new dumphex, abbreviates runs of zeros

src/user/dumphex/dumphex.c

@@ -2,28 +2,80 @@
 #include <knob/user.h>
 #include <knob/format.h>
 
+#define LINE_LEN 16
+
+void print_zero_line(uint32_t offset) {
+}
+
 void main(const char *path) {
   struct file *f = open_file(path);
   if (!f) {
     tell_user_sz("Couldn't open file.\n");
     return;
   }
-  char buf[] = { ' ', '\0', '\0', '\0' };
-  uint8_t v;
-  uint32_t a = 0;
-  while (read_from_file(f, 1, &v)) {
-    if (!(a & 0xf)) {
-      char buf2[] = {'0', 'x', '\0', '\0', '\0', '\0',
-                               '\0', '\0', '\0', '\0', '\0' };
-      itosz_h32(a, buf2 + 2);
-      tell_user_sz(buf2);
-      tell_user_sz(" |");
+
+  uint8_t line[LINE_LEN + 2];
+  uint8_t len;
+  uint32_t offset = -LINE_LEN;
+
+  enum {
+    ZR_NO,
+    ZR_FIRST,
+    ZR_REST
+  } zero_run;
+
+  char nbuf[9];
+
+  while ((len = read_from_file(f, LINE_LEN, line))) {
+    offset += LINE_LEN;
+
+    for (uint8_t i = 0; i < LINE_LEN; ++i)
+      if (line[i]) {
+        zero_run = ZR_NO;
+        goto print_normal;
+      }
+
+    switch (zero_run) {
+    case ZR_NO:
+      zero_run = ZR_FIRST;
+      _log_string("0x");
+      itosz_h32(offset, nbuf);
+      _log_string(nbuf);
+      _log_string(" | 00 00 00 00 00 00 00 00 "
+                     "00 00 00 00 00 00 00 00 |\n");
+      continue;
+    case ZR_FIRST:
+      zero_run = ZR_REST;
+      tell_user_sz("...\n");
+    case ZR_REST:
+      continue;
     }
-    itosz_h8(v, buf + 1);
-    tell_user_sz(buf);
-    if (!(++a & 0xf))
-      tell_user_sz("\n");
+
+  print_normal:
+    _log_string("0x");
+    itosz_h32(offset, nbuf);
+    _log_string(nbuf);
+    _log_string(" |");
+
+    nbuf[0] = ' ';
+    for (uint8_t i = 0; i < len; ++i) {
+      itosz_h8(line[i], nbuf + 1);
+      _log_string(nbuf);
+    }
+
+    for (uint8_t i = len; i < LINE_LEN; ++i)
+      _log_string("   ");
+
+    _log_string(" | ");
+
+    for (uint8_t i = 0; i < len; ++i)
+      if ((line[i] < 0x20) || (line[i] > 0x7e))
+        line[i] = ' ';
+    line[len] = '\n';
+    line[len + 1] = '\0';
+
+    _log_string(line);
   }
-  tell_user_sz("\n");
+
   close_file(f);
 }