Adding upstream version 0.8.0.upstream/0.8.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 827 insertions, 0 deletions

diff --git a/lib/nghttp3_ksl.c b/lib/nghttp3_ksl.c
new file mode 100644
index 0000000..adea677
--- /dev/null
+++ b/lib/nghttp3_ksl.c
@@ -0,0 +1,827 @@
+/*
+ * nghttp3
+ *
+ * Copyright (c) 2019 nghttp3 contributors
+ * Copyright (c) 2018 ngtcp2 contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include "nghttp3_ksl.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <stdio.h>
+
+#include "nghttp3_macro.h"
+#include "nghttp3_mem.h"
+#include "nghttp3_range.h"
+
+static nghttp3_ksl_blk null_blk = {{{NULL, NULL, 0, 0, {0}}}};
+
+static size_t ksl_nodelen(size_t keylen) {
+  return (sizeof(nghttp3_ksl_node) + keylen - sizeof(uint64_t) + 0xfu) &
+         ~(uintptr_t)0xfu;
+}
+
+static size_t ksl_blklen(size_t nodelen) {
+  return sizeof(nghttp3_ksl_blk) + nodelen * NGHTTP3_KSL_MAX_NBLK -
+         sizeof(uint64_t);
+}
+
+/*
+ * ksl_node_set_key sets |key| to |node|.
+ */
+static void ksl_node_set_key(nghttp3_ksl *ksl, nghttp3_ksl_node *node,
+                             const void *key) {
+  memcpy(node->key, key, ksl->keylen);
+}
+
+void nghttp3_ksl_init(nghttp3_ksl *ksl, nghttp3_ksl_compar compar,
+                      size_t keylen, const nghttp3_mem *mem) {
+  size_t nodelen = ksl_nodelen(keylen);
+
+  nghttp3_objalloc_init(&ksl->blkalloc,
+                        ((ksl_blklen(nodelen) + 0xfu) & ~(uintptr_t)0xfu) * 8,
+                        mem);
+
+  ksl->head = NULL;
+  ksl->front = ksl->back = NULL;
+  ksl->compar = compar;
+  ksl->keylen = keylen;
+  ksl->nodelen = nodelen;
+  ksl->n = 0;
+}
+
+static nghttp3_ksl_blk *ksl_blk_objalloc_new(nghttp3_ksl *ksl) {
+  return nghttp3_objalloc_ksl_blk_len_get(&ksl->blkalloc,
+                                          ksl_blklen(ksl->nodelen));
+}
+
+static void ksl_blk_objalloc_del(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk) {
+  nghttp3_objalloc_ksl_blk_release(&ksl->blkalloc, blk);
+}
+
+static int ksl_head_init(nghttp3_ksl *ksl) {
+  nghttp3_ksl_blk *head = ksl_blk_objalloc_new(ksl);
+  if (!head) {
+    return NGHTTP3_ERR_NOMEM;
+  }
+
+  head->next = head->prev = NULL;
+  head->n = 0;
+  head->leaf = 1;
+
+  ksl->head = head;
+  ksl->front = ksl->back = head;
+
+  return 0;
+}
+
+#ifdef NOMEMPOOL
+/*
+ * ksl_free_blk frees |blk| recursively.
+ */
+static void ksl_free_blk(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk) {
+  size_t i;
+
+  if (!blk->leaf) {
+    for (i = 0; i < blk->n; ++i) {
+      ksl_free_blk(ksl, nghttp3_ksl_nth_node(ksl, blk, i)->blk);
+    }
+  }
+
+  ksl_blk_objalloc_del(ksl, blk);
+}
+#endif /* NOMEMPOOL */
+
+void nghttp3_ksl_free(nghttp3_ksl *ksl) {
+  if (!ksl || !ksl->head) {
+    return;
+  }
+
+#ifdef NOMEMPOOL
+  ksl_free_blk(ksl, ksl->head);
+#endif /* NOMEMPOOL */
+
+  nghttp3_objalloc_free(&ksl->blkalloc);
+}
+
+/*
+ * ksl_split_blk splits |blk| into 2 nghttp3_ksl_blk objects.  The new
+ * nghttp3_ksl_blk is always the "right" block.
+ *
+ * It returns the pointer to the nghttp3_ksl_blk created which is the
+ * located at the right of |blk|, or NULL which indicates out of
+ * memory error.
+ */
+static nghttp3_ksl_blk *ksl_split_blk(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk) {
+  nghttp3_ksl_blk *rblk;
+
+  rblk = ksl_blk_objalloc_new(ksl);
+  if (rblk == NULL) {
+    return NULL;
+  }
+
+  rblk->next = blk->next;
+  blk->next = rblk;
+  if (rblk->next) {
+    rblk->next->prev = rblk;
+  } else if (ksl->back == blk) {
+    ksl->back = rblk;
+  }
+  rblk->prev = blk;
+  rblk->leaf = blk->leaf;
+
+  rblk->n = blk->n / 2;
+
+  memcpy(rblk->nodes, blk->nodes + ksl->nodelen * (blk->n - rblk->n),
+         ksl->nodelen * rblk->n);
+
+  blk->n -= rblk->n;
+
+  assert(blk->n >= NGHTTP3_KSL_MIN_NBLK);
+  assert(rblk->n >= NGHTTP3_KSL_MIN_NBLK);
+
+  return rblk;
+}
+
+/*
+ * ksl_split_node splits a node included in |blk| at the position |i|
+ * into 2 adjacent nodes.  The new node is always inserted at the
+ * position |i+1|.
+ *
+ * It returns 0 if it succeeds, or one of the following negative error
+ * codes:
+ *
+ * NGHTTP3_ERR_NOMEM
+ *   Out of memory.
+ */
+static int ksl_split_node(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk, size_t i) {
+  nghttp3_ksl_node *node;
+  nghttp3_ksl_blk *lblk = nghttp3_ksl_nth_node(ksl, blk, i)->blk, *rblk;
+
+  rblk = ksl_split_blk(ksl, lblk);
+  if (rblk == NULL) {
+    return NGHTTP3_ERR_NOMEM;
+  }
+
+  memmove(blk->nodes + (i + 2) * ksl->nodelen,
+          blk->nodes + (i + 1) * ksl->nodelen,
+          ksl->nodelen * (blk->n - (i + 1)));
+
+  node = nghttp3_ksl_nth_node(ksl, blk, i + 1);
+  node->blk = rblk;
+  ++blk->n;
+  ksl_node_set_key(ksl, node,
+                   nghttp3_ksl_nth_node(ksl, rblk, rblk->n - 1)->key);
+
+  node = nghttp3_ksl_nth_node(ksl, blk, i);
+  ksl_node_set_key(ksl, node,
+                   nghttp3_ksl_nth_node(ksl, lblk, lblk->n - 1)->key);
+
+  return 0;
+}
+
+/*
+ * ksl_split_head splits a head (root) block.  It increases the height
+ * of skip list by 1.
+ *
+ * It returns 0 if it succeeds, or one of the following negative error
+ * codes:
+ *
+ * NGHTTP3_ERR_NOMEM
+ *   Out of memory.
+ */
+static int ksl_split_head(nghttp3_ksl *ksl) {
+  nghttp3_ksl_blk *rblk = NULL, *lblk, *nhead = NULL;
+  nghttp3_ksl_node *node;
+
+  rblk = ksl_split_blk(ksl, ksl->head);
+  if (rblk == NULL) {
+    return NGHTTP3_ERR_NOMEM;
+  }
+
+  lblk = ksl->head;
+
+  nhead = ksl_blk_objalloc_new(ksl);
+  if (nhead == NULL) {
+    ksl_blk_objalloc_del(ksl, rblk);
+    return NGHTTP3_ERR_NOMEM;
+  }
+  nhead->next = nhead->prev = NULL;
+  nhead->n = 2;
+  nhead->leaf = 0;
+
+  node = nghttp3_ksl_nth_node(ksl, nhead, 0);
+  ksl_node_set_key(ksl, node,
+                   nghttp3_ksl_nth_node(ksl, lblk, lblk->n - 1)->key);
+  node->blk = lblk;
+
+  node = nghttp3_ksl_nth_node(ksl, nhead, 1);
+  ksl_node_set_key(ksl, node,
+                   nghttp3_ksl_nth_node(ksl, rblk, rblk->n - 1)->key);
+  node->blk = rblk;
+
+  ksl->head = nhead;
+
+  return 0;
+}
+
+/*
+ * insert_node inserts a node whose key is |key| with the associated
+ * |data| at the index of |i|.  This function assumes that the number
+ * of nodes contained by |blk| is strictly less than
+ * NGHTTP3_KSL_MAX_NBLK.
+ */
+static void ksl_insert_node(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk, size_t i,
+                            const nghttp3_ksl_key *key, void *data) {
+  nghttp3_ksl_node *node;
+
+  assert(blk->n < NGHTTP3_KSL_MAX_NBLK);
+
+  memmove(blk->nodes + (i + 1) * ksl->nodelen, blk->nodes + i * ksl->nodelen,
+          ksl->nodelen * (blk->n - i));
+
+  node = nghttp3_ksl_nth_node(ksl, blk, i);
+  ksl_node_set_key(ksl, node, key);
+  node->data = data;
+
+  ++blk->n;
+}
+
+static size_t ksl_bsearch(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk,
+                          const nghttp3_ksl_key *key,
+                          nghttp3_ksl_compar compar) {
+  size_t i;
+  nghttp3_ksl_node *node;
+
+  for (i = 0, node = (nghttp3_ksl_node *)(void *)blk->nodes;
+       i < blk->n && compar((nghttp3_ksl_key *)node->key, key);
+       ++i, node = (nghttp3_ksl_node *)(void *)((uint8_t *)node + ksl->nodelen))
+    ;
+
+  return i;
+}
+
+int nghttp3_ksl_insert(nghttp3_ksl *ksl, nghttp3_ksl_it *it,
+                       const nghttp3_ksl_key *key, void *data) {
+  nghttp3_ksl_blk *blk;
+  nghttp3_ksl_node *node;
+  size_t i;
+  int rv;
+
+  if (!ksl->head) {
+    rv = ksl_head_init(ksl);
+    if (rv != 0) {
+      return rv;
+    }
+  }
+
+  blk = ksl->head;
+
+  if (blk->n == NGHTTP3_KSL_MAX_NBLK) {
+    rv = ksl_split_head(ksl);
+    if (rv != 0) {
+      return rv;
+    }
+    blk = ksl->head;
+  }
+
+  for (;;) {
+    i = ksl_bsearch(ksl, blk, key, ksl->compar);
+
+    if (blk->leaf) {
+      if (i < blk->n &&
+          !ksl->compar(key, nghttp3_ksl_nth_node(ksl, blk, i)->key)) {
+        if (it) {
+          *it = nghttp3_ksl_end(ksl);
+        }
+        return NGHTTP3_ERR_INVALID_ARGUMENT;
+      }
+      ksl_insert_node(ksl, blk, i, key, data);
+      ++ksl->n;
+      if (it) {
+        nghttp3_ksl_it_init(it, ksl, blk, i);
+      }
+      return 0;
+    }
+
+    if (i == blk->n) {
+      /* This insertion extends the largest key in this subtree. */
+      for (; !blk->leaf;) {
+        node = nghttp3_ksl_nth_node(ksl, blk, blk->n - 1);
+        if (node->blk->n == NGHTTP3_KSL_MAX_NBLK) {
+          rv = ksl_split_node(ksl, blk, blk->n - 1);
+          if (rv != 0) {
+            return rv;
+          }
+          node = nghttp3_ksl_nth_node(ksl, blk, blk->n - 1);
+        }
+        ksl_node_set_key(ksl, node, key);
+        blk = node->blk;
+      }
+      ksl_insert_node(ksl, blk, blk->n, key, data);
+      ++ksl->n;
+      if (it) {
+        nghttp3_ksl_it_init(it, ksl, blk, blk->n - 1);
+      }
+      return 0;
+    }
+
+    node = nghttp3_ksl_nth_node(ksl, blk, i);
+
+    if (node->blk->n == NGHTTP3_KSL_MAX_NBLK) {
+      rv = ksl_split_node(ksl, blk, i);
+      if (rv != 0) {
+        return rv;
+      }
+      if (ksl->compar((nghttp3_ksl_key *)node->key, key)) {
+        node = nghttp3_ksl_nth_node(ksl, blk, i + 1);
+        if (ksl->compar((nghttp3_ksl_key *)node->key, key)) {
+          ksl_node_set_key(ksl, node, key);
+        }
+      }
+    }
+
+    blk = node->blk;
+  }
+}
+
+/*
+ * ksl_remove_node removes the node included in |blk| at the index of
+ * |i|.
+ */
+static void ksl_remove_node(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk, size_t i) {
+  memmove(blk->nodes + i * ksl->nodelen, blk->nodes + (i + 1) * ksl->nodelen,
+          ksl->nodelen * (blk->n - (i + 1)));
+
+  --blk->n;
+}
+
+/*
+ * ksl_merge_node merges 2 nodes which are the nodes at the index of
+ * |i| and |i + 1|.
+ *
+ * If |blk| is the direct descendant of head (root) block and the head
+ * block contains just 2 nodes, the merged block becomes head block,
+ * which decreases the height of |ksl| by 1.
+ *
+ * This function returns the pointer to the merged block.
+ */
+static nghttp3_ksl_blk *ksl_merge_node(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk,
+                                       size_t i) {
+  nghttp3_ksl_blk *lblk, *rblk;
+
+  assert(i + 1 < blk->n);
+
+  lblk = nghttp3_ksl_nth_node(ksl, blk, i)->blk;
+  rblk = nghttp3_ksl_nth_node(ksl, blk, i + 1)->blk;
+
+  assert(lblk->n + rblk->n < NGHTTP3_KSL_MAX_NBLK);
+
+  memcpy(lblk->nodes + ksl->nodelen * lblk->n, rblk->nodes,
+         ksl->nodelen * rblk->n);
+
+  lblk->n += rblk->n;
+  lblk->next = rblk->next;
+  if (lblk->next) {
+    lblk->next->prev = lblk;
+  } else if (ksl->back == rblk) {
+    ksl->back = lblk;
+  }
+
+  ksl_blk_objalloc_del(ksl, rblk);
+
+  if (ksl->head == blk && blk->n == 2) {
+    ksl_blk_objalloc_del(ksl, ksl->head);
+    ksl->head = lblk;
+  } else {
+    ksl_remove_node(ksl, blk, i + 1);
+    ksl_node_set_key(ksl, nghttp3_ksl_nth_node(ksl, blk, i),
+                     nghttp3_ksl_nth_node(ksl, lblk, lblk->n - 1)->key);
+  }
+
+  return lblk;
+}
+
+/*
+ * ksl_shift_left moves the first nodes in blk->nodes[i]->blk->nodes
+ * to blk->nodes[i - 1]->blk->nodes in a manner that they have the
+ * same amount of nodes as much as possible.
+ */
+static void ksl_shift_left(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk, size_t i) {
+  nghttp3_ksl_node *lnode, *rnode;
+  size_t n;
+
+  assert(i > 0);
+
+  lnode = nghttp3_ksl_nth_node(ksl, blk, i - 1);
+  rnode = nghttp3_ksl_nth_node(ksl, blk, i);
+
+  assert(lnode->blk->n < NGHTTP3_KSL_MAX_NBLK);
+  assert(rnode->blk->n > NGHTTP3_KSL_MIN_NBLK);
+
+  n = (lnode->blk->n + rnode->blk->n + 1) / 2 - lnode->blk->n;
+
+  assert(n > 0);
+  assert(lnode->blk->n <= NGHTTP3_KSL_MAX_NBLK - n);
+  assert(rnode->blk->n >= NGHTTP3_KSL_MIN_NBLK + n);
+
+  memcpy(lnode->blk->nodes + ksl->nodelen * lnode->blk->n, rnode->blk->nodes,
+         ksl->nodelen * n);
+
+  lnode->blk->n += (uint32_t)n;
+  rnode->blk->n -= (uint32_t)n;
+
+  ksl_node_set_key(
+      ksl, lnode,
+      nghttp3_ksl_nth_node(ksl, lnode->blk, lnode->blk->n - 1)->key);
+
+  memmove(rnode->blk->nodes, rnode->blk->nodes + ksl->nodelen * n,
+          ksl->nodelen * rnode->blk->n);
+}
+
+/*
+ * ksl_shift_right moves the last nodes in blk->nodes[i]->blk->nodes
+ * to blk->nodes[i + 1]->blk->nodes in a manner that they have the
+ * same amount of nodes as much as possible..
+ */
+static void ksl_shift_right(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk, size_t i) {
+  nghttp3_ksl_node *lnode, *rnode;
+  size_t n;
+
+  assert(i < blk->n - 1);
+
+  lnode = nghttp3_ksl_nth_node(ksl, blk, i);
+  rnode = nghttp3_ksl_nth_node(ksl, blk, i + 1);
+
+  assert(lnode->blk->n > NGHTTP3_KSL_MIN_NBLK);
+  assert(rnode->blk->n < NGHTTP3_KSL_MAX_NBLK);
+
+  n = (lnode->blk->n + rnode->blk->n + 1) / 2 - rnode->blk->n;
+
+  assert(n > 0);
+  assert(lnode->blk->n >= NGHTTP3_KSL_MIN_NBLK + n);
+  assert(rnode->blk->n <= NGHTTP3_KSL_MAX_NBLK - n);
+
+  memmove(rnode->blk->nodes + ksl->nodelen * n, rnode->blk->nodes,
+          ksl->nodelen * rnode->blk->n);
+
+  rnode->blk->n += (uint32_t)n;
+  lnode->blk->n -= (uint32_t)n;
+
+  memcpy(rnode->blk->nodes, lnode->blk->nodes + ksl->nodelen * lnode->blk->n,
+         ksl->nodelen * n);
+
+  ksl_node_set_key(
+      ksl, lnode,
+      nghttp3_ksl_nth_node(ksl, lnode->blk, lnode->blk->n - 1)->key);
+}
+
+/*
+ * key_equal returns nonzero if |lhs| and |rhs| are equal using the
+ * function |compar|.
+ */
+static int key_equal(nghttp3_ksl_compar compar, const nghttp3_ksl_key *lhs,
+                     const nghttp3_ksl_key *rhs) {
+  return !compar(lhs, rhs) && !compar(rhs, lhs);
+}
+
+int nghttp3_ksl_remove_hint(nghttp3_ksl *ksl, nghttp3_ksl_it *it,
+                            const nghttp3_ksl_it *hint,
+                            const nghttp3_ksl_key *key) {
+  nghttp3_ksl_blk *blk = hint->blk;
+
+  assert(ksl->head);
+
+  if (blk->n <= NGHTTP3_KSL_MIN_NBLK) {
+    return nghttp3_ksl_remove(ksl, it, key);
+  }
+
+  ksl_remove_node(ksl, blk, hint->i);
+
+  --ksl->n;
+
+  if (it) {
+    if (hint->i == blk->n && blk->next) {
+      nghttp3_ksl_it_init(it, ksl, blk->next, 0);
+    } else {
+      nghttp3_ksl_it_init(it, ksl, blk, hint->i);
+    }
+  }
+
+  return 0;
+}
+
+int nghttp3_ksl_remove(nghttp3_ksl *ksl, nghttp3_ksl_it *it,
+                       const nghttp3_ksl_key *key) {
+  nghttp3_ksl_blk *blk = ksl->head;
+  nghttp3_ksl_node *node;
+  size_t i;
+
+  if (!ksl->head) {
+    return NGHTTP3_ERR_INVALID_ARGUMENT;
+  }
+
+  if (!blk->leaf && blk->n == 2 &&
+      nghttp3_ksl_nth_node(ksl, blk, 0)->blk->n == NGHTTP3_KSL_MIN_NBLK &&
+      nghttp3_ksl_nth_node(ksl, blk, 1)->blk->n == NGHTTP3_KSL_MIN_NBLK) {
+    blk = ksl_merge_node(ksl, ksl->head, 0);
+  }
+
+  for (;;) {
+    i = ksl_bsearch(ksl, blk, key, ksl->compar);
+
+    if (i == blk->n) {
+      if (it) {
+        *it = nghttp3_ksl_end(ksl);
+      }
+      return NGHTTP3_ERR_INVALID_ARGUMENT;
+    }
+
+    if (blk->leaf) {
+      if (ksl->compar(key, nghttp3_ksl_nth_node(ksl, blk, i)->key)) {
+        if (it) {
+          *it = nghttp3_ksl_end(ksl);
+        }
+        return NGHTTP3_ERR_INVALID_ARGUMENT;
+      }
+      ksl_remove_node(ksl, blk, i);
+      --ksl->n;
+      if (it) {
+        if (blk->n == i && blk->next) {
+          nghttp3_ksl_it_init(it, ksl, blk->next, 0);
+        } else {
+          nghttp3_ksl_it_init(it, ksl, blk, i);
+        }
+      }
+      return 0;
+    }
+
+    node = nghttp3_ksl_nth_node(ksl, blk, i);
+
+    if (node->blk->n > NGHTTP3_KSL_MIN_NBLK) {
+      blk = node->blk;
+      continue;
+    }
+
+    assert(node->blk->n == NGHTTP3_KSL_MIN_NBLK);
+
+    if (i + 1 < blk->n &&
+        nghttp3_ksl_nth_node(ksl, blk, i + 1)->blk->n > NGHTTP3_KSL_MIN_NBLK) {
+      ksl_shift_left(ksl, blk, i + 1);
+      blk = node->blk;
+      continue;
+    }
+
+    if (i > 0 &&
+        nghttp3_ksl_nth_node(ksl, blk, i - 1)->blk->n > NGHTTP3_KSL_MIN_NBLK) {
+      ksl_shift_right(ksl, blk, i - 1);
+      blk = node->blk;
+      continue;
+    }
+
+    if (i + 1 < blk->n) {
+      blk = ksl_merge_node(ksl, blk, i);
+      continue;
+    }
+
+    assert(i > 0);
+
+    blk = ksl_merge_node(ksl, blk, i - 1);
+  }
+}
+
+nghttp3_ksl_it nghttp3_ksl_lower_bound(nghttp3_ksl *ksl,
+                                       const nghttp3_ksl_key *key) {
+  nghttp3_ksl_blk *blk = ksl->head;
+  nghttp3_ksl_it it;
+  size_t i;
+
+  if (!blk) {
+    nghttp3_ksl_it_init(&it, ksl, &null_blk, 0);
+    return it;
+  }
+
+  for (;;) {
+    i = ksl_bsearch(ksl, blk, key, ksl->compar);
+
+    if (blk->leaf) {
+      if (i == blk->n && blk->next) {
+        blk = blk->next;
+        i = 0;
+      }
+      nghttp3_ksl_it_init(&it, ksl, blk, i);
+      return it;
+    }
+
+    if (i == blk->n) {
+      /* This happens if descendant has smaller key.  Fast forward to
+         find last node in this subtree. */
+      for (; !blk->leaf; blk = nghttp3_ksl_nth_node(ksl, blk, blk->n - 1)->blk)
+        ;
+      if (blk->next) {
+        blk = blk->next;
+        i = 0;
+      } else {
+        i = blk->n;
+      }
+      nghttp3_ksl_it_init(&it, ksl, blk, i);
+      return it;
+    }
+    blk = nghttp3_ksl_nth_node(ksl, blk, i)->blk;
+  }
+}
+
+nghttp3_ksl_it nghttp3_ksl_lower_bound_compar(nghttp3_ksl *ksl,
+                                              const nghttp3_ksl_key *key,
+                                              nghttp3_ksl_compar compar) {
+  nghttp3_ksl_blk *blk = ksl->head;
+  nghttp3_ksl_it it;
+  size_t i;
+
+  if (!blk) {
+    nghttp3_ksl_it_init(&it, ksl, &null_blk, 0);
+    return it;
+  }
+
+  for (;;) {
+    i = ksl_bsearch(ksl, blk, key, compar);
+
+    if (blk->leaf) {
+      if (i == blk->n && blk->next) {
+        blk = blk->next;
+        i = 0;
+      }
+      nghttp3_ksl_it_init(&it, ksl, blk, i);
+      return it;
+    }
+
+    if (i == blk->n) {
+      /* This happens if descendant has smaller key.  Fast forward to
+         find last node in this subtree. */
+      for (; !blk->leaf; blk = nghttp3_ksl_nth_node(ksl, blk, blk->n - 1)->blk)
+        ;
+      if (blk->next) {
+        blk = blk->next;
+        i = 0;
+      } else {
+        i = blk->n;
+      }
+      nghttp3_ksl_it_init(&it, ksl, blk, i);
+      return it;
+    }
+    blk = nghttp3_ksl_nth_node(ksl, blk, i)->blk;
+  }
+}
+
+void nghttp3_ksl_update_key(nghttp3_ksl *ksl, const nghttp3_ksl_key *old_key,
+                            const nghttp3_ksl_key *new_key) {
+  nghttp3_ksl_blk *blk = ksl->head;
+  nghttp3_ksl_node *node;
+  size_t i;
+
+  assert(ksl->head);
+
+  for (;;) {
+    i = ksl_bsearch(ksl, blk, old_key, ksl->compar);
+
+    assert(i < blk->n);
+    node = nghttp3_ksl_nth_node(ksl, blk, i);
+
+    if (blk->leaf) {
+      assert(key_equal(ksl->compar, (nghttp3_ksl_key *)node->key, old_key));
+      ksl_node_set_key(ksl, node, new_key);
+      return;
+    }
+
+    if (key_equal(ksl->compar, (nghttp3_ksl_key *)node->key, old_key) ||
+        ksl->compar((nghttp3_ksl_key *)node->key, new_key)) {
+      ksl_node_set_key(ksl, node, new_key);
+    }
+
+    blk = node->blk;
+  }
+}
+
+static void ksl_print(nghttp3_ksl *ksl, nghttp3_ksl_blk *blk, size_t level) {
+  size_t i;
+  nghttp3_ksl_node *node;
+
+  fprintf(stderr, "LV=%zu n=%u\n", level, blk->n);
+
+  if (blk->leaf) {
+    for (i = 0; i < blk->n; ++i) {
+      node = nghttp3_ksl_nth_node(ksl, blk, i);
+      fprintf(stderr, " %" PRId64, *(int64_t *)(void *)node->key);
+    }
+    fprintf(stderr, "\n");
+    return;
+  }
+
+  for (i = 0; i < blk->n; ++i) {
+    ksl_print(ksl, nghttp3_ksl_nth_node(ksl, blk, i)->blk, level + 1);
+  }
+}
+
+size_t nghttp3_ksl_len(nghttp3_ksl *ksl) { return ksl->n; }
+
+void nghttp3_ksl_clear(nghttp3_ksl *ksl) {
+  if (!ksl->head) {
+    return;
+  }
+
+#ifdef NOMEMPOOL
+  ksl_free_blk(ksl, ksl->head);
+#endif /* NOMEMPOOL */
+
+  ksl->front = ksl->back = ksl->head = NULL;
+  ksl->n = 0;
+
+  nghttp3_objalloc_clear(&ksl->blkalloc);
+}
+
+void nghttp3_ksl_print(nghttp3_ksl *ksl) {
+  if (!ksl->head) {
+    return;
+  }
+
+  ksl_print(ksl, ksl->head, 0);
+}
+
+nghttp3_ksl_it nghttp3_ksl_begin(const nghttp3_ksl *ksl) {
+  nghttp3_ksl_it it;
+
+  if (ksl->head) {
+    nghttp3_ksl_it_init(&it, ksl, ksl->front, 0);
+  } else {
+    nghttp3_ksl_it_init(&it, ksl, &null_blk, 0);
+  }
+
+  return it;
+}
+
+nghttp3_ksl_it nghttp3_ksl_end(const nghttp3_ksl *ksl) {
+  nghttp3_ksl_it it;
+
+  if (ksl->head) {
+    nghttp3_ksl_it_init(&it, ksl, ksl->back, ksl->back->n);
+  } else {
+    nghttp3_ksl_it_init(&it, ksl, &null_blk, 0);
+  }
+
+  return it;
+}
+
+void nghttp3_ksl_it_init(nghttp3_ksl_it *it, const nghttp3_ksl *ksl,
+                         nghttp3_ksl_blk *blk, size_t i) {
+  it->ksl = ksl;
+  it->blk = blk;
+  it->i = i;
+}
+
+void nghttp3_ksl_it_prev(nghttp3_ksl_it *it) {
+  assert(!nghttp3_ksl_it_begin(it));
+
+  if (it->i == 0) {
+    it->blk = it->blk->prev;
+    it->i = it->blk->n - 1;
+  } else {
+    --it->i;
+  }
+}
+
+int nghttp3_ksl_it_begin(const nghttp3_ksl_it *it) {
+  return it->i == 0 && it->blk->prev == NULL;
+}
+
+int nghttp3_ksl_range_compar(const nghttp3_ksl_key *lhs,
+                             const nghttp3_ksl_key *rhs) {
+  const nghttp3_range *a = lhs, *b = rhs;
+  return a->begin < b->begin;
+}
+
+int nghttp3_ksl_range_exclusive_compar(const nghttp3_ksl_key *lhs,
+                                       const nghttp3_ksl_key *rhs) {
+  const nghttp3_range *a = lhs, *b = rhs;
+  return a->begin < b->begin &&
+         !(nghttp3_max(a->begin, b->begin) < nghttp3_min(a->end, b->end));
+}