vppinfra: clib_bitmap fix

In clib_bitmap_set_region and clib_bitmap_set_multiple the index of
the last bit to set was off by 1. If this index was pointing to the
last bit of the bitmap, another uword would have been allocated,
even though it was unnecessary.

Moreover, in clib_bitmap_set_region, bits in the last word were not
properly set. Indeed, the n_bits_left value is wrong since n_bits
is not decreased by the number of already set bits.

Type: fix

Signed-off-by: Maxime Peim <mpeim@cisco.com>
Change-Id: I8d7ef6f47abb9f1f64f38297da2c59509d74dd72

2 files changed, 144 insertions, 33 deletions

diff --git a/src/plugins/unittest/bitmap_test.c b/src/plugins/unittest/bitmap_test.c
index adee9764f46..f01b8bb6811 100644
--- a/src/plugins/unittest/bitmap_test.c
+++ b/src/plugins/unittest/bitmap_test.c
@@ -16,51 +16,162 @@
 #include <vppinfra/bitmap.h>
 
 static clib_error_t *
+check_bitmap (const char *test_name, const uword *bm, u32 expected_len, ...)
+{
+  clib_error_t *error = 0;
+  u32 i;
+  uword expected_value;
+
+  va_list va;
+  va_start (va, expected_len);
+
+  if (vec_len (bm) != expected_len)
+    {
+      error = clib_error_create ("%s failed, wrong "
+				 "bitmap's size (%u != %u expected)",
+				 test_name, vec_len (bm), expected_len);
+      goto done;
+    }
+
+  for (i = 0; i < expected_len; ++i)
+    {
+      expected_value = va_arg (va, uword);
+      if (bm[i] != expected_value)
+	{
+	  error = clib_error_create (
+	    "%s failed, wrong "
+	    "bitmap's value at index %u (%u != %u expected)",
+	    test_name, i, bm[i], expected_value);
+	  break;
+	}
+    }
+
+done:
+  va_end (va);
+  return error;
+}
+
+static clib_error_t *
 test_bitmap_command_fn (vlib_main_t * vm,
 			unformat_input_t * input, vlib_cli_command_t * cmd)
 {
-  u64 *bm = 0;
-  u64 *bm2 = 0;
-  u64 *dup;
-  uword junk;
+  clib_error_t *error = 0;
+  uword *bm = 0;
+  uword *bm2 = 0;
+  uword *dup = 0;
 
-  bm = clib_bitmap_set_multiple (bm, 2, ~0ULL, BITS (uword));
+  /*  bm should look like:
+   *          bm[0]     bm[1]
+   *  LSB |0011...11|1100...00| MSB
+   */
+  bm = clib_bitmap_set_multiple (0, 2, ~0ULL, BITS (uword));
+  error = check_bitmap ("clib_bitmap_set_multiple 1", bm, 2, ~0ULL << 2, 3);
+  if (error != 0)
+    goto done;
+
+  /*  bm2 should look like:
+   *	    bm2[0]
+   *  LSB |11...11| MSB
+   */
+  bm2 = clib_bitmap_set_multiple (0, 0, ~0ULL, BITS (uword));
+  error = check_bitmap ("clib_bitmap_set_multiple 2", bm2, 1, ~0ULL);
+  if (error != 0)
+    goto done;
 
-  junk = clib_bitmap_next_clear (bm, 3);
-  junk = clib_bitmap_next_clear (bm, 65);
+  /*  bm should look like:
+   *	      bm[0]      bm[1]
+   *  LSB |0011...1100|000...000| MSB
+   */
+  bm = clib_bitmap_set_multiple (bm, 2, pow2_mask (BITS (uword) - 3),
+				 BITS (uword));
+  error = check_bitmap ("clib_bitmap_set_multiple 3", bm, 2,
+			pow2_mask (BITS (uword) - 3) << 2, 0);
+  if (error != 0)
+    goto done;
 
-  bm2 = clib_bitmap_set_multiple (bm2, 0, ~0ULL, BITS (uword));
-  vec_set_len (bm2, 1);
-  junk = clib_bitmap_next_clear (bm2, 0);
+  /*  bm2 should look like:
+   *	     bm2[0]
+   *  LSB |101...111| MSB
+   */
+  bm2 = clib_bitmap_xori (bm2, 1);
+  error = check_bitmap ("clib_bitmap_xori 1", bm2, 1, ~0ULL ^ 2);
+  if (error != 0)
+    goto done;
 
+  /*  bm should look like:
+   *	       bm[0]      bm[1]
+   *  LSB |0011...1100|000...001| MSB
+   */
+  bm = clib_bitmap_xori (bm, 2 * BITS (uword) - 1);
+  error = check_bitmap ("clib_bitmap_xori 2", bm, 2,
+			pow2_mask (BITS (uword) - 3) << 2,
+			1ULL << (BITS (uword) - 1));
+  if (error != 0)
+    goto done;
 
-  bm = clib_bitmap_set_multiple (bm, 2, ~0ULL, BITS (uword) - 3);
-  junk = clib_bitmap_get_multiple (bm, 2, BITS (uword));
-  junk = clib_bitmap_first_set (bm);
-  junk = 1 << 3;
-  bm = clib_bitmap_xori (bm, junk);
-  bm = clib_bitmap_andi (bm, junk);
-  bm = clib_bitmap_xori_notrim (bm, junk);
-  bm = clib_bitmap_andi_notrim (bm, junk);
+  /*  bm should look like:
+   *         bm[0]      bm[1]
+   *  LSB |00100...00|000...001| MSB
+   */
+  bm = clib_bitmap_andi (bm, 2);
+  error =
+    check_bitmap ("clib_bitmap_andi", bm, 2, 4, 1ULL << (BITS (uword) - 1));
+  if (error != 0)
+    goto done;
 
-  bm = clib_bitmap_set_multiple (bm, 2, ~0ULL, BITS (uword) - 3);
-  bm2 = clib_bitmap_set_multiple (bm2, 2, ~0ULL, BITS (uword) - 3);
+  /*  bm should look like:
+   *	     bm[0]
+   *  LSB |00100...00| MSB
+   */
+  bm = clib_bitmap_xori (bm, 2 * BITS (uword) - 1);
+  error = check_bitmap ("clib_bitmap_xori 3", bm, 1, 4);
+  if (error != 0)
+    goto done;
 
+  /*  bm and bm2 should look like:
+   *	     bm[0]     bm[1]
+   *  LSB |0011...11|1100...00| MSB
+   *         bm2[0]    bm2[1]
+   *  LSB |101...111|0011...11| MSB
+   */
+  bm = clib_bitmap_set_multiple (bm, 2, ~0ULL, BITS (uword));
+  bm2 =
+    clib_bitmap_set_multiple (bm2, BITS (uword) + 2, ~0ULL, BITS (uword) - 3);
   dup = clib_bitmap_dup_and (bm, bm2);
-  vec_free (dup);
-  dup = clib_bitmap_dup_andnot (bm, bm2);
-  vec_free (dup);
+  error = check_bitmap ("clib_bitmap_dup_and", dup, 1, bm[0] & bm2[0]);
+  if (error != 0)
+    goto done;
+
+  /*  bm should look like:
+   *	     bm[0]    bm[1]   ...   bm[3]
+   *  LSB |0011...11|11...11| ... |11...11| MSB
+   */
+  bm = clib_bitmap_set_region (bm, 5, 1, 4 * BITS (uword) - 5);
+  error = check_bitmap ("clib_bitmap_set_region 1", bm, 4, ~0ULL << 2, ~0ULL,
+			~0ULL, ~0ULL);
+  if (error != 0)
+    goto done;
+
+  /*  bm should look like:
+   *	     bm[0]    bm[1]   ...      bm[3]
+   *  LSB |0011...11|11...11| ... |11...1100000| MSB
+   */
+  bm = clib_bitmap_set_region (bm, 4 * BITS (uword) - 5, 0, 5);
+  error = check_bitmap ("clib_bitmap_set_region 2", bm, 4, ~0ULL << 2, ~0ULL,
+			~0ULL, pow2_mask (BITS (uword) - 5));
+  if (error != 0)
+    goto done;
+
+done:
   vec_free (bm);
   vec_free (bm2);
+  vec_free (dup);
 
-  return 0;
+  return error;
 }
 
-
-
 /* *INDENT-OFF* */
-VLIB_CLI_COMMAND (test_bihash_command, static) =
-{
+VLIB_CLI_COMMAND (test_bitmap_command, static) = {
   .path = "test bitmap",
   .short_help = "Coverage test for bitmap.h",
   .function = test_bitmap_command_fn,
diff --git a/src/vppinfra/bitmap.h b/src/vppinfra/bitmap.h
index ec3f0a03891..d579afd9979 100644
--- a/src/vppinfra/bitmap.h
+++ b/src/vppinfra/bitmap.h
@@ -305,7 +305,7 @@ clib_bitmap_set_multiple (uword * bitmap, uword i, uword value, uword n_bits)
   i1 = i % BITS (bitmap[0]);
 
   /* Allocate bitmap. */
-  clib_bitmap_vec_validate (bitmap, (i + n_bits) / BITS (bitmap[0]));
+  clib_bitmap_vec_validate (bitmap, (i + n_bits - 1) / BITS (bitmap[0]));
   l = vec_len (bitmap);
 
   m = ~0;
@@ -339,14 +339,15 @@ clib_bitmap_set_multiple (uword * bitmap, uword i, uword value, uword n_bits)
 always_inline uword *
 clib_bitmap_set_region (uword * bitmap, uword i, uword value, uword n_bits)
 {
-  uword a0, a1, b0;
+  uword a0, a1, b0, b1;
   uword i_end, mask;
 
   a0 = i / BITS (bitmap[0]);
   a1 = i % BITS (bitmap[0]);
 
-  i_end = i + n_bits;
+  i_end = i + n_bits - 1;
   b0 = i_end / BITS (bitmap[0]);
+  b1 = i_end % BITS (bitmap[0]);
 
   clib_bitmap_vec_validate (bitmap, b0);
 
@@ -364,8 +365,7 @@ clib_bitmap_set_region (uword * bitmap, uword i, uword value, uword n_bits)
 
   if (a0 == b0)
     {
-      word n_bits_left = n_bits - (BITS (bitmap[0]) - a1);
-      mask = pow2_mask (n_bits_left);
+      mask = (uword) ~0 >> (BITS (bitmap[0]) - b1 - 1);
       if (value)
 	bitmap[a0] |= mask;
       else