| Index: third_party/sqlite/sqlite-src-3080704/tool/logest.c
|
| diff --git a/third_party/sqlite/sqlite-src-3080704/tool/logest.c b/third_party/sqlite/sqlite-src-3080704/tool/logest.c
|
| new file mode 100644
|
| index 0000000000000000000000000000000000000000..347fa68a4f4ee5a4cb72a8748fa7f1a60cbcb022
|
| --- /dev/null
|
| +++ b/third_party/sqlite/sqlite-src-3080704/tool/logest.c
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| @@ -0,0 +1,170 @@
|
| +/*
|
| +** 2013-06-10
|
| +**
|
| +** 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 contains a simple command-line utility for converting from
|
| +** integers and LogEst values and back again and for doing simple
|
| +** arithmetic operations (multiple and add) on LogEst values.
|
| +**
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| +** Usage:
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| +**
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| +** ./LogEst ARGS
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| +**
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| +** See the showHelp() routine for a description of valid arguments.
|
| +** Examples:
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| +**
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| +** To convert 123 from LogEst to integer:
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| +**
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| +** ./LogEst ^123
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| +**
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| +** To convert 123456 from integer to LogEst:
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| +**
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| +** ./LogEst 123456
|
| +**
|
| +*/
|
| +#include <stdio.h>
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| +#include <stdlib.h>
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| +#include <ctype.h>
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| +#include <assert.h>
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| +#include <string.h>
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| +#include "sqlite3.h"
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| +
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| +typedef short int LogEst; /* 10 times log2() */
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| +
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| +LogEst logEstMultiply(LogEst a, LogEst b){ return a+b; }
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| +LogEst logEstAdd(LogEst a, LogEst b){
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| + static const unsigned char x[] = {
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| + 10, 10, /* 0,1 */
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| + 9, 9, /* 2,3 */
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| + 8, 8, /* 4,5 */
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| + 7, 7, 7, /* 6,7,8 */
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| + 6, 6, 6, /* 9,10,11 */
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| + 5, 5, 5, /* 12-14 */
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| + 4, 4, 4, 4, /* 15-18 */
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| + 3, 3, 3, 3, 3, 3, /* 19-24 */
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| + 2, 2, 2, 2, 2, 2, 2, /* 25-31 */
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| + };
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| + if( a<b ){ LogEst t = a; a = b; b = t; }
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| + if( a>b+49 ) return a;
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| + if( a>b+31 ) return a+1;
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| + return a+x[a-b];
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| +}
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| +LogEst logEstFromInteger(sqlite3_uint64 x){
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| + static LogEst a[] = { 0, 2, 3, 5, 6, 7, 8, 9 };
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| + LogEst y = 40;
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| + if( x<8 ){
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| + if( x<2 ) return 0;
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| + while( x<8 ){ y -= 10; x <<= 1; }
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| + }else{
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| + while( x>255 ){ y += 40; x >>= 4; }
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| + while( x>15 ){ y += 10; x >>= 1; }
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| + }
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| + return a[x&7] + y - 10;
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| +}
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| +static sqlite3_uint64 logEstToInt(LogEst x){
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| + sqlite3_uint64 n;
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| + if( x<10 ) return 1;
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| + n = x%10;
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| + x /= 10;
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| + if( n>=5 ) n -= 2;
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| + else if( n>=1 ) n -= 1;
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| + if( x>=3 ) return (n+8)<<(x-3);
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| + return (n+8)>>(3-x);
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| +}
|
| +static LogEst logEstFromDouble(double x){
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| + sqlite3_uint64 a;
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| + LogEst e;
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| + assert( sizeof(x)==8 && sizeof(a)==8 );
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| + if( x<=0.0 ) return -32768;
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| + if( x<0.01 ) return -logEstFromDouble(1.0/x);
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| + if( x<1.0 ) return logEstFromDouble(100.0*x) - 66;
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| + if( x<1024.0 ) return logEstFromInteger((sqlite3_uint64)(1024.0*x)) - 100;
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| + if( x<=2000000000.0 ) return logEstFromInteger((sqlite3_uint64)x);
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| + memcpy(&a, &x, 8);
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| + e = (a>>52) - 1022;
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| + return e*10;
|
| +}
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| +
|
| +int isInteger(const char *z){
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| + while( z[0]>='0' && z[0]<='9' ) z++;
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| + return z[0]==0;
|
| +}
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| +
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| +int isFloat(const char *z){
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| + char c;
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| + while( ((c=z[0])>='0' && c<='9') || c=='.' || c=='E' || c=='e'
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| + || c=='+' || c=='-' ) z++;
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| + return z[0]==0;
|
| +}
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| +
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| +static void showHelp(const char *zArgv0){
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| + printf("Usage: %s ARGS...\n", zArgv0);
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| + printf("Arguments:\n"
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| + " NUM Convert NUM from integer to LogEst and push onto the stack\n"
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| + " ^NUM Interpret NUM as a LogEst and push onto stack\n"
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| + " x Multiple the top two elements of the stack\n"
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| + " + Add the top two elements of the stack\n"
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| + " dup Dupliate the top element on the stack\n"
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| + " inv Take the reciprocal of the top of stack. N = 1/N.\n"
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| + " log Find the LogEst of the number on top of stack\n"
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| + " nlogn Compute NlogN where N is the top of stack\n"
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| + );
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| + exit(1);
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| +}
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| +
|
| +int main(int argc, char **argv){
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| + int i;
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| + int n = 0;
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| + LogEst a[100];
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| + for(i=1; i<argc; i++){
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| + const char *z = argv[i];
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| + if( strcmp(z,"+")==0 ){
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| + if( n>=2 ){
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| + a[n-2] = logEstAdd(a[n-2],a[n-1]);
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| + n--;
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| + }
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| + }else if( strcmp(z,"x")==0 ){
|
| + if( n>=2 ){
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| + a[n-2] = logEstMultiply(a[n-2],a[n-1]);
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| + n--;
|
| + }
|
| + }else if( strcmp(z,"dup")==0 ){
|
| + if( n>0 ){
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| + a[n] = a[n-1];
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| + n++;
|
| + }
|
| + }else if( strcmp(z,"log")==0 ){
|
| + if( n>0 ) a[n-1] = logEstFromInteger(a[n-1]) - 33;
|
| + }else if( strcmp(z,"nlogn")==0 ){
|
| + if( n>0 ) a[n-1] += logEstFromInteger(a[n-1]) - 33;
|
| + }else if( strcmp(z,"inv")==0 ){
|
| + if( n>0 ) a[n-1] = -a[n-1];
|
| + }else if( z[0]=='^' ){
|
| + a[n++] = atoi(z+1);
|
| + }else if( isInteger(z) ){
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| + a[n++] = logEstFromInteger(atoi(z));
|
| + }else if( isFloat(z) && z[0]!='-' ){
|
| + a[n++] = logEstFromDouble(atof(z));
|
| + }else{
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| + showHelp(argv[0]);
|
| + }
|
| + }
|
| + for(i=n-1; i>=0; i--){
|
| + if( a[i]<-40 ){
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| + printf("%5d (%f)\n", a[i], 1.0/(double)logEstToInt(-a[i]));
|
| + }else if( a[i]<10 ){
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| + printf("%5d (%f)\n", a[i], logEstToInt(a[i]+100)/1024.0);
|
| + }else{
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| + sqlite3_uint64 x = logEstToInt(a[i]+100)*100/1024;
|
| + printf("%5d (%lld.%02lld)\n", a[i], x/100, x%100);
|
| + }
|
| + }
|
| + return 0;
|
| +}
|
|
|