+#include "vimpl.h"
+
+#define vi_malloc vi->mm.malloc
+#define vi_free vi->mm.free
+#define vi_realloc vi->mm.realloc
+
+#define vi_open vi->fop.open
+#define vi_size vi->fop.size
+#define vi_close vi->fop.close
+#define vi_map vi->fop.map
+#define vi_unmap vi->fop.unmap
+#define vi_read vi->fop.read
+#define vi_write vi->fop.write
+#define vi_seek vi->fop.seek
+
+#ifdef HAVE_LIBC
+static const struct vi_alloc stdalloc = { malloc, free, realloc };
+#endif
+
+struct visor *vi_create(struct vi_alloc *mm)
+{
+ struct visor *vi;
+
+#ifdef HAVE_LIBC
+ if(!mm) mm = &stdalloc;
+#else
+ if(!mm) return 0;
+#endif
+
+ if(!(vi = mm->malloc(sizeof *vi))) {
+ return 0;
+ }
+ memset(vi, 0, sizeof *vi);
+ vi->mm = *mm;
+
+ return vi;
+}
+
+void vi_destroy(struct visor *vi)
+{
+ while(vi->buflist) {
+ vi_delete_buf(vi, vi->buflist);
+ }
+ vi_free(vi);
+}
+
+void vi_set_fileops(struct visor *vi, struct vi_fileops *fop)
+{
+ vi->fop = *fop;
+}
+
+void vi_set_ttyops(struct visor *vi, struct vi_ttyops *tty)
+{
+ vi->tty = *tty;
+}
+
+struct vi_buffer *vi_new_buf(struct visor *vi, const char *path)
+{
+ struct vi_buffer *nb;
+
+ if(!(nb = vi_malloc(sizeof *nb))) {
+ vi_error(vi, "failed to allocate new buffer\n");
+ return 0;
+ }
+ memset(nb, 0, sizeof *nb);
+ nb->vi = vi;
+
+ if(path) {
+ if(vi_buf_read(nb, path) == -1) {
+ vi_free(nb);
+ return 0;
+ }
+ }
+
+ if(vi->buflist) {
+ struct vi_buffer *last = vi->buflist->prev;
+ nb->prev = last;
+ nb->next = vi->buflist;
+ last->next = nb;
+ vi->buflist->prev = nb;
+ } else {
+ nb->next = nb->prev = nb;
+ vi->buflist = nb;
+ }
+ return nb;
+}
+
+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 spoffs, unsigned long size)
+{
+ 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 * 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) {
+ 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, &spoffs))) {
+ if(spoffs > 0) {
+ split_span(vb, sp++, spoffs, 1);
+ } else {
+ split_span(vb, sp++, 0, 0);
+ }
+ } else {
+ sp = vb->spans + vb->num_spans;
+ }
+
+ sp->src = src;
+ sp->start = 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, VI_RDONLY | VI_CREAT))) {
+ 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, 0, 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)
+{
+ int i, wbuf_count;
+ struct visor *vi = vb->vi;
+ vi_file *fp;
+ static char wbuf[512];
+
+ if(!path) path = vb->path;
+ if(!path) {
+ vi_error(vi, "failed to write buffer, unknown path\n");
+ return -1;
+ }
+
+ if(!(fp = vi_open(path, VI_WRONLY | VI_CREAT))) {
+ vi_error(vi, "failed to open %s for writing\n", path);
+ return -1;
+ }
+
+ wbuf_count = 0;
+ for(i=0; i<vb->num_spans; i++) {
+ struct vi_span *sp = vb->spans + i;
+ const char *sptxt = vi_buf_span_text(vb, sp);
+ int n, count = 0;
+ while(count < sp->size) {
+ n = sp->size - count;
+ if(n > sizeof wbuf - wbuf_count) {
+ n = sizeof wbuf - wbuf_count;
+ }
+ memcpy(wbuf + wbuf_count, sptxt + count, n);
+ count += n;
+ wbuf_count += n;
+ }
+
+ if(wbuf_count >= sizeof wbuf) {
+ vi_write(fp, wbuf, wbuf_count);
+ }
+ }
+
+ if(wbuf_count > 0) {
+ vi_write(fp, wbuf, wbuf_count);
+ }
+ vi_close(fp);
+ return 0;
+}
+
+long vi_buf_size(struct vi_buffer *vb)
+{
+ int i;
+ long sz = 0;
+
+ for(i=0; i<vb->num_spans; i++) {
+ sz += vb->spans[i].size;
+ }
+ return sz;
+}
+
+struct vi_span *vi_buf_find_span(struct vi_buffer *vb, vi_addr at, vi_addr *soffs)
+{
+ int i;
+ 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;
+ }
+ }
+ return 0;
+}