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package pgtype
import (
"database/sql/driver"
"encoding/binary"
"encoding/json"
"fmt"
"strconv"
"time"
"github.com/jackc/pgx/v5/internal/pgio"
)
type DateScanner interface {
ScanDate(v Date) error
}
type DateValuer interface {
DateValue() (Date, error)
}
type Date struct {
Time time.Time
InfinityModifier InfinityModifier
Valid bool
}
// ScanDate implements the [DateScanner] interface.
func (d *Date) ScanDate(v Date) error {
*d = v
return nil
}
// DateValue implements the [DateValuer] interface.
func (d Date) DateValue() (Date, error) {
return d, nil
}
const (
negativeInfinityDayOffset = -2147483648
infinityDayOffset = 2147483647
)
// Scan implements the [database/sql.Scanner] interface.
func (dst *Date) Scan(src any) error {
if src == nil {
*dst = Date{}
return nil
}
switch src := src.(type) {
case string:
return scanPlanTextAnyToDateScanner{}.Scan([]byte(src), dst)
case time.Time:
*dst = Date{Time: src, Valid: true}
return nil
}
return fmt.Errorf("cannot scan %T", src)
}
// Value implements the [database/sql/driver.Valuer] interface.
func (src Date) Value() (driver.Value, error) {
if !src.Valid {
return nil, nil
}
if src.InfinityModifier != Finite {
return src.InfinityModifier.String(), nil
}
return src.Time, nil
}
// MarshalJSON implements the [encoding/json.Marshaler] interface.
func (src Date) MarshalJSON() ([]byte, error) {
if !src.Valid {
return []byte("null"), nil
}
var s string
switch src.InfinityModifier {
case Finite:
s = src.Time.Format("2006-01-02")
case Infinity:
s = "infinity"
case NegativeInfinity:
s = "-infinity"
}
return json.Marshal(s)
}
// UnmarshalJSON implements the [encoding/json.Unmarshaler] interface.
func (dst *Date) UnmarshalJSON(b []byte) error {
var s *string
err := json.Unmarshal(b, &s)
if err != nil {
return err
}
if s == nil {
*dst = Date{}
return nil
}
switch *s {
case "infinity":
*dst = Date{Valid: true, InfinityModifier: Infinity}
case "-infinity":
*dst = Date{Valid: true, InfinityModifier: -Infinity}
default:
t, err := time.ParseInLocation("2006-01-02", *s, time.UTC)
if err != nil {
return err
}
*dst = Date{Time: t, Valid: true}
}
return nil
}
type DateCodec struct{}
func (DateCodec) FormatSupported(format int16) bool {
return format == TextFormatCode || format == BinaryFormatCode
}
func (DateCodec) PreferredFormat() int16 {
return BinaryFormatCode
}
func (DateCodec) PlanEncode(m *Map, oid uint32, format int16, value any) EncodePlan {
if _, ok := value.(DateValuer); !ok {
return nil
}
switch format {
case BinaryFormatCode:
return encodePlanDateCodecBinary{}
case TextFormatCode:
return encodePlanDateCodecText{}
}
return nil
}
type encodePlanDateCodecBinary struct{}
func (encodePlanDateCodecBinary) Encode(value any, buf []byte) (newBuf []byte, err error) {
date, err := value.(DateValuer).DateValue()
if err != nil {
return nil, err
}
if !date.Valid {
return nil, nil
}
var daysSinceDateEpoch int32
switch date.InfinityModifier {
case Finite:
tUnix := time.Date(date.Time.Year(), date.Time.Month(), date.Time.Day(), 0, 0, 0, 0, time.UTC).Unix()
dateEpoch := time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC).Unix()
secSinceDateEpoch := tUnix - dateEpoch
daysSinceDateEpoch = int32(secSinceDateEpoch / 86400)
case Infinity:
daysSinceDateEpoch = infinityDayOffset
case NegativeInfinity:
daysSinceDateEpoch = negativeInfinityDayOffset
}
return pgio.AppendInt32(buf, daysSinceDateEpoch), nil
}
type encodePlanDateCodecText struct{}
func (encodePlanDateCodecText) Encode(value any, buf []byte) (newBuf []byte, err error) {
date, err := value.(DateValuer).DateValue()
if err != nil {
return nil, err
}
if !date.Valid {
return nil, nil
}
switch date.InfinityModifier {
case Finite:
// Year 0000 is 1 BC
bc := false
year := date.Time.Year()
if year <= 0 {
year = -year + 1
bc = true
}
yearBytes := strconv.AppendInt(make([]byte, 0, 6), int64(year), 10)
for i := len(yearBytes); i < 4; i++ {
buf = append(buf, '0')
}
buf = append(buf, yearBytes...)
buf = append(buf, '-')
if date.Time.Month() < 10 {
buf = append(buf, '0')
}
buf = strconv.AppendInt(buf, int64(date.Time.Month()), 10)
buf = append(buf, '-')
if date.Time.Day() < 10 {
buf = append(buf, '0')
}
buf = strconv.AppendInt(buf, int64(date.Time.Day()), 10)
if bc {
buf = append(buf, " BC"...)
}
case Infinity:
buf = append(buf, "infinity"...)
case NegativeInfinity:
buf = append(buf, "-infinity"...)
}
return buf, nil
}
func (DateCodec) PlanScan(m *Map, oid uint32, format int16, target any) ScanPlan {
switch format {
case BinaryFormatCode:
switch target.(type) {
case DateScanner:
return scanPlanBinaryDateToDateScanner{}
}
case TextFormatCode:
switch target.(type) {
case DateScanner:
return scanPlanTextAnyToDateScanner{}
}
}
return nil
}
type scanPlanBinaryDateToDateScanner struct{}
func (scanPlanBinaryDateToDateScanner) Scan(src []byte, dst any) error {
scanner := (dst).(DateScanner)
if src == nil {
return scanner.ScanDate(Date{})
}
if len(src) != 4 {
return fmt.Errorf("invalid length for date: %v", len(src))
}
dayOffset := int32(binary.BigEndian.Uint32(src))
switch dayOffset {
case infinityDayOffset:
return scanner.ScanDate(Date{InfinityModifier: Infinity, Valid: true})
case negativeInfinityDayOffset:
return scanner.ScanDate(Date{InfinityModifier: -Infinity, Valid: true})
default:
t := time.Date(2000, 1, int(1+dayOffset), 0, 0, 0, 0, time.UTC)
return scanner.ScanDate(Date{Time: t, Valid: true})
}
}
type scanPlanTextAnyToDateScanner struct{}
func (scanPlanTextAnyToDateScanner) Scan(src []byte, dst any) error {
scanner := (dst).(DateScanner)
if src == nil {
return scanner.ScanDate(Date{})
}
// Check infinity cases first
if len(src) == 8 && string(src) == "infinity" {
return scanner.ScanDate(Date{InfinityModifier: Infinity, Valid: true})
}
if len(src) == 9 && string(src) == "-infinity" {
return scanner.ScanDate(Date{InfinityModifier: -Infinity, Valid: true})
}
// Format: YYYY-MM-DD or YYYY...-MM-DD BC
// Minimum: 10 chars (2000-01-01), with BC: 13 chars
if len(src) < 10 {
return fmt.Errorf("invalid date format")
}
// Check for BC suffix
bc := false
datePart := src
if len(src) >= 13 && string(src[len(src)-3:]) == " BC" {
bc = true
datePart = src[:len(src)-3]
}
// Find year-month separator (first dash after at least 4 digits)
yearEnd := -1
for i := 4; i < len(datePart); i++ {
if datePart[i] == '-' {
yearEnd = i
break
}
if datePart[i] < '0' || datePart[i] > '9' {
return fmt.Errorf("invalid date format")
}
}
if yearEnd == -1 || yearEnd+6 > len(datePart) {
return fmt.Errorf("invalid date format")
}
// Validate: -MM-DD structure after year
if datePart[yearEnd+3] != '-' {
return fmt.Errorf("invalid date format")
}
// Parse year
year, err := parseDigits(datePart[:yearEnd])
if err != nil {
return fmt.Errorf("invalid date format")
}
// Parse month (2 digits)
month, err := parse2Digits(datePart[yearEnd+1 : yearEnd+3])
if err != nil {
return fmt.Errorf("invalid date format")
}
// Parse day (2 digits)
day, err := parse2Digits(datePart[yearEnd+4 : yearEnd+6])
if err != nil {
return fmt.Errorf("invalid date format")
}
// Ensure nothing extra after day
if yearEnd+6 != len(datePart) {
return fmt.Errorf("invalid date format")
}
if bc {
year = -year + 1
}
t := time.Date(int(year), time.Month(month), int(day), 0, 0, 0, 0, time.UTC)
return scanner.ScanDate(Date{Time: t, Valid: true})
}
// parse2Digits parses exactly 2 ASCII digits.
func parse2Digits(b []byte) (int64, error) {
if len(b) != 2 {
return 0, fmt.Errorf("expected 2 digits")
}
d1, d2 := b[0], b[1]
if d1 < '0' || d1 > '9' || d2 < '0' || d2 > '9' {
return 0, fmt.Errorf("expected digits")
}
return int64(d1-'0')*10 + int64(d2-'0'), nil
}
// parseDigits parses a sequence of ASCII digits.
func parseDigits(b []byte) (int64, error) {
if len(b) == 0 {
return 0, fmt.Errorf("empty")
}
var n int64
for _, c := range b {
if c < '0' || c > '9' {
return 0, fmt.Errorf("non-digit")
}
n = n*10 + int64(c-'0')
}
return n, nil
}
func (c DateCodec) DecodeDatabaseSQLValue(m *Map, oid uint32, format int16, src []byte) (driver.Value, error) {
if src == nil {
return nil, nil
}
var date Date
err := codecScan(c, m, oid, format, src, &date)
if err != nil {
return nil, err
}
if date.InfinityModifier != Finite {
return date.InfinityModifier.String(), nil
}
return date.Time, nil
}
func (c DateCodec) DecodeValue(m *Map, oid uint32, format int16, src []byte) (any, error) {
if src == nil {
return nil, nil
}
var date Date
err := codecScan(c, m, oid, format, src, &date)
if err != nil {
return nil, err
}
if date.InfinityModifier != Finite {
return date.InfinityModifier, nil
}
return date.Time, nil
}