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Overview
Comment:Reduce the size of the compiled binary by a couple of hundred bytes by using a thigher packing of a transformation table in date.c. Suggested by forum post 4f6efbb2a9.
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SHA3-256: c75ba4fa644d338d22813c17172b9975411fe6197e07fd584e3209e3beb78036
User & Date: drh 2021-12-23 00:16:06
Context
2021-12-24
13:30
Raise an error if a schema name is attached to the table-alias name of a subquery or view. See forum post 021a33600b for the bug report. (check-in: 8af8c153 user: drh tags: trunk)
2021-12-23
00:16
Reduce the size of the compiled binary by a couple of hundred bytes by using a thigher packing of a transformation table in date.c. Suggested by forum post 4f6efbb2a9. (check-in: c75ba4fa user: drh tags: trunk)
2021-12-21
16:59
Update the README.md to instruct the user to remove the final comment line from the "manifest" file before using it to compute the check-in hash. (check-in: 7b4f9d95 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/date.c.
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**
**            'NNN days'
**
** Where NNN is an arbitrary floating-point number and "days" can be one
** of several units of time.
*/
static const struct {
  u8 eType;           /* Transformation type code */
  u8 nName;           /* Length of th name */
  char *zName;        /* Name of the transformation */
  double rLimit;      /* Maximum NNN value for this transform */
  double rXform;      /* Constant used for this transform */
} aXformType[] = {
  { 0, 6, "second", 464269060800.0, 1000.0         },
  { 0, 6, "minute", 7737817680.0,   60000.0        },
  { 0, 4, "hour",   128963628.0,    3600000.0      },
  { 0, 3, "day",    5373485.0,      86400000.0     },
  { 1, 5, "month",  176546.0,       2592000000.0   },
  { 2, 4, "year",   14713.0,        31536000000.0  },
};

/*
** Process a modifier to a date-time stamp.  The modifiers are
** as follows:
**
**     NNN days








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**
**            'NNN days'
**
** Where NNN is an arbitrary floating-point number and "days" can be one
** of several units of time.
*/
static const struct {

  u8 nName;           /* Length of the name */
  char zName[7];      /* Name of the transformation */
  float rLimit;       /* Maximum NNN value for this transform */
  float rXform;       /* Constant used for this transform */
} aXformType[] = {
  { 6, "second", 4.6427e+14,       1.0  },
  { 6, "minute", 7.7379e+12,      60.0  },
  { 4, "hour",   1.2897e+11,    3600.0  },
  { 3, "day",    5373485.0,    86400.0  },
  { 5, "month",  176546.0,   2592000.0  },
  { 4, "year",   14713.0,   31536000.0  },
};

/*
** Process a modifier to a date-time stamp.  The modifiers are
** as follows:
**
**     NNN days
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      rc = 1;
      rRounder = r<0 ? -0.5 : +0.5;
      for(i=0; i<ArraySize(aXformType); i++){
        if( aXformType[i].nName==n
         && sqlite3_strnicmp(aXformType[i].zName, z, n)==0
         && r>-aXformType[i].rLimit && r<aXformType[i].rLimit
        ){
          switch( aXformType[i].eType ){
            case 1: { /* Special processing to add months */
              int x;

              computeYMD_HMS(p);
              p->M += (int)r;
              x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
              p->Y += x;
              p->M -= x*12;
              p->validJD = 0;
              r -= (int)r;
              break;
            }
            case 2: { /* Special processing to add years */
              int y = (int)r;

              computeYMD_HMS(p);
              p->Y += y;
              p->validJD = 0;
              r -= (int)r;
              break;
            }
          }
          computeJD(p);
          p->iJD += (sqlite3_int64)(r*aXformType[i].rXform + rRounder);
          rc = 0;
          break;
        }
      }
      clearYMD_HMS_TZ(p);
      break;
    }








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      rc = 1;
      rRounder = r<0 ? -0.5 : +0.5;
      for(i=0; i<ArraySize(aXformType); i++){
        if( aXformType[i].nName==n
         && sqlite3_strnicmp(aXformType[i].zName, z, n)==0
         && r>-aXformType[i].rLimit && r<aXformType[i].rLimit
        ){
          switch( i ){
            case 4: { /* Special processing to add months */
              int x;
              assert( strcmp(aXformType[i].zName,"month")==0 );
              computeYMD_HMS(p);
              p->M += (int)r;
              x = p->M>0 ? (p->M-1)/12 : (p->M-12)/12;
              p->Y += x;
              p->M -= x*12;
              p->validJD = 0;
              r -= (int)r;
              break;
            }
            case 5: { /* Special processing to add years */
              int y = (int)r;
              assert( strcmp(aXformType[i].zName,"year")==0 );
              computeYMD_HMS(p);
              p->Y += y;
              p->validJD = 0;
              r -= (int)r;
              break;
            }
          }
          computeJD(p);
          p->iJD += (sqlite3_int64)(r*1000.0*aXformType[i].rXform + rRounder);
          rc = 0;
          break;
        }
      }
      clearYMD_HMS_TZ(p);
      break;
    }
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