From 7d43c876a4517e23a31b7364f4522868ac1401df Mon Sep 17 00:00:00 2001
From: jpirnay <jens@pirnay.com>
Date: Wed, 25 Mar 2026 17:35:19 +0100
Subject: [PATCH 1/2] Remove 2GB limit for XTC files

---
 lib/Xtc/Xtc/XtcParser.cpp | 25 +++++++++++++++++++++----
 lib/Xtc/Xtc/XtcTypes.h    |  6 +++---
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/lib/Xtc/Xtc/XtcParser.cpp b/lib/Xtc/Xtc/XtcParser.cpp
index 12e8a61d..5af11e61 100644
--- a/lib/Xtc/Xtc/XtcParser.cpp
+++ b/lib/Xtc/Xtc/XtcParser.cpp
@@ -12,9 +12,25 @@
 #include <Logging.h>
 
 #include <cstring>
+#include <limits>
 
 namespace xtc {
 
+namespace {
+
+bool canSeekToOffset(const uint64_t offset) {
+  return offset <= static_cast<uint64_t>(std::numeric_limits<size_t>::max());
+}
+
+bool seekToOffset(FsFile& file, const uint64_t offset) {
+  if (!canSeekToOffset(offset)) {
+    return false;
+  }
+  return file.seek(static_cast<size_t>(offset));
+}
+
+}  // namespace
+
 XtcParser::XtcParser()
     : m_isOpen(false),
       m_defaultWidth(DISPLAY_WIDTH),
@@ -186,7 +202,7 @@ XtcError XtcParser::readPageTable() {
       return XtcError::READ_ERROR;
     }
 
-    m_pageTable[i].offset = static_cast<uint32_t>(entry.dataOffset);
+    m_pageTable[i].offset = entry.dataOffset;
     m_pageTable[i].size = entry.dataSize;
     m_pageTable[i].width = entry.width;
     m_pageTable[i].height = entry.height;
@@ -331,8 +347,8 @@ size_t XtcParser::loadPage(uint32_t pageIndex, uint8_t* buffer, size_t bufferSiz
   const PageInfo& page = m_pageTable[pageIndex];
 
   // Seek to page data
-  if (!m_file.seek(page.offset)) {
-    LOG_DBG("XTC", "Failed to seek to page %u at offset %lu", pageIndex, page.offset);
+  if (!seekToOffset(m_file, page.offset)) {
+    LOG_DBG("XTC", "Failed to seek to page %u at offset %llu", pageIndex, static_cast<unsigned long long>(page.offset));
     m_lastError = XtcError::READ_ERROR;
     return 0;
   }
@@ -399,7 +415,8 @@ XtcError XtcParser::loadPageStreaming(uint32_t pageIndex,
   const PageInfo& page = m_pageTable[pageIndex];
 
   // Seek to page data
-  if (!m_file.seek(page.offset)) {
+  if (!seekToOffset(m_file, page.offset)) {
+    LOG_DBG("XTC", "Failed to seek to page %u at offset %llu", pageIndex, static_cast<unsigned long long>(page.offset));
     return XtcError::READ_ERROR;
   }
 
diff --git a/lib/Xtc/Xtc/XtcTypes.h b/lib/Xtc/Xtc/XtcTypes.h
index 5cee691d..83dfd340 100644
--- a/lib/Xtc/Xtc/XtcTypes.h
+++ b/lib/Xtc/Xtc/XtcTypes.h
@@ -86,15 +86,15 @@ struct XtgPageHeader {
 };
 #pragma pack(pop)
 
-// Page information (internal use, optimized for memory)
+// Page information (internal use)
 struct PageInfo {
-  uint32_t offset;   // File offset to page data (max 4GB file size)
+  uint64_t offset;   // File offset to page data
   uint32_t size;     // Data size (bytes)
   uint16_t width;    // Page width
   uint16_t height;   // Page height
   uint8_t bitDepth;  // 1 = XTG (1-bit), 2 = XTH (2-bit grayscale)
   uint8_t padding;   // Alignment padding
-};  // 16 bytes total
+};  // 20 bytes total
 
 struct ChapterInfo {
   std::string name;

From afe0b8222806edb1214d93c32905536178aa3f2c Mon Sep 17 00:00:00 2001
From: jpirnay <jens@pirnay.com>
Date: Wed, 25 Mar 2026 17:53:18 +0100
Subject: [PATCH 2/2] Cover remaining seeks

---
 lib/Xtc/Xtc/XtcParser.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/Xtc/Xtc/XtcParser.cpp b/lib/Xtc/Xtc/XtcParser.cpp
index 5af11e61..52adcc76 100644
--- a/lib/Xtc/Xtc/XtcParser.cpp
+++ b/lib/Xtc/Xtc/XtcParser.cpp
@@ -186,7 +186,7 @@ XtcError XtcParser::readPageTable() {
   }
 
   // Seek to page table
-  if (!m_file.seek(m_header.pageTableOffset)) {
+  if (!seekToOffset(m_file, m_header.pageTableOffset)) {
     LOG_DBG("XTC", "Failed to seek to page table at %llu", m_header.pageTableOffset);
     return XtcError::READ_ERROR;
   }
@@ -272,7 +272,7 @@ XtcError XtcParser::readChapters() {
     return XtcError::OK;
   }
 
-  if (!m_file.seek(chapterOffset)) {
+  if (!seekToOffset(m_file, chapterOffset)) {
     return XtcError::READ_ERROR;
   }