foo

[visor] / libvisor / src / visor.c

diff --git a/libvisor/src/visor.c b/libvisor/src/visor.c
index cefc924..12b5a02 100644 (file)
--- 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;
                }
        }