Factor out draw_str() and friends.

1 files changed, 118 insertions, 0 deletions

diff --git a/lib/linestack.c b/lib/linestack.c
new file mode 100644
index 00000000..b06c97e7
--- /dev/null
+++ b/lib/linestack.c
@@ -0,0 +1,118 @@
+#include "toys.h"
+
+// Insert one stack into another before position in old stack.
+// (Does not copy contents of strings, just shuffles index array contents.)
+void linestack_addstack(struct linestack **lls, struct linestack *throw,
+  long pos)
+{
+  struct linestack *catch = *lls;
+
+  if (CFG_TOYBOX_DEBUG)
+    if (pos > catch->len) error_exit("linestack_addstack past end.");
+
+  // Make a hole, allocating more space if necessary.
+  if (catch->len+throw->len >= catch->max) {
+    // New size rounded up to next multiple of 64, allocate and copy start.
+    catch->max = ((catch->len+throw->len)|63)+1;
+    *lls = xmalloc(sizeof(struct linestack)+catch->max*sizeof(struct ptr_len));
+    memcpy(*lls, catch, sizeof(struct linestack)+pos*sizeof(struct ptr_len));
+  }
+
+  // Copy end (into new allocation if necessary)
+  if (pos != catch->len)
+    memmove((*lls)->idx+pos+throw->len, catch->idx+pos,
+      (catch->len-pos)*sizeof(struct ptr_len));
+
+  // Cleanup if we had to realloc.
+  if (catch != *lls) {
+    free(catch);
+    catch = *lls;
+  }
+
+  memcpy(catch->idx+pos, throw->idx, throw->len*sizeof(struct ptr_len));
+  catch->len += throw->len;
+}
+
+void linestack_insert(struct linestack **lls, long pos, char *line, long len)
+{
+  // alloca() was in 32V and Turbo C for DOS, but isn't in posix or c99.
+  // I'm not thrashing the heap for this, but this should work even if
+  // a broken compiler adds gratuitous padding.
+  struct {
+    struct linestack ls;
+    struct ptr_len pl;
+  } ls;
+
+  ls.ls.len = ls.ls.max = 1;
+  ls.ls.idx[0].ptr = line;
+  ls.ls.idx[0].len = len;
+  linestack_addstack(lls, &ls.ls, pos);
+}
+
+void linestack_append(struct linestack **lls, char *line)
+{
+  linestack_insert(lls, (*lls)->len, line, strlen(line));
+}
+
+struct linestack *linestack_load(char *name)
+{
+  FILE *fp = fopen(name, "r");
+  struct linestack *ls;
+
+  if (!fp) return 0;
+
+  ls = xzalloc(sizeof(struct linestack));
+
+  for (;;) {
+    char *line = 0;
+    ssize_t len;
+
+    if ((len = getline(&line, (void *)&len, fp))<1) break;
+    if (line[len-1]=='\n') len--;
+    linestack_insert(&ls, ls->len, line, len);
+  }
+  fclose(fp);
+
+  return ls;
+}
+
+// Show width many columns, negative means from right edge. Write unprintable
+// chars through escout() instead of write(). If out=0 just measure.
+// Returns width in columns.
+int crunch_str(char **str, int width, FILE *out,
+  int (*escout)(FILE *out, wchar_t wc))
+{
+  int columns = 0, col, bytes, lowlen = escout(0, 0);
+  char *start, *end;
+
+  for (end = start = *str; *end;) {
+    wchar_t wc;
+
+    if (width>=0 && columns+lowlen>width) break;
+
+    bytes = mbrtowc(&wc, end, 99, 0);
+    if (bytes<0 || wc<32 || (col = wcwidth(wc))<0) {
+      bytes = 1;
+      col = escout(out, *end);
+    } else if (out) fwrite(end, bytes, 1, out);
+    end += bytes;
+  }
+  *str = end;
+
+  return columns;
+}
+
+int draw_str(char *start, int width, int (*escout)(FILE *out, wchar_t wc))
+{
+  return crunch_str(&start, width, stdout, escout);
+}
+
+int draw_rstr(char *start, int width, int (*escout)(FILE *out, wchar_t wc))
+{
+  char *s = start;
+  int len = crunch_str(&s, -1, 0, escout);
+
+  s = start;
+  if (len > width) crunch_str(&s, len-width, 0, escout);
+  return crunch_str(&s, width, stdout, escout);
+}