Adds cheat support

Cheats use RetroArch .cht file format. Cheats are loaded from
[save_dir]/cheats/[name].cht, where name is the name of the ROM
without extension. Cheat menu only shows when cheat file is found.

7 files changed, 343 insertions, 12 deletions

diff --git a/Makefile b/Makefile
index e1db308..e67cb70 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ SYSROOT   = $(shell $(CC) --print-sysroot)
 
 PROCS     = -j4
 
-OBJS      = libpicofe/input.o libpicofe/in_sdl.o libpicofe/linux/in_evdev.o libpicofe/linux/plat.o libpicofe/fonts.o libpicofe/readpng.o libpicofe/config_file.o config.o core.o menu.o main.o options.o overrides.o scale.o unzip.o util.o
+OBJS      = libpicofe/input.o libpicofe/in_sdl.o libpicofe/linux/in_evdev.o libpicofe/linux/plat.o libpicofe/fonts.o libpicofe/readpng.o libpicofe/config_file.o cheat.o config.o core.o menu.o main.o options.o overrides.o scale.o unzip.o util.o
 
 BIN       = picoarch
 
diff --git a/cheat.c b/cheat.c
new file mode 100644
index 0000000..6b57993
--- /dev/null
+++ b/cheat.c
@@ -0,0 +1,224 @@
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "cheat.h"
+#include "main.h"
+#include "util.h"
+
+#define MAX_DESC_LEN 27
+#define MAX_LINE_LEN 52
+#define MAX_LINES 3
+
+static size_t parse_count(FILE *file) {
+	size_t count = 0;
+	fscanf(file, " cheats = %d\n", &count);
+	return count;
+}
+
+static const char *find_val(const char *start) {
+	start--;
+	while(!isspace(*++start))
+		;
+
+	while(isspace(*++start))
+		;
+
+	if (*start != '=')
+		return NULL;
+
+	while(isspace(*++start))
+		;
+
+	return start;
+}
+
+static int parse_bool(const char *ptr, int *out) {
+	if (!strncasecmp(ptr, "true", 4)) {
+		*out = 1;
+	} else if (!strncasecmp(ptr, "false", 5)) {
+		*out = 0;
+	} else {
+		return -1;
+	}
+
+	return 0;
+}
+
+static int parse_string(const char *ptr, char *buf, size_t len) {
+	int index = 0;
+	size_t input_len = strlen(ptr);
+
+	buf[0] = '\0';
+
+	if (*ptr++ != '"')
+		return -1;
+
+	while (*ptr != '\0' && *ptr != '"' && index < len - 1) {
+		if (*ptr == '\\' && index < input_len - 1) {
+			ptr++;
+			buf[index++] = *ptr++;
+		} else if (*ptr == '&' && !strncmp(ptr, "&quot;", 6)) {
+			buf[index++] = '"';
+			ptr += 6;
+		} else {
+			buf[index++] = *ptr++;
+		}
+	}
+
+	if (*ptr != '"') {
+		buf[0] = '\0';
+		return -1;
+	}
+
+	buf[index] = '\0';
+	return 0;
+}
+
+static int parse_cheats(struct cheats *cheats, FILE *file) {
+	int ret = -1;
+	char line[512];
+	char buf[512];
+	const char *ptr;
+
+	do {
+		if (!fgets(line, sizeof(line), file)) {
+			ret = 0;
+			break;
+		}
+
+		if (line[strlen(line) - 1] != '\n' && !feof(file)) {
+			PA_WARN("Cheat line too long\n");
+			continue;
+		}
+
+		if ((ptr = strstr(line, "cheat"))) {
+			int index = -1;
+			struct cheat *cheat;
+			size_t len;
+			sscanf(ptr, "cheat%d", &index);
+
+			if (index >= cheats->count)
+				continue;
+			cheat = &cheats->cheats[index];
+
+			if (strstr(ptr, "_desc")) {
+				ptr = find_val(ptr);
+				if (!ptr || parse_string(ptr, buf, sizeof(buf))) {
+					PA_WARN("Couldn't parse cheat %d description\n", index);
+					continue;
+				}
+
+				len = strlen(buf);
+				if (len == 0)
+					continue;
+
+				cheat->name = calloc(len+1, sizeof(char));
+				if (!cheat->name)
+					goto finish;
+
+				strncpy((char *)cheat->name, buf, len);
+				string_truncate((char *)cheat->name, MAX_DESC_LEN);
+
+				if (len >= MAX_DESC_LEN) {
+					cheat->info = calloc(len+1, sizeof(char));
+					if (!cheat->info)
+						goto finish;
+
+					strncpy((char *)cheat->info, buf, len);
+					string_wrap((char *)cheat->info, MAX_LINE_LEN, MAX_LINES);
+				}
+			} else if (strstr(ptr, "_code")) {
+				ptr = find_val(ptr);
+				if (!ptr || parse_string(ptr, buf, sizeof(buf))) {
+					PA_WARN("Couldn't parse cheat %d code\n", index);
+					continue;
+				}
+
+				len = strlen(buf);
+				if (len == 0)
+					continue;
+
+				cheat->code = calloc(len+1, sizeof(char));
+				if (!cheat->code)
+					goto finish;
+
+				strncpy((char *)cheat->code, buf, len);
+			} else if (strstr(ptr, "_enable")) {
+				ptr = find_val(ptr);
+				if (!ptr || parse_bool(ptr, &cheat->enabled)) {
+					PA_WARN("Couldn't parse cheat %d enabled\n", index);
+					continue;
+				}
+			}
+		}
+	} while(1);
+
+finish:
+	return ret;
+}
+
+struct cheats *cheats_load(const char *filename) {
+	int success = 0;
+	struct cheats *cheats = NULL;
+	FILE *file = NULL;
+	size_t i;
+
+	file = fopen(filename, "r");
+	if (!file)
+		goto finish;
+
+	PA_INFO("Loading cheats from %s\n", filename);
+
+	cheats = calloc(1, sizeof(struct cheats));
+	if (!cheats) {
+		PA_ERROR("Couldn't allocate memory for cheats\n");
+		goto finish;
+	}
+
+	cheats->count = parse_count(file);
+	if (cheats->count <= 0) {
+		PA_ERROR("Couldn't read cheat count\n");
+		goto finish;
+	}
+
+	cheats->cheats = calloc(cheats->count, sizeof(struct cheat));
+	if (!cheats->cheats) {
+		PA_ERROR("Couldn't allocate memory for cheats\n");
+		goto finish;
+	}
+
+	if (parse_cheats(cheats, file)) {
+		PA_ERROR("Error reading cheat %d\n", i);
+		goto finish;
+	}
+
+	success = 1;
+finish:
+
+	if (!success) {
+		cheats_free(cheats);
+		cheats = NULL;
+	}
+
+	if (file)
+		fclose(file);
+
+	return cheats;
+}
+
+void cheats_free(struct cheats *cheats) {
+	size_t i;
+	if (cheats) {
+		for (i = 0; i < cheats->count; i++) {
+			struct cheat *cheat = &cheats->cheats[i];
+			if (cheat) {
+				free((char *)cheat->name);
+				free((char *)cheat->info);
+				free((char *)cheat->code);
+			}
+		}
+		free(cheats->cheats);
+	}
+	free(cheats);
+}
diff --git a/cheat.h b/cheat.h
new file mode 100644
index 0000000..0f255b9
--- /dev/null
+++ b/cheat.h
@@ -0,0 +1,22 @@
+#ifndef __CHEAT_H_
+#define __CHEAT_H_
+
+#include <stdlib.h>
+
+struct cheat {
+	const char *name;
+	const char *info;
+	int enabled;
+	const char *code;
+};
+
+struct cheats {
+	int enabled;
+	size_t count;
+	struct cheat *cheats;
+};
+
+struct cheats *cheats_load(const char *filename);
+void cheats_free(struct cheats *cheats);
+
+#endif
diff --git a/core.c b/core.c
index 500145b..3a801e5 100644
--- a/core.c
+++ b/core.c
@@ -6,6 +6,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
+#include "cheat.h"
 #include "core.h"
 #include "libpicofe/input.h"
 #include "main.h"
@@ -19,6 +20,7 @@ struct core_cbs current_core;
 char core_path[MAX_PATH];
 char content_path[MAX_PATH];
 static struct string_list *extensions;
+struct cheats *cheats;
 
 double sample_rate;
 double frame_rate;
@@ -115,7 +117,7 @@ static void core_free_game_info(struct retro_game_info *game_info) {
 	}
 }
 
-static void gamepak_related_name(char *buf, size_t len, const char *new_extension)
+static void gamepak_related_name(char *buf, size_t len, const char *subdir, const char *new_extension)
 {
 	char filename[MAX_PATH];
 	char *dot;
@@ -127,13 +129,13 @@ static void gamepak_related_name(char *buf, size_t len, const char *new_extensio
 	if (dot)
 		*dot = 0;
 
-	snprintf(buf, len, "%s%s%s", save_dir, filename, new_extension);
+	snprintf(buf, len, "%s%s%s%s", save_dir, subdir, filename, new_extension);
 }
 
 void config_file_name(char *buf, size_t len, int is_game)
 {
 	if (is_game && content_path[0]) {
-		gamepak_related_name(buf, len, ".cfg");
+		gamepak_related_name(buf, len, "", ".cfg");
 	} else {
 		snprintf(buf, len, "%s%s", config_dir, "picoarch.cfg");
 	}
@@ -153,7 +155,7 @@ void sram_write(void) {
 		return;
 	}
 
-	gamepak_related_name(filename, MAX_PATH, ".sav");
+	gamepak_related_name(filename, MAX_PATH, "", ".sav");
 
 	sram_file = fopen(filename, "w");
 	if (!sram_file) {
@@ -182,7 +184,7 @@ void sram_read(void) {
 		return;
 	}
 
-	gamepak_related_name(filename, MAX_PATH, ".sav");
+	gamepak_related_name(filename, MAX_PATH, "", ".sav");
 
 	sram_file = fopen(filename, "r");
 	if (!sram_file) {
@@ -206,7 +208,7 @@ void state_file_name(char *name, size_t size, int slot) {
 	char extension[5] = {0};
 
 	snprintf(extension, 5, ".st%d", slot);
-	gamepak_related_name(name, MAX_PATH, extension);
+	gamepak_related_name(name, MAX_PATH, "", extension);
 }
 
 int state_read(void) {
@@ -676,6 +678,7 @@ int core_load_content(const char *path) {
 	struct retro_game_info game_info = {0};
 	struct retro_system_av_info av_info = {0};
 	int ret = -1;
+	char cheats_path[MAX_PATH] = {0};
 
 	if (core_load_game_info(path, &game_info)) {
 		goto finish;
@@ -686,6 +689,12 @@ int core_load_content(const char *path) {
 		goto finish;
 	}
 
+	gamepak_related_name(cheats_path, sizeof(cheats_path), "cheats/", ".cht");
+	if (cheats_path[0] != '\0') {
+		cheats = cheats_load(cheats_path);
+		core_apply_cheats(cheats);
+	}
+
 	sram_read();
 
 	current_core.retro_get_system_av_info(&av_info);
@@ -700,7 +709,7 @@ int core_load_content(const char *path) {
 	aspect_ratio = av_info.geometry.aspect_ratio;
 
 #ifdef MMENU
-	gamepak_related_name(save_template_path, MAX_PATH, ".st%i");
+	gamepak_related_name(save_template_path, MAX_PATH, "", ".st%i");
 #endif
 
 	ret = 0;
@@ -709,9 +718,27 @@ finish:
 	return ret;
 }
 
+void core_apply_cheats(struct cheats *cheats) {
+	if (!cheats)
+		return;
+
+	if (!current_core.retro_cheat_reset || !current_core.retro_cheat_set)
+		return;
+
+	current_core.retro_cheat_reset();
+	for (int i = 0; i < cheats->count; i++) {
+		if (cheats->cheats[i].enabled) {
+			current_core.retro_cheat_set(i, cheats->cheats[i].enabled, cheats->cheats[i].code);
+		}
+	}
+}
+
 void core_unload_content(void) {
 	sram_write();
 
+	cheats_free(cheats);
+	cheats = NULL;
+
 	current_core.retro_unload_game();
 	if (temp_rom[0]) {
 		remove(temp_rom);
diff --git a/core.h b/core.h
index 34143ef..8958e9e 100644
--- a/core.h
+++ b/core.h
@@ -1,6 +1,7 @@
 #ifndef _CORE_H__
 #define _CORE_H__
 
+#include "cheat.h"
 #include "libretro.h"
 #include "main.h"
 
@@ -32,6 +33,7 @@ struct core_cbs {
 extern struct core_cbs current_core;
 extern char core_path[MAX_PATH];
 extern char content_path[MAX_PATH];
+extern struct cheats *cheats;
 
 extern double sample_rate;
 extern double frame_rate;
@@ -60,6 +62,7 @@ bool disc_replace_index(unsigned index, const char *content_path);
 void core_extract_name(const char* core_file, char *buf, size_t len);
 int core_load(const char *corefile);
 int core_load_content(const char *path);
+void core_apply_cheats(struct cheats *cheats);
 void core_unload_content(void);
 const char **core_extensions(void);
 void core_unload(void);
diff --git a/main.c b/main.c
index c1df689..08f83d1 100644
--- a/main.c
+++ b/main.c
@@ -553,10 +553,9 @@ int main(int argc, char **argv) {
 		if (ResumeSlot) resume_slot = ResumeSlot();
 	}
 #endif
-
+	show_startup_message();
 	state_resume();
 
-	show_startup_message();
 	do {
 		count_fps();
 		adjust_audio();
diff --git a/menu.c b/menu.c
index 6ba1488..2674007 100644
--- a/menu.c
+++ b/menu.c
@@ -26,6 +26,7 @@ typedef enum
 	MA_MAIN_SAVE_STATE,
 	MA_MAIN_LOAD_STATE,
 	MA_MAIN_DISC_CTRL,
+	MA_MAIN_CHEATS,
 	MA_MAIN_CORE_SEL,
 	MA_MAIN_CONTENT_SEL,
 	MA_MAIN_RESET_GAME,
@@ -365,6 +366,60 @@ static int menu_loop_disc(int id, int keys)
 	return 0;
 }
 
+static int menu_loop_cheats_page(int offset, int keys) {
+	static int sel = 0;
+	menu_entry *e_menu_cheats;
+	size_t i, menu_idx;
+
+	/* cheats + 2 for possible "Next page" +  NULL */
+	e_menu_cheats = (menu_entry *)calloc(cheats->count + 2, sizeof(menu_entry));
+
+	if (!e_menu_cheats) {
+		PA_ERROR("Error allocating cheats\n");
+		return 0;
+	}
+
+	for (i = offset, menu_idx = 0; i < cheats->count && menu_idx < MENU_ITEMS_PER_PAGE; i++) {
+		struct cheat *cheat = &cheats->cheats[i];
+		menu_entry *option;
+
+		option = &e_menu_cheats[menu_idx];
+
+		option->name = cheat->name;
+		option->beh = MB_OPT_ONOFF;
+		option->var = &cheat->enabled;
+		option->enabled = 1;
+		option->mask = 1;
+		option->need_to_save = 1;
+		option->selectable = 1;
+		option->help = cheat->info;
+		menu_idx++;
+	}
+
+	if (i < cheats->count) {
+		menu_entry *option;
+		option = &e_menu_cheats[menu_idx];
+		option->name = "Next page";
+		option->beh = MB_OPT_CUSTOM;
+		option->id = i;
+		option->enabled = 1;
+		option->selectable = 1;
+		option->handler = menu_loop_cheats_page;
+	}
+
+	me_loop(e_menu_cheats, &sel);
+	free(e_menu_cheats);
+
+	return 0;
+}
+
+static int menu_loop_cheats(int id, int keys)
+{
+	int ret = menu_loop_cheats_page(0, keys);
+	core_apply_cheats(cheats);
+	return ret;
+}
+
 static int menu_loop_core_options_page(int offset, int keys) {
 	static int sel = 0;
 	menu_entry *e_menu_core_options;
@@ -564,7 +619,7 @@ static menu_entry e_menu_main[] =
 	mee_handler_id("Save state",         MA_MAIN_SAVE_STATE,  main_menu_handler),
 	mee_handler_id("Load state",         MA_MAIN_LOAD_STATE,  main_menu_handler),
 	mee_handler_id("Disc control",       MA_MAIN_DISC_CTRL,   menu_loop_disc),
-	/* mee_handler_id("Cheats",             MA_MAIN_CHEATS,      main_menu_handler), */
+	mee_handler_id("Cheats",             MA_MAIN_CHEATS,      menu_loop_cheats),
 	mee_handler   ("Options",            menu_loop_options),
 	mee_handler_id("Reset game",         MA_MAIN_RESET_GAME,  main_menu_handler),
 	mee_handler_id("Load new game",      MA_MAIN_CONTENT_SEL, menu_loop_select_content),
@@ -619,7 +674,8 @@ void menu_loop(void)
 
 	me_enable(e_menu_main, MA_MAIN_SAVE_STATE, state_allowed());
 	me_enable(e_menu_main, MA_MAIN_LOAD_STATE, state_allowed());
-
+	me_enable(e_menu_main, MA_MAIN_CHEATS, cheats != NULL);
+	
 	me_enable(e_menu_main, MA_MAIN_DISC_CTRL, needs_disc_ctrl);
 
 #ifdef MMENU