From 25bc35fbadebbf28eed3c89978e435d2df557b42 Mon Sep 17 00:00:00 2001
From: Ian C <ianc@noddybox.co.uk>
Date: Tue, 6 Jan 2004 02:06:37 +0000
Subject: Devel checkin - added util and snap objects and non-working TAP
 support

---
 src/snap.c | 200 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 200 insertions(+)
 create mode 100644 src/snap.c

(limited to 'src/snap.c')

diff --git a/src/snap.c b/src/snap.c
new file mode 100644
index 0000000..c67c0bf
--- /dev/null
+++ b/src/snap.c
@@ -0,0 +1,200 @@
+/*
+
+    espec - Sinclair Spectrum emulator
+
+    Copyright (C) 2003  Ian Cowburn (ianc@noddybox.demon.co.uk)
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    -------------------------------------------------------------------------
+
+    Utilities for handling snapshots
+
+*/
+static const char ident[]="$Id$";
+
+#include "snap.h"
+
+static const char ident_h[]=ESPEC_SNAP_H;
+
+
+/* ---------------------------------------- MACROS
+*/
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+
+#define ROMLEN 0x4000
+
+
+/* ---------------------------------------- PRIVATE FUNCTIONS
+*/
+static Z80Word GetLSBWord(FILE *fp)
+{
+    if (fp)
+    {
+        int c1,c2;
+
+        c1=getc(fp);
+        c2=getc(fp);
+
+        if (c1==EOF || c2==EOF)
+            return 0;
+
+        return c1+(c2<<8);
+    }
+    else
+        return 0;
+}
+
+
+static void PutLSBWord(FILE *fp, Z80Word w)
+{
+    if (fp)
+    {
+	putc(w&0xff,fp);
+	putc(w>>8,fp);
+    }
+}
+
+
+static Z80Byte GetByte(FILE *fp)
+{
+    int c;
+
+    if (!fp || (c=getc(fp))==EOF)
+        return 0;
+
+    return c;
+}
+
+
+static void PutByte(FILE *fp, Z80Byte b)
+{
+    putc(b,fp);
+}
+
+
+
+/* ---------------------------------------- INTERFACES
+*/
+int TAPLoad(FILE *fp, Z80Byte id, Z80Word *addr, Z80Word *len, Z80Byte *mem)
+{
+    Z80Word blen;
+    Z80Byte type,b,csum,tape_csum;
+
+    if (!fp)
+    	return FALSE;
+
+    /* Get length (wrapping file if at eof)
+    */
+    blen=GetLSBWord(fp);
+
+    if (feof(fp))
+    {
+    	rewind(fp);
+	blen=GetLSBWord(fp);
+    }
+
+    type=GetByte(fp);
+    csum=id;
+
+    /* Have we found the requested block?
+    */
+    if (id==type)
+    {
+    	/* Knock of block type
+	*/
+	blen--;
+
+	while(blen && *len)
+	{
+	    b=GetByte(fp);
+	    csum^=b;
+
+	    if (*addr>=ROMLEN)
+	    	mem[*addr]=b;
+
+	    (*addr)++;
+	    (*len)--;
+	    blen--;
+	}
+
+	/* Get the checksum
+	*/
+	if (blen)
+	{
+	    tape_csum=GetByte(fp);
+	    blen--;
+	}
+	else
+	    tape_csum=b;
+
+	/* In case we've been request less bytes than the block size
+	*/
+	while(blen--)
+	    fgetc(fp);
+
+	/* Check the checksum
+	*/
+	return csum==tape_csum;
+    }
+    else
+    {
+    	/* If it's the wrong type, skip it
+	*/
+	while(blen--)
+	    fgetc(fp);
+
+	return FALSE;
+    }
+}
+
+
+int TAPSave(FILE *fp, Z80Byte id, Z80Word *addr, Z80Word *len, Z80Byte *mem)
+{
+    Z80Byte csum;
+
+    if (!fp)
+    	return FALSE;
+
+    /* Write out the length and ID byte
+    */
+    PutLSBWord(fp,(*len)+2);
+    PutByte(fp,id);
+
+    /* Write out data and calc checksum
+    */
+    csum=id;
+
+    while(*len)
+    {
+    	PutByte(fp,mem[*addr]);
+	csum^=mem[*addr];
+	(*addr)++;
+	(*len)--;
+    }
+
+    PutByte(fp,csum);
+
+    return TRUE;
+}
+
+
+/* END OF FILE */
-- 
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