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changed binary date / datetime to string #195

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Merged
merged 3 commits into from
Dec 15, 2013
Merged

changed binary date / datetime to string #195

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f38e41d
changed binary date / datetime to string
arnehormann Dec 12, 2013
8f8d1a6
no longer cache len(...)
arnehormann Dec 13, 2013
ba3e6d4
applied modulo and allocation optimizations, added test
arnehormann Dec 15, 2013
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4 changes: 2 additions & 2 deletions packets.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1048,7 +1048,7 @@ func (rows *binaryRows) readRow(dest []driver.Value) error {
if rows.mc.parseTime {
dest[i], err = parseBinaryDateTime(num, data[pos:], rows.mc.cfg.loc)
} else {
dest[i], err = formatBinaryDate(num, data[pos:])
dest[i], err = formatBinaryDateTime(data[pos:pos+int(num)], false)
}

if err == nil {
Expand Down Expand Up @@ -1116,7 +1116,7 @@ func (rows *binaryRows) readRow(dest []driver.Value) error {
if rows.mc.parseTime {
dest[i], err = parseBinaryDateTime(num, data[pos:], rows.mc.cfg.loc)
} else {
dest[i], err = formatBinaryDateTime(num, data[pos:])
dest[i], err = formatBinaryDateTime(data[pos:pos+int(num)], true)
}

if err == nil {
Expand Down
100 changes: 54 additions & 46 deletions utils.go
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Original file line number Diff line number Diff line change
Expand Up @@ -503,55 +503,63 @@ func parseBinaryDateTime(num uint64, data []byte, loc *time.Location) (driver.Va
return nil, fmt.Errorf("Invalid DATETIME-packet length %d", num)
}

func formatBinaryDate(num uint64, data []byte) (driver.Value, error) {
switch num {
case 0:
return []byte("0000-00-00"), nil
func formatBinaryDateTime(src []byte, withTime bool) (driver.Value, error) {
const zeroDateTimeMicros = "0000-00-00 00:00:00.000000"
srclen := len(src)
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@julienschmidt julienschmidt Dec 13, 2013

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You don't need to cache the length. The great thing about how slices and strings in Go are designed, is that getting the length is just reading an int64 - no indirection, no function calls: MOVQ src+8(FP),BX

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@arnehormann arnehormann Dec 13, 2013

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I know. It reads smoother to me. But that's a bad habit, I'll change it.

var dst []byte
if withTime {
if srclen == 11 {
dst = []byte(zeroDateTimeMicros)
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@julienschmidt julienschmidt Dec 13, 2013

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you could save []byte(zeroDateTimeMicros) as a global var to get rid of one allocation

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@julienschmidt julienschmidt Dec 13, 2013

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Sorry, this only works if you don't edit the values (len=0, I guess).
But see my comment on your gist

} else {
dst = []byte(zeroDateTimeMicros[:19])
}
} else {
dst = []byte(zeroDateTimeMicros[:10])
}
switch srclen {
case 11:
microsecs := binary.LittleEndian.Uint32(src[7:11])
dst[20] += byte((microsecs / 100000) % 10)
dst[21] += byte((microsecs / 10000) % 10)
dst[22] += byte((microsecs / 1000) % 10)
dst[23] += byte((microsecs / 100) % 10)
dst[24] += byte((microsecs / 10) % 10)
dst[25] += byte(microsecs % 10)
fallthrough
case 7:
hour := src[4]
minute := src[5]
second := src[6]
dst[11] += (hour / 10) % 10
dst[12] += hour % 10
dst[14] += (minute / 10) % 10
dst[15] += minute % 10
dst[17] += (second / 10) % 10
dst[18] += second % 10
fallthrough
case 4:
return []byte(fmt.Sprintf(
"%04d-%02d-%02d",
binary.LittleEndian.Uint16(data[:2]),
data[2],
data[3],
)), nil
}
return nil, fmt.Errorf("Invalid DATE-packet length %d", num)
}

func formatBinaryDateTime(num uint64, data []byte) (driver.Value, error) {
switch num {
year := binary.LittleEndian.Uint16(src[:2])
month := src[2]
day := src[3]
dst[0] += byte((year / 1000) % 10)
dst[1] += byte((year / 100) % 10)
dst[2] += byte((year / 10) % 10)
dst[3] += byte(year % 10)
dst[5] += (month / 10) % 10
dst[6] += month % 10
dst[8] += (day / 10) % 10
dst[9] += day % 10
return dst, nil
case 0:
return []byte("0000-00-00 00:00:00"), nil
case 4:
return []byte(fmt.Sprintf(
"%04d-%02d-%02d 00:00:00",
binary.LittleEndian.Uint16(data[:2]),
data[2],
data[3],
)), nil
case 7:
return []byte(fmt.Sprintf(
"%04d-%02d-%02d %02d:%02d:%02d",
binary.LittleEndian.Uint16(data[:2]),
data[2],
data[3],
data[4],
data[5],
data[6],
)), nil
case 11:
return []byte(fmt.Sprintf(
"%04d-%02d-%02d %02d:%02d:%02d.%06d",
binary.LittleEndian.Uint16(data[:2]),
data[2],
data[3],
data[4],
data[5],
data[6],
binary.LittleEndian.Uint32(data[7:11]),
)), nil
return dst, nil
}
return nil, fmt.Errorf("Invalid DATETIME-packet length %d", num)
var mode string
if withTime {
mode = "DATETIME"
} else {
mode = "DATE"
}
return nil, fmt.Errorf("invalid %s-packet length %d", mode, srclen)
}

/******************************************************************************
Expand Down