+
+static int remove_buf(struct visor *vi, struct vi_buffer *vb)
+{
+ if(!vi->buflist) {
+ vi_error(vi, "failed to remove a buffer which doesn't exist\n");
+ return -1;
+ }
+
+ if(vb->next == vb) {
+ if(vi->buflist != vb) {
+ vi_error(vi, "failed to remove buffer, buffer list inconsistency\n");
+ return -1;
+ }
+ vi->buflist = 0;
+ return 0;
+ }
+
+ if(vi->buflist == vb) {
+ vi->buflist = vb->next;
+ }
+ vb->prev->next = vb->next;
+ vb->next->prev = vb->prev;
+ vb->next = vb->prev = vb;
+ return 0;
+}
+
+int vi_delete_buf(struct visor *vi, struct vi_buffer *vb)
+{
+ if(remove_buf(vi, vb) == -1) {
+ return -1;
+ }
+
+ vi_free(vb->path);
+ vi_free(vb->orig);
+ vi_free(vb->add);
+ vi_free(vb->spans);
+ return 0;
+}
+
+int vi_num_buf(struct visor *vi)
+{
+ int count;
+ struct vi_buffer *vb;
+
+ if(!vi->buflist) return 0;
+
+ count = 1;
+ vb = vi->buflist->next;
+ while(vb != vi->buflist) {
+ count++;
+ vb = vb->next;
+ }
+ return count;
+}
+
+struct vi_buffer *vi_getcur_buf(struct visor *vi)
+{
+ return vi->buflist;
+}
+
+void vi_setcur_buf(struct visor *vi, struct vi_buffer *vb)
+{
+ vi->buflist = vb;
+}
+
+struct vi_buffer *vi_next_buf(struct visor *vi)
+{
+ return vi->buflist ? vi->buflist->next : 0;
+}
+
+struct vi_buffer *vi_prev_buf(struct visor *vi)
+{
+ return vi->buflist ? vi->buflist->prev : 0;
+}
+
+/* split_span splits the span sp. if size > 0 it moves the second part to sp+2,
+ * leaving an empty place at sp+1 for the new span. The start point of the
+ * second part is adjusted by size.
+ *
+ * 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)
+{
+ struct vi_span *tail = sp + (size ? 2 : 1);
+ int num_move = vb->num_spans - sp - 1;
+
+ memmove(tail + 1, sp + 1, num_move);
+ vb->num_span += tail - sp;
+
+ sp->size ... CONTINUE HERE.
+}
+
+static int add_span(struct vi_buffer *vb, vi_addr at, int src, vi_addr start, unsigned long size)
+{
+ int i;
+ struct visor *vi = vb->vi;
+ struct vi_span *sp;
+
+ /* make sure we have space for at least two new spans (split + add) */
+ if(vb->num_spans + 1 >= vb->max_spans) {
+ int newmax = vb->max_spans > 0 ? (vb->max_spans << 1) : 16;
+ struct vi_span *tmp = vi_realloc(vb->spans, newmax * sizeof *tmp);
+ if(!tmp) return -1;
+ vb->spans = tmp;
+ vb->max_spans = newmax;
+ }
+
+ if((sp = vi_buf_find_span(vb, at))) {
+ split_span(vb, sp++, at, size);
+ } else {
+ sp = vb->spans + vb->num_spans;
+ }
+
+ sp->src = src;
+ sp->addr = start;
+ sp->size = size;
+ vb->num_spans++;
+ return 0;
+}
+
+void vi_buf_reset(struct vi_buffer *vb)
+{
+ struct visor *vi = vb->vi;
+ struct vi_buffer *prev, *next;
+
+ vi_free(vb->path);
+
+ if(vb->fp) {
+ if(vb->file_mapped) vi_unmap(vb->fp);
+ vi_close(vb->fp);
+ }
+ vi_free(vb->orig);
+ vi_free(vb->add);
+ vi_free(vb->spans);
+
+ prev = vb->prev;
+ next = vb->next;
+ memset(vb, 0, sizeof *vb);
+ vb->prev = prev;
+ vb->next = next;
+}
+
+int vi_buf_read(struct vi_buffer *vb, const char *path)
+{
+ struct visor *vi = vb->vi;
+ vi_file *fp;
+ unsigned long fsz;
+ int plen;
+
+ vi_buf_reset(vb);
+
+ if(!(fp = vi_open(path))) {
+ return -1;
+ }
+ plen = strlen(path);
+ if(!(vb->path = vi_malloc(plen + 1))) {
+ vi_error(vi, "failed to allocate path name buffer\n");
+ vi_buf_reset(vb);
+ return -1;
+ }
+ memcpy(vb->path, path, plen + 1);
+
+ vb->num_spans = 0;
+
+ if((fsz = vi_size(fp))) {
+ /* existing file, map it into memory, or failing that read it */
+ if(!vi->fop.map || !(vb->orig = vi_map(fp))) {
+ if(!(vb->orig = vi_malloc(fsz))) {
+ vi_buf_reset(vb);
+ return -1;
+ }
+ } else {
+ vb->file_mapped = 1;
+ }
+
+ if(add_span(vb, SPAN_ORIG, 0, fsz) == -1) {
+ vi_error(vi, "failed to allocate span\n");
+ vi_buf_reset(vb);
+ return -1;
+ }
+ }
+ vb->orig_size = fsz;
+ return 0;
+}
+
+int vi_buf_write(struct vi_buffer *vb, const char *path)
+{
+}