Add `gfx` tool for graphics postprocessing

tools/Makefile

@@ -6,7 +6,8 @@ all: \
 	scan_includes \
 	palette \
 	pokemon_animation \
-	pokemon_animation_graphics
+	pokemon_animation_graphics \
+	gfx
 	@:
 
 %: %.c

tools/common.h

@@ -0,0 +1,37 @@
+#ifndef GUARD_COMMON_H
+#define GUARD_COMMON_H
+
+int __getopt_long_i__;
+#define getopt_long(c, v, s, l) getopt_long(c, v, s, l, &__getopt_long_i__)
+
+FILE *fopen_verbose(char *filename, char *mode) {
+	FILE *f = fopen(filename, mode);
+	if (!f) {
+		fprintf(stderr, "Could not open file: \"%s\"\n", filename);
+	}
+	return f;
+}
+
+uint8_t *read_u8(char *filename, int *size) {
+	FILE *f = fopen_verbose(filename, "rb");
+	if (!f) {
+		exit(1);
+	}
+	fseek(f, 0, SEEK_END);
+	*size = ftell(f);
+	rewind(f);
+	uint8_t *data = malloc(*size);
+	fread(data, 1, *size, f);
+	fclose(f);
+	return data;
+}
+
+void write_u8(char *filename, uint8_t *data, int size) {
+	FILE *f = fopen_verbose(filename, "wb");
+	if (f) {
+		fwrite(data, 1, size, f);
+		fclose(f);
+	}
+}
+
+#endif // GUARD_COMMON_H

tools/gfx.c

@@ -0,0 +1,120 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <getopt.h>
+#include <string.h>
+
+#include "common.h"
+
+static void usage(void) {
+	fprintf(stderr, "Usage: gfx [--trim-whitespace] [--remove-whitespace] [-d depth] [-h] [-o outfile] infile \n");
+}
+
+struct Options {
+	int trim_whitespace;
+	int remove_whitespace;
+	int help;
+	char *outfile;
+	int depth;
+};
+
+struct Options Options = {
+	.depth = 2,
+};
+
+void get_args(int argc, char *argv[]) {
+	struct option long_options[] = {
+		{"remove-whitespace", no_argument, &Options.remove_whitespace, 1},
+		{"trim-whitespace", no_argument, &Options.trim_whitespace, 1},
+		{"depth", required_argument, 0, 'd'},
+		{"help", no_argument, 0, 'h'},
+		{0}
+	};
+	for (int opt = 0; opt != -1;) {
+		switch(opt = getopt_long(argc, argv, "ho:d:", long_options)) {
+		case 'h':
+			Options.help = true;
+			break;
+		case 'o':
+			Options.outfile = optarg;
+			break;
+		case 'd':
+			Options.depth = strtoul(optarg, NULL, 0);
+			break;
+		case 0:
+		case -1:
+			break;
+		default:
+			printf("ay %d", opt);
+			usage();
+			exit(1);
+			break;
+		}
+	}
+}
+
+bool is_whitespace(uint8_t *tile, int tile_size) {
+	uint8_t WHITESPACE = 0;
+	for (int i = 0; i < tile_size; i++) {
+		if (tile[i] != WHITESPACE) {
+			return false;
+		}
+	}
+	return true;
+}
+
+void trim_whitespace(char *infile, char *outfile) {
+	int size;
+	uint8_t *data = read_u8(infile, &size);
+	int tile_size = Options.depth * 8;
+	for (int i = size - tile_size; i > 0; i -= tile_size) {
+		if (is_whitespace(&data[i], tile_size)) {
+			size = i;
+		} else {
+			break;
+		}
+	}
+	write_u8(outfile, data, size);
+}
+
+void remove_whitespace(char *infile, char *outfile) {
+	int size;
+	uint8_t *data = read_u8(infile, &size);
+	int tile_size = Options.depth * 8;
+	int i = 0;
+	for (int j = 0; i < size && j < size; i += tile_size, j += tile_size) {
+		while (is_whitespace(&data[j], tile_size)) {
+			j += tile_size;
+		}
+		if (j > i) {
+			memcpy(&data[i], &data[j], tile_size);
+		}
+	}
+	size = i;
+	write_u8(outfile, data, size);
+}
+
+int main(int argc, char *argv[]) {
+	get_args(argc, argv);
+	argc -= optind;
+	argv += optind;
+	if (Options.help) {
+		usage();
+		return 0;
+	}
+	if (argc < 1) {
+		usage();
+		exit(1);
+	}
+	char *infile = argv[0];
+	if (Options.remove_whitespace) {
+		if (Options.outfile) {
+			remove_whitespace(infile, Options.outfile);
+		}
+	} else if (Options.trim_whitespace) {
+		if (Options.outfile) {
+			trim_whitespace(infile, Options.outfile);
+		}
+	}
+	return 0;
+}