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Comment:Add the "varint.c" utility program in the tool directory.
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SHA1: ea5d56be5fe14934e4dbe9c17d46b058f487a231
User & Date: drh 2014-10-31 10:31:59
Context
2014-10-31
12:22
Simplify the math slightly, and reduce by one the number of loop iterations, for the loop in balance_nonroot() that moves cells between pages. check-in: 2e838db8 user: drh tags: trunk
10:31
Add the "varint.c" utility program in the tool directory. check-in: ea5d56be user: drh tags: trunk
02:51
Remove an unnecessary branch from balance_nonroot(). check-in: 9fc7c88e user: drh tags: trunk
Changes
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Added tool/varint.c.

            1  +/*
            2  +** A utility program to translate SQLite varints into decimal and decimal
            3  +** integers into varints.
            4  +*/
            5  +#include <stdio.h>
            6  +#include <string.h>
            7  +#include <stdlib.h>
            8  +
            9  +#if defined(_MSC_VER) || defined(__BORLANDC__)
           10  +  typedef __int64 i64;
           11  +  typedef unsigned __int64 u64;
           12  +#else
           13  +  typedef long long int i64;
           14  +  typedef unsigned long long int u64;
           15  +#endif
           16  +
           17  +static int hexValue(char c){
           18  +  if( c>='0' && c<='9' ) return c - '0';
           19  +  if( c>='a' && c<='f' ) return c - 'a' + 10;
           20  +  if( c>='A' && c<='F' ) return c - 'A' + 10;
           21  +  return -1;
           22  +}
           23  +
           24  +static char toHex(unsigned char c){
           25  +  return "0123456789abcdef"[c&0xf];
           26  +}
           27  +
           28  +static int putVarint(unsigned char *p, u64 v){
           29  +  int i, j, n;
           30  +  unsigned char buf[10];
           31  +  if( v & (((u64)0xff000000)<<32) ){
           32  +    p[8] = (unsigned char)v;
           33  +    v >>= 8;
           34  +    for(i=7; i>=0; i--){
           35  +      p[i] = (unsigned char)((v & 0x7f) | 0x80);
           36  +      v >>= 7;
           37  +    }
           38  +    return 9;
           39  +  }    
           40  +  n = 0;
           41  +  do{
           42  +    buf[n++] = (unsigned char)((v & 0x7f) | 0x80);
           43  +    v >>= 7;
           44  +  }while( v!=0 );
           45  +  buf[0] &= 0x7f;
           46  +  for(i=0, j=n-1; j>=0; j--, i++){
           47  +    p[i] = buf[j];
           48  +  }
           49  +  return n;
           50  +}
           51  +
           52  +
           53  +int main(int argc, char **argv){
           54  +  int i;
           55  +  u64 x;
           56  +  u64 uX = 0;
           57  +  i64 iX;
           58  +  int n;
           59  +  unsigned char zHex[20];
           60  +
           61  +  if( argc==1 ){
           62  +    fprintf(stderr, 
           63  +         "Usage:\n"
           64  +         "  %s HH HH HH ...   Convert varint to decimal\n"
           65  +         "  %s DDDDD          Convert decimal to varint\n"
           66  +         "                    Add '+' or '-' before DDDDD to disambiguate.\n",
           67  +         argv[0], argv[0]);
           68  +    exit(1);
           69  +  }
           70  +  if( argc>2 
           71  +   || (strlen(argv[1])==2 && hexValue(argv[1][0])>=0 && hexValue(argv[1][1])>=0)
           72  +  ){
           73  +    /* Hex to decimal */
           74  +    for(i=1; i<argc && i<9; i++){
           75  +      if( strlen(argv[i])!=2 ){
           76  +        fprintf(stderr, "Not a hex byte: %s\n", argv[i]);
           77  +        exit(1);
           78  +      }
           79  +      x = (hexValue(argv[i][0])<<4) + hexValue(argv[i][1]);
           80  +      uX = (uX<<7) + (x&0x7f);
           81  +      if( (x&0x80)==0 ) break;
           82  +    }
           83  +    if( i==9 && i<argc ){
           84  +      if( strlen(argv[i])!=2 ){
           85  +        fprintf(stderr, "Not a hex byte: %s\n", argv[i]);
           86  +        exit(1);
           87  +      }
           88  +      x = (hexValue(argv[i][0])<<4) + hexValue(argv[i][1]);
           89  +      uX = (uX<<8) + x;
           90  +    }
           91  +    i++;
           92  +    if( i<argc ){
           93  +      fprintf(stderr, "Extra arguments: %s...\n", argv[i]);
           94  +      exit(1);
           95  +    }
           96  +  }else{
           97  +    char *z = argv[1];
           98  +    int sign = 1;
           99  +    if( z[0]=='+' ) z++;
          100  +    else if( z[0]=='-' ){ z++; sign = -1; }
          101  +    uX = 0;
          102  +    while( z[0] ){
          103  +      if( z[0]<'0' || z[0]>'9' ){
          104  +        fprintf(stderr, "Not a decimal number: %s", argv[1]);
          105  +        exit(1);
          106  +      }
          107  +      uX = uX*10 + z[0] - '0';
          108  +      z++;
          109  +    }
          110  +    if( sign<0 ){
          111  +      memcpy(&iX, &uX, 8);
          112  +      iX = -iX;
          113  +      memcpy(&uX, &iX, 8);
          114  +    }
          115  +  }
          116  +  n = putVarint(zHex, uX);
          117  +  printf("%lld =", (i64)uX);
          118  +  for(i=0; i<n; i++){
          119  +    printf(" %c%c", toHex(zHex[i]>>4), toHex(zHex[i]&0x0f));
          120  +  }
          121  +  printf("\n");
          122  +  return 0;
          123  +}