1 files changed, 127 insertions, 0 deletions
diff --git a/xc/programs/Xserver/hw/xfree86/ddc/edid.c b/xc/programs/Xserver/hw/xfree86/ddc/edid.c
new file mode 100644
index 000000000..6b2a909e1
--- /dev/null
+++ b/xc/programs/Xserver/hw/xfree86/ddc/edid.c
@@ -0,0 +1,127 @@
+/* $XFree86: xc/programs/Xserver/hw/xfree86/ddc/edid.c,v 1.2 1999/01/14 13:04:14 dawes Exp $ */
+
+/* edid.c:  retrieve EDID record from raw DDC1 data stream: data 
+ * is contained in an array of unsigned int each unsigned int 
+ * contains one bit if bit is 0 unsigned int has to be zero else 
+ * unsigned int > 0 
+ * 
+ * Copyright 1998 by Egbert Eich <Egbert.Eich@Physik.TU-Darmstadt.DE>
+ */
+#include "misc.h"
+#include "xf86.h"
+#include "xf86_ansic.h"
+#include "xf86_OSproc.h"
+#include "xf86DDC.h"
+
+int checksum(unsigned char *, int);
+static int find_start(unsigned int *);
+static unsigned char * find_header(unsigned char *);
+static unsigned char * resort(unsigned char *);
+
+unsigned char *
+GetEDID_DDC1(unsigned int *s_ptr)
+{
+    unsigned char *d_block, *d_pos;
+    unsigned int *s_pos, *s_end;
+    int s_start;
+    int i,j;
+    s_start = find_start(s_ptr);
+    if (s_start==-1) return NULL;
+    s_end = s_ptr + NUM;
+    s_pos = s_ptr + s_start;
+    d_block=xalloc(EDID1_LEN);
+    if (!d_block) return NULL;
+    d_pos = d_block;
+    for (i=0;i<EDID1_LEN;i++) {
+	for (j=0;j<8;j++) {
+	    *d_pos <<= 1;
+	    if (*s_pos) {
+		*d_pos |= 0x01;
+	    }
+	    s_pos++; if (s_pos == s_end) s_pos=s_ptr;
+	};
+	s_pos++; if (s_pos == s_end) s_pos=s_ptr;
+	d_pos++;
+    }
+    xfree(s_ptr);
+    if (d_block && checksum(d_block,EDID1_LEN)) return NULL;
+    return (resort(d_block));
+}
+
+int
+checksum(unsigned char *block, int len)
+{
+    int i, result = 0;
+    for (i=0;i<len;i++)
+	result += block[i];
+#ifdef DEBUG
+    if (result & 0xFF) ErrorF("DDC checksum not correct\n");
+#endif
+    return (result&0xFF);
+}
+
+static int
+find_start(unsigned int *ptr)
+{
+    unsigned int comp[9], test[9];
+    int i,j;
+  
+    for (i=0;i<9;i++){
+	comp[i] = *(ptr++);
+	test[i] = 1;
+    }
+    for (i=0;i<127;i++){
+	for (j=0;j<9;j++){
+	    test[j] = test[j] & !(comp[j] ^ *(ptr++));
+	}
+    }
+    for (i=0;i<9;i++)
+	if (test[i]) return (i+1);
+    return (-1);
+}
+
+static unsigned char *
+find_header(unsigned char *block)
+{
+    unsigned char *ptr, *head_ptr, *end;
+    unsigned char header[]={0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00};
+ 
+    ptr = block;
+    end = block + EDID1_LEN;
+    while (ptr<end) {
+	int i;
+	head_ptr = ptr;
+	for (i=0;i<8;i++){
+	    if (header[i] != *(head_ptr++)) break;
+	    if (head_ptr == end) head_ptr = block;
+	}
+	if (i==8) break;
+	ptr++; 
+    }
+    if (ptr == end) return (NULL);
+    return (ptr);
+}
+
+static unsigned char *
+resort(unsigned char *s_block)
+{
+    unsigned char *d_new, *d_ptr, *d_end, *s_ptr, *s_end;
+    unsigned char tmp;
+
+    s_end = s_block + EDID1_LEN;
+    d_new = xalloc(EDID1_LEN);
+    if (!d_new) return NULL;
+    d_end = d_new + EDID1_LEN;
+
+    s_ptr = find_header(s_block);
+    if (!s_ptr) return NULL;
+    for (d_ptr=d_new;d_ptr<d_end;d_ptr++){
+	tmp = *(s_ptr++);
+	*d_ptr = tmp; 
+	if (s_ptr == s_end) s_ptr = s_block;
+    }
+    xfree(s_block);
+    return (d_new);
+}
+
+