From 2ac64e7b95dd26df77d0e386fadd00c2e2151ca1 Mon Sep 17 00:00:00 2001
From: Ian C <ianc@noddybox.co.uk>
Date: Tue, 17 Jan 2017 15:46:24 +0000
Subject: Added 3-byte word output to cpcout and added small tool for
 investigating CPC CDT files.

---
 src/cpcout.c       |  12 +++++
 src/example/dump.c | 129 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 141 insertions(+)
 create mode 100644 src/example/dump.c

diff --git a/src/cpcout.c b/src/cpcout.c
index b962340..53496ea 100644
--- a/src/cpcout.c
+++ b/src/cpcout.c
@@ -70,6 +70,18 @@ static void WriteWord(FILE *fp, int w)
 }
 
 
+static void Write3(FILE *fp, unsigned long l)
+{
+    int f;
+
+    for(f = 0; f < 3; f++)
+    {
+        WriteByte(fp, l & 0xff);
+        l >>= 8u;
+    }
+}
+
+
 static void WriteLong(FILE *fp, unsigned long l)
 {
     int f;
diff --git a/src/example/dump.c b/src/example/dump.c
new file mode 100644
index 0000000..93713de
--- /dev/null
+++ b/src/example/dump.c
@@ -0,0 +1,129 @@
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+
+typedef struct
+{
+    int len;
+    unsigned char *addr;
+} Block;
+
+static int Word(FILE *fp)
+{
+    int i0;
+    int i1;
+
+    i0 = getc(stdin);
+    i1 = getc(stdin);
+
+    return i0 | i1 << 8;
+}
+
+static int Triplet(FILE *fp)
+{
+    int i0;
+    int i1;
+    int i2;
+
+    i0 = getc(stdin);
+    i1 = getc(stdin);
+    i2 = getc(stdin);
+
+    return i0 | i1 << 8 | i2 << 16;
+}
+
+static Block *DumpBlock(FILE *fp)
+{
+    Block *block;
+
+    Word(fp);	/* PILOT */
+    Word(fp);	/* SYNC1 */
+    Word(fp);	/* SYNC2 */
+    Word(fp);	/* ZERO */
+    Word(fp);	/* ONE */
+    Word(fp);	/* PILOT LEN */
+    getc(fp);	/* USED BITS */
+    Word(fp);	/* PAUSE */
+
+    block = malloc(sizeof *block);
+
+    block->len = Triplet(fp);	/* LEN */
+    block->addr = malloc(block->len);
+    fread(block->addr, 1, block->len, fp);
+
+    return block;
+}
+
+static void CompareEnds(Block **block, int count)
+{
+    int f;
+    int n;
+    int min;
+    int done;
+
+    min = 0xffffff;
+
+    for(f=0; f < count; f++)
+    {
+    	if (block[f]->len < min)
+	{
+	    min = block[f]->len;
+	}
+    }
+
+    done = 0;
+
+    for(f = 0; f < min && !done; f++)
+    {
+    	for(n = 0; n < count - 1 && !done; n++)
+	{
+	    if (block[n]->addr[block[n]->len - 1 - f] !=
+	    		block[n+1]->addr[block[n+1]->len - 1 - f])
+	    {
+	    	done = 1;
+	    }
+	}
+    }
+
+    if (done)
+    {
+	printf("Last %d bytes match\n", --f);
+
+	for(n = 0; n < f; n++)
+	{
+	    if (n > 0)
+	    {
+	    	printf(" ");
+	    }
+
+	    printf("%x", (unsigned)block[0]->addr[block[0]->len - 1 - n]);
+	}
+
+	printf("\n");
+    }
+}
+
+int main(int argc, char *argv)
+{
+    int ch;
+    int count;
+    int f;
+    Block *block[256] = {0};
+
+    ch = getc(stdin);
+
+    while(ch != EOF)
+    {
+    	if (ch == 0x11)
+	{
+	    block[count++] = DumpBlock(stdin);
+	}
+
+	ch = getc(stdin);
+    }
+
+    printf("Got %d blocks\n", count);
+
+    CompareEnds(block, count);
+}
-- 
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