From e5c4907791f354da8ebe39100c7dbef7dc349708 Mon Sep 17 00:00:00 2001
From: AJR <ajrhacker@users.noreply.github.com>
Date: Sun, 22 Oct 2023 10:38:48 -0400
Subject: [PATCH] Disallow zero-length regions in ROM definitions and software
 lists

---
 hash/amiga_a3000.xml     |  8 ++++----
 hash/apricot_flop.xml    | 28 ++++++++++++++--------------
 hash/msx1_cart.xml       |  2 +-
 hash/oric1_cass.xml      |  2 +-
 hash/to7_cass.xml        |  2 +-
 src/emu/softlist_dev.cpp |  2 ++
 src/emu/validity.cpp     |  2 ++
 7 files changed, 25 insertions(+), 21 deletions(-)

diff --git a/hash/amiga_a3000.xml b/hash/amiga_a3000.xml
index 092ad0d040b..2e3c6ac0f83 100644
--- a/hash/amiga_a3000.xml
+++ b/hash/amiga_a3000.xml
@@ -70,7 +70,7 @@ SuperKickstart disks, SCSI installation disks and AMIX
 		</part>
 		<part name="tape" interface="a3000_cass">
 			<feature name="part_id" value="Installation Tape"/>
-			<dataarea name="cass" size="0">
+			<dataarea name="cass" size="1">
 				<rom name="cass" size="0" status="nodump" />
 			</dataarea>
 		</part>
@@ -94,7 +94,7 @@ SuperKickstart disks, SCSI installation disks and AMIX
 		</part>
 		<part name="tape" interface="a3000_cass">
 			<feature name="part_id" value="Installation Tape"/>
-			<dataarea name="cass" size="0">
+			<dataarea name="cass" size="1">
 				<rom name="cass" size="0" status="nodump" />
 			</dataarea>
 		</part>
@@ -118,7 +118,7 @@ SuperKickstart disks, SCSI installation disks and AMIX
 		</part>
 		<part name="tape" interface="a3000_cass">
 			<feature name="part_id" value="Installation Tape"/>
-			<dataarea name="cass" size="0">
+			<dataarea name="cass" size="1">
 				<rom name="cass" size="0" status="nodump" />
 			</dataarea>
 		</part>
@@ -148,7 +148,7 @@ SuperKickstart disks, SCSI installation disks and AMIX
 		</part>
 		<part name="tape" interface="a3000_cass">
 			<feature name="part_id" value="Installation Tape"/>
-			<dataarea name="cass" size="0">
+			<dataarea name="cass" size="1">
 				<rom name="cass" size="0" status="nodump" />
 			</dataarea>
 		</part>
diff --git a/hash/apricot_flop.xml b/hash/apricot_flop.xml
index 22105547d86..5808fe6d25b 100644
--- a/hash/apricot_flop.xml
+++ b/hash/apricot_flop.xml
@@ -199,7 +199,7 @@ license:CC0-1.0
 			</dataarea>
 		</part>
 		<part name="flop2" interface="floppy_3_5">
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="dbase2_2.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
@@ -395,7 +395,7 @@ license:CC0-1.0
 		</part>
 		<part name="e" interface="floppy_3_5">
 			<feature name="part_id" value="Disk E (Server Backup)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="networks_13b_f_e.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
@@ -474,7 +474,7 @@ license:CC0-1.0
 		<publisher>ACT</publisher>
 		<part name="a" interface="floppy_3_5">
 			<feature name="part_id" value="Disk A (Server Boot)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="networks_13b_xi_a.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
@@ -498,7 +498,7 @@ license:CC0-1.0
 		</part>
 		<part name="e" interface="floppy_3_5">
 			<feature name="part_id" value="Disk E (Server Backup)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="networks_13b_xi_e.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
@@ -511,7 +511,7 @@ license:CC0-1.0
 		<publisher>ACT</publisher>
 		<part name="a" interface="floppy_3_5">
 			<feature name="part_id" value="Disk A (Server Boot)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="point32_11_a.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
@@ -523,13 +523,13 @@ license:CC0-1.0
 		</part>
 		<part name="c" interface="floppy_3_5">
 			<feature name="part_id" value="Disk C (Portable/F-Series Workstation)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="point32_11_c.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
 		<part name="d" interface="floppy_3_5">
 			<feature name="part_id" value="Disk D (Bank Boot)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="point32_11_d.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
@@ -542,7 +542,7 @@ license:CC0-1.0
 		<publisher>ACT</publisher>
 		<part name="a" interface="floppy_3_5">
 			<feature name="part_id" value="Disk A (Server Boot)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="point32_12_a.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
@@ -554,19 +554,19 @@ license:CC0-1.0
 		</part>
 		<part name="c" interface="floppy_3_5">
 			<feature name="part_id" value="Disk C (Portable/F-Series Workstation)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="point32_12_c.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
 		<part name="d" interface="floppy_3_5">
 			<feature name="part_id" value="Disk D (Bank Boot)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="point32_12_d.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
 		<part name="e" interface="floppy_3_5">
 			<feature name="part_id" value="Disk E (Server Backup)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="point32_12_e.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
@@ -579,7 +579,7 @@ license:CC0-1.0
 		<publisher>ACT</publisher>
 		<part name="a" interface="floppy_3_5">
 			<feature name="part_id" value="Disk A (Server Boot)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="point32_12b_a.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
@@ -603,7 +603,7 @@ license:CC0-1.0
 		</part>
 		<part name="e" interface="floppy_3_5">
 			<feature name="part_id" value="Disk E (Server Backup)" />
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="point32_12b_e.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
@@ -754,7 +754,7 @@ license:CC0-1.0
 			</dataarea>
 		</part>
 		<part name="flop2" interface="floppy_3_5">
-			<dataarea name="flop" size="0">
+			<dataarea name="flop" size="1">
 				<rom name="supercalc3_2.dsk" size="0" status="nodump"/>
 			</dataarea>
 		</part>
diff --git a/hash/msx1_cart.xml b/hash/msx1_cart.xml
index 807673be30c..41f92fee56d 100644
--- a/hash/msx1_cart.xml
+++ b/hash/msx1_cart.xml
@@ -11090,7 +11090,7 @@ Right/left cursor keys select tape baud rate 1200/2400 respectively.
 			</dataarea>
 		</part>
 		<part name="cass" interface="msx_cass">
-			<dataarea name="cass" size="0">
+			<dataarea name="cass" size="1">
 				<rom name="cass" size="0" status="nodump"/>
 			</dataarea>
 		</part>
diff --git a/hash/oric1_cass.xml b/hash/oric1_cass.xml
index 3c7708c172c..e33895e7141 100644
--- a/hash/oric1_cass.xml
+++ b/hash/oric1_cass.xml
@@ -2755,7 +2755,7 @@ The cassette stops during the game loading
 		</part>
 		<part name="cass2" interface="oric1_cass">
 			<feature name="part_id" value="FACE B - ATMOS"/>
-			<dataarea name="cass" size="0">
+			<dataarea name="cass" size="1">
 				<rom name="Mission Impossible - Face B.tap" size="0" status="nodump"/>
 			</dataarea>
 		</part>
diff --git a/hash/to7_cass.xml b/hash/to7_cass.xml
index f317a574de1..f2e25be8a0e 100644
--- a/hash/to7_cass.xml
+++ b/hash/to7_cass.xml
@@ -3490,7 +3490,7 @@ Thanks to DCMOTO (http://dcmoto.free.fr) for info!
 		</part>
 		<part name="cass2" interface="to_cass">
 			<feature name="part_id" value="Side B"/>
-			<dataarea name="cass" size="0">
+			<dataarea name="cass" size="1">
 				<rom name="image-et-signes-2_to7.k7" size="0" crc="00000000" status="nodump" />
 			</dataarea>
 		</part>
diff --git a/src/emu/softlist_dev.cpp b/src/emu/softlist_dev.cpp
index 595e0bb9a73..b65f5f28300 100644
--- a/src/emu/softlist_dev.cpp
+++ b/src/emu/softlist_dev.cpp
@@ -576,6 +576,8 @@ void software_list_device::internal_validity_check(validity_checker &valid)
 						current_length = ROMREGION_GETLENGTH(romp);
 						if (!data_area_map.emplace(romp->name(), current_length).second)
 							osd_printf_error("%s: %s part %s data area has duplicate name '%s'\n", m_filename, shortname, part.name(), romp->name());
+						if (current_length == 0)
+							osd_printf_error("%s: %s part %s data area '%s' has zero length\n", m_filename, shortname, part.name(), romp->name());
 					}
 					else if (ROMENTRY_ISFILE(romp)) // if this is a file, make sure it is properly formatted
 					{
diff --git a/src/emu/validity.cpp b/src/emu/validity.cpp
index 6b44a324ade..4cb6202b4d9 100644
--- a/src/emu/validity.cpp
+++ b/src/emu/validity.cpp
@@ -2204,6 +2204,8 @@ void validity_checker::validate_roms(device_t &root)
 				current_length = ROMREGION_GETLENGTH(romp);
 				if (!m_region_map.emplace(fulltag, current_length).second)
 					osd_printf_error("Multiple ROM_REGIONs with the same tag '%s' defined\n", fulltag);
+				if (current_length == 0)
+					osd_printf_error("ROM region '%s' has zero length\n", fulltag);
 			}
 			else if (ROMENTRY_ISSYSTEM_BIOS(romp)) // If this is a system bios, make sure it is using the next available bios number
 			{