Forgot to commit this one during the "search by age" changes.

[libucw.git] / lib / sorter.h

diff --git a/lib/sorter.h b/lib/sorter.h
index be2e80a33b12dade3daffafc9683626998d7b5c0..d1f059fccec58f0240748dc7dc0777cb78eaa27d 100644 (file)
--- a/lib/sorter.h
+++ b/lib/sorter.h
@@ -21,6 +21,8 @@
  *                     deleted as soon as possible
  *  SORT_INPUT_FILE    input is a file with this name
  *  SORT_INPUT_FB      input is a fastbuf stream
+ *                     (can be safely NULL if you want to treat original
+ *                     input in a different way by file read functions)
  *  SORT_INPUT_FBPAIR  input is a pair of fastbuf streams
  *                     (not supported by the presorter)
  *  SORT_OUTPUT_FILE   output is a file with this name
@@ -46,9 +48,11 @@
  *                     fetch data belonging to a just fetched key and store
  *                     them to memory following the key, but not over limit.
  *                     Returns a pointer to first byte after the data
- *                     or NULL if the data don't fit.
- *                     Important: keys carrying no data must be position
- *                     independent.
+ *                     or NULL if the data don't fit. For variable-length
+ *                     keys, it can use the rest of SORT_KEY and even return
+ *                     pointer before end of the key.
+ *                     Important: before PREFIX_fetch_item() succeeds, the key
+ *                     must be position independent, the sorter can copy it.
  *  void PREFIX_store_item(struct fastbuf *f, SORT_KEY *k)
  *                     [used only with SORT_PRESORT]
  *                     write key and all its data read with PREFIX_fetch_data
@@ -159,7 +163,7 @@ P(pass)(struct fastbuf **fb1, struct fastbuf **fb2)
        {
          P(merge_data)(in1, in2, out1, kin1, kin2);
          SWAP(kin1, kprev1, ktmp);
-         next1 = P(fetch_key)(in1, kin1); /* FIXME: Re-use other code? */
+         next1 = P(fetch_key)(in1, kin1);
          run1 = next1 && (P(compare)(kprev1, kin1) LESS 0);
          SWAP(kin2, kprev2, ktmp);
          next2 = P(fetch_key)(in2, kin2);
@@ -372,14 +376,14 @@ struct fastbuf *fb1, struct fastbuf *fb2
 #ifdef SORT_INPUT_FILE
   struct fastbuf *fb1, *fb2;
   fb1 = bopen(inname, O_RDONLY, sorter_stream_bufsize);
-#ifdef SORT_DELETE_INPUT
-  fb1->is_temp_file = SORT_DELETE_INPUT;
-#endif
   fb2 = NULL;
 #elif defined(SORT_INPUT_FB)
   struct fastbuf *fb2 = NULL;
 #endif
 
+#ifdef SORT_DELETE_INPUT
+  fb1->is_temp_file = SORT_DELETE_INPUT;
+#endif
   sorter_pass_counter = 1;
 #ifdef SORT_PRESORT
   P(presort)(&fb1, &fb2);