From c691ec6607db63cd5becddbaa647cb3b4970df03 Mon Sep 17 00:00:00 2001
From: Rangi <sylvie.oukaour+rangi42@gmail.com>
Date: Tue, 21 Jul 2026 14:31:05 -0400
Subject: [PATCH] Use `std::optional<uint64_t>` instead of `long` with a
 special -1 sentinel for `seekSize`

---
 include/util.hpp    |  2 +-
 src/asm/actions.cpp |  6 +++---
 src/asm/section.cpp | 24 +++++++++++++-----------
 src/link/output.cpp | 13 +++++++------
 src/util.cpp        | 10 +++++-----
 5 files changed, 29 insertions(+), 26 deletions(-)

diff --git a/include/util.hpp b/include/util.hpp
index 1ec2c49d..daabfabc 100644
--- a/include/util.hpp
+++ b/include/util.hpp
@@ -27,7 +27,7 @@ int xfclose(FILE *file);
 int xclose(int fd);
 
 // Measure file size with `fseek` and `ftell` idiom
-long seekSize(FILE *file);
+std::optional<uint64_t> seekSize(FILE *file);
 
 // Locale-independent character class functions
 bool isNewline(int c);
diff --git a/src/asm/actions.cpp b/src/asm/actions.cpp
index de1ba1ce..7ab356e5 100644
--- a/src/asm/actions.cpp
+++ b/src/asm/actions.cpp
@@ -151,11 +151,11 @@ std::optional<std::string> act_ReadFile(std::string const &name, uint32_t maxLen
 	Defer closeFile{[&] { xfclose(file); }};
 
 	size_t readSize = maxLen;
-	if (long fileSize = seekSize(file); fileSize != -1) {
+	if (std::optional<uint64_t> fileSize = seekSize(file); fileSize.has_value()) {
 		// If the file is seekable and shorter than the max length,
 		// just read as many bytes as there are
-		if (static_cast<size_t>(fileSize) < readSize) {
-			readSize = fileSize;
+		if (*fileSize < readSize) {
+			readSize = *fileSize;
 		}
 		// LCOV_EXCL_START
 	} else if (errno != ESPIPE) {
diff --git a/src/asm/section.cpp b/src/asm/section.cpp
index 165b5fb8..e5c6d49f 100644
--- a/src/asm/section.cpp
+++ b/src/asm/section.cpp
@@ -977,13 +977,14 @@ bool sect_BinaryFile(std::string const &name, uint32_t startPos) {
 	}
 	Defer closeFile{[&] { xfclose(file); }};
 
-	if (long fileSize = seekSize(file); fileSize != -1) {
-		if (startPos > static_cast<size_t>(fileSize)) {
+	if (std::optional<uint64_t> fileSize = seekSize(file); fileSize.has_value()) {
+		if (startPos > *fileSize) {
 			error(
-			    "Specified start position (%" PRIu32 ") is greater than length of \"%s\" (%ld)",
+			    "Specified start position (%" PRIu32 ") is greater than length of \"%s\" (%" PRIu64
+			    ")",
 			    startPos,
 			    name.c_str(),
-			    fileSize
+			    *fileSize
 			);
 			return false;
 		}
@@ -1037,23 +1038,24 @@ bool sect_BinaryFileSlice(std::string const &name, uint32_t startPos, uint32_t l
 	}
 	Defer closeFile{[&] { xfclose(file); }};
 
-	if (long fileSize = seekSize(file); fileSize != -1) {
-		if (startPos > static_cast<size_t>(fileSize)) {
+	if (std::optional<uint64_t> fileSize = seekSize(file); fileSize.has_value()) {
+		if (startPos > *fileSize) {
 			error(
-			    "Specified start position (%" PRIu32 ") is greater than length of \"%s\" (%ld)",
+			    "Specified start position (%" PRIu32 ") is greater than length of \"%s\" (%" PRIu64
+			    ")",
 			    startPos,
 			    name.c_str(),
-			    fileSize
+			    *fileSize
 			);
 			return false;
-		} else if (startPos + length > static_cast<size_t>(fileSize)) {
+		} else if (startPos + length > *fileSize) {
 			error(
 			    "Specified range in `INCBIN` file \"%s\" is out of bounds (%" PRIu32 " + %" PRIu32
-			    " > %ld)",
+			    " > %" PRIu64 ")",
 			    name.c_str(),
 			    startPos,
 			    length,
-			    fileSize
+			    *fileSize
 			);
 			return false;
 		}
diff --git a/src/link/output.cpp b/src/link/output.cpp
index 6869c300..aca09b44 100644
--- a/src/link/output.cpp
+++ b/src/link/output.cpp
@@ -6,6 +6,7 @@
 #include <deque>
 #include <errno.h>
 #include <inttypes.h>
+#include <optional>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -112,23 +113,23 @@ static uint32_t checkOverlaySize() {
 		return 0;
 	}
 
-	long overlaySize = seekSize(overlayFile);
+	std::optional<uint64_t> overlaySize = seekSize(overlayFile);
 
-	if (overlaySize == -1) {
+	if (!overlaySize.has_value()) {
 		warnx("Overlay file is not seekable, cannot check if properly formed");
 		return 0;
 	}
 
-	if (overlaySize % BANK_SIZE) {
+	if (*overlaySize % BANK_SIZE) {
 		warnx("Overlay file does not have a size multiple of 0x4000");
-	} else if (options.is32kMode && overlaySize != 0x8000) {
+	} else if (options.is32kMode && *overlaySize != 0x8000) {
 		warnx("Overlay is not exactly 0x8000 bytes large");
 	}
-	if (overlaySize < 0x8000) {
+	if (*overlaySize < 0x8000) {
 		warnx("Overlay is less than 0x8000 bytes large");
 	}
 
-	return (overlaySize + BANK_SIZE - 1) / BANK_SIZE;
+	return (*overlaySize + BANK_SIZE - 1) / BANK_SIZE;
 }
 
 // Expand `sections[SECTTYPE_ROMX]` to cover all the overlay banks.
diff --git a/src/util.cpp b/src/util.cpp
index 27bd3490..5384107a 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -25,18 +25,18 @@ int xclose(int fd) {
 	return close(fd);
 }
 
-long seekSize(FILE *file) {
+std::optional<uint64_t> seekSize(FILE *file) {
 	if (fseek(file, 0, SEEK_END) != 0) {
-		return -1;
+		return std::nullopt;
 	}
 	long size = ftell(file);
 	if (size < 0) {
-		return -1;
+		return std::nullopt;
 	}
 	if (fseek(file, 0, SEEK_SET) != 0) {
-		return -1;
+		return std::nullopt;
 	}
-	return size;
+	return static_cast<uint64_t>(size);
 }
 
 bool isNewline(int c) {