Add the anycollseq.c loadable extension in etc/misc

FossilOrigin-Name: d7b9813cb17615c3d00afd6994a4309d6d48c8e924b6cd813c543e1fa65c7719

1 files changed, 58 insertions, 0 deletions

diff --git a/ext/misc/anycollseq.c b/ext/misc/anycollseq.c
new file mode 100644
index 000000000..27b7049d5
--- /dev/null
+++ b/ext/misc/anycollseq.c
@@ -0,0 +1,58 @@
+/*
+** 2017-04-16
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file implements a run-time loadable extension to SQLite that
+** registers a sqlite3_collation_needed() callback to register a fake
+** collating function for any unknown collating sequence.  The fake
+** collating function works like BINARY.
+**
+** This extension can be used to load schemas that contain one or more
+** unknown collating sequences.
+*/
+#include "sqlite3ext.h"
+SQLITE_EXTENSION_INIT1
+#include <string.h>
+
+static int anyCollFunc(
+  void *NotUsed,
+  int nKey1, const void *pKey1,
+  int nKey2, const void *pKey2
+){
+  int rc, n;
+  n = nKey1<nKey2 ? nKey1 : nKey2;
+  rc = memcmp(pKey1, pKey2, n);
+  if( rc==0 ) rc = nKey1 - nKey2;
+  return rc;
+}
+
+static void anyCollNeeded(
+  void *NotUsed,
+  sqlite3 *db,
+  int eTextRep,
+  const char *zCollName
+){
+  sqlite3_create_collation(db, zCollName, eTextRep, 0, anyCollFunc); 
+}
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int sqlite3_anycollseq_init(
+  sqlite3 *db, 
+  char **pzErrMsg, 
+  const sqlite3_api_routines *pApi
+){
+  int rc = SQLITE_OK;
+  SQLITE_EXTENSION_INIT2(pApi);
+  rc = sqlite3_collation_needed(db, 0, anyCollNeeded);
+  return rc;
+}