harddisk: Support non-CHD harddisk images in raw and 2MG format [R. Belmont]

src/devices/imagedev/harddriv.cpp

@@ -75,7 +75,7 @@ harddisk_image_device::~harddisk_image_device()
 
 void harddisk_image_device::device_config_complete()
 {
-	add_format("chd", "CHD Hard drive", "chd,hd", hd_option_spec);
+	add_format("chd", "CHD Hard drive", "chd,hd,hdv,2mg", hd_option_spec);
 }
 
 const util::option_guide &harddisk_image_device::create_option_guide() const
@@ -176,8 +176,11 @@ void harddisk_image_device::call_unload()
 		m_hard_disk_handle = nullptr;
 	}
 
-	m_origchd.close();
+	if (m_chd)
-	m_diffchd.close();
+	{
+		m_origchd.close();
+		m_diffchd.close();
+	}
 	m_chd = nullptr;
 }
 
@@ -227,7 +230,6 @@ static chd_error open_disk_diff(emu_options &options, const char *name, chd_file
 image_init_result harddisk_image_device::internal_load_hd()
 {
 	chd_error err = CHDERR_NONE;
-
 	m_chd = nullptr;
 
 	if (m_hard_disk_handle != nullptr)
@@ -243,20 +245,24 @@ image_init_result harddisk_image_device::internal_load_hd()
 	}
 	else
 	{
-		err = m_origchd.open(image_core_file(), true);
+		if (is_filetype("chd"))
-		if (err == CHDERR_NONE)
 		{
-			m_chd = &m_origchd;
+			err = m_origchd.open(image_core_file(), true);
-		}
+
-		else if (err == CHDERR_FILE_NOT_WRITEABLE)
-		{
-			err = m_origchd.open(image_core_file(), false);
 			if (err == CHDERR_NONE)
 			{
-				err = open_disk_diff(device().machine().options(), basename_noext(), m_origchd, m_diffchd);
+				m_chd = &m_origchd;
+			}
+			else if (err == CHDERR_FILE_NOT_WRITEABLE)
+			{
+				err = m_origchd.open(image_core_file(), false);
 				if (err == CHDERR_NONE)
 				{
-					m_chd = &m_diffchd;
+					err = open_disk_diff(device().machine().options(), basename_noext(), m_origchd, m_diffchd);
+					if (err == CHDERR_NONE)
+					{
+						m_chd = &m_diffchd;
+					}
 				}
 			}
 		}
@@ -269,6 +275,30 @@ image_init_result harddisk_image_device::internal_load_hd()
 		if (m_hard_disk_handle != nullptr)
 			return image_init_result::PASS;
 	}
+	else
+	{
+		if (is_open())
+		{
+			uint32_t skip = 0;
+			char header[64];
+
+			fseek(0, SEEK_SET);
+			fread(header, 64);
+
+			// check for 2MG format
+			if (!memcmp(header, "2IMG", 4))
+			{
+				skip = header[0x18] | (header[0x19] << 8) | (header[0x1a] << 16) | (header[0x1b] << 24);
+				osd_printf_verbose("harddriv: found 2MG, creator is %c%c%c%c, data at %08x\n", header[4], header[5], header[6], header[7], skip);
+			}
+
+			m_hard_disk_handle = hard_disk_open(image_core_file(), skip);
+			if (m_hard_disk_handle != nullptr)
+				return image_init_result::PASS;
+		}
+
+		return image_init_result::FAIL;
+	}
 
 	/* if we had an error, close out the CHD */
 	m_origchd.close();

src/devices/imagedev/harddriv.h

@@ -51,7 +51,7 @@ public:
 	virtual bool must_be_loaded() const override { return 0; }
 	virtual bool is_reset_on_load() const override { return 0; }
 	virtual const char *image_interface() const override { return m_interface; }
-	virtual const char *file_extensions() const override { return "chd,hd"; }
+	virtual const char *file_extensions() const override { return "chd,hd,hdv,2mg"; }
 	virtual const util::option_guide &create_option_guide() const override;
 
 	// specific implementation

src/devices/machine/idehd.cpp

@@ -838,7 +838,7 @@ void ide_hdd_device::device_reset()
 
 		// build the features page
 		uint32_t metalength;
-		if (m_handle->read_metadata (HARD_DISK_IDENT_METADATA_TAG, 0, &m_buffer[0], 512, metalength) == CHDERR_NONE)
+		if (m_handle && m_handle->read_metadata (HARD_DISK_IDENT_METADATA_TAG, 0, &m_buffer[0], 512, metalength) == CHDERR_NONE)
 		{
 			for( int w = 0; w < 256; w++ )
 			{

src/lib/util/harddisk.cpp

@@ -9,12 +9,10 @@
 ***************************************************************************/
 
 #include <assert.h>
-
 #include "harddisk.h"
-
+#include "osdcore.h"
 #include <stdlib.h>
 
-
 /***************************************************************************
     TYPE DEFINITIONS
 ***************************************************************************/
@@ -22,6 +20,7 @@
 struct hard_disk_file
 {
 	chd_file *          chd;                /* CHD file */
+	util::core_file     *fhandle;           /* core_file if not a CHD */
 	hard_disk_info      info;               /* hard disk info */
 };
 
@@ -63,10 +62,49 @@ hard_disk_file *hard_disk_open(chd_file *chd)
 
 	/* fill in the data */
 	file->chd = chd;
+	file->fhandle = nullptr;
 	file->info.cylinders = cylinders;
 	file->info.heads = heads;
 	file->info.sectors = sectors;
 	file->info.sectorbytes = sectorbytes;
+	file->info.fileoffset = 0;
+	return file;
+}
+
+hard_disk_file *hard_disk_open(util::core_file &corefile, uint32_t skipoffs)
+{
+	hard_disk_file *file;
+
+	/* allocate memory for the hard disk file */
+	file = (hard_disk_file *)malloc(sizeof(hard_disk_file));
+	if (file == nullptr)
+		return nullptr;
+
+	file->chd = nullptr;
+	file->fhandle = &corefile;
+	file->info.sectorbytes = 512;
+	file->info.cylinders = 0;
+	file->info.heads = 0;
+	file->info.sectors = 0;
+	file->info.fileoffset = skipoffs;
+
+	// attempt to guess geometry in case this is an ATA situation
+	for (uint32_t totalsectors = (corefile.size() - skipoffs) / file->info.sectorbytes; ; totalsectors++)
+		for (uint32_t cursectors = 63; cursectors > 1; cursectors--)
+			if (totalsectors % cursectors == 0)
+			{
+				uint32_t totalheads = totalsectors / cursectors;
+				for (uint32_t curheads = 16; curheads > 1; curheads--)
+					if (totalheads % curheads == 0)
+					{
+						file->info.cylinders = totalheads / curheads;
+						file->info.heads = curheads;
+						file->info.sectors = cursectors;
+						osd_printf_verbose("Guessed CHS of %d/%d/%d\n", file->info.cylinders, file->info.heads, file->info.sectors);
+						return file;
+					}
+			}
+
 	return file;
 }
 
@@ -77,6 +115,11 @@ hard_disk_file *hard_disk_open(chd_file *chd)
 
 void hard_disk_close(hard_disk_file *file)
 {
+	if (file->fhandle)
+	{
+		file->fhandle->flush();
+	}
+
 	free(file);
 }
 
@@ -132,8 +175,18 @@ hard_disk_info *hard_disk_get_info(hard_disk_file *file)
 
 uint32_t hard_disk_read(hard_disk_file *file, uint32_t lbasector, void *buffer)
 {
-	chd_error err = file->chd->read_units(lbasector, buffer);
+	if (file->chd)
-	return (err == CHDERR_NONE);
+	{
+		chd_error err = file->chd->read_units(lbasector, buffer);
+		return (err == CHDERR_NONE);
+	}
+	else
+	{
+		uint32_t actual = 0;
+		file->fhandle->seek(file->info.fileoffset + (lbasector * file->info.sectorbytes), SEEK_SET);
+		actual = file->fhandle->read(buffer, file->info.sectorbytes);
+		return (actual == file->info.sectorbytes);
+	}
 }
 
 
@@ -156,6 +209,16 @@ uint32_t hard_disk_read(hard_disk_file *file, uint32_t lbasector, void *buffer)
 
 uint32_t hard_disk_write(hard_disk_file *file, uint32_t lbasector, const void *buffer)
 {
-	chd_error err = file->chd->write_units(lbasector, buffer);
+	if (file->chd)
-	return (err == CHDERR_NONE);
+	{
+		chd_error err = file->chd->write_units(lbasector, buffer);
+		return (err == CHDERR_NONE);
+	}
+	else
+	{
+		uint32_t actual = 0;
+		file->fhandle->seek(file->info.fileoffset + (lbasector * file->info.sectorbytes), SEEK_SET);
+		actual = file->fhandle->write(buffer, file->info.sectorbytes);
+		return (actual == file->info.sectorbytes);
+	}
 }

src/lib/util/harddisk.h

@@ -29,6 +29,7 @@ struct hard_disk_info
 	uint32_t          heads;
 	uint32_t          sectors;
 	uint32_t          sectorbytes;
+	uint32_t          fileoffset;       // offset in the file where the HDD image starts.  not valid for CHDs.
 };
 
 
@@ -38,6 +39,8 @@ struct hard_disk_info
 ***************************************************************************/
 
 hard_disk_file *hard_disk_open(chd_file *chd);
+hard_disk_file *hard_disk_open(util::core_file &corefile, uint32_t skipoffs);
+
 void hard_disk_close(hard_disk_file *file);
 
 chd_file *hard_disk_get_chd(hard_disk_file *file);