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.

1 files changed, 224 insertions, 0 deletions

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);
+}