1 files changed, 133 insertions, 0 deletions
diff --git a/bin/xx.c b/bin/xx.c
new file mode 100644
index 00000000..e610c276
--- /dev/null
+++ b/bin/xx.c
@@ -0,0 +1,133 @@
+/* Copyright (c) 2017, June McEnroe <programble@gmail.com>
+ *
+ * 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 <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+static bool zero(const uint8_t *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;
+    bool ascii;
+    bool offset;
+    bool skip;
+} options = { 16, 8, true, true, false };
+
+static void dump(FILE *file) {
+    bool skip = false;
+
+    uint8_t 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.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) {
+    uint8_t byte;
+    int match;
+    while (0 < (match = fscanf(file, " %hhx", &byte))) {
+        printf("%c", byte);
+    }
+    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:rsz"))) {
+        switch (opt) {
+            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 '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;
+}