_bool(gconf, GCONF_NAME(fahrenheit), NULL))
+	if (subsurface_get_conf("fahrenheit", PREF_BOOL))
 		output_units.temperature = FAHRENHEIT;
 	/* an unset key is FALSE - all these are hidden by default */
-	visible_cols.cylinder = gconf_client_get_bool(gconf, GCONF_NAME(CYLINDER), NULL);
-	visible_cols.temperature = gconf_client_get_bool(gconf, GCONF_NAME(TEMPERATURE), NULL);
-	visible_cols.nitrox = gconf_client_get_bool(gconf, GCONF_NAME(NITROX), NULL);
-	visible_cols.otu = gconf_client_get_bool(gconf, GCONF_NAME(OTU), NULL);
-	visible_cols.sac = gconf_client_get_bool(gconf, GCONF_NAME(SAC), NULL);
-		
-	divelist_font = gconf_client_get_string(gconf, GCONF_NAME(divelist_font), NULL);
-#elif defined WIN32
-	DWORD len = 4;
-	LONG success;
-	HKEY hkey;
-
-	success = RegOpenKeyEx(	HKEY_CURRENT_USER, TEXT("Software\\subsurface"), 0,
-			KEY_QUERY_VALUE, &hkey);
-
-	output_units.length = get_from_registry(hkey, "feet");
-	output_units.pressure = get_from_registry(hkey, "psi");
-	output_units.volume = get_from_registry(hkey, "cuft");
-	output_units.temperature = get_from_registry(hkey, "fahrenheit");
-	visible_cols.temperature = get_from_registry(hkey, "temperature");
-	visible_cols.cylinder = get_from_registry(hkey, "cylinder");
-	visible_cols.nitrox = get_from_registry(hkey, "nitrox");
-	visible_cols.sac = get_from_registry(hkey, "sac");
-	visible_cols.otu = get_from_registry(hkey, "otu");
-
-	divelist_font = malloc(80);
-	len = 80;
-	success = RegQueryValueEx(hkey, TEXT("divelist_font"), NULL, NULL,
-				(LPBYTE) divelist_font, &len );
-	if (success != ERROR_SUCCESS) {
-		/* that's what happens the first time we start - just use the default */
-		free(divelist_font);
-		divelist_font = NULL;
-	}
-	RegCloseKey(hkey);
-#elif defined __APPLE__
-#define BOOL_FROM_CFSTRING(_pl,_key) \
-	strcmp("0", CFStringGetCStringPtr(CFDictionaryGetValue(_pl, CFSTR(_key)), 0) ? : "")
-
-	CFPropertyListRef propertyList;
-	CFStringRef errorString;
-	CFDataRef resourceData;
-	Boolean status;
-	SInt32 errorCode;
-
-	fileURL = CFURLCreateWithFileSystemPath(kCFAllocatorDefault,
-						CFSTR("subsurface.pref"),// file path name
-						kCFURLPOSIXPathStyle,    // interpret as POSIX path
-						false );                 // is it a directory?
-
-	status = CFURLCreateDataAndPropertiesFromResource(kCFAllocatorDefault,
-							fileURL, &resourceData,
-							NULL, NULL, &errorCode);
-	propertyList = CFPropertyListCreateFromXMLData(kCFAllocatorDefault,
-						resourceData, kCFPropertyListImmutable,
-						&errorString);
-	CFRelease(resourceData);
-	output_units.length = BOOL_FROM_CFSTRING(propertyList, "feet") ? FEET : METERS;
-	output_units.pressure = BOOL_FROM_CFSTRING(propertyList, "psi") ? PSI : BAR;
-	output_units.volume = BOOL_FROM_CFSTRING(propertyList, "cuft") ? CUFT : LITER;
-	output_units.temperature = BOOL_FROM_CFSTRING(propertyList, "fahrenheit") ? FAHRENHEIT : CELSIUS;
-	visible_cols.temperature = BOOL_FROM_CFSTRING(propertyList, "TEMPERATURE");
-	visible_cols.cylinder = BOOL_FROM_CFSTRING(propertyList, "CYLINDER");
-	visible_cols.nitrox = BOOL_FROM_CFSTRING(propertyList, "NITROX");
-	visible_cols.sac = BOOL_FROM_CFSTRING(propertyList, "SAC");
-	visible_cols.otu = BOOL_FROM_CFSTRING(propertyList, "OTU");
-	CFRelease(propertyList);
-#endif
+	visible_cols.cylinder = PTR_TO_BOOL(subsurface_get_conf("CYLINDER", PREF_BOOL));
+	visible_cols.temperature = PTR_TO_BOOL(subsurface_get_conf("TEMPERATURE", PREF_BOOL));
+	visible_cols.nitrox = PTR_TO_BOOL(subsurface_get_conf("NITROX", PREF_BOOL));
+	visible_cols.otu = PTR_TO_BOOL(subsurface_get_conf("OTU", PREF_BOOL));
+	visible_cols.sac = PTR_TO_BOOL(subsurface_get_conf("SAC", PREF_BOOL));
+
+	divelist_font = subsurface_get_conf("divelist_font", PREF_STRING);
+
 	if (!divelist_font)
 		divelist_font = DIVELIST_DEFAULT_FONT;
 
diff --git a/linux.c b/linux.c
new file mode 100644
index 000000000..2edcf85a1
--- /dev/null
+++ b/linux.c
@@ -0,0 +1,48 @@
+/* linux.c */
+/* implements Linux specific functions */
+#include "display-gtk.h"
+#include <gconf/gconf-client.h>
+
+GConfClient *gconf;
+
+static char *gconf_name(char *name)
+{
+	static char buf[255] = "/apps/subsurface/";
+
+	snprintf(buf, 255, "/apps/subsurface/%s", name);
+
+	return buf;
+}
+
+void subsurface_open_conf(void)
+{
+	gconf = gconf_client_get_default();
+}
+
+void subsurface_set_conf(char *name, pref_type_t type, const void *value)
+{
+	switch (type) {
+	case PREF_BOOL:
+		gconf_client_set_bool(gconf, gconf_name(name), value != NULL, NULL);
+		break;
+	case PREF_STRING:
+		gconf_client_set_string(gconf, gconf_name(name), value, NULL);
+	}
+}
+
+const void *subsurface_get_conf(char *name, pref_type_t type)
+{
+	switch (type) {
+	case PREF_BOOL:
+		return gconf_client_get_bool(gconf, gconf_name(name), NULL) ? (void *) 1 : NULL;
+	case PREF_STRING:
+		return gconf_client_get_string(gconf, gconf_name(name), NULL);
+	}
+	/* we shouldn't get here */
+	return NULL;
+}
+
+void subsurface_close_conf(void)
+{
+	/* this is a no-op */
+}
diff --git a/macos.c b/macos.c
new file mode 100644
index 000000000..b48f20d87
--- /dev/null
+++ b/macos.c
@@ -0,0 +1,91 @@
+/* macos.c */
+/* implements Mac OS X specific functions */
+#include "display-gtk.h"
+#include <CoreFoundation/CoreFoundation.h>
+
+static CFURLRef fileURL;
+static CFPropertyListRef propertyList;
+static CFMutableDictionaryRef dict = NULL;
+
+/* macos defines CFSTR to create a CFString object from a constant,
+ * but no similar macros if a C string variable is supposed to be
+ * the argument. We add this here (hardcoding the default allocator
+ * and MacRoman encoding */
+#define CFSTR_VAR(_var) CFStringCreateWithCStringNoCopy(kCFAllocatorDefault,	\
+					(_var), kCFStringEncodingMacRoman,	\
+					kCFAllocatorNull)
+
+void subsurface_open_conf(void)
+{
+	CFStringRef errorString;
+	CFDataRef resourceData;
+	Boolean status;
+	SInt32 errorCode;
+
+	fileURL = CFURLCreateWithFileSystemPath(kCFAllocatorDefault,
+						CFSTR("subsurface.pref"),// file path name
+						kCFURLPOSIXPathStyle,    // interpret as POSIX path
+						false );                 // is it a directory?
+
+	status = CFURLCreateDataAndPropertiesFromResource(kCFAllocatorDefault,
+							fileURL, &resourceData,
+							NULL, NULL, &errorCode);
+	if (status) {
+		propertyList = CFPropertyListCreateFromXMLData(kCFAllocatorDefault,
+							resourceData, kCFPropertyListImmutable,
+							&errorString);
+		CFRelease(resourceData);
+	}
+}
+
+void subsurface_set_conf(char *name, pref_type_t type, const void *value)
+{
+	if (!dict)
+		dict = CFDictionaryCreateMutable(kCFAllocatorDefault, 0,
+						&kCFTypeDictionaryKeyCallBacks,
+						&kCFTypeDictionaryValueCallBacks);
+	switch (type) {
+	case PREF_BOOL:
+		CFDictionarySetValue(dict, CFSTR_VAR(name), value == NULL ? CFSTR("0") : CFSTR("1"));
+		break;
+	case PREF_STRING:
+		CFDictionarySetValue(dict, CFSTR_VAR(name), CFSTR_VAR(value));
+	}
+}
+const void *subsurface_get_conf(char *name, pref_type_t type)
+{
+	CFStringRef dict_entry;
+
+	/* if no settings exist, we return the value for FALSE */
+	if (!propertyList)
+		return NULL;
+
+	switch (type) {
+	case PREF_BOOL:
+		dict_entry = CFDictionaryGetValue(propertyList, CFSTR_VAR(name));
+		if (dict_entry && ! CFStringCompare(CFSTR("1"), dict_entry, 0))
+			return (void *) 1;
+		else
+			return NULL;
+	case PREF_STRING:
+		return CFStringGetCStringPtr(CFDictionaryGetValue(propertyList,
+						CFSTR_VAR(name)), kCFStringEncodingMacRoman);
+	}
+	/* we shouldn't get here, but having this line makes the compiler happy */
+	return NULL;
+}
+
+void subsurface_close_conf(void)
+{
+	Boolean status;
+	SInt32 errorCode;
+	CFDataRef xmlData;
+
+	propertyList = dict;
+	dict = NULL;
+	xmlData = CFPropertyListCreateXMLData(kCFAllocatorDefault, propertyList);
+	status = CFURLWriteDataAndPropertiesToResource (fileURL, xmlData, NULL, &errorCode);
+	// some error handling - but really, what can we do?
+	CFRelease(xmlData);
+	CFRelease(propertyList);
+}
diff --git a/windows.c b/windows.c
new file mode 100644
index 000000000..df04aa0f2
--- /dev/null
+++ b/windows.c
@@ -0,0 +1,77 @@
+/* windows.c */
+/* implements Windows specific functions */
+#include "display-gtk.h"
+#include <windows.h>
+
+static HKEY hkey;
+
+static int get_from_registry(HKEY hkey, const char *key)
+{
+	DWORD value;
+	DWORD len = 4;
+	LONG success;
+
+	success = RegQueryValueEx(hkey, TEXT(key), NULL, NULL,
+				(LPBYTE) &value, &len );
+	if (success != ERROR_SUCCESS)
+		return FALSE; /* that's what happens the first time we start */
+	return value;
+}
+
+void subsurface_open_conf(void)
+{
+	LONG success;
+
+	success = RegOpenKeyEx(HKEY_CURRENT_USER, TEXT("Software\\subsurface"), 0,
+			KEY_QUERY_VALUE, &hkey);
+	if (success != ERROR_SUCCESS) {
+		success = RegCreateKeyEx(HKEY_CURRENT_USER, TEXT("Software\\subsurface"),
+					0L, NULL, REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS,
+					NULL, &hkey, NULL);
+		if (success != ERROR_SUCCESS)
+			printf("CreateKey Software\\subsurface failed %ld\n", success);
+	}
+}
+
+void subsurface_set_conf(char *name, pref_type_t type, const void *value)
+{
+	switch (type) {
+	case PREF_BOOL:
+		/* we simply store the value as DWORD */
+		RegSetValueEx(hkey, TEXT(name), 0, REG_DWORD, (DWORD)value, 4);
+		break;
+	case PREF_STRING:
+		RegSetValueEx(hkey, TEXT(name), 0, REG_SZ, value, strlen(value));
+	}
+}
+
+const void *subsurface_get_conf(char *name, pref_type_t type)
+{
+	char *string;
+	int len;
+
+	switch (type) {
+	case PREF_BOOL:
+		return get_from_registry(hkey, name) ? (void *) 1 : NULL;
+	case PREF_STRING:
+		string = malloc(80);
+		len = 80;
+		success = RegQueryValueEx(hkey, TEXT(name), NULL, NULL,
+					(LPBYTE) string, &len );
+		if (success != ERROR_SUCCESS) {
+			/* that's what happens the first time we start - just return NULL */
+			free(string);
+			return NULL;
+		}
+		return string;
+	}
+	/* we shouldn't get here */
+	return NULL;
+}
+
+void subsurface_close_conf(void)
+{
+	if (RegFlushKey(hkey) != ERROR_SUCCESS)
+		printf("RegFlushKey failed %ld\n");
+	RegCloseKey(hkey);
+}