[develop] Add inital datel cheat support from filesystem (#204)

## Description
This pull request adds a file parser for cheat code support.
If a file named the same as the selected rom with the extension .cht is
found, it will attempt to parse the file for cheat codes and place them
in `menu->boot_params->cheat_list` per the cheat backend API.

Cheat files should be formatted this way:
```
# Super mario 64 infinite lives
8033B21D 0064

# 120 stars
80207723 0001
8020770B 00C7
50001101 0000
8020770C 00FF
```

The parser ignores lines that start with a '#', are under 12 characters
or over 15 characters. Every other line should be valid cheat code
inputs with the code on the left, and the value on the right separated
by a space.

## Motivation and Context
<!--- What does this sample do? What problem does it solve? -->
Adds some initial cheat support in the frontend to allow users to modify
their games more easily, and take advantage of the backend API.

## How Has This Been Tested?
Tested on real hardware with a Summercart64 and Super Mario 64.

## Screenshots
<!-- (if appropriate): -->

## Types of changes
<!--- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [x] Improvement (non-breaking change that adds a new feature)
- [ ] Bug fix (fixes an issue)
- [ ] Breaking change (breaking change)
- [x] Documentation Improvement
- [ ] Config and build (change in the configuration and build system,
has no impact on code or features)

## Checklist:
<!--- Go over all the following points, and put an `x` in all the boxes
that apply. -->
<!--- If you're unsure about any of these, don't hesitate to ask. We're
here to help! -->
- [x] My code follows the code style of this project.
- [x] My change requires a change to the documentation.
- [x] I have updated the documentation accordingly.
- [ ] I have added tests to cover my changes.
- [ ] All new and existing tests passed.

<!--- It would be nice if you could sign off your contribution by
replacing the name with your GitHub user name and GitHub email contact.
-->
Signed-off-by: XLuma 


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- **New Features**
	- Added support for loading and managing cheat codes for N64 ROMs
	- Introduced ability to enable/disable cheats for specific ROMs
	- Added file type recognition for `.cht` cheat files

- **Documentation**
- Updated documentation with details about cheat code support, including
Datel cart compatibility and supported code types

- **Bug Fixes**
	- Implemented comprehensive error handling for cheat file loading
	- Added file parsing support for cheat codes

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Robin Jones <networkfusion@users.noreply.github.com>

Makefile

@@ -43,6 +43,7 @@ SRCS = \
 	menu/actions.c \
 	menu/bookkeeping.c \
 	menu/cart_load.c \
+	menu/cheat_load.c \
 	menu/disk_info.c \
 	menu/fonts.c \
 	menu/hdmi.c \

README.md

@@ -40,6 +40,7 @@ This menu aims to support as many N64 flashcarts as possible. The current state
 * N64 ROM autoload.
 * ROM information descriptions.
 * ROM history and favorites (pre-release only).
+* ROM cheat file support (pre-release only).
 
 
 ## Documentation

docs/00_index.md

@@ -5,7 +5,7 @@
 - [Initial Setup of an SD Card](./10_getting_started_sd.md)
 - [Basic Controls](./11_menu_controls.md)
 - [ROM Configuration](./12_rom_configuration.md)
-- [Cheats (Gameshark, etc.)](./13_datel_cheats.md)
+<!-- - [Cheats (Gameshark, etc.)](./13_datel_cheats.md) -->
 - [ROM Patches (Hacks, Fan Translations, etc.)](./14_rom_patches.md)
 - [Controller PAKs](./15_controller_paks.md)
 - [Background Images](./16_background_images.md)

docs/13_datel_cheats.md

@@ -1,6 +1,8 @@
 [Return to the index](./00_index.md)
 ## Cheats (Gameshark, etc.)
 
+**THIS FEATURE IS EXPERIMENTAL**
+
 The N64FlashcartMenu supports the cheat code types made popular by the peripherals:
 - GameShark
 - Action Replay
@@ -10,39 +12,41 @@ Another product by Blaze, called the Xploder64/Xplorer64 also existed in some re
 **WARNING**: It is not advised to connect a physical cheat cartridge in conjunction with most flashcarts.
 
 
-The N64FlashcartMenu can only support cheat codes based on Datel carts when also using an Expansion Pak.
+The N64FlashcartMenu can only support cheat codes based on Datel carts when **also** using an Expansion Pak.
 
 Caveats:
 - Something about cheats and expansion paks.
-
-The current code types are supported:
-- 80 (description here)
-- D0 (description here)
-- Fx (description here)
-- ...
-
-The codes XX are not supported, because...
 - e.g. they rely on the button.
 
+### File parsing support
+If a file named the same as the selected rom with the extension `.cht` is found, it will attempt to parse the file for cheat codes and place them in `menu->boot_params->cheat_list` per the cheat backend API.
+
+The parser ignores lines that start with a `#` or `$`, are under 12 characters or over 15 characters. Every other line needs to be a valid cheat code input with the code on the left, and the value on the right separated by a space.
+
+Cheat files should be formatted this way:
 ```
-// Example cheat codes for the game "Majoras Mask USA"
-uint32_t cheats[] = {
-    // Enable code
-    0xF1096820,
-    0x2400,
-    0xFF000220,
-    0x0000,
-    // Inventory Editor (assigned to L)
-    0xD01F9B91,
-    0x0020,
-    0x803FDA3F,
-    0x0002,
-    // Last 2 entries must be 0
-    0,
-    0,
-};
+# Super mario 64 infinite lives
+8033B21D 0064
+
+# 120 stars
+80207723 0001
+8020770B 00C7
+50001101 0000
+8020770C 00FF
 ```
 
-And pass this array as a boot parameter: `menu->boot_params->cheat_list = cheats;`
+Another example:
+```
+# Example cheat codes for the game "Majoras Mask USA"
+# Enable code
+F1096820 2400
+FF000220 0000
+# Inventory Editor (assigned to L)
+D01F9B91 0020
+803FDA3F 0002
+```
+
+The cheat file needs to be enabled for the specific game (press `R` within the Rom Info).
+
 
 Check the [Pull Requests](https://github.com/Polprzewodnikowy/N64FlashcartMenu/pulls) for work towards GUI editor support.

docs/65_experimental.md

@@ -1,6 +1,9 @@
 [Return to the index](./00_index.md)
 ## Experimental Features (Subject to change)
 
+### Cheats
+See: [Cheats (Gameshark, etc.)](./13_datel_cheats.md)
+
 ### ROM info descriptions (pre-release only)
 To show a ROM description in the N64 ROM information screen, add a `.ini` file next to the game ROM file with the same name and the following content:
 ```ini
@@ -15,4 +18,3 @@ Add a `font64` file to the `sd:/menu/` directory called `custom.font64`.
 
 <!-- Would be best if we can just link to an actual copy of Mkfont executable file and not expect people to compile libdragon -->
 You can build a font64 file with `Mkfont`, one of `libdragon`'s tools. At the time of writing, you will need to obtain `libdragon`'s [preview branch artifacts](https://github.com/DragonMinded/libdragon/actions/workflows/build-tool-windows.yml) to find out a copy of the prebuilt Windows executable. [Read its related Wiki page](https://github.com/DragonMinded/libdragon/wiki/Mkfont) for usage information.
-

src/menu/cart_load.c

@@ -6,6 +6,7 @@
 #include "path.h"
 #include "utils/fs.h"
 #include "utils/utils.h"
+#include "cheat_load.h"
 
 #ifndef SAVES_SUBDIRECTORY
 #define SAVES_SUBDIRECTORY      "saves"

src/menu/cheat_load.c

@@ -0,0 +1,197 @@
+/**
+ * @brief Cheat file support
+ * 
+ * @authors Mena and XLuma
+ */
+
+#include "cheat_load.h"
+#include "../utils/fs.h"
+
+#include <string.h>
+#include <libdragon.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include "views/views.h"
+
+
+char *cheat_load_convert_error_message (cheat_load_err_t err) {
+    switch (err) {
+        case CHEAT_LOAD_OK: return "Cheats loaded OK";
+        case CHEAT_LOAD_ERR_NO_CHEAT_FILE: return "No cheat file found";
+        case CHEAT_LOAD_ERR_SIZE_FAILED: return "Error occured acquiring cheat size";
+        case CHEAT_LOAD_ERR_CHEAT_EMPTY: return "Cheat file is empty";
+        case CHEAT_LOAD_ERR_CHEAT_TOO_LARGE: return "Cheat file is too large (over 128KiB)";
+        case CHEAT_LOAD_ERR_MALLOC_FAILED: return "Error occured allocating memory for file";
+        case CHEAT_LOAD_ERR_READ_FAILED: return "Error occured during file read";
+        case CHEAT_LOAD_ERR_CLOSE_FAILED: return "Error occured during file close";
+        default: return "Unknown error [CHEAT_LOAD]";
+    }
+}
+
+static int find_str (char const *s, char c) {
+    int	i;
+    int	nb_str;
+
+    i = 0;
+    nb_str = 0;
+    if (!s[0]) {
+        return (0);
+    }
+    while (s[i] && s[i] == c) {
+        i++;
+    }
+    while (s[i]) {
+        if (s[i] == c) {
+            nb_str++;
+            while (s[i] && s[i] == c) {
+                i++;
+            }
+            continue;
+        }
+        i++;
+    }
+    if (s[i - 1] != c) {
+        nb_str++;
+    }
+    return (nb_str);
+}
+
+static void get_next_str (char **next_str, size_t *next_strlen, char c) {
+    size_t i;
+
+    *next_str += *next_strlen;
+    *next_strlen = 0;
+    i = 0;
+    while (**next_str && **next_str == c) {
+        (*next_str)++;
+    }
+    while ((*next_str)[i]) {
+        if ((*next_str)[i] == c) {
+            return;
+        }
+        (*next_strlen)++;
+        i++;
+    }
+}
+
+static char **free_tab (char **tab) {
+    int i;
+
+    i = 0;
+    while (tab[i]) {
+        free(tab[i]);
+        i++;
+    }
+    free(tab);
+    return (NULL);
+}
+
+char **ft_split (char const *s, char c) {
+    char **tab;
+    char *next_str;
+    size_t next_strlen;
+    int i;
+
+    i = -1;
+    if (!s) {
+        return (NULL);
+    }
+    tab = malloc(sizeof(char *) * (find_str(s, c) + 1));
+    if (!tab) {
+        return (NULL);
+    }
+    next_str = (char *)s;
+    next_strlen = 0;
+    while (++i < find_str(s, c)) {
+        get_next_str(&next_str, &next_strlen, c);
+        tab[i] = (char *)malloc(sizeof(char) * (next_strlen + 1));
+        if (!tab[i]) {
+            return (free_tab(tab));
+        }
+        strlcpy(tab[i], next_str, next_strlen + 1);
+    }
+    tab[i] = NULL;
+    return (tab);
+}
+
+cheat_load_err_t load_cheats (menu_t *menu) {
+    FILE *cheatsFile;
+    struct stat st;
+    size_t cheatsLength;
+    path_t *path = path_clone(menu->load.rom_path);
+
+    // Parse cheats from file
+    path_ext_replace(path, "cht");
+    if((cheatsFile = fopen(path_get(path), "rb")) == NULL) {
+        path_free(path);
+        return CHEAT_LOAD_OK; // no file is not an error.
+    }
+
+    if (fstat(fileno(cheatsFile), &st)){
+        path_free(path);
+        return CHEAT_LOAD_ERR_SIZE_FAILED;
+    }
+
+    cheatsLength = st.st_size;
+    if (cheatsLength <= 0) {
+        path_free(path);
+        return CHEAT_LOAD_ERR_CHEAT_EMPTY;
+    }
+    if (cheatsLength > KiB(128)) {
+        path_free(path);
+        return CHEAT_LOAD_ERR_CHEAT_TOO_LARGE;
+    }
+
+    char *cheatsContent = NULL;
+    if((cheatsContent = malloc((cheatsLength + 1) * sizeof(char))) == NULL) {
+        path_free(path);
+        return CHEAT_LOAD_ERR_MALLOC_FAILED;
+    }
+    if(fread(cheatsContent, cheatsLength, 1, cheatsFile) != 1) {
+        path_free(path);
+        return CHEAT_LOAD_ERR_READ_FAILED;
+    }
+
+    cheatsContent[cheatsLength] = '\0';
+    if(fclose(cheatsFile) != 0){
+        path_free(path);
+        return CHEAT_LOAD_ERR_CLOSE_FAILED;
+    }
+    cheatsFile = NULL;
+ 
+    char **tab = ft_split(cheatsContent, '\n');
+    size_t lines = 1;
+    for (size_t i = 0; tab[i] != NULL; i++) {
+        lines++;
+    }
+
+    free(cheatsContent);
+
+    uint32_t  *cheats = (uint32_t*)malloc(((lines * sizeof(uint32_t)) * 2) + 2);
+    memset(cheats, 0, ((lines * sizeof(uint32_t)) * 2) + 2);
+    size_t cheatIndex = 0;
+    for(size_t i = 0; tab[i] != NULL; i++) {
+        // ignore titles 
+        if (tab[i][0] == '#' || tab[i][0] == '$') {
+            continue;
+        }
+        // ignore empty, too small or too big lines
+        if (strlen(tab[i]) < 12 || strlen(tab[i]) > 15) {
+            continue;
+        }
+        char **splitCheat = ft_split(tab[i], ' ');
+        uint32_t cheatValue1 = strtoul(splitCheat[0], NULL, 16);
+        uint32_t cheatValue2 = strtoul(splitCheat[1], NULL, 16);
+        cheats[cheatIndex] = cheatValue1;
+        cheats[cheatIndex + 1] = cheatValue2;
+        free_tab(splitCheat);
+        cheatIndex += 2;
+    }
+    free_tab(tab);
+
+    cheats[cheatIndex] = 0;
+    cheats[cheatIndex + 1] = 0;
+    menu->boot_params->cheat_list = cheats;
+
+    return CHEAT_LOAD_OK;
+}

src/menu/cheat_load.h

@@ -0,0 +1,26 @@
+/***
+ * @file cheat_load.h
+ * @brief Cheat loading functions
+ */
+
+#include "path.h"
+#include "utils/fs.h"
+#include "utils/utils.h"
+#include "menu_state.h"
+
+/** @brief Cheat code loading enum */
+
+typedef enum {
+    CHEAT_LOAD_OK,
+    CHEAT_LOAD_ERR_NO_CHEAT_FILE,
+    CHEAT_LOAD_ERR_SIZE_FAILED,
+    CHEAT_LOAD_ERR_CHEAT_EMPTY,
+    CHEAT_LOAD_ERR_CHEAT_TOO_LARGE,
+    CHEAT_LOAD_ERR_MALLOC_FAILED,
+    CHEAT_LOAD_ERR_READ_FAILED,
+    CHEAT_LOAD_ERR_CLOSE_FAILED,
+    CHEAT_LOAD_ERR_UNKNOWN_ERROR
+} cheat_load_err_t;
+
+cheat_load_err_t load_cheats (menu_t *menu);
+char *cheat_load_convert_error_message (cheat_load_err_t err);

src/menu/rom_info.c

@@ -857,6 +857,8 @@ static rom_err_t save_override (path_t *path, const char *id, int value, int def
 
     if (value == default_value) {
         mini_err = mini_delete_value(rom_info_ini, "custom_boot", id);
+    } else if (strncmp(id, "cheat_codes", strlen("cheat_codes"))) {
+        mini_err = mini_set_bool(rom_info_ini, NULL, id, value);
     } else {
         mini_err = mini_set_int(rom_info_ini, "custom_boot", id, value);
     }
@@ -962,6 +964,11 @@ rom_err_t rom_info_override_tv_type (path_t *path, rom_info_t *rom_info, rom_tv_
     return save_override(path, "tv_type", rom_info->boot_override.tv_type, ROM_TV_TYPE_AUTOMATIC);
 }
 
+rom_err_t rom_setting_set_cheats (path_t *path, rom_info_t *rom_info, bool enabled) {
+    rom_info->settings.cheats_enabled = enabled;
+    return save_override(path, "cheat_codes", enabled, false);
+}
+
 rom_err_t rom_info_load (path_t *path, rom_info_t *rom_info) {
     FILE *f;
     rom_header_t rom_header;

src/menu/rom_info.h

@@ -247,4 +247,6 @@ rom_err_t rom_info_override_save_type (path_t *path, rom_info_t *rom_info, rom_s
 rom_tv_type_t rom_info_get_tv_type (rom_info_t *rom_info);
 rom_err_t rom_info_override_tv_type (path_t *path, rom_info_t *rom_info, rom_tv_type_t tv_type);
 
+rom_err_t rom_setting_set_cheats (path_t *path, rom_info_t *rom_info, bool enabled);
+
 #endif

src/menu/views/file_info.c

@@ -15,6 +15,7 @@ static const char *image_extensions[] = { "png", "jpg", "gif", NULL };
 static const char *music_extensions[] = { "mp3", "wav", "ogg", "wma", "flac", NULL };
 static const char *controller_pak_extensions[] = { "mpk", "pak", NULL };
 static const char *emulator_extensions[] = { "nes", "smc", "gb", "gbc", "sms", "gg", "chf", NULL };
+static const char *cheat_extensions[] = {"cht", NULL};
 
 
 static struct stat st;
@@ -44,6 +45,9 @@ static char *format_file_type (char *name, bool is_directory) {
     } else if (file_has_extensions(name, emulator_extensions)) {
         return " Type: Emulator ROM file\n";
     }
+    else if (file_has_extensions(name, cheat_extensions)) {
+        return " Type: Cheats\n";
+    }
     return " Type: Unknown file\n";
 }
 

src/menu/views/load_rom.c

@@ -6,6 +6,7 @@
 #include <string.h>
 #include "utils/fs.h"
 #include "../bookkeeping.h"
+#include "../cheat_load.h"
 
 static bool show_extra_info_message = false;
 static component_boxart_t *boxart;
@@ -166,6 +167,23 @@ static void add_favorite (menu_t *menu, void *arg) {
     bookkeeping_favorite_add(&menu->bookkeeping, menu->load.rom_path, NULL, BOOKKEEPING_TYPE_ROM);
 }
 
+static void set_cheat_option(menu_t *menu, void *arg) {
+    bool enabled = (bool)arg;
+    if (enabled == true) {
+        cheat_load_err_t err = load_cheats(menu);
+        if (err != CHEAT_LOAD_OK) {
+            menu_show_error(menu, cheat_load_convert_error_message(err));
+        }
+    }
+    if (enabled == false) {
+        if (menu->boot_params->cheat_list != NULL) {
+            free(menu->boot_params->cheat_list);
+        }
+    }
+    rom_setting_set_cheats(menu->load.rom_path, &menu->load.rom_info, enabled);
+    menu->browser.reload = true;
+}
+
 static component_context_menu_t set_cic_type_context_menu = { .list = {
     {.text = "Automatic", .action = set_cic_type, .arg = (void *) (ROM_CIC_TYPE_AUTOMATIC) },
     {.text = "CIC-6101", .action = set_cic_type, .arg = (void *) (ROM_CIC_TYPE_6101) },
@@ -204,10 +222,17 @@ static component_context_menu_t set_tv_type_context_menu = { .list = {
     COMPONENT_CONTEXT_MENU_LIST_END,
 }};
 
+static component_context_menu_t set_cheat_options_menu = { .list = {
+    { .text = "Enable", .action = set_cheat_option, .arg = (void *) (true)},
+    { .text = "Disable", .action = set_cheat_option, .arg = (void *) (false)},
+    COMPONENT_CONTEXT_MENU_LIST_END,
+}};
+
 static component_context_menu_t options_context_menu = { .list = {
     { .text = "Set CIC Type", .submenu = &set_cic_type_context_menu },
     { .text = "Set Save Type", .submenu = &set_save_type_context_menu },
     { .text = "Set TV Type", .submenu = &set_tv_type_context_menu },
+    { .text = "Set Cheats", .submenu = &set_cheat_options_menu },
     { .text = "Set ROM to autoload", .action = set_autoload_type },
     { .text = "Add to favorites", .action = add_favorite },
     COMPONENT_CONTEXT_MENU_LIST_END,
@@ -367,7 +392,6 @@ static void load (menu_t *menu) {
         case ROM_TV_TYPE_MPAL: menu->boot_params->tv_type = BOOT_TV_TYPE_MPAL; break;
         default: menu->boot_params->tv_type = BOOT_TV_TYPE_PASSTHROUGH; break;
     }
-    menu->boot_params->cheat_list = NULL;
 }
 
 static void deinit (void) {