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Overview
| Comment: | Change the way that the random() SQL function prevents the maximum negative integer so that it is testable. (CVS 6436) |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: | 995f2b9b1031fadc85e179701536b9dd4153654b |
| User & Date: | drh 2009-04-02 14:05:22 |
Context
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2009-04-02
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| 16:59 | Disable the query flattening optimization when the subquery is a compound query with an ORDER BY clause. Ticket #3773 shows why that combination does not work. (CVS 6437) check-in: 23f90d50 user: drh tags: trunk | |
| 14:05 | Change the way that the random() SQL function prevents the maximum negative integer so that it is testable. (CVS 6436) check-in: 995f2b9b user: drh tags: trunk | |
| 13:36 | Use ALWAYS and NEVER macros on unchangeable conditions within func.c. (CVS 6435) check-in: eb65e64e user: drh tags: trunk | |
Changes
Changes to src/func.c.
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** This file contains the C functions that implement various SQL ** functions of SQLite. ** ** There is only one exported symbol in this file - the function ** sqliteRegisterBuildinFunctions() found at the bottom of the file. ** All other code has file scope. ** ** $Id: func.c,v 1.229 2009/04/02 13:36:37 drh Exp $ */ #include "sqliteInt.h" #include <stdlib.h> #include <assert.h> #include "vdbeInt.h" /* ................................................................................ sqlite3_context *context, int NotUsed, sqlite3_value **NotUsed2 ){ sqlite_int64 r; UNUSED_PARAMETER2(NotUsed, NotUsed2); sqlite3_randomness(sizeof(r), &r); if( (r<<1)==0 ) r = 0; /* Prevent 0x8000.... as the result so that we */ /* can always do abs() of the result */ sqlite3_result_int64(context, r); } /* ** Implementation of randomblob(N). Return a random blob ** that is N bytes long. */ |
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** This file contains the C functions that implement various SQL ** functions of SQLite. ** ** There is only one exported symbol in this file - the function ** sqliteRegisterBuildinFunctions() found at the bottom of the file. ** All other code has file scope. ** ** $Id: func.c,v 1.230 2009/04/02 14:05:22 drh Exp $ */ #include "sqliteInt.h" #include <stdlib.h> #include <assert.h> #include "vdbeInt.h" /* ................................................................................ sqlite3_context *context, int NotUsed, sqlite3_value **NotUsed2 ){ sqlite_int64 r; UNUSED_PARAMETER2(NotUsed, NotUsed2); sqlite3_randomness(sizeof(r), &r); if( r<0 ){ /* We need to prevent a random number of 0x8000000000000000 ** (or -9223372036854775808) since when you do abs() of that ** number of you get the same value back again. To do this ** in a way that is testable, mask the sign bit off of negative ** values, resulting in a positive value. Then take the ** 2s complement of that positive value. The end result can ** therefore be no less than -9223372036854775807. */ r = -(r ^ (((sqlite3_int64)1)<<63)); } sqlite3_result_int64(context, r); } /* ** Implementation of randomblob(N). Return a random blob ** that is N bytes long. */ |