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Overview
Comment: | Add the zorder.c extension implementing zorder() and unzorder() SQL functions. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA3-256: |
a57a77dc0cc9fbaa9d5b134422f7a8cc |
User & Date: | drh 2018-02-09 20:49:15.905 |
Context
2018-02-09
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23:25 | Improve the performance of the built-in REPLACE() function in cases where it does many substitutions that make the string larger. OSSFuzz is reporting intermittant timeouts when running a test where it does a REPLACE() on a 930KB random blob. Perhaps this enhancement will fix that. (check-in: fab2c2b07b user: drh tags: trunk) | |
20:49 | Add the zorder.c extension implementing zorder() and unzorder() SQL functions. (check-in: a57a77dc0c user: drh tags: trunk) | |
15:42 | Make the tests in func6.test more robust against implementation changes. (check-in: b685d32310 user: dan tags: trunk) | |
Changes
Added ext/misc/zorder.c.
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 | /* ** 2018-02-09 ** ** 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. ** ****************************************************************************** ** ** SQL functions for z-order (Morton code) transformations. ** ** zorder(X0,X0,..,xN) Generate an N+1 dimension Morton code ** ** unzorder(Z,N,I) Extract the I-th dimension from N-dimensional ** Morton code Z. */ #include "sqlite3ext.h" SQLITE_EXTENSION_INIT1 #include <assert.h> #include <string.h> /* ** Functions: zorder(X0,X1,....) ** ** Convert integers X0, X1, ... into morton code. ** ** The output is a signed 64-bit integer. If any argument is too large, ** an error is thrown. */ static void zorderFunc( sqlite3_context *context, int argc, sqlite3_value **argv ){ sqlite3_int64 z, x[63]; int i, j; z = 0; for(i=0; i<argc; i++){ x[i] = sqlite3_value_int64(argv[i]); } if( argc>0 ){ for(i=0; i<63; i++){ j = i%argc; z |= (x[j]&1)<<i; x[j] >>= 1; } } sqlite3_result_int64(context, z); for(i=0; i<argc; i++){ if( x[i] ){ sqlite3_result_error(context, "parameter too large", -1); } } } /* ** Functions: unzorder(Z,N,I) ** ** Assuming that Z is an N-dimensional Morton code, extract the I-th ** dimension. */ static void unzorderFunc( sqlite3_context *context, int argc, sqlite3_value **argv ){ sqlite3_int64 z, n, i, x; int j, k; z = sqlite3_value_int64(argv[0]); n = sqlite3_value_int64(argv[1]); i = sqlite3_value_int64(argv[2]); x = 0; for(k=0, j=i; j<63; j+=n, k++){ x |= ((z>>j)&1)<<k; } sqlite3_result_int64(context, x); } #ifdef _WIN32 __declspec(dllexport) #endif int sqlite3_zorder_init( sqlite3 *db, char **pzErrMsg, const sqlite3_api_routines *pApi ){ int rc = SQLITE_OK; SQLITE_EXTENSION_INIT2(pApi); (void)pzErrMsg; /* Unused parameter */ rc = sqlite3_create_function(db, "zorder", -1, SQLITE_UTF8, 0, zorderFunc, 0, 0); if( rc==SQLITE_OK ){ rc = sqlite3_create_function(db, "unzorder", 3, SQLITE_UTF8, 0, unzorderFunc, 0, 0); } return rc; } |