add checksums

src/render.cpp

@@ -30,12 +30,14 @@ String8 to_pretty_size(Arena *arena, u64 bytes)
 	return push_str8f(arena, "%zu B", bytes);
 }
 
+// @Speed: instead of calling this function for every displayed byte, prefill an array
+// of byte -> color only once and then just index it at `off`.
 internal
 u32 mem_edit_bg_color_fn(const u8 *, u64 off, void *user_data)
 {
   App_State *app = reinterpret_cast<App_State *>(user_data);
   const RNTuple_Data &rdata = app->rndata;
-  u64 rblob_sz = rdata.rblob_header_size;
+  u64 rblob_sz = rdata.rblob_header_size; // @Incomplete
 
   off += app->vsettings.base_display_addr;
 
@@ -45,26 +47,33 @@ u32 mem_edit_bg_color_fn(const u8 *, u64 off, void *user_data)
 
   // Handle pages
   // fast case: `off` is in the same page info as previous `off`.
-  if (app->last_pinfo->range.start < off && off < app->last_pinfo->range.end())
+  if (app->last_pinfo->range.start < off && off < app->last_pinfo->range.end()) {
+    if (off >= app->last_pinfo->range.end() - app->last_pinfo->checksum_size())
+      return COL(app->vsettings.col_checksum);
     return COL(app->vsettings.col_page);
+  }
 
   // still fast case: `off is in the next page info as the previous.
-  if (app->last_pinfo->next)
+  if (app->last_pinfo->next) // don't check if it's checksum, since it's the first byte of the page
     app->last_pinfo = app->last_pinfo->next;
 
   if (app->last_pinfo && app->last_pinfo->range.start <= off && off < app->last_pinfo->range.end()) {
     if (off == app->last_pinfo->range.start)
       return COL(app->vsettings.col_page_start);
-    else
+    if (off >= app->last_pinfo->range.end() - app->last_pinfo->checksum_size())
+      return COL(app->vsettings.col_checksum);
     return COL(app->vsettings.col_page);
   }
 
   if (rdata.rng_anchor_key.start <= off && off < rdata.rng_anchor_key.end()) return COL(app->vsettings.col_key);
   if (rdata.rng_header.start - rblob_sz <= off && off < rdata.rng_header.start) return COL(app->vsettings.col_key);
   if (rdata.rng_footer.start - rblob_sz <= off && off < rdata.rng_footer.start) return COL(app->vsettings.col_key);
-  if (rdata.rng_anchor.start <= off && off < rdata.rng_anchor.end()) return COL(app->vsettings.col_anchor);
+  if (rdata.rng_anchor.start <= off && off < rdata.rng_anchor.end() - 8) return COL(app->vsettings.col_anchor);
-  if (rdata.rng_header.start <= off && off < rdata.rng_header.end()) return COL(app->vsettings.col_header);
+  if (rdata.rng_anchor.end() - 8 <= off && off < rdata.rng_anchor.end()) return COL(app->vsettings.col_checksum);
-  if (rdata.rng_footer.start <= off && off < rdata.rng_footer.end()) return COL(app->vsettings.col_footer);
+  if (rdata.rng_header.start <= off && off < rdata.rng_header.end() - 8) return COL(app->vsettings.col_header);
+  if (rdata.rng_header.end() - 8 <= off && off < rdata.rng_header.end()) return COL(app->vsettings.col_checksum);
+  if (rdata.rng_footer.start <= off && off < rdata.rng_footer.end() - 8) return COL(app->vsettings.col_footer);
+  if (rdata.rng_footer.end() - 8 <= off && off < rdata.rng_footer.end()) return COL(app->vsettings.col_checksum);
 
   // Slow page group lookup, ideally only done once per render when last_pinfo is invalid.
   for (Page_Info_Chunk *chunk = rdata.page_chunks; chunk; chunk = chunk->next) {
@@ -79,7 +88,8 @@ u32 mem_edit_bg_color_fn(const u8 *, u64 off, void *user_data)
           if (pinfo->range.start <= off && off < pinfo->range.end()) {
             app->last_pinfo = pinfo;
             if (pinfo->range.start == off) return COL(app->vsettings.col_page_start);
-            else return COL(app->vsettings.col_page);
+            if (off >= pinfo->range.end() - pinfo->checksum_size()) return COL(app->vsettings.col_checksum);
+            return COL(app->vsettings.col_page);
           }
         }
       }
@@ -118,6 +128,7 @@ Viewer_Settings make_viewer_settings()
   COL(col_tfile,  90, 90, 90);
   COL(col_page,   125, 0, 125);
   COL(col_page_start, 200, 0, 200);
+  COL(col_checksum, 134, 65, 25);
 #undef COL
   return settings;
 }
@@ -237,6 +248,10 @@ void update_and_render(Arena *arena, App_State &app, f32 delta_time_ms)
         ImGui::PopItemWidth();
       }
 
+      ImGui::ColorEdit3("_Checksum", app.vsettings.col_checksum, flags);
+      ImGui::SameLine(); 
+      if (ImGui::Button("Checksum")) {} // TODO jump to next checksum
+
       ImGui::Separator();
       ImGui::Text("Num pages: %lu", app.rndata.n_pages);
       ImGui::Text("Num elements: %lu", app.rndata.n_elems);

src/render.h

@@ -1,11 +1,12 @@
 struct Viewer_Settings {
-  float col_anchor[3];
+  f32 col_anchor[3];
-  float col_header[3];
+  f32 col_header[3];
-  float col_footer[3];
+  f32 col_footer[3];
-  float col_key[3];
+  f32 col_key[3];
-  float col_tfile[3];
+  f32 col_tfile[3];
-  float col_page[3];
+  f32 col_page[3];
-  float col_page_start[3];
+  f32 col_page_start[3];
+  f32 col_checksum[3];
 
   u64 base_display_addr;
   u64 latest_page_gone_to;

src/rntuple.cpp

@@ -91,8 +91,8 @@ void gather_metadata(Arena *arena, RMicroFileReader &reader, const RNTuple_File_
         const u64 checksum_size = sizeof(u64);
         Page_Info_Node *pinfo = arena_push<Page_Info_Node>(arena);
         pinfo->range.start = page_info.fLocator.GetPosition<u64>(); 
-        pinfo->range.len = page_info.fLocator.fBytesOnStorage + page_info.fHasChecksum * checksum_size;
+        pinfo->range.len = page_info.fLocator.fBytesOnStorage + (page_info.fHasChecksum) * checksum_size;
-        pinfo->n_elems = page_info.fNElements;
+        pinfo->n_elems = page_info.fHasChecksum ? -page_info.fNElements : page_info.fNElements;
 
         if (!pinfo_head) {
           // first node inserted

src/rntuple.h

@@ -8,8 +8,12 @@ struct Byte_Range {
 struct Page_Info_Node {
   Page_Info_Node *next;
 
-  Byte_Range range; // len of range includes the checksum
+  Byte_Range range; // len includes checksum
-  u32 n_elems;
+  i32 n_elems; // negative = page has checksum
+
+  u64 checksum_size() const {
+    return (n_elems < 0) * 8;
+  }
 };
 
 static const Page_Info_Node invalid_pinfo {};