Introduce plat_get_skin_dir and update plat_get_root_dir functions

On GP2X and Pandora, plat_get_root_dir points to the directory
in which the PicoDrive executable is found. On regular Linux,
it now points to the '.picodrive' directory inside the user's home
folder.

plat_get_skin_dir now points to the 'skin' directory inside the
data directory.

The data directory can be set with PICO_DATA_DIR at compile time.
If that variable is not set, the data directory is set to the
directory of the PicoDrive executable.

linux/plat.c

@@ -19,6 +19,7 @@
 #include <unistd.h>
 #include <sys/mman.h>
 #include <errno.h>
+#include <sys/stat.h>
 
 #include "../plat.h"
 
@@ -40,24 +41,54 @@ int plat_is_dir(const char *path)
 	return 0;
 }
 
-int plat_get_root_dir(char *dst, int len)
+static int plat_get_data_dir(char *dst, int len)
 {
-	int j, ret;
-
-	ret = readlink("/proc/self/exe", dst, len - 1);
+#ifdef PICO_DATA_DIR
+	memcpy(dst, PICO_DATA_DIR, sizeof PICO_DATA_DIR);
+	return sizeof(PICO_DATA_DIR) - 1;
+#else
+	int j, ret = readlink("/proc/self/exe", dst, len - 1);
 	if (ret < 0) {
 		perror("readlink");
 		ret = 0;
 	}
 	dst[ret] = 0;
 
-	for (j = strlen(dst); j > 0; j--)
+	for (j = ret - 1; j > 0; j--)
 		if (dst[j] == '/') {
 			dst[++j] = 0;
 			break;
 		}
-
 	return j;
+#endif
+}
+
+int plat_get_skin_dir(char *dst, int len)
+{
+	int ret = plat_get_data_dir(dst, len);
+	if (ret < 0)
+		return ret;
+
+	memcpy(dst + ret, "skin/", sizeof "skin/");
+	return ret + sizeof("skin/") - 1;
+}
+
+#ifndef PICO_HOME_DIR
+#define PICO_HOME_DIR "/.picodrive/"
+#endif
+int plat_get_root_dir(char *dst, int len)
+{
+#if defined(__GP2X__) || defined(PANDORA)
+	return plat_get_data_dir(dst, len);
+#else
+	char *home = getenv("HOME");
+	size_t nb = strlen(home);
+
+	memcpy(dst, home, nb);
+	memcpy(dst + nb, PICO_HOME_DIR, sizeof PICO_HOME_DIR);
+	mkdir(dst, 0755);
+	return nb + sizeof(PICO_HOME_DIR) - 1;
+#endif
 }
 
 #ifdef __GP2X__

menu.c

@@ -239,7 +239,7 @@ static char tolower_simple(char c)
 
 void menu_init_base(void)
 {
-	int i, c, l;
+	int i, c, l, pos;
 	unsigned char *fd, *fds;
 	char buff[256];
 	FILE *f;
@@ -294,17 +294,18 @@ void menu_init_base(void)
 	}
 
 	// load custom font and selector (stored as 1st symbol in font table)
-	emu_make_path(buff, "skin/font.png", sizeof(buff));
+	pos = plat_get_skin_dir(buff, sizeof(buff));
+	strcpy(buff + pos, "font.png");
 	readpng(menu_font_data, buff, READPNG_FONT,
 		MENU_X2 ? 256 : 128, MENU_X2 ? 320 : 160);
 	// default selector symbol is '>'
 	memcpy(menu_font_data, menu_font_data + ((int)'>') * me_mfont_w * me_mfont_h / 2,
 		me_mfont_w * me_mfont_h / 2);
-	emu_make_path(buff, "skin/selector.png", sizeof(buff));
+	strcpy(buff + pos, "selector.png");
 	readpng(menu_font_data, buff, READPNG_SELECTOR, me_mfont_w, me_mfont_h);
 
 	// load custom colors
-	emu_make_path(buff, "skin/skin.txt", sizeof(buff));
+	strcpy(buff + pos, "skin.txt");
 	f = fopen(buff, "r");
 	if (f != NULL)
 	{

plat.h

@@ -104,6 +104,9 @@ void plat_video_wait_vsync(void);
 /* return the dir/ where configs, saves, bios, etc. are found */
 int  plat_get_root_dir(char *dst, int len);
 
+/* return the dir/ where skin files are found */
+int  plat_get_skin_dir(char *dst, int len);
+
 int  plat_is_dir(const char *path);
 int  plat_wait_event(int *fds_hnds, int count, int timeout_ms);
 void plat_sleep_ms(int ms);