fb-file: some comments and automatic tests

[libucw.git] / lib / sorter / s-fixint.h

diff --git a/lib/sorter/s-fixint.h b/lib/sorter/s-fixint.h
index 2eca66fff2f14054dc444c0ecbbe34239e46fb24..972f04004e8241f8af1c7bb0427d7d4de8770609 100644 (file)
--- a/lib/sorter/s-fixint.h
+++ b/lib/sorter/s-fixint.h
@@ -7,6 +7,8 @@
  *     of the GNU Lesser General Public License.
  */
 
+#include "lib/stkstring.h"
+
 #define ASORT_PREFIX(x) SORT_PREFIX(array_##x)
 #define ASORT_KEY_TYPE P(key)
 #define ASORT_ELT(i) ary[i]
@@ -14,27 +16,65 @@
 #define ASORT_EXTRA_ARGS , P(key) *ary
 #include "lib/arraysort.h"
 
+/*
+ *  This is a more efficient implementation of the internal sorter,
+ *  which runs under the following assumptions:
+ *
+ *     - the keys have fixed (and small) size
+ *     - no data are present after the key
+ *     - unification does not require any workspace
+ */
+
+static size_t P(internal_workspace)(void)
+{
+  size_t workspace = 0;
+#ifdef CONFIG_UNIFY
+  workspace = sizeof(P(key) *);
+#endif
+#if 0          // FIXME: Workspace for radix-sort if needed
+  workspace = MAX(workspace, sizeof(P(key)));
+#endif
+  return workspace;
+}
+
+static uns P(internal_num_keys)(struct sort_context *ctx)
+{
+  size_t bufsize = ctx->big_buf_size;
+  size_t workspace = P(internal_workspace)();
+  if (workspace)
+    bufsize -= CPU_PAGE_SIZE;
+  u64 maxkeys = bufsize / (sizeof(P(key)) + workspace);
+  return MIN(maxkeys, ~0U);                                    // The number of records must fit in uns
+}
+
 static int P(internal)(struct sort_context *ctx, struct sort_bucket *bin, struct sort_bucket *bout, struct sort_bucket *bout_only)
 {
   sorter_alloc_buf(ctx);
   struct fastbuf *in = sbuck_read(bin);
   P(key) *buf = ctx->big_buf;
-  size_t bufsize = ctx->big_buf_half_size;     /* FIXME: In some cases, we can use the whole buffer */
-#ifdef CPU_64BIT_POINTERS
-  bufsize = MIN((u64)bufsize, (u64)~0U * sizeof(P(key)));      // The number of records must fit in uns
-#endif
-  uns maxkeys = bufsize / sizeof(P(key));
+  uns maxkeys = P(internal_num_keys)(ctx);
 
-  SORT_XTRACE(3, "s-fixint: Reading (maxkeys=%u)", maxkeys);
+  SORT_XTRACE(4, "s-fixint: Reading (maxkeys=%u)", maxkeys);
   uns n = 0;
   while (n < maxkeys && P(read_key)(in, &buf[n]))
     n++;
+  if (!n)
+    return 0;
+  void *workspace UNUSED = ALIGN_PTR(&buf[n], CPU_PAGE_SIZE);
 
-  SORT_XTRACE(3, "s-fixint: Sorting %u items", n);
+  SORT_XTRACE(3, "s-fixint: Sorting %u items (%s items, %s workspace)",
+       n,
+       stk_fsize(n * sizeof(P(key))),
+       stk_fsize(n * P(internal_workspace)()));
+  timestamp_t timer;
+  init_timer(&timer);
   P(array_sort)(n, buf);
+  ctx->total_int_time += get_timer(&timer);
 
-  SORT_XTRACE(3, "s-fixint: Writing");
-  struct fastbuf *out = sbuck_write((n < maxkeys) ? bout_only : bout);
+  SORT_XTRACE(4, "s-fixint: Writing");
+  if (n < maxkeys)
+    bout = bout_only;
+  struct fastbuf *out = sbuck_write(bout);
   bout->runs++;
   uns merged UNUSED = 0;
   for (uns i=0; i<n; i++)
@@ -42,7 +82,18 @@ static int P(internal)(struct sort_context *ctx, struct sort_bucket *bin, struct
 #ifdef SORT_UNIFY
       if (i < n-1 && !P(compare)(&buf[i], &buf[i+1]))
        {
-         ASSERT(0);                    /* FIXME: Implement */
+         P(key) **keys = workspace;
+         uns n = 2;
+         keys[0] = &buf[i];
+         keys[1] = &buf[i+1];
+         while (!P(compare)(&buf[i], &buf[i+n]))
+           {
+             keys[n] = &buf[i+n];
+             n++;
+           }
+         P(write_merged)(out, keys, NULL, n, NULL);
+         merged += n - 1;
+         i += n - 1;
          continue;
        }
 #endif
@@ -61,5 +112,5 @@ static int P(internal)(struct sort_context *ctx, struct sort_bucket *bin, struct
 static u64
 P(internal_estimate)(struct sort_context *ctx, struct sort_bucket *b UNUSED)
 {
-  return ctx->big_buf_half_size;
+  return P(internal_num_keys)(ctx) * sizeof(P(key)) - 1;       // -1 since if the buffer is full, we don't recognize EOF
 }