From: drh <drh@noemail.net>
Date: Tue, 9 Aug 2016 21:08:42 +0000 (+0000)
Subject: Prototype for the remember(V,PTR) extension function.
X-Git-Tag: version-3.16.0~87^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=refs%2Fheads%2FrememberFunc;p=thirdparty%2Fsqlite.git

Prototype for the remember(V,PTR) extension function.

FossilOrigin-Name: f0942c362f45ca1e986e142dbdd3ad957626dfb1
---

diff --git a/Makefile.in b/Makefile.in
index 9b2fe86cf4..852d023356 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -429,6 +429,7 @@ TESTSRC += \
   $(TOP)/ext/misc/nextchar.c \
   $(TOP)/ext/misc/percentile.c \
   $(TOP)/ext/misc/regexp.c \
+  $(TOP)/ext/misc/remember.c \
   $(TOP)/ext/misc/series.c \
   $(TOP)/ext/misc/spellfix.c \
   $(TOP)/ext/misc/totype.c \
diff --git a/Makefile.msc b/Makefile.msc
index cd866ce4a4..d696df7551 100644
--- a/Makefile.msc
+++ b/Makefile.msc
@@ -1305,6 +1305,7 @@ TESTEXT = \
   $(TOP)\ext\misc\nextchar.c \
   $(TOP)\ext\misc\percentile.c \
   $(TOP)\ext\misc\regexp.c \
+  $(TOP)\ext\misc\remember.c \
   $(TOP)\ext\misc\series.c \
   $(TOP)\ext\misc\spellfix.c \
   $(TOP)\ext\misc\totype.c \
diff --git a/ext/misc/remember.c b/ext/misc/remember.c
new file mode 100644
index 0000000000..aa3eff8a3f
--- /dev/null
+++ b/ext/misc/remember.c
@@ -0,0 +1,68 @@
+/*
+** 2016-08-09
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file demonstrates how to create an SQL function that is a pass-through
+** for integer values (it returns a copy of its argument) but also saves the
+** value that is passed through into a C-language variable.  The address of
+** the C-language variable is supplied as the second argument.
+**
+** This allows, for example, a counter to incremented and the original
+** value retrieved, atomically, using a single statement:
+**
+**    UPDATE counterTab SET cnt=remember(cnt,$PTR)+1 WHERE id=$ID
+**
+** Prepare the above statement once.  Then to use it, bind the address
+** of the output variable to $PTR and the id of the counter to $ID and
+** run the prepared statement.
+**
+** One can imagine doing similar things with floating-point values and
+** strings, but this demonstration extension will stick to using just
+** integers.
+*/
+#include "sqlite3ext.h"
+SQLITE_EXTENSION_INIT1
+#include <assert.h>
+
+/*
+**      remember(V,PTR)
+**
+** Return the integer value V.  Also save the value of V in a
+** C-language variable whose address is PTR.
+*/
+static void rememberFunc(
+  sqlite3_context *pCtx,
+  int argc,
+  sqlite3_value **argv
+){
+  sqlite3_int64 v;
+  sqlite3_int64 ptr;
+  assert( argc==2 );
+  v = sqlite3_value_int64(argv[0]);
+  ptr = sqlite3_value_int64(argv[1]);
+  *((sqlite3_int64*)ptr) = v;
+  sqlite3_result_int64(pCtx, v);
+}
+
+#ifdef _WIN32
+__declspec(dllexport)
+#endif
+int sqlite3_remember_init(
+  sqlite3 *db, 
+  char **pzErrMsg, 
+  const sqlite3_api_routines *pApi
+){
+  int rc = SQLITE_OK;
+  SQLITE_EXTENSION_INIT2(pApi);
+  rc = sqlite3_create_function(db, "remember", 2, SQLITE_UTF8, 0,
+                               rememberFunc, 0, 0);
+  return rc;
+}
diff --git a/main.mk b/main.mk
index 451837ffff..6c8afbef59 100644
--- a/main.mk
+++ b/main.mk
@@ -334,6 +334,7 @@ TESTSRC += \
   $(TOP)/ext/misc/nextchar.c \
   $(TOP)/ext/misc/percentile.c \
   $(TOP)/ext/misc/regexp.c \
+  $(TOP)/ext/misc/remember.c \
   $(TOP)/ext/misc/series.c \
   $(TOP)/ext/misc/spellfix.c \
   $(TOP)/ext/misc/totype.c \
diff --git a/manifest b/manifest
index 850a297904..87310ef875 100644
--- a/manifest
+++ b/manifest
@@ -1,8 +1,8 @@
-C Fix\sharmless\scompiler\swarning.
-D 2016-08-09T21:01:52.333
-F Makefile.in cfd8fb987cd7a6af046daa87daa146d5aad0e088
+C Prototype\sfor\sthe\sremember(V,PTR)\sextension\sfunction.
+D 2016-08-09T21:08:42.832
+F Makefile.in 6b7b3d1c441dd80a22cf0103061fc0815ca86294
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
-F Makefile.msc d66d0395c38571aab3804f8db0fa20707ae4609a
+F Makefile.msc 7ec77041ea6d86996c7b9f8ad2cf463e1eb24846
 F README.md 8ecc12493ff9f820cdea6520a9016001cb2e59b7
 F VERSION cb29eb11e493dd85b3eeec4053c03949bf98478e
 F aclocal.m4 a5c22d164aff7ed549d53a90fa56d56955281f50
@@ -217,6 +217,7 @@ F ext/misc/json1.c 9799e4252b305edcbe659329eec3ca80ed85f968
 F ext/misc/nextchar.c 35c8b8baacb96d92abbb34a83a997b797075b342
 F ext/misc/percentile.c 92699c8cd7d517ff610e6037e56506f8904dae2e
 F ext/misc/regexp.c a68d25c659bd2d893cd1215667bbf75ecb9dc7d4
+F ext/misc/remember.c 8440f8d0b452c5cdefb62b57135ccd1267aa729d
 F ext/misc/rot13.c 1ac6f95f99b575907b9b09c81a349114cf9be45a
 F ext/misc/scrub.c 1c5bfb8b0cd18b602fcb55755e84abf0023ac2fb
 F ext/misc/series.c e11e534ada797d5b816d7e7a93c022306563ca35
@@ -309,7 +310,7 @@ F ext/userauth/userauth.c 5fa3bdb492f481bbc1709fc83c91ebd13460c69e
 F install-sh 9d4de14ab9fb0facae2f48780b874848cbf2f895 x
 F ltmain.sh 3ff0879076df340d2e23ae905484d8c15d5fdea8
 F magic.txt 8273bf49ba3b0c8559cb2774495390c31fd61c60
-F main.mk 1883ecab643b136e8ab3fdc33785e6ea8b5ceb46
+F main.mk e9a25e0027df155957ea88ef317a7c80b1372537
 F mkso.sh fd21c06b063bb16a5d25deea1752c2da6ac3ed83
 F mptest/config01.test 3c6adcbc50b991866855f1977ff172eb6d901271
 F mptest/config02.test 4415dfe36c48785f751e16e32c20b077c28ae504
@@ -394,7 +395,7 @@ F src/sqliteLimit.h c0373387c287c8d0932510b5547ecde31b5da247
 F src/status.c a9e66593dfb28a9e746cba7153f84d49c1ddc4b1
 F src/table.c 5226df15ab9179b9ed558d89575ea0ce37b03fc9
 F src/tclsqlite.c bdae822f21e229b6daced15938b6343ce44ef454
-F src/test1.c 0a0909cf7962d2359db329c08d15b90b4b6e724f
+F src/test1.c 4276cd840acf0fc5f2b04250c9343b209cc60e1b
 F src/test2.c b7174313e993754303a8b33c43df7c44b46857ab
 F src/test3.c 1339a40be39650ae83894b6578f971dc7f96ea8a
 F src/test4.c 18ec393bb4d0ad1de729f0b94da7267270f3d8e6
@@ -1118,7 +1119,7 @@ F test/symlink.test c9ebe7330d228249e447038276bfc8a7b22f4849
 F test/sync.test 2f84bdbc2b2df1fcb0220575b4b9f8cea94b7529
 F test/syscall.test f59ba4e25f7ba4a4c031026cc2ef8b6e4b4c639c
 F test/sysfault.test c9f2b0d8d677558f74de750c75e12a5454719d04
-F test/tabfunc01.test 50a9fb379f9747fd0d40ea6d8fa3a101361bb537
+F test/tabfunc01.test 8b2ef53caa37854864c89e1e57e8a10efd4f5e43
 F test/table.test b708f3e5fa2542fa51dfab21fc07b36ea445cb2f
 F test/tableapi.test 2674633fa95d80da917571ebdd759a14d9819126
 F test/tableopts.test dba698ba97251017b7c80d738c198d39ab747930
@@ -1510,7 +1511,10 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 14864f2b8470fe98dbd17f59963bf1be8d4962f9
-R 3c3d32515aedcf447480f55f3548a5e0
+P 9a5a4f6e3bc265fecf79a7f63d14abbf239da636
+R a4aeba273d85b5b6518de32b9203944f
+T *branch * rememberFunc
+T *sym-rememberFunc *
+T -sym-trunk *
 U drh
-Z 4951f1f9d58f89a54689c68080c6d7fb
+Z c510cdb1fe7f1007d6a0bc0b22076879
diff --git a/manifest.uuid b/manifest.uuid
index a3c154d615..71390237f6 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-9a5a4f6e3bc265fecf79a7f63d14abbf239da636
\ No newline at end of file
+f0942c362f45ca1e986e142dbdd3ad957626dfb1
\ No newline at end of file
diff --git a/src/test1.c b/src/test1.c
index aced552173..b4197ef73d 100644
--- a/src/test1.c
+++ b/src/test1.c
@@ -6764,6 +6764,7 @@ static int SQLITE_TCLAPI tclLoadStaticExtensionCmd(
   extern int sqlite3_nextchar_init(sqlite3*,char**,const sqlite3_api_routines*);
   extern int sqlite3_percentile_init(sqlite3*,char**,const sqlite3_api_routines*);
   extern int sqlite3_regexp_init(sqlite3*,char**,const sqlite3_api_routines*);
+  extern int sqlite3_remember_init(sqlite3*,char**,const sqlite3_api_routines*);
   extern int sqlite3_series_init(sqlite3*,char**,const sqlite3_api_routines*);
   extern int sqlite3_spellfix_init(sqlite3*,char**,const sqlite3_api_routines*);
   extern int sqlite3_totype_init(sqlite3*,char**,const sqlite3_api_routines*);
@@ -6783,6 +6784,7 @@ static int SQLITE_TCLAPI tclLoadStaticExtensionCmd(
     { "nextchar",              sqlite3_nextchar_init             },
     { "percentile",            sqlite3_percentile_init           },
     { "regexp",                sqlite3_regexp_init               },
+    { "remember",              sqlite3_remember_init             },
     { "series",                sqlite3_series_init               },
     { "spellfix",              sqlite3_spellfix_init             },
     { "totype",                sqlite3_totype_init               },
diff --git a/test/tabfunc01.test b/test/tabfunc01.test
index 19d3cc66d5..f25d070847 100644
--- a/test/tabfunc01.test
+++ b/test/tabfunc01.test
@@ -23,6 +23,7 @@ ifcapable !vtab {
 }
 load_static_extension db series
 load_static_extension db carray
+load_static_extension db remember
 
 do_execsql_test tabfunc01-1.1 {
   SELECT *, '|' FROM generate_series WHERE start=1 AND stop=9 AND step=2;
@@ -172,6 +173,19 @@ do_test tabfunc01-720 {
     SELECT b FROM t600, carray($PTR,5,'int64') WHERE a=value;
   }
 } {(005) (007) (013) (017) (023)}
+do_test tabfunc01-721 {
+  db eval {
+    SELECT remember(123,$PTR);
+    SELECT value FROM carray($PTR,5,'int64');
+  }
+} {123 123 7 13 17 23}
+do_test tabfunc01-722 {
+  set PTR2 [expr {$PTR+16}]
+  db eval {
+    SELECT remember(987,$PTR2);
+    SELECT value FROM carray($PTR,5,'int64');
+  }
+} {987 123 7 987 17 23}
 
 do_test tabfunc01-730 {
   set PTR [doublearray_addr 5.0 7.0 13.0 17.0 23.0]