Makefile

@@ -6,15 +6,15 @@ SHARED_LIB = libsparsemap.so
 LIBS =  -lm
 #CFLAGS = -Wall -Wextra -Wpedantic -Of -std=c11 -Iinclude/ -fPIC
 #CFLAGS = -Wall -Wextra -Wpedantic -Og -g -std=c11 -Iinclude/ -fPIC
-#CFLAGS = -DSPARSEMAP_DIAGNOSTIC -DDEBUG -Wall -Wextra -Wpedantic -O0 -g -std=c11 -Iinclude/ -fPIC
+CFLAGS = -DSPARSEMAP_DIAGNOSTIC -DDEBUG -Wall -Wextra -Wpedantic -O0 -g -std=c11 -Iinclude/ -fPIC
-CFLAGS = -DSPARSEMAP_DIAGNOSTIC -DDEBUG -Wall -Wextra -Wpedantic -Ofast -g -std=c11 -Iinclude/ -fPIC
+#CFLAGS = -DSPARSEMAP_DIAGNOSTIC -DDEBUG -Wall -Wextra -Wpedantic -Ofast -g -std=c11 -Iinclude/ -fPIC
 #CFLAGS = -Wall -Wextra -Wpedantic -Og -g -std=c11 -Iinclude/ -fPIC
 #CFLAGS = -Wall -Wextra -Wpedantic -Ofast -g -std=c11 -Iinclude/ -fPIC
 #CFLAGS = -DSPARSEMAP_DIAGNOSTIC -DDEBUG -Wall -Wextra -Wpedantic -Og -g -fsanitize=address,leak,object-size,pointer-compare,pointer-subtract,null,return,bounds,pointer-overflow,undefined -fsanitize-address-use-after-scope -std=c11 -Iinclude/ -fPIC
 #CFLAGS = -Wall -Wextra -Wpedantic -Og -g -fsanitize=all -fhardened -std=c11 -Iinclude/ -fPIC
 
-#TEST_FLAGS = -DDEBUG -Wall -Wextra -Wpedantic -O0 -g -std=c11 -Iinclude/ -Itests/ -fPIC
+TEST_FLAGS = -DDEBUG -Wall -Wextra -Wpedantic -O0 -g -std=c11 -Iinclude/ -Itests/ -fPIC
-TEST_FLAGS = -Wall -Wextra -Wpedantic -Ofast -g -std=c11 -Iinclude/ -Itests/ -fPIC
+#TEST_FLAGS = -Wall -Wextra -Wpedantic -Ofast -g -std=c11 -Iinclude/ -Itests/ -fPIC
 #TEST_FLAGS = -Wall -Wextra -Wpedantic -Og -g -std=c11 -Iinclude/ -Itests/ -fPIC
 #TEST_FLAGS = -DDEBUG -Wall -Wextra -Wpedantic -Og -g -fsanitize=address,leak,object-size,pointer-compare,pointer-subtract,null,return,bounds,pointer-overflow,undefined -fsanitize-address-use-after-scope -std=c11 -Iinclude/ -fPIC
 

src/sparsemap.c

@@ -264,15 +264,15 @@ __sm_chunk_increase_capacity(__sm_chunk_t *chunk, size_t capacity)
 
   size_t increased = 0;
   register uint8_t *p = (uint8_t *)chunk->m_data;
-  for (size_t i = 0; i < sizeof(sm_bitvec_t); i++) {
+  for (size_t i = 0; i < sizeof(sm_bitvec_t); i++, p++) {
     if (!*p || *p == 0xff) {
       continue;
     }
     for (int j = 0; j < SM_FLAGS_PER_INDEX_BYTE; j++) {
       size_t flags = SM_CHUNK_GET_FLAGS(*p, j);
       if (flags == SM_PAYLOAD_NONE) {
-        p[i] &= ~((sm_bitvec_t)SM_PAYLOAD_ONES << (j * 2));
+        *p &= ~((sm_bitvec_t)SM_PAYLOAD_ONES << (j * 2));
-        p[i] |= ((sm_bitvec_t)SM_PAYLOAD_ZEROS << (j * 2));
+        *p |= ((sm_bitvec_t)SM_PAYLOAD_ZEROS << (j * 2));
         increased += SM_BITS_PER_VECTOR;
         if (increased + initial_capacity == capacity) {
           __sm_assert(__sm_chunk_get_capacity(chunk) == capacity);
@@ -962,8 +962,8 @@ __sm_remove_data(sparsemap_t *map, size_t offset, size_t gap_size)
  *
  * @param[in] chunk The chunk in question.
  * @param[in] offset The offset of the first bit in the chunk to be merged.
- * @todo merge vectors rather than call sparsemap_set() in a loop
  */
+#if 0
 void
 __sm_merge_chunk(sparsemap_t *chunk, sparsemap_idx_t offset, __sm_chunk_t src)
 {
@@ -974,7 +974,7 @@ __sm_merge_chunk(sparsemap_t *chunk, sparsemap_idx_t offset, __sm_chunk_t src)
     }
   }
 }
-#if 0
+#endif
 void
 __sm_merge_chunk(sparsemap_t *map, sparsemap_idx_t idx, sparsemap_idx_t capacity, __sm_chunk_t *dst_chunk, __sm_chunk_t *src_chunk)
 {
@@ -1003,7 +1003,6 @@ __sm_merge_chunk(sparsemap_t *map, sparsemap_idx_t idx, sparsemap_idx_t capacity
     }
   }
 }
-#endif
 
 /*
  * The following is the "Sparsemap" implementation, it uses chunks (code above)
@@ -1190,7 +1189,7 @@ sparsemap_set(sparsemap_t *map, sparsemap_idx_t idx, bool value)
     __sm_append_data(map, &buf[0], sizeof(buf));
 
     uint8_t *p = __sm_get_chunk_data(map, 0);
-    *(sm_idx_t *)p = __sm_get_chunk_aligned_offset(idx); // TODO: vector aligned?
+    *(sm_idx_t *)p = __sm_get_vector_aligned_offset(idx); // TODO: vector or chunk aligned?
 
     __sm_set_chunk_count(map, 1);
 
@@ -1411,35 +1410,6 @@ size_t
 sparsemap_count(sparsemap_t *map)
 {
   return sparsemap_rank(map, 0, SPARSEMAP_IDX_MAX, true);
-#if 0
-  size_t c = 0, count = __sm_get_chunk_count(map);
-
-  if (count == 0) {
-    return 0;
-  }
-  uint8_t *p = __sm_get_chunk_data(map, 0);
-  for (size_t i = 0; i < count; i++) {
-    p += sizeof(sm_idx_t);
-    __sm_chunk_t chunk;
-    __sm_chunk_init(&chunk, p);
-    for (size_t m = 0; m < sizeof(sm_bitvec_t); m++, p++) {
-      for (int n = 0; n < SM_FLAGS_PER_INDEX_BYTE; n++) {
-        size_t flags = SM_CHUNK_GET_FLAGS(*p, n);
-        if (flags == SM_PAYLOAD_NONE) {
-          continue;
-        } else if (flags == SM_PAYLOAD_ZEROS) {
-          continue;
-        } else if (flags == SM_PAYLOAD_ONES) {
-          c += SM_BITS_PER_VECTOR;
-        } else if (flags == SM_PAYLOAD_MIXED) {
-          sm_bitvec_t w = chunk.m_data[1 + __sm_chunk_get_position(&chunk, m * SM_FLAGS_PER_INDEX_BYTE + n)];
-          c += popcountll(w);
-        }
-      }
-    }
-  }
-  return c;
-#endif
 }
 
 void
@@ -1463,75 +1433,121 @@ sparsemap_scan(sparsemap_t *map, void (*scanner)(sm_idx_t[], size_t, void *aux),
 }
 
 int
-sparsemap_merge(sparsemap_t *map, sparsemap_t *other)
+sparsemap_merge(sparsemap_t *destination, sparsemap_t *source)
 {
   uint8_t *src, *dst;
-  size_t src_count = __sm_get_chunk_count(other);
+  size_t src_count = __sm_get_chunk_count(source);
-  size_t dst_count = __sm_get_chunk_count(map);
+  sparsemap_idx_t src_starting_offset = sparsemap_get_starting_offset(source);
-  size_t max_chunk_count = src_count + dst_count;
+  sparsemap_idx_t src_ending_offset = sparsemap_get_ending_offset(source);
-  ssize_t difference = map->m_capacity - (other->m_data_used + src_count * (sizeof(sm_idx_t) + sizeof(sm_bitvec_t) * 2));
+  sparsemap_idx_t dst_ending_offset = sparsemap_get_ending_offset(destination);
+
+  if (src_count == 0) {
+    return 0;
+  }
+
+  ssize_t remaining_capacity = destination->m_capacity - destination->m_data_used -
+    (source->m_data_used + src_count * (sizeof(sm_idx_t) + sizeof(sm_bitvec_t) * 2));
 
   /* Estimate worst-case overhead required for merge. */
-  if (difference <= 0) {
+  if (remaining_capacity <= 0) {
     errno = ENOSPC;
-    return -difference;
+    return -remaining_capacity;
   }
 
-  dst = __sm_get_chunk_data(map, 0);
+  size_t i = src_starting_offset;
-  src = __sm_get_chunk_data(other, 0);
+  size_t merge_end_offset = __sm_get_chunk_aligned_offset(src_ending_offset) + SM_CHUNK_MAX_CAPACITY;
-  for (size_t i = 0; i < max_chunk_count && src_count; i++) {
+  while (i <= merge_end_offset) {
+    ssize_t src_offset = __sm_get_chunk_offset(source, i);
+    src = __sm_get_chunk_data(source, src_offset);
     sm_idx_t src_start = *(sm_idx_t *)src;
+    __sm_chunk_t src_chunk;
+    __sm_chunk_init(&src_chunk, src + sizeof(sm_idx_t));
+    size_t src_capacity = __sm_chunk_get_capacity(&src_chunk);
+    ssize_t dst_offset = __sm_get_chunk_offset(destination, src_start);
+    if (dst_offset >= 0) {
+      dst = __sm_get_chunk_data(destination, dst_offset);
       sm_idx_t dst_start = *(sm_idx_t *)dst;
-    src_start = __sm_get_chunk_aligned_offset(src_start);
-    dst_start = __sm_get_chunk_aligned_offset(dst_start);
-    if (src_start > dst_start && dst_count > 0) {
       __sm_chunk_t dst_chunk;
       __sm_chunk_init(&dst_chunk, dst + sizeof(sm_idx_t));
-      dst += sizeof(sm_idx_t) + __sm_chunk_get_size(&dst_chunk);
+      size_t dst_capacity = __sm_chunk_get_capacity(&dst_chunk);
-      dst_count--;
+
-      continue;
+      /* Source chunk precedes next destination chunk. */
-    }
+      if ((src_start + src_capacity) <= dst_start) {
-    if (src_start == dst_start && dst_count > 0) {
-      /* Chunks overlap, merge them. */
-      __sm_chunk_t src_chunk;
-      __sm_chunk_init(&src_chunk, src + sizeof(sm_idx_t));
-      __sm_chunk_t dst_chunk;
-      __sm_chunk_init(&dst_chunk, dst + sizeof(sm_idx_t));
-      __sm_merge_chunk(map, src_start, src_chunk);
-      *(sm_idx_t *)dst = __sm_get_chunk_aligned_offset(src_start);
-      src += sizeof(sm_idx_t) + __sm_chunk_get_size(&src_chunk);
-      dst += sizeof(sm_idx_t) + __sm_chunk_get_size(&dst_chunk);
-      dst_count--;
-      src_count--;
-      continue;
-    }
-    if (src_start < dst_start || dst_count == 0) {
-      __sm_chunk_t src_chunk;
-      __sm_chunk_init(&src_chunk, src + sizeof(sm_idx_t));
         size_t src_size = __sm_chunk_get_size(&src_chunk);
-      if (dst_count == 0) {
+        size_t offset = __sm_get_chunk_offset(destination, dst_start);
-        __sm_append_data(map, src, sizeof(sm_idx_t) + src_size);
+        __sm_insert_data(destination, offset, src, sizeof(sm_idx_t) + src_size);
-      } else {
+        /* Update the chunk count and data_used. */
-        size_t offset = __sm_get_chunk_offset(map, dst_start);
+        __sm_set_chunk_count(destination, __sm_get_chunk_count(destination) + 1);
-        __sm_insert_data(map, offset, src, sizeof(sm_idx_t) + src_size);
+        i += src_capacity;
+        continue;
       }
 
+      /* Source chunk follows next destination chunk. */
+      if (src_start >= (dst_start + dst_capacity)) {
+        size_t src_size = __sm_chunk_get_size(&src_chunk);
+        __sm_append_data(destination, src, sizeof(sm_idx_t) + src_size);
+        /* Update the chunk count and data_used. */
+        __sm_set_chunk_count(destination, __sm_get_chunk_count(destination) + 1);
+        i += src_capacity;
+        continue;
+      }
+
+      if (src_start == dst_start) {
+        if (dst_capacity < src_capacity) {
+          __sm_chunk_increase_capacity(&dst_chunk, src_capacity);
+          dst_capacity = __sm_chunk_get_capacity(&dst_chunk);
+        }
+        __sm_merge_chunk(destination, src_start, dst_capacity, &dst_chunk, &src_chunk);
+        i += dst_capacity;
+        continue;
+      }
+
+      if (dst_start < src_start) {
+        if (dst_capacity < src_capacity) {
+          __sm_chunk_increase_capacity(&dst_chunk, src_capacity);
+        }
+        size_t src_end = src_start + src_capacity;
+        sparsemap_idx_t n = src_start;
+        while (n < src_end) {
+          if (sparsemap_is_set(source, n)) {
+            sparsemap_set(destination, n, true);
+          }
+          n++;
+        }
+        i = src_end;
+        continue;
+      }
+      assert(!"shouldn't be here"); // TODO...
+    } else {
+      if (src_start > dst_ending_offset || dst_offset == -1) {
+        /* Starting offset is after destination chunks, so append data. */
+        size_t src_size = __sm_chunk_get_size(&src_chunk);
+        __sm_append_data(destination, src, sizeof(sm_idx_t) + src_size);
+
         /* Update the chunk count and data_used. */
-      __sm_set_chunk_count(map, __sm_get_chunk_count(map) + 1);
+        __sm_set_chunk_count(destination, __sm_get_chunk_count(destination) + 1);
 
-      /* Carry on to the next chunk. */
+        i += src_capacity;
-      __sm_chunk_t dst_chunk;
+        continue;
-      __sm_chunk_init(&dst_chunk, dst + sizeof(sm_idx_t));
+      } else {
-      src += sizeof(sm_idx_t) + __sm_chunk_get_size(&src_chunk);
+        /* Source chunk precedes next destination chunk. */
-      dst += sizeof(sm_idx_t) + __sm_chunk_get_size(&dst_chunk);
+        size_t src_size = __sm_chunk_get_size(&src_chunk);
-      src_count--;
+        size_t offset = __sm_get_chunk_offset(destination, src_start);
+        __sm_insert_data(destination, offset, src, sizeof(sm_idx_t) + src_size);
+
+        /* Update the chunk count and data_used. */
+        __sm_set_chunk_count(destination, __sm_get_chunk_count(destination) + 1);
+
+        i += src_capacity;
+        continue;
+      }
     }
   }
   return 0;
 }
-#if 0
+
 int
-sparsemap_merge(sparsemap_t *destination, sparsemap_t *source)
+__sparsemap_merge(sparsemap_t *destination, sparsemap_t *source)
 {
   uint8_t *src, *dst;
   size_t src_count = __sm_get_chunk_count(source);
@@ -1551,66 +1567,80 @@ sparsemap_merge(sparsemap_t *destination, sparsemap_t *source)
   for (size_t i = 0; i < max_chunk_count && src_count; i++) {
     sm_idx_t src_start = *(sm_idx_t *)src;
     sm_idx_t dst_start = *(sm_idx_t *)dst;
-    src_start = __sm_get_chunk_aligned_offset(src_start);
-    dst_start = __sm_get_chunk_aligned_offset(dst_start);
-    if (src_start > dst_start && dst_count > 0) {
-      __sm_chunk_t dst_chunk;
-      __sm_chunk_init(&dst_chunk, dst + sizeof(sm_idx_t));
-      dst += sizeof(sm_idx_t) + __sm_chunk_get_size(&dst_chunk);
-      dst_count--;
-      continue;
-    }
-    if (src_start == dst_start && dst_count > 0) {
-      /* Chunks overlap, merge them. */
     __sm_chunk_t src_chunk;
     __sm_chunk_init(&src_chunk, src + sizeof(sm_idx_t));
     __sm_chunk_t dst_chunk;
     __sm_chunk_init(&dst_chunk, dst + sizeof(sm_idx_t));
     size_t src_capacity = __sm_chunk_get_capacity(&src_chunk);
     size_t dst_capacity = __sm_chunk_get_capacity(&dst_chunk);
-      if (dst_capacity < src_capacity) {
+    /* Chunks do not overlap. */
-        __sm_chunk_increase_capacity(&dst_chunk, src_capacity);
-      }
-      if (*(sm_idx_t *)dst > *(sm_idx_t *)src) {
-        *(sm_idx_t *)dst = *(sm_idx_t *)src;
-      }
-      __sm_merge_chunk(destination, src_start, src_capacity, &dst_chunk, &src_chunk);
-      src += sizeof(sm_idx_t) + __sm_chunk_get_size(&src_chunk);
-      dst += sizeof(sm_idx_t) + __sm_chunk_get_size(&dst_chunk);
-      dst_count--;
-      src_count--;
-      continue;
-    }
-    if (src_start < dst_start || dst_count == 0) {
-      __sm_chunk_t src_chunk;
-      __sm_chunk_init(&src_chunk, src + sizeof(sm_idx_t));
-      size_t src_size = __sm_chunk_get_size(&src_chunk);
     if (dst_count == 0) {
+      /* No destination chunks, so append data. */
+      size_t src_size = __sm_chunk_get_size(&src_chunk);
       __sm_append_data(destination, src, sizeof(sm_idx_t) + src_size);
-      } else {
-        size_t offset = __sm_get_chunk_offset(destination, dst_start);
-        __sm_insert_data(destination, offset, src, sizeof(sm_idx_t) + src_size);
-      }
 
       /* Update the chunk count and data_used. */
       __sm_set_chunk_count(destination, __sm_get_chunk_count(destination) + 1);
+      src_count--;
+      src += sizeof(sm_idx_t) + __sm_chunk_get_size(&src_chunk);
+    } else if (src_start >= (dst_start + dst_capacity) || dst_start >= (src_start + src_capacity)) {
+      if (src_start < dst_start) {
+        /* Source chunk precedes next destination chunk. */
+        size_t src_size = __sm_chunk_get_size(&src_chunk);
+        size_t offset = __sm_get_chunk_offset(destination, dst_start);
+        __sm_insert_data(destination, offset, src, sizeof(sm_idx_t) + src_size);
 
-      /* Carry on to the next chunk. */
+        /* Update the chunk count and data_used. */
-      __sm_chunk_t dst_chunk;
+        __sm_set_chunk_count(destination, __sm_get_chunk_count(destination) + 1);
-      __sm_chunk_init(&dst_chunk, dst + sizeof(sm_idx_t));
+        src_count--;
+        src += sizeof(sm_idx_t) + __sm_chunk_get_size(&src_chunk);
+      } else {
+        /* Source chunk follows destination chunk. */
+        dst_count--;
+        dst += sizeof(sm_idx_t) + __sm_chunk_get_size(&dst_chunk);
+        continue;
+      }
+    } else {
+      /* Chunks overlap to some degree, determine the overlapping range. */
+      if (dst_capacity < src_capacity) {
+        __sm_chunk_increase_capacity(&dst_chunk, src_capacity);
+        dst_capacity = __sm_chunk_get_capacity(&dst_chunk);
+      }
+      sparsemap_idx_t src_end = src_start + src_capacity;
+      sparsemap_idx_t dst_end = dst_start + dst_capacity;
+      sparsemap_idx_t overlap_start = (src_start > dst_start) ? src_start : dst_start;
+      sparsemap_idx_t overlap_end = (src_end < dst_end) ? src_end : dst_end;
+      size_t overlap_length = overlap_end - overlap_start;
+      if (overlap_length == src_capacity) {
+        /* 100% overlap */
+        __sm_merge_chunk(destination, src_start, overlap_length, &dst_chunk, &src_chunk);
+        src_count--;
+        dst_count--;
         src += sizeof(sm_idx_t) + __sm_chunk_get_size(&src_chunk);
         dst += sizeof(sm_idx_t) + __sm_chunk_get_size(&dst_chunk);
+      } else {
+        /* Potentially three sections to merge. */
+        if (src_start < overlap_start) {
+          __sm_merge_chunk(destination, src_start, overlap_length - src_start, &dst_chunk, &src_chunk);
+        }
+        __sm_merge_chunk(destination, overlap_start, overlap_end - overlap_start, &dst_chunk, &src_chunk);
+        if (overlap_end < dst_end) {
+          __sm_merge_chunk(destination, overlap_end, dst_end - overlap_end, &dst_chunk, &src_chunk);
+        }
         src_count--;
+        dst_count--;
+        src += sizeof(sm_idx_t) + __sm_chunk_get_size(&src_chunk);
+        dst += sizeof(sm_idx_t) + __sm_chunk_get_size(&dst_chunk);
+      }
     }
   }
   return 0;
 }
-#endif
 
 sparsemap_idx_t
 sparsemap_split(sparsemap_t *map, sparsemap_idx_t offset, sparsemap_t *other)
 {
-  if (!(offset == SPARSEMAP_IDX_MAX) && (offset < 0 || offset >= sparsemap_get_ending_offset(map))) {
+  if (!(offset == SPARSEMAP_IDX_MAX) && offset >= sparsemap_get_ending_offset(map)) {
     return 0;
   }
 
@@ -1677,6 +1707,7 @@ sparsemap_split(sparsemap_t *map, sparsemap_idx_t offset, sparsemap_t *other)
       other->m_data_used += sizeof(sm_idx_t) + sizeof(sm_bitvec_t);
     }
 
+    sm_idx_t start = *(sm_idx_t *)src;
     src += sizeof(sm_idx_t);
     __sm_chunk_t s_chunk;
     __sm_chunk_init(&s_chunk, src);
@@ -1687,13 +1718,14 @@ sparsemap_split(sparsemap_t *map, sparsemap_idx_t offset, sparsemap_t *other)
     __sm_chunk_reduce_capacity(&d_chunk, __sm_get_vector_aligned_offset(capacity - (offset % capacity)));
 
     /* Now copy the bits. */
-    sparsemap_idx_t d = offset;
     sparsemap_idx_t b = __sm_get_vector_aligned_offset(offset % capacity);
-    for (size_t j = offset % capacity; j < capacity; j++, d++) {
+    for (size_t j = start; j < capacity + start; j++) {
-      if (__sm_chunk_is_set(&s_chunk, j)) {
+      if (j >= offset) {
-        assert(sparsemap_set(other, d, true) == d);
+        if (__sm_chunk_is_set(&s_chunk, j - start)) {
-        if (j > b && (j - b) % capacity < SM_BITS_PER_VECTOR) {
+          sparsemap_set(other, j, true);
-          sparsemap_set(map, d, false);
+          if (j >= b && (j - b) % capacity < SM_BITS_PER_VECTOR) {
+            sparsemap_set(map, j, false);
+          }
         }
       }
     }
@@ -1704,7 +1736,8 @@ sparsemap_split(sparsemap_t *map, sparsemap_idx_t offset, sparsemap_t *other)
     i++;
 
     /* Reduce the capacity of the source-chunk effectively erases bits. */
-    __sm_chunk_reduce_capacity(&s_chunk, b + SM_BITS_PER_VECTOR);
+    size_t r = __sm_get_vector_aligned_offset(((offset - start) % capacity) + SM_BITS_PER_VECTOR);
+    __sm_chunk_reduce_capacity(&s_chunk, r);
   }
 
   /* Now continue with all remaining chunks. */

tests/test.c

@@ -733,15 +733,15 @@ test_api_split(const MunitParameter params[], void *data)
 
       sparsemap_split(map, seg + off, &portion);
 
-      for (sparsemap_idx_t i = 0; i < off; i++) {
+      for (sparsemap_idx_t i = seg; i < seg + 1024; i++) {
-        assert_true(sparsemap_is_set(map, i + seg));
+        if (i < seg + off) {
-        assert_false(sparsemap_is_set(&portion, i + seg));
+          assert_true(sparsemap_is_set(map, i));
+          assert_false(sparsemap_is_set(&portion, i));
+        } else {
+          assert_false(sparsemap_is_set(map, i));
+          assert_true(sparsemap_is_set(&portion, i));
         }
-      for (sparsemap_idx_t i = off + 1; i < 1024; i++) {
-        assert_false(sparsemap_is_set(map, i + seg));
-        assert_true(sparsemap_is_set(&portion, i + seg));
       }
-
       sparsemap_clear(map);
       sparsemap_clear(&portion);
     }
@@ -820,10 +820,8 @@ test_api_merge(const MunitParameter params[], void *data)
   // Merge a single set bit in the first chunk into the empty map.
   sparsemap_set(other, 0, true);
   sparsemap_merge(map, other);
-
   assert_true(sparsemap_is_set(other, 0));
   assert_true(sparsemap_is_set(map, 0));
-
   sparsemap_clear(map);
   sparsemap_clear(other);
 
@@ -831,49 +829,42 @@ test_api_merge(const MunitParameter params[], void *data)
   sparsemap_set(map, 0, true);
   sparsemap_set(other, 0, true);
   sparsemap_merge(map, other);
-
+  assert_true(sparsemap_is_set(map, 0));
   sparsemap_clear(map);
   sparsemap_clear(other);
 
   // Merge an empty map with one that has the first bit set.
   sparsemap_set(map, 0, true);
   sparsemap_merge(map, other);
-
   assert_true(sparsemap_is_set(map, 0));
-
   sparsemap_clear(map);
   sparsemap_clear(other);
 
   sparsemap_set(other, 2049, true);
   sparsemap_merge(map, other);
-
   assert_true(sparsemap_is_set(map, 2049));
-
   sparsemap_clear(map);
   sparsemap_clear(other);
+
   sparsemap_set(other, 1, true);
   sparsemap_set(other, 2049, true);
   sparsemap_set(map, 2050, true);
   sparsemap_set(other, 4097, true);
   sparsemap_set(map, 6113, true);
   sparsemap_set(other, 8193, true);
-
   sparsemap_merge(map, other);
-
   assert_true(sparsemap_is_set(map, 1));
   assert_true(sparsemap_is_set(map, 2049));
   assert_true(sparsemap_is_set(map, 2050));
   assert_true(sparsemap_is_set(map, 4097));
   assert_true(sparsemap_is_set(map, 6113));
   assert_true(sparsemap_is_set(map, 8193));
-
   for (int i = 0; i < 10000; i++) {
     if (i == 2049 || i == 1 || i == 2050 || i == 4097 || i == 6113 || i == 8193)
       continue;
     else
       assert_false(sparsemap_is_set(map, i));
   }
-
   sparsemap_clear(map);
   sparsemap_clear(other);
 
@@ -883,15 +874,33 @@ test_api_merge(const MunitParameter params[], void *data)
   for (int i = 2049; i < 4096; i++) {
     sparsemap_set(other, i, true);
   }
-
   sparsemap_merge(map, other);
-
   assert(sparsemap_is_set(map, 0));
   assert(sparsemap_is_set(map, 2048));
   assert(sparsemap_is_set(map, 8193));
   for (int i = 2049; i < 4096; i++) {
     assert(sparsemap_is_set(map, i));
   }
+  sparsemap_clear(map);
+  sparsemap_clear(other);
+
+  for (int i = 2049; i < 4096; i++) {
+    sparsemap_set(map, i, true);
+  }
+  sparsemap_split(map, 2051, other);
+  for (int i = 2049; i < 4096; i++) {
+    if (i < 2051) {
+      assert_true(sparsemap_is_set(map, i));
+      assert_false(sparsemap_is_set(other, i));
+    } else {
+      assert_false(sparsemap_is_set(map, i));
+      assert_true(sparsemap_is_set(other, i));
+    }
+  }
+  sparsemap_merge(map, other);
+  for (int i = 2049; i < 4096; i++) {
+    sparsemap_is_set(map, i);
+  }
 
   munit_free(other);
   return MUNIT_OK;