1 files changed, 142 insertions, 0 deletions
diff --git a/bin/xx.c b/bin/xx.c
new file mode 100644
index 00000000..39d7ec07
--- /dev/null
+++ b/bin/xx.c
@@ -0,0 +1,142 @@
+/* Copyright (C) 2017  June McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <ctype.h>
+#include <err.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+typedef unsigned char byte;
+
+static bool zero(const byte *ptr, size_t size) {
+	for (size_t i = 0; i < size; ++i) {
+		if (ptr[i]) return false;
+	}
+	return true;
+}
+
+static struct {
+	size_t cols;
+	size_t group;
+	size_t blank;
+	bool ascii;
+	bool offset;
+	bool skip;
+} options = { 16, 8, 0, true, true, false };
+
+static void dump(FILE *file) {
+	bool skip = false;
+
+	byte buf[options.cols];
+	size_t offset = 0;
+	for (
+		size_t size;
+		(size = fread(buf, 1, sizeof(buf), file));
+		offset += size
+	) {
+		if (options.skip) {
+			if (zero(buf, size)) {
+				if (!skip) printf("*\n");
+				skip = true;
+				continue;
+			} else {
+				skip = false;
+			}
+		}
+
+		if (options.blank) {
+			if (offset && offset % options.blank == 0) {
+				printf("\n");
+			}
+		}
+
+		if (options.offset) {
+			printf("%08zX:  ", offset);
+		}
+
+		for (size_t i = 0; i < sizeof(buf); ++i) {
+			if (options.group) {
+				if (i && !(i % options.group)) {
+					printf(" ");
+				}
+			}
+			if (i < size) {
+				printf("%02hhX ", buf[i]);
+			} else {
+				printf("   ");
+			}
+		}
+
+		if (options.ascii) {
+			printf(" ");
+			for (size_t i = 0; i < size; ++i) {
+				if (options.group) {
+					if (i && !(i % options.group)) {
+						printf(" ");
+					}
+				}
+				printf("%c", isprint(buf[i]) ? buf[i] : '.');
+			}
+		}
+
+		printf("\n");
+	}
+}
+
+static void undump(FILE *file) {
+	byte c;
+	int match;
+	while (0 < (match = fscanf(file, " %hhx", &c))) {
+		printf("%c", c);
+	}
+	if (!match) errx(EX_DATAERR, "invalid input");
+}
+
+int main(int argc, char *argv[]) {
+	bool reverse = false;
+	const char *path = NULL;
+
+	int opt;
+	while (0 < (opt = getopt(argc, argv, "ac:g:p:rsz"))) {
+		switch (opt) {
+			break; case 'a': options.ascii ^= true;
+			break; case 'c': options.cols = strtoul(optarg, NULL, 0);
+			break; case 'g': options.group = strtoul(optarg, NULL, 0);
+			break; case 'p': options.blank = strtoul(optarg, NULL, 0);
+			break; case 'r': reverse = true;
+			break; case 's': options.offset ^= true;
+			break; case 'z': options.skip ^= true;
+			break; default: return EX_USAGE;
+		}
+	}
+	if (argc > optind) path = argv[optind];
+	if (!options.cols) return EX_USAGE;
+
+	FILE *file = path ? fopen(path, "r") : stdin;
+	if (!file) err(EX_NOINPUT, "%s", path);
+
+	if (reverse) {
+		undump(file);
+	} else {
+		dump(file);
+	}
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+
+	return EX_OK;
+}