Initial attempt at guessing engine structure

hex-dump.c

@@ -0,0 +1,72 @@
+// XXX: Taken from the wonderful https://stackoverflow.com/a/7776146
+
+#include <stdio.h>
+
+void hexDump (
+    const char * desc,
+    const void * addr,
+    const int len,
+    int perLine
+) {
+    // Silently ignore silly per-line values.
+
+    if (perLine < 4 || perLine > 64) perLine = 16;
+
+    int i;
+    unsigned char buff[perLine+1];
+    const unsigned char * pc = (const unsigned char *)addr;
+
+    // Output description if given.
+
+    if (desc != NULL) printf ("%s:\n", desc);
+
+    // Length checks.
+
+    if (len == 0) {
+        printf("  ZERO LENGTH\n");
+        return;
+    }
+    if (len < 0) {
+        printf("  NEGATIVE LENGTH: %d\n", len);
+        return;
+    }
+
+    // Process every byte in the data.
+
+    for (i = 0; i < len; i++) {
+        // Multiple of perLine means new or first line (with line offset).
+
+        if ((i % perLine) == 0) {
+            // Only print previous-line ASCII buffer for lines beyond first.
+
+            if (i != 0) printf ("  %s\n", buff);
+
+            // Output the offset of current line.
+
+            printf ("  %04x ", i);
+        }
+
+        // Now the hex code for the specific character.
+
+        printf (" %02x", pc[i]);
+
+        // And buffer a printable ASCII character for later.
+
+        if ((pc[i] < 0x20) || (pc[i] > 0x7e)) // isprint() may be better.
+            buff[i % perLine] = '.';
+        else
+            buff[i % perLine] = pc[i];
+        buff[(i % perLine) + 1] = '\0';
+    }
+
+    // Pad out last line if not exactly perLine characters.
+
+    while ((i % perLine) != 0) {
+        printf ("   ");
+        i++;
+    }
+
+    // And print the final ASCII buffer.
+
+    printf ("  %s\n", buff);
+}