From 1cae5e22834e299b993e902320012703c9315070 Mon Sep 17 00:00:00 2001
From: Enno Rehling <enno.rehling@gmail.com>
Date: Wed, 23 Feb 2011 22:18:58 -0800
Subject: [PATCH] Added quicklist, a linked list with better cache
 characteristics.

---
 src/build/util.c         |   1 +
 src/util.vcxproj         |   2 +
 src/util.vcxproj.filters |   6 ++
 src/util/quicklist.c     | 115 +++++++++++++++++++++++++++++++++++++++
 src/util/quicklist.h     |  35 ++++++++++++
 5 files changed, 159 insertions(+)
 create mode 100644 src/util/quicklist.c
 create mode 100644 src/util/quicklist.h

diff --git a/src/build/util.c b/src/build/util.c
index dfae8d012..c9a6897aa 100644
--- a/src/build/util.c
+++ b/src/build/util.c
@@ -19,6 +19,7 @@
 #include <util/goodies.c>
 #include <util/language.c>
 #include <util/lists.c>
+#include <util/quicklist.c>
 #include <util/log.c>
 #include <util/message.c>
 #include <util/nrmessage.c>
diff --git a/src/util.vcxproj b/src/util.vcxproj
index 6c774d665..b744abb18 100644
--- a/src/util.vcxproj
+++ b/src/util.vcxproj
@@ -109,6 +109,7 @@
     <ClInclude Include="util\nrmessage_struct.h" />
     <ClInclude Include="util\parser.h" />
     <ClInclude Include="util\patricia.h" />
+    <ClInclude Include="util\quicklist.h" />
     <ClInclude Include="util\rand.h" />
     <ClInclude Include="util\resolve.h" />
     <ClInclude Include="util\rng.h" />
@@ -145,6 +146,7 @@
     <ClCompile Include="util\nrmessage.c" />
     <ClCompile Include="util\parser.c" />
     <ClCompile Include="util\patricia.c" />
+    <ClCompile Include="util\quicklist.c" />
     <ClCompile Include="util\rand.c" />
     <ClCompile Include="util\resolve.c" />
     <ClCompile Include="util\sql.c" />
diff --git a/src/util.vcxproj.filters b/src/util.vcxproj.filters
index 237444227..6d6e644bf 100644
--- a/src/util.vcxproj.filters
+++ b/src/util.vcxproj.filters
@@ -107,6 +107,9 @@
     <ClInclude Include="util\xml.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="util\quicklist.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="util\argstack.c">
@@ -199,5 +202,8 @@
     <ClCompile Include="util\xml.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="util\quicklist.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/src/util/quicklist.c b/src/util/quicklist.c
new file mode 100644
index 000000000..729d2ec37
--- /dev/null
+++ b/src/util/quicklist.c
@@ -0,0 +1,115 @@
+/*
+Copyright (c) 2010-2011, Enno Rehling <enno@eressea.de>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+**/
+
+#include "quicklist.h"
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#define QL_MAXSIZE 14 /* total struct is 64 bytes */
+#define QL_LIMIT 8
+
+typedef struct quicklist {
+  struct quicklist * next;
+  int num_elements;
+  void * elements[QL_MAXSIZE];
+} quicklist;
+
+
+void * ql_get(quicklist * ql, int index) {
+  return (ql && index<ql->num_elements)?ql->elements[index]:ql_get(ql->next, index-ql->num_elements);
+}
+
+int ql_length(const quicklist * ql) {
+  return ql?ql->num_elements+ql_length(ql->next):0;
+}
+
+void ql_push(quicklist ** qlp, void * data) {
+  quicklist * ql = 0;
+  while(*qlp && ((*qlp)->next || (*qlp)->num_elements==QL_MAXSIZE)) {
+    qlp = &(*qlp)->next;
+  }
+  if (!*qlp) {
+    ql = malloc(sizeof(quicklist));
+    ql->num_elements = 0;
+    ql->next = 0;
+    *qlp = ql;
+  } else {
+    ql = *qlp;
+  }
+  ql->elements[ql->num_elements++] = data;
+}
+
+int ql_delete(quicklist ** qlp, int index) {
+  quicklist * ql = *qlp;
+  if (index<0) return EINVAL;
+  if (ql && index>=ql->num_elements) {
+    return ql_delete(&ql->next, index-ql->num_elements);
+  } else if (ql) {
+    if (index+1<ql->num_elements) {
+      memmove(ql->elements+index, ql->elements+index+1, (ql->num_elements-index-1)*sizeof(void*));
+    }
+    --ql->num_elements;
+    if (ql->num_elements==0) {
+      *qlp = ql->next;
+      free(ql);
+    } else if (ql->next && ql->num_elements<QL_LIMIT) {
+      quicklist * qn = ql->next;
+      if (ql->num_elements+qn->num_elements>QL_MAXSIZE) {
+        memcpy(ql->elements+ql->num_elements, qn->elements, sizeof(void*));
+        --qn->num_elements;
+        ++ql->num_elements;
+        memmove(qn->elements, qn->elements+1, qn->num_elements*sizeof(void*));
+      } else {
+        memcpy(ql->elements+ql->num_elements, qn->elements, qn->num_elements*sizeof(void*));
+        ql->num_elements += qn->num_elements;
+        ql->next = qn->next;
+        free(qn);
+      }
+    }
+  }
+  return 0;
+}
+
+int ql_insert(quicklist ** qlp, int index, void * data) {
+  quicklist * ql = *qlp;
+  if (ql) {
+    if (index>=QL_MAXSIZE) {
+      return ql_insert(&ql->next, index-ql->num_elements, data);
+    } else if (ql->num_elements<QL_MAXSIZE) {
+      memmove(ql->elements+index+1, ql->elements+index, (ql->num_elements-index)*sizeof(void*));
+      ql->elements[index]=data;
+      ++ql->num_elements;
+    } else {
+      quicklist * qn = malloc(sizeof(quicklist));
+      qn->next = ql->next;
+      ql->next = qn;
+      qn->num_elements = QL_LIMIT;
+      ql->num_elements -= QL_LIMIT;
+      memcpy(qn->elements, ql->elements+ql->num_elements-QL_LIMIT, QL_LIMIT*sizeof(void*));
+      if (index<=ql->num_elements) {
+        return ql_insert(qlp, index, data);
+      } else {
+        return ql_insert(&ql->next, index-ql->num_elements, data);
+      }
+    }
+  } else if (index==0) {
+    ql_push(qlp, data);
+  } else {
+    return EINVAL;
+  }
+  return 0;
+}
diff --git a/src/util/quicklist.h b/src/util/quicklist.h
new file mode 100644
index 000000000..d77ebcf94
--- /dev/null
+++ b/src/util/quicklist.h
@@ -0,0 +1,35 @@
+/*
+Copyright (c) 2010-2011, Enno Rehling <enno@eressea.de>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+**/
+
+#ifndef _QUICKLIST_H
+#define _QUICKLIST_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* see http://en.wikipedia.org/wiki/Unrolled_linked_list */
+struct quicklist;
+void * ql_get(struct quicklist * ql, int index);
+int ql_length(const struct quicklist * ql);
+void ql_push(struct quicklist ** qlp, void * data);
+int ql_delete(struct quicklist ** qlp, int index);
+int ql_insert(struct quicklist ** qlp, int index, void * data);
+
+#ifdef __cplusplus
+}
+#endif
+#endif