X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=visor;a=blobdiff_plain;f=libvisor%2Fsrc%2Fvisor.c;h=12b5a02ab0b730b54a80395d7eb98763269ea3a2;hp=cefc924618d2445571873b100d0362c2d38377bf;hb=94c867869ece77f27cf3c8b637d44e13d86f5b88;hpb=a4536cf08230dba14f221b661abd7804fcc1ebbc

diff --git a/libvisor/src/visor.c b/libvisor/src/visor.c
index cefc924..12b5a02 100644
--- a/libvisor/src/visor.c
+++ b/libvisor/src/visor.c
@@ -186,20 +186,44 @@ struct vi_buffer *vi_prev_buf(struct visor *vi)
  * It can't fail, because it's always called with the span array having at
  * least two empty slots (see: add_span).
  */
-void split_span(struct vi_buffer *vb, struct vi_span *sp, vi_addr at, unsigned long size)
+void split_span(struct vi_buffer *vb, struct vi_span *sp, vi_addr spoffs, unsigned long size)
 {
-	struct vi_span *tail = sp + (size ? 2 : 1);
+	int newseg = size > 0 ? 1 : 0;
+	struct vi_span *tail = sp + newseg + 1;
 	int num_move = vb->spans + vb->num_spans - sp - 1;
 
-	memmove(tail + 1, sp + 1, num_move);
+	memmove(tail + 1, sp + 1, num_move * sizeof *sp);
 	vb->num_spans += tail - sp;
 
+	*tail = *sp;
+	sp->size = spoffs;
+	tail->start += spoffs;
+	tail->size -= spoffs;
+
+	sp = tail;
+	for(;;) {
+		if(size <= tail->size) {
+			tail->size -= size;
+			break;
+		}
+		size -= tail->size;
+		tail->size = 0;
+		tail++;
+	}
+
+	if(tail > sp) {
+		/* we produced one or more zero-sized spans, drop them */
+		num_move = vb->num_spans - (tail - sp);
+		memmove(sp, tail, num_move * sizeof *sp);
+		vb->num_spans -= num_move;
+	}
 }
 
 static int add_span(struct vi_buffer *vb, vi_addr at, int src, vi_addr start, unsigned long size)
 {
 	struct visor *vi = vb->vi;
 	struct vi_span *sp;
+	vi_addr spoffs;
 
 	/* make sure we have space for at least two new spans (split + add) */
 	if(vb->num_spans + 1 >= vb->max_spans) {
@@ -210,8 +234,12 @@ static int add_span(struct vi_buffer *vb, vi_addr at, int src, vi_addr start, un
 		vb->max_spans = newmax;
 	}
 
-	if((sp = vi_buf_find_span(vb, at))) {
-		split_span(vb, sp++, at, size);
+	if((sp = vi_buf_find_span(vb, at, &spoffs))) {
+		if(spoffs > 0) {
+			split_span(vb, sp++, spoffs, 1);
+		} else {
+			split_span(vb, sp++, 0, 0);
+		}
 	} else {
 		sp = vb->spans + vb->num_spans;
 	}
@@ -243,6 +271,7 @@ void vi_buf_reset(struct vi_buffer *vb)
 	memset(vb, 0, sizeof *vb);
 	vb->prev = prev;
 	vb->next = next;
+	vb->vi = vi;
 }
 
 int vi_buf_read(struct vi_buffer *vb, const char *path)
@@ -344,14 +373,16 @@ long vi_buf_size(struct vi_buffer *vb)
 	return sz;
 }
 
-struct vi_span *vi_buf_find_span(struct vi_buffer *vb, vi_addr at)
+struct vi_span *vi_buf_find_span(struct vi_buffer *vb, vi_addr at, vi_addr *soffs)
 {
 	int i;
-	long sz = 0;
+	long sz = 0, prev_sz;
 
 	for(i=0; i<vb->num_spans; i++) {
+		prev_sz = sz;
 		sz += vb->spans[i].size;
 		if(sz > at) {
+			if(soffs) *soffs = at - prev_sz;
 			return vb->spans + i;
 		}
 	}