parse hexadecimals as int args

src/argparse.cpp

@@ -33,14 +33,35 @@ internal
 Conv_Res str_to_u64(String8 s)
 {
   Conv_Res res {};
-  for (u64 i = 0; i < s.size; ++i) {
+  if (s.size > 2 && s[0] == '0' && s[1] == 'x') {
-    u8 c = s.str[i];
+    // hexadecimal
-    if (c >= '0' && c <= '9') {
+    for (u64 i = 2; i < s.size; ++i) {
-      res.num *= 10;
+      u8 c = s.str[i];
-      res.num += c - '0';
+      if (c >= '0' && c <= '9') {
-    } else {
+        res.num *= 16;
-      res.error = true;
+        res.num += c - '0';
-      break;
+      } else if (c >= 'A' && c <= 'F') {
+        res.num *= 16;
+        res.num += 10 + c - 'A';
+      } else if (c >= 'a' && c <= 'f') {
+        res.num *= 16;
+        res.num += 10 + c - 'a';
+      } else {
+        res.error = true;
+        break;
+      }
+    }
+  } else {
+    // decimal
+    for (u64 i = 0; i < s.size; ++i) {
+      u8 c = s.str[i];
+      if (c >= '0' && c <= '9') {
+        res.num *= 10;
+        res.num += c - '0';
+      } else {
+        res.error = true;
+        break;
+      }
     }
   }
   return res;

src/render.cpp

@@ -553,7 +553,7 @@ String8 render_range_to_string(Arena *arena, App_State &app, u64 len, u64 n_cols
     u64 off = start + i;
 
     /// Select color
-    u32 byte_col = mem_edit_bg_color_fn(data, off, &app);
+    u32 byte_col = mem_edit_bg_color_fn(data + start, i, &app);
     // piggyback off mem_edit_bg_color_fn instead of rewriting the color-choosing logic.
     // Kinda dumb code but we don't need speed here since we're printing this one-off.
     Ansi_Color acol = viewer_to_ansi_color(app.viewer, viewer, byte_col);

src/str.h

@@ -3,6 +3,7 @@ struct String8 {
   u64 size;
 
   const char *c() const { return reinterpret_cast<const char *>(str); }
+  u8 operator[](u64 idx) const { return str[idx]; }
 };
 
 #define str8(s) String8 { (u8*)(s), sizeof(s) - 1 }