** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
-** $Id: util.c,v 1.64 2003/06/02 06:17:10 jplyon Exp $
+** $Id: util.c,v 1.65 2003/06/05 14:27:56 drh Exp $
*/
#include "sqliteInt.h"
#include <stdarg.h>
return N<0 ? 0 : *a - *b;
}
-#if 0 /* NOT USED */
-/*
-** The sortStrCmp() function below is used to order elements according
-** to the ORDER BY clause of a SELECT. The sort order is a little different
-** from what one might expect. This note attempts to describe what is
-** going on.
-**
-** We want the main string comparision function used for sorting to
-** sort both numbers and alphanumeric words into the correct sequence.
-** The same routine should do both without prior knowledge of which
-** type of text the input represents. It should even work for strings
-** which are a mixture of text and numbers. (It does not work for
-** numeric substrings in exponential notation, however.)
-**
-** To accomplish this, we keep track of a state number while scanning
-** the two strings. The states are as follows:
-**
-** 1 Beginning of word
-** 2 Arbitrary text
-** 3 Integer
-** 4 Negative integer
-** 5 Real number
-** 6 Negative real
-**
-** The scan begins in state 1, beginning of word. Transitions to other
-** states are determined by characters seen, as shown in the following
-** chart:
-**
-** Current State Character Seen New State
-** -------------------- -------------- -------------------
-** 0 Beginning of word "-" 3 Negative integer
-** digit 2 Integer
-** space 0 Beginning of word
-** otherwise 1 Arbitrary text
-**
-** 1 Arbitrary text space 0 Beginning of word
-** digit 2 Integer
-** otherwise 1 Arbitrary text
-**
-** 2 Integer space 0 Beginning of word
-** "." 4 Real number
-** digit 2 Integer
-** otherwise 1 Arbitrary text
-**
-** 3 Negative integer space 0 Beginning of word
-** "." 5 Negative Real num
-** digit 3 Negative integer
-** otherwise 1 Arbitrary text
-**
-** 4 Real number space 0 Beginning of word
-** digit 4 Real number
-** otherwise 1 Arbitrary text
-**
-** 5 Negative real num space 0 Beginning of word
-** digit 5 Negative real num
-** otherwise 1 Arbitrary text
-**
-** To implement this state machine, we first classify each character
-** into on of the following categories:
-**
-** 0 Text
-** 1 Space
-** 2 Digit
-** 3 "-"
-** 4 "."
-**
-** Given an arbitrary character, the array charClass[] maps that character
-** into one of the atove categories.
-*/
-static const unsigned char charClass[] = {
- /* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
-/* 0x */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 0,
-/* 1x */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* 2x */ 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 4, 0,
-/* 3x */ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 0, 0, 0, 0, 0, 0,
-/* 4x */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* 5x */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* 6x */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* 7x */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* 8x */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* 9x */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* Ax */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* Bx */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* Cx */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* Dx */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* Ex */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-/* Fx */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-};
-#define N_CHAR_CLASS 5
-
-/*
-** Given the current state number (0 thru 5), this array figures
-** the new state number given the character class.
-*/
-static const unsigned char stateMachine[] = {
- /* Text, Space, Digit, "-", "." */
- 1, 0, 2, 3, 1, /* State 0: Beginning of word */
- 1, 0, 2, 1, 1, /* State 1: Arbitrary text */
- 1, 0, 2, 1, 4, /* State 2: Integer */
- 1, 0, 3, 1, 5, /* State 3: Negative integer */
- 1, 0, 4, 1, 1, /* State 4: Real number */
- 1, 0, 5, 1, 1, /* State 5: Negative real num */
-};
-
-/* This routine does a comparison of two strings. Case is used only
-** if useCase!=0. Numeric substrings compare in numerical order for the
-** most part but this routine does not understand exponential notation.
-*/
-static int sortStrCmp(const char *atext, const char *btext, int useCase){
- register unsigned char *a, *b, *map, ca, cb;
- int result;
- register int cclass = 0;
-
- a = (unsigned char *)atext;
- b = (unsigned char *)btext;
- if( useCase ){
- do{
- if( (ca= *a++)!=(cb= *b++) ) break;
- cclass = stateMachine[cclass*N_CHAR_CLASS + charClass[ca]];
- }while( ca!=0 );
- }else{
- map = UpperToLower;
- do{
- if( (ca=map[*a++])!=(cb=map[*b++]) ) break;
- cclass = stateMachine[cclass*N_CHAR_CLASS + charClass[ca]];
- }while( ca!=0 );
- if( ca>='[' && ca<='`' ) cb = b[-1];
- if( cb>='[' && cb<='`' ) ca = a[-1];
- }
- switch( cclass ){
- case 0:
- case 1: {
- if( isdigit(ca) && isdigit(cb) ){
- cclass = 2;
- }
- break;
- }
- default: {
- break;
- }
- }
- switch( cclass ){
- case 2:
- case 3: {
- if( isdigit(ca) ){
- if( isdigit(cb) ){
- int acnt, bcnt;
- acnt = bcnt = 0;
- while( isdigit(*a++) ) acnt++;
- while( isdigit(*b++) ) bcnt++;
- result = acnt - bcnt;
- if( result==0 ) result = ca-cb;
- }else{
- result = 1;
- }
- }else if( isdigit(cb) ){
- result = -1;
- }else if( ca=='.' ){
- result = 1;
- }else if( cb=='.' ){
- result = -1;
- }else{
- result = ca - cb;
- cclass = 2;
- }
- if( cclass==3 ) result = -result;
- break;
- }
- case 0:
- case 1:
- case 4: {
- result = ca - cb;
- break;
- }
- case 5: {
- result = cb - ca;
- };
- }
- return result;
-}
-#endif /* NOT USED */
-
/*
** Return TRUE if z is a pure numeric string. Return FALSE if the
** string contains any character which is not part of a number.
projects / thirdparty / sqlite.git / commitdiff
