Build the Virtual Console patches with `make red_vc` and `make blue_vc` (#351)

1 files changed, 469 insertions, 0 deletions

diff --git a/tools/make_patch.c b/tools/make_patch.c
new file mode 100644
index 00000000..29d798f6
--- /dev/null
+++ b/tools/make_patch.c
@@ -0,0 +1,469 @@
+#define PROGRAM_NAME "make_patch"
+#define USAGE_OPTS "labels.sym constants.sym patched.gbc original.gbc vc.patch.template vc.patch"
+
+#include "common.h"
+
+#include <ctype.h>
+
+struct Buffer {
+	size_t item_size;
+	size_t size;
+	size_t capacity;
+	void *data;
+};
+
+struct Symbol {
+	struct Symbol *next;
+	unsigned int address;
+	unsigned int offset;
+	char name[]; // C99 FAM
+};
+
+struct Patch {
+	unsigned int offset;
+	unsigned int size;
+};
+
+struct Buffer *buffer_create(size_t item_size) {
+	struct Buffer *buffer = xmalloc(sizeof(*buffer));
+	buffer->item_size = item_size;
+	buffer->size = 0;
+	buffer->capacity = 0x10;
+	buffer->data = xmalloc(buffer->capacity * item_size);
+	return buffer;
+}
+
+void buffer_append(struct Buffer *buffer, const void *item) {
+	if (buffer->size >= buffer->capacity) {
+		buffer->capacity = (buffer->capacity + 1) * 2;
+		buffer->data = xrealloc(buffer->data, buffer->capacity * buffer->item_size);
+	}
+	memcpy((char *)buffer->data + (buffer->size++ * buffer->item_size), item, buffer->item_size);
+}
+
+void buffer_free(struct Buffer *buffer) {
+	free(buffer->data);
+	free(buffer);
+}
+
+void symbol_append(struct Symbol **symbols, const char *name, int bank, int address) {
+	size_t name_len = strlen(name) + 1;
+	struct Symbol *symbol = xmalloc(sizeof(*symbol) + name_len);
+	symbol->address = address;
+	symbol->offset = address < 0x8000
+		? (bank > 0 ? address + (bank - 1) * 0x4000 : address) // ROM addresses are relative to their bank
+		: address - 0x8000; // RAM addresses are relative to the start of all RAM
+	memcpy(symbol->name, name, name_len);
+	symbol->next = *symbols;
+	*symbols = symbol;
+}
+
+void symbol_free(struct Symbol *symbols) {
+	for (struct Symbol *next; symbols; symbols = next) {
+		next = symbols->next;
+		free(symbols);
+	}
+}
+
+const struct Symbol *symbol_find(const struct Symbol *symbols, const char *name) {
+	size_t name_len = strlen(name);
+	for (const struct Symbol *symbol = symbols; symbol; symbol = symbol->next) {
+		size_t sym_name_len = strlen(symbol->name);
+		if (name_len > sym_name_len) {
+			continue;
+		}
+		const char *sym_name = symbol->name;
+		if (name[0] == '.') {
+			// If `name` is a local label, compare it to the local part of `symbol->name`
+			sym_name += sym_name_len - name_len;
+		}
+		if (!strcmp(sym_name, name)) {
+			return symbol;
+		}
+	}
+	error_exit("Error: Unknown symbol: \"%s\"\n", name);
+}
+
+const struct Symbol *symbol_find_cat(const struct Symbol *symbols, const char *prefix, const char *suffix) {
+	char *sym_name = xmalloc(strlen(prefix) + strlen(suffix) + 1);
+	sprintf(sym_name, "%s%s", prefix, suffix);
+	const struct Symbol *symbol = symbol_find(symbols, sym_name);
+	free(sym_name);
+	return symbol;
+}
+
+int parse_number(const char *input, int base) {
+	char *endptr;
+	int n = (int)strtol(input, &endptr, base);
+	if (endptr == input || *endptr || n < 0) {
+		error_exit("Error: Cannot parse number: \"%s\"\n", input);
+	}
+	return n;
+}
+
+void parse_symbol_value(char *input, int *restrict bank, int *restrict address) {
+	char *colon = strchr(input, ':');
+	if (!colon) {
+		error_exit("Error: Cannot parse bank+address: \"%s\"\n", input);
+	}
+	*colon++ = '\0';
+	*bank = parse_number(input, 16);
+	*address = parse_number(colon, 16);
+}
+
+void parse_symbols(const char *filename, struct Symbol **symbols) {
+	FILE *file = xfopen(filename, 'r');
+	struct Buffer *buffer = buffer_create(1);
+
+	enum { SYM_PRE, SYM_VALUE, SYM_SPACE, SYM_NAME } state = SYM_PRE;
+	int bank = 0;
+	int address = 0;
+
+	for (;;) {
+		int c = getc(file);
+		if (c == EOF || c == '\n' || c == '\r' || c == ';' || (state == SYM_NAME && (c == ' ' || c == '\t'))) {
+			if (state == SYM_NAME) {
+				// The symbol name has ended; append the buffered symbol
+				buffer_append(buffer, &(char []){'\0'});
+				symbol_append(symbols, buffer->data, bank, address);
+			}
+			// Skip to the next line, ignoring anything after the symbol value and name
+			state = SYM_PRE;
+			while (c != EOF && c != '\n' && c != '\r') {
+				c = getc(file);
+			}
+			if (c == EOF) {
+				break;
+			}
+		} else if (c != ' ' && c != '\t') {
+			if (state == SYM_PRE || state == SYM_SPACE) {
+				// The symbol value or name has started; buffer its contents
+				if (++state == SYM_NAME) {
+					// The symbol name has started; parse the buffered value
+					buffer_append(buffer, &(char []){'\0'});
+					parse_symbol_value(buffer->data, &bank, &address);
+				}
+				buffer->size = 0;
+			}
+			buffer_append(buffer, &c);
+		} else if (state == SYM_VALUE) {
+			// The symbol value has ended; wait to see if a name comes after it
+			state = SYM_SPACE;
+		}
+	}
+
+	fclose(file);
+	buffer_free(buffer);
+}
+
+int strfind(const char *s, const char *list[], int count) {
+	for (int i = 0; i < count; i++) {
+		if (!strcmp(s, list[i])) {
+			return i;
+		}
+	}
+	return -1;
+}
+
+#define vstrfind(s, ...) strfind(s, (const char *[]){__VA_ARGS__}, sizeof (const char *[]){__VA_ARGS__} / sizeof(const char *))
+
+int parse_arg_value(const char *arg, bool absolute, const struct Symbol *symbols, const char *patch_name) {
+	// Comparison operators for "ConditionValueB" evaluate to their particular values
+	int op = vstrfind(arg, "==", ">", "<", ">=", "<=", "!=", "||");
+	if (op >= 0) {
+		return op == 6 ? 0x11 : op; // "||" is 0x11
+	}
+
+	// Literal numbers evaluate to themselves
+	if (isdigit((unsigned)arg[0]) || arg[0] == '+') {
+		return parse_number(arg, 0);
+	}
+
+	// Symbols evaluate to their offset or address, plus an optional offset mod
+	int offset_mod = 0;
+	char *plus = strchr(arg, '+');
+	if (plus) {
+		offset_mod = parse_number(plus, 0);
+		*plus = '\0';
+	}
+	const char *sym_name = !strcmp(arg, "@") ? patch_name : arg; // "@" is the current patch label
+	const struct Symbol *symbol = symbol_find(symbols, sym_name);
+	return (absolute ? symbol->offset : symbol->address) + offset_mod;
+}
+
+void interpret_command(char *command, const struct Symbol *current_hook, const struct Symbol *symbols, struct Buffer *patches, FILE *restrict new_rom, FILE *restrict orig_rom, FILE *restrict output) {
+	// Strip all leading spaces and all but one trailing space
+	int x = 0;
+	for (int i = 0; command[i]; i++) {
+		if (!isspace((unsigned)command[i]) || (i > 0 && !isspace((unsigned)command[i - 1]))) {
+			command[x++] = command[i];
+		}
+	}
+	command[x - (x > 0 && isspace((unsigned)command[x - 1]))] = '\0';
+
+	// Count the arguments
+	int argc = 0;
+	for (const char *c = command; *c; c++) {
+		if (isspace((unsigned)*c)) {
+			argc++;
+		}
+	}
+
+	// Get the arguments
+	char *argv[argc]; // VLA
+	char *arg = command;
+	for (int i = 0; i < argc; i++) {
+		while (*arg && !isspace((unsigned)*arg)) {
+			arg++;
+		}
+		if (!*arg) {
+			break;
+		}
+		*arg++ = '\0';
+		argv[i] = arg;
+	}
+
+	// Use the arguments
+	if (vstrfind(command, "patch", "PATCH", "patch_", "PATCH_", "patch/", "PATCH/") >= 0) {
+		if (argc > 2) {
+			error_exit("Error: Invalid arguments for command: \"%s\"\n", command);
+		}
+		if (!current_hook) {
+			error_exit("Error: No current patch for command: \"%s\"\n", command);
+		}
+		int current_offset = current_hook->offset + (argc > 0 ? parse_number(argv[0], 0) : 0);
+		if (fseek(orig_rom, current_offset, SEEK_SET)) {
+			error_exit("Error: Cannot seek to \"vc_patch %s\" in the original ROM\n", current_hook->name);
+		}
+		if (fseek(new_rom, current_offset, SEEK_SET)) {
+			error_exit("Error: Cannot seek to \"vc_patch %s\" in the new ROM\n", current_hook->name);
+		}
+		int length;
+		if (argc == 2) {
+			length = parse_number(argv[1], 0);
+		} else {
+			const struct Symbol *current_hook_end = symbol_find_cat(symbols, current_hook->name, "_End");
+			length = current_hook_end->offset - current_offset;
+		}
+		buffer_append(patches, &(struct Patch){current_offset, length});
+		bool modified = false;
+		if (length == 1) {
+			int c = getc(new_rom);
+			modified = c != getc(orig_rom);
+			fprintf(output, isupper((unsigned)command[0]) ? "0x%02X" : "0x%02x", c);
+		} else {
+			if (command[strlen(command) - 1] != '/') {
+				fprintf(output, command[strlen(command) - 1] == '_' ? "a%d: " : "a%d:", length);
+			}
+			for (int i = 0; i < length; i++) {
+				if (i) {
+					putc(' ', output);
+				}
+				int c = getc(new_rom);
+				modified |= c != getc(orig_rom);
+				fprintf(output, isupper((unsigned)command[0]) ? "%02X" : "%02x", c);
+			}
+		}
+		if (!modified) {
+			fprintf(stderr, PROGRAM_NAME ": Warning: \"vc_patch %s\" doesn't alter the ROM\n", current_hook->name);
+		}
+
+	} else if (vstrfind(command, "dws", "DWS", "dws_", "DWS_", "dws/", "DWS/") >= 0) {
+		if (argc < 1) {
+			error_exit("Error: Invalid arguments for command: \"%s\"\n", command);
+		}
+		if (command[strlen(command) - 1] != '/') {
+			fprintf(output, command[strlen(command) - 1] == '_' ? "a%d: " : "a%d:", argc * 2);
+		}
+		for (int i = 0; i < argc; i++) {
+			int value = parse_arg_value(argv[i], false, symbols, current_hook->name);
+			if (value > 0xffff) {
+				error_exit("Error: Invalid value for \"%s\" argument: 0x%x\n", command, value);
+			}
+			if (i) {
+				putc(' ', output);
+			}
+			fprintf(output, isupper((unsigned)command[0]) ? "%02X %02X": "%02x %02x", value & 0xff, value >> 8);
+		}
+
+	} else if (vstrfind(command, "db", "DB", "db_", "DB_", "db/", "DB/") >= 0) {
+		if (argc != 1) {
+			error_exit("Error: Invalid arguments for command: \"%s\"\n", command);
+		}
+		int value = parse_arg_value(argv[0], false, symbols, current_hook->name);
+		if (value > 0xff) {
+			error_exit("Error: Invalid value for \"%s\" argument: 0x%x\n", command, value);
+		}
+		if (command[strlen(command) - 1] != '/') {
+			fputs(command[strlen(command) - 1] == '_' ? "a1: " : "a1:", output);
+		}
+		fprintf(output, isupper((unsigned)command[0]) ? "%02X" : "%02x", value);
+
+	} else if (vstrfind(command, "hex", "HEX", "HEx", "Hex", "heX", "hEX", "hex~", "HEX~", "HEx~", "Hex~", "heX~", "hEX~") >= 0) {
+		if (argc != 1 && argc != 2) {
+			error_exit("Error: Invalid arguments for command: \"%s\"\n", command);
+		}
+		int value = parse_arg_value(argv[0], command[strlen(command) - 1] != '~', symbols, current_hook->name);
+		int padding = argc > 1 ? parse_number(argv[1], 0) : 2;
+		if (vstrfind(command, "HEx", "HEx~") >= 0) {
+			fprintf(output, "0x%0*X%02x", padding - 2, value >> 8, value & 0xff);
+		} else if (vstrfind(command, "Hex", "Hex~") >= 0) {
+			fprintf(output, "0x%0*X%03x", padding - 3, value >> 12, value & 0xfff);
+		} else if (vstrfind(command, "heX", "heX~") >= 0) {
+			fprintf(output, "0x%0*x%02X", padding - 2, value >> 8, value & 0xff);
+		} else if (vstrfind(command, "hEX", "hEX~") >= 0) {
+			fprintf(output, "0x%0*x%03X", padding - 3, value >> 12, value & 0xfff);
+		} else {
+			fprintf(output, isupper((unsigned)command[0]) ? "0x%0*X" : "0x%0*x", padding, value);
+		}
+
+	} else {
+		error_exit("Error: Unknown command: \"%s\"\n", command);
+	}
+}
+
+void skip_to_next_line(FILE *restrict input, FILE *restrict output) {
+	for (int c = getc(input); c != EOF; c = getc(input)) {
+		putc(c, output);
+		if (c == '\n' || c == '\r') {
+			break;
+		}
+	}
+}
+
+struct Buffer *process_template(const char *template_filename, const char *patch_filename, FILE *restrict new_rom, FILE *restrict orig_rom, const struct Symbol *symbols) {
+	FILE *input = xfopen(template_filename, 'r');
+	FILE *output = xfopen(patch_filename, 'w');
+
+	struct Buffer *patches = buffer_create(sizeof(struct Patch));
+	struct Buffer *buffer = buffer_create(1);
+
+	// The ROM checksum will always differ
+	buffer_append(patches, &(struct Patch){0x14e, 2});
+	// The Stadium data (see stadium.c) will always differ
+	unsigned int rom_size = (unsigned int)xfsize("", orig_rom);
+	unsigned int stadium_size = 24 + 6 + 2 + (rom_size / 0x2000) * 2;
+	buffer_append(patches, &(struct Patch){rom_size - stadium_size, stadium_size});
+
+	// Fill in the template
+	const struct Symbol *current_hook = NULL;
+	for (int c = getc(input); c != EOF; c = getc(input)) {
+		switch (c) {
+		case ';':
+			// ";" comments until the end of the line
+			putc(c, output);
+			skip_to_next_line(input, output);
+			break;
+
+		case '{':
+			// "{...}" is a template command; buffer its contents
+			buffer->size = 0;
+			for (c = getc(input); c != EOF && c != '}'; c = getc(input)) {
+				buffer_append(buffer, &c);
+			}
+			buffer_append(buffer, &(char []){'\0'});
+			// Interpret the command in the context of the current patch
+			interpret_command(buffer->data, current_hook, symbols, patches, new_rom, orig_rom, output);
+			break;
+
+		case '[':
+			// "[...]" is a patch label; buffer its contents
+			putc(c, output);
+			bool alternate = false;
+			buffer->size = 0;
+			for (c = getc(input); c != EOF; c = getc(input)) {
+				if (!alternate && c == '@') {
+					// "@" designates an alternate name for the ".VC_" label
+					alternate = true;
+					buffer->size = 0;
+				} else if (c == ']') {
+					putc(c, output);
+					break;
+				} else {
+					if (!alternate) {
+						putc(c, output);
+						if (!isalnum(c) && c != '_') {
+							// Convert non-identifier characters to underscores
+							c = '_';
+						}
+					}
+					buffer_append(buffer, &c);
+				}
+			}
+			buffer_append(buffer, &(char []){'\0'});
+			// The current patch should have a corresponding ".VC_" label
+			current_hook = symbol_find_cat(symbols, ".VC_", buffer->data);
+			skip_to_next_line(input, output);
+			break;
+
+		default:
+			putc(c, output);
+		}
+	}
+
+	rewind(orig_rom);
+	rewind(new_rom);
+
+	fclose(input);
+	fclose(output);
+	buffer_free(buffer);
+	return patches;
+}
+
+int compare_patch(const void *patch1, const void *patch2) {
+	unsigned int offset1 = ((const struct Patch *)patch1)->offset;
+	unsigned int offset2 = ((const struct Patch *)patch2)->offset;
+	return offset1 > offset2 ? 1 : offset1 < offset2 ? -1 : 0;
+}
+
+bool verify_completeness(FILE *restrict orig_rom, FILE *restrict new_rom, struct Buffer *patches) {
+	qsort(patches->data, patches->size, patches->item_size, compare_patch);
+	for (unsigned int offset = 0, index = 0; ; offset++) {
+		int orig_byte = getc(orig_rom);
+		int new_byte = getc(new_rom);
+		if (orig_byte == EOF || new_byte == EOF) {
+			return orig_byte == new_byte;
+		}
+		struct Patch *patch = &((struct Patch *)patches->data)[index];
+		if (index < patches->size && patch->offset == offset) {
+			if (fseek(orig_rom, patch->size, SEEK_CUR)) {
+				return false;
+			}
+			if (fseek(new_rom, patch->size, SEEK_CUR)) {
+				return false;
+			}
+			offset += patch->size;
+			index++;
+		} else if (orig_byte != new_byte) {
+			fprintf(stderr, PROGRAM_NAME ": Warning: Unpatched difference at offset: 0x%x\n", offset);
+			fprintf(stderr, "    Original ROM value: 0x%02x\n", orig_byte);
+			fprintf(stderr, "    Patched ROM value: 0x%02x\n", new_byte);
+			fprintf(stderr, "    Current patch offset: 0x%06x\n", patch->offset);
+			return false;
+		}
+	}
+}
+
+int main(int argc, char *argv[]) {
+	if (argc != 7) {
+		usage_exit(1);
+	}
+
+	struct Symbol *symbols = NULL;
+	parse_symbols(argv[1], &symbols);
+	parse_symbols(argv[2], &symbols);
+
+	FILE *new_rom = xfopen(argv[3], 'r');
+	FILE *orig_rom = xfopen(argv[4], 'r');
+	struct Buffer *patches = process_template(argv[5], argv[6], new_rom, orig_rom, symbols);
+
+	if (!verify_completeness(orig_rom, new_rom, patches)) {
+		fprintf(stderr, PROGRAM_NAME ": Warning: Not all ROM differences are defined by \"%s\"\n", argv[6]);
+	}
+
+	symbol_free(symbols);
+	fclose(new_rom);
+	fclose(orig_rom);
+	buffer_free(patches);
+	return 0;
+}