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Overview
Comment:Implementation of the INSTR() SQL function, as found in SQL Server, MySQL, and Oracle.
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SHA1: 49ccae964f3a8ae5aab87f56503121e09424545f
User & Date: drh 2012-10-25 03:07:29.004
Context
2012-11-05
13:51
Add the INSTR() SQL function. (check-in: a4c181cbcf user: drh tags: trunk)
2012-10-25
03:07
Implementation of the INSTR() SQL function, as found in SQL Server, MySQL, and Oracle. (Closed-Leaf check-in: 49ccae964f user: drh tags: instr)
2012-10-19
02:10
Make sure substructure elements have proper alignment in the ICU tokenizers of FTS2 and FTS3. (check-in: aaa2d9b0db user: drh tags: trunk)
Changes
Side-by-Side Diff Ignore Whitespace Patch
Changes to src/func.c.
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      double rVal = sqlite3_value_double(argv[0]);
      if( rVal<0 ) rVal = -rVal;
      sqlite3_result_double(context, rVal);
      break;
    }
  }
}

/*
** Implementation of the instr() function.
**
** instr(haystack,needle) finds the first occurrence of needle
** in haystack and returns the number of previous characters plus 1,
** or 0 if needle does not occur within haystack.
**
** If both haystack and needle are BLOBs, then the result is one more than
** the number of bytes in haystack prior to the first occurrence of needle,
** or 0 if needle never occurs in haystack.
*/
static void instrFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  const unsigned char *zHaystack;
  const unsigned char *zNeedle;
  int nHaystack;
  int nNeedle;
  int typeHaystack, typeNeedle;
  int N = 1;
  int isText;

  typeHaystack = sqlite3_value_type(argv[0]);
  typeNeedle = sqlite3_value_type(argv[1]);
  if( typeHaystack==SQLITE_NULL || typeNeedle==SQLITE_NULL ) return;
  nHaystack = sqlite3_value_bytes(argv[0]);
  nNeedle = sqlite3_value_bytes(argv[1]);
  if( typeHaystack==SQLITE_BLOB && typeNeedle==SQLITE_BLOB ){
    zHaystack = sqlite3_value_blob(argv[0]);
    zNeedle = sqlite3_value_blob(argv[1]);
    isText = 0;
  }else{
    zHaystack = sqlite3_value_text(argv[0]);
    zNeedle = sqlite3_value_text(argv[1]);
    isText = 1;
  }
  while( nNeedle<=nHaystack && memcmp(zHaystack, zNeedle, nNeedle)!=0 ){
    N++;
    do{
      nHaystack--;
      zHaystack++;
    }while( isText && (zHaystack[0]&0xc0)==0x80 );
  }
  if( nNeedle>nHaystack ) N = 0;
  sqlite3_result_int(context, N);
}

/*
** Implementation of the substr() function.
**
** substr(x,p1,p2)  returns p2 characters of x[] beginning with p1.
** p1 is 1-indexed.  So substr(x,1,1) returns the first character
** of x.  If x is text, then we actually count UTF-8 characters.
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    FUNCTION(min,                0, 0, 1, 0                ),
    AGGREGATE(min,               1, 0, 1, minmaxStep,      minMaxFinalize ),
    FUNCTION(max,               -1, 1, 1, minmaxFunc       ),
    FUNCTION(max,                0, 1, 1, 0                ),
    AGGREGATE(max,               1, 1, 1, minmaxStep,      minMaxFinalize ),
    FUNCTION2(typeof,            1, 0, 0, typeofFunc,  SQLITE_FUNC_TYPEOF),
    FUNCTION2(length,            1, 0, 0, lengthFunc,  SQLITE_FUNC_LENGTH),
    FUNCTION(instr,              2, 0, 0, instrFunc        ),
    FUNCTION(substr,             2, 0, 0, substrFunc       ),
    FUNCTION(substr,             3, 0, 0, substrFunc       ),
    FUNCTION(abs,                1, 0, 0, absFunc          ),
#ifndef SQLITE_OMIT_FLOATING_POINT
    FUNCTION(round,              1, 0, 0, roundFunc        ),
    FUNCTION(round,              2, 0, 0, roundFunc        ),
#endif
︙
Added test/instr.test. 



















































































































































































































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# 2012 October 24
#
# 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 regression tests for SQLite library.  The
# focus of this file is testing the built-in INSTR() functions.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Create a table to work with.
#
do_test instr-1.1 {
  db eval {SELECT instr('abcdefg','a');}
} {1}
do_test instr-1.2 {
  db eval {SELECT instr('abcdefg','b');}
} {2}
do_test instr-1.3 {
  db eval {SELECT instr('abcdefg','c');}
} {3}
do_test instr-1.4 {
  db eval {SELECT instr('abcdefg','d');}
} {4}
do_test instr-1.5 {
  db eval {SELECT instr('abcdefg','e');}
} {5}
do_test instr-1.6 {
  db eval {SELECT instr('abcdefg','f');}
} {6}
do_test instr-1.7 {
  db eval {SELECT instr('abcdefg','g');}
} {7}
do_test instr-1.8 {
  db eval {SELECT instr('abcdefg','h');}
} {0}
do_test instr-1.9 {
  db eval {SELECT instr('abcdefg','abcdefg');}
} {1}
do_test instr-1.10 {
  db eval {SELECT instr('abcdefg','abcdefgh');}
} {0}
do_test instr-1.11 {
  db eval {SELECT instr('abcdefg','bcdefg');}
} {2}
do_test instr-1.12 {
  db eval {SELECT instr('abcdefg','bcdefgh');}
} {0}
do_test instr-1.13 {
  db eval {SELECT instr('abcdefg','cdefg');}
} {3}
do_test instr-1.14 {
  db eval {SELECT instr('abcdefg','cdefgh');}
} {0}
do_test instr-1.15 {
  db eval {SELECT instr('abcdefg','defg');}
} {4}
do_test instr-1.16 {
  db eval {SELECT instr('abcdefg','defgh');}
} {0}
do_test instr-1.17 {
  db eval {SELECT instr('abcdefg','efg');}
} {5}
do_test instr-1.18 {
  db eval {SELECT instr('abcdefg','efgh');}
} {0}
do_test instr-1.19 {
  db eval {SELECT instr('abcdefg','fg');}
} {6}
do_test instr-1.20 {
  db eval {SELECT instr('abcdefg','fgh');}
} {0}
do_test instr-1.21 {
  db eval {SELECT coalesce(instr('abcdefg',NULL),'nil');}
} {nil}
do_test instr-1.22 {
  db eval {SELECT coalesce(instr(NULL,'x'),'nil');}
} {nil}
do_test instr-1.23 {
  db eval {SELECT instr(12345,34);}
} {3}
do_test instr-1.24 {
  db eval {SELECT instr(123456.78,34);}
} {3}
do_test instr-1.25 {
  db eval {SELECT instr(123456.78,x'3334');}
} {3}
do_test instr-1.26 {
  db eval {SELECT instr('äbcdefg','efg');}
} {5}
do_test instr-1.27 {
  db eval {SELECT instr('€xyzzy','xyz');}
} {2}
do_test instr-1.28 {
  db eval {SELECT instr('abc€xyzzy','xyz');}
} {5}
do_test instr-1.29 {
  db eval {SELECT instr('abc€xyzzy','€xyz');}
} {4}
do_test instr-1.30 {
  db eval {SELECT instr('abc€xyzzy','c€xyz');}
} {3}
do_test instr-1.31 {
  db eval {SELECT instr(x'0102030405',x'01');}
} {1}
do_test instr-1.32 {
  db eval {SELECT instr(x'0102030405',x'02');}
} {2}
do_test instr-1.33 {
  db eval {SELECT instr(x'0102030405',x'03');}
} {3}
do_test instr-1.34 {
  db eval {SELECT instr(x'0102030405',x'04');}
} {4}
do_test instr-1.35 {
  db eval {SELECT instr(x'0102030405',x'05');}
} {5}
do_test instr-1.36 {
  db eval {SELECT instr(x'0102030405',x'06');}
} {0}
do_test instr-1.37 {
  db eval {SELECT instr(x'0102030405',x'0102030405');}
} {1}
do_test instr-1.38 {
  db eval {SELECT instr(x'0102030405',x'02030405');}
} {2}
do_test instr-1.39 {
  db eval {SELECT instr(x'0102030405',x'030405');}
} {3}
do_test instr-1.40 {
  db eval {SELECT instr(x'0102030405',x'0405');}
} {4}
do_test instr-1.41 {
  db eval {SELECT instr(x'0102030405',x'0506');}
} {0}
do_test instr-1.42 {
  db eval {SELECT instr(x'0102030405',x'');}
} {1}
do_test instr-1.43 {
  db eval {SELECT instr(x'',x'');}
} {1}
do_test instr-1.44 {
  db eval {SELECT instr('','');}
} {1}
do_test instr-1.45 {
  db eval {SELECT instr('abcdefg','');}
} {1}
unset -nocomplain longstr
set longstr abcdefghijklmonpqrstuvwxyz
append longstr $longstr
append longstr $longstr
append longstr $longstr
append longstr $longstr
append longstr $longstr
append longstr $longstr
append longstr $longstr
append longstr $longstr
append longstr $longstr
append longstr $longstr
append longstr $longstr
append longstr $longstr
# puts [string length $longstr]
append longstr Xabcde
do_test instr-1.46 {
  db eval {SELECT instr($longstr,'X');}
} {106497}
do_test instr-1.47 {
  db eval {SELECT instr($longstr,'Y');}
} {0}
do_test instr-1.48 {
  db eval {SELECT instr($longstr,'Xa');}
} {106497}
do_test instr-1.49 {
  db eval {SELECT instr($longstr,'zXa');}
} {106496}
set longstr [string map {a ä} $longstr]
do_test instr-1.50 {
  db eval {SELECT instr($longstr,'X');}
} {106497}
do_test instr-1.51 {
  db eval {SELECT instr($longstr,'Y');}
} {0}
do_test instr-1.52 {
  db eval {SELECT instr($longstr,'Xä');}
} {106497}
do_test instr-1.53 {
  db eval {SELECT instr($longstr,'zXä');}
} {106496}
do_test instr-1.54 {
  db eval {SELECT instr(x'78c3a4e282ac79','x');}
} {1}
do_test instr-1.55 {
  db eval {SELECT instr(x'78c3a4e282ac79','y');}
} {4}
do_test instr-1.56 {
  db eval {SELECT instr(x'78c3a4e282ac79',x'79');}
} {7}
do_test instr-1.57 {
  db eval {SELECT instr('xä€y',x'79');}
} {4}


finish_test