/
dbfstruct.go
308 lines (259 loc) · 7.33 KB
/
dbfstruct.go
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package dbf
import (
"fmt"
"reflect"
"strconv"
"strings"
"time"
"github.com/pkg/errors"
)
type Iterator struct {
dt *DbfTable
index int
last int
offset int
}
func (dt *DbfTable) NewIterator() *Iterator {
return &Iterator{dt: dt, index: -1, offset: -1, last: dt.NumRecords()}
}
func (it *Iterator) Index() int {
return it.index
}
// Next iterates over records in the table.
func (it *Iterator) Next() bool {
for it.index++; it.index < it.last; it.index++ {
if !it.dt.IsDeleted(it.index) {
return true
}
}
return false // it.index < it.last
}
// Read data into struct.
func (it *Iterator) Read(spec interface{}) error {
return it.dt.Read(it.index, spec)
}
// Write record where iterator points to.
func (it *Iterator) Write(spec interface{}) (int, error) {
return it.dt.Write(it.index, spec)
}
// Delete row under iterator. This is possible because rows are marked as deleted
// but are not physically deleted.
func (it *Iterator) Delete() {
it.dt.Delete(it.index)
}
// Row data as raw slice.
func (it *Iterator) Row() []string {
return it.dt.Row(it.index)
}
// Create schema based on the spec struct.
func (dt *DbfTable) Create(spec interface{}) error {
s := reflect.ValueOf(spec)
if s.Kind() == reflect.Ptr {
s = s.Elem()
}
if s.Kind() != reflect.Struct {
return errors.New("dbf: spec parameter must be a struct")
}
var err error
typeOfSpec := s.Type()
for i := 0; i < s.NumField(); i++ {
f := s.Field(i)
if typeOfSpec.Field(i).PkgPath != "" || typeOfSpec.Field(i).Anonymous {
continue // ignore unexported or embedded fields
}
dbfTag := typeOfSpec.Field(i).Tag.Get("dbf")
// ignore '-' tags
if dbfTag == "-" {
continue
}
fieldName := dbfTag
if fieldName == "" {
fieldName = typeOfSpec.Field(i).Name
}
var size uint8
dbfSizeTag := typeOfSpec.Field(i).Tag.Get("size")
if dbfSizeTag != "" && dbfSizeTag != "-" {
n, err := strconv.ParseUint(dbfSizeTag, 0, 8)
if err != nil {
return errors.Errorf("dbf: invalid struct tag %s", dbfSizeTag)
}
size = uint8(n)
}
var precision uint8
dbfPrecTag := typeOfSpec.Field(i).Tag.Get("precision")
if dbfPrecTag != "" && dbfPrecTag != "-" {
n, err := strconv.ParseUint(dbfPrecTag, 0, 8)
if err != nil {
return errors.Errorf("dbf: invalid struct tag %s", dbfPrecTag)
}
precision = uint8(n)
}
switch f.Kind() {
default:
return errors.Errorf("dbf: unsupported type %s for database table schema, use dash to omit", f.Kind())
case reflect.String:
if size == 0 || size > 50 {
size = 50
}
err = dt.AddTextField(fieldName, size)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
if size == 0 || size > 17 {
size = 17
}
err = dt.AddIntField(fieldName, size)
case reflect.Float32, reflect.Float64:
if size == 0 || size > 17 {
size = 17
}
if precision == 0 || precision > 8 {
precision = 8
}
err = dt.AddFloatField(fieldName, size, precision)
case reflect.Bool:
err = dt.AddBoolField(fieldName)
case reflect.Struct:
if f.Type() != reflect.TypeOf(time.Time{}) {
return errors.Errorf("unsupported type '%s' for database table schema, use dash to omit", f.Type())
}
dt.AddDateField(fieldName)
}
if err != nil {
return err
}
}
return nil
}
// Append record to table.
func (dt *DbfTable) Append(spec interface{}) (int, error) {
return dt.Write(dt.AddRecord(), spec)
}
// Write data into DbfTable from the spec.
func (dt *DbfTable) Write(row int, spec interface{}) (int, error) {
s := reflect.ValueOf(spec)
if s.Kind() == reflect.Ptr {
s = s.Elem()
}
if s.Kind() != reflect.Struct {
return -1, errors.New("dbf: spec parameter must be a struct")
}
typeOfSpec := s.Type()
for i := 0; i < s.NumField(); i++ {
f := s.Field(i)
if typeOfSpec.Field(i).PkgPath != "" || typeOfSpec.Field(i).Anonymous {
continue // ignore unexported or embedded fields
}
dbfTag := typeOfSpec.Field(i).Tag.Get("dbf")
// ignore '-' tags
if dbfTag == "-" {
continue
}
fieldName := dbfTag
if fieldName == "" {
fieldName = typeOfSpec.Field(i).Name
}
val := ""
switch f.Kind() {
default:
return -1, errors.Errorf("unsupported type '%s' for database table schema, use dash to omit", f.Type())
case reflect.String:
val = f.String()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
val = fmt.Sprintf("%d", f.Int())
case reflect.Float32, reflect.Float64:
val = fmt.Sprintf("%f", f.Float())
case reflect.Bool:
val = "f"
if f.Bool() {
val = "t"
}
case reflect.Struct:
if f.Type() != reflect.TypeOf(time.Time{}) {
return -1, errors.Errorf("unsupported type '%s' for database table schema, use dash to omit", f.Type())
}
val = f.Interface().(time.Time).Format("20060102")
}
dt.SetFieldValueByName(row, fieldName, val)
}
return row, nil
}
// Read data into the spec from DbfTable.
func (dt *DbfTable) Read(row int, spec interface{}) error {
v := reflect.ValueOf(spec)
if v.Kind() != reflect.Ptr {
panic("dbf: must be a pointer")
}
s := v.Elem()
if s.Kind() != reflect.Struct {
panic("dbf: spec parameter must be a struct")
}
typeOfSpec := s.Type()
for i := 0; i < s.NumField(); i++ {
f := s.Field(i)
if f.CanSet() {
fieldType := typeOfSpec.Field(i)
dbfTag := fieldType.Tag.Get("dbf")
// ignore '-' tags
if dbfTag == "-" {
continue
}
fieldName := dbfTag
if fieldName == "" {
fieldName = fieldType.Name
}
var value string
if fieldType.Tag.Get("raw") != "" {
value = dt.RawFieldValueByName(row, fieldName)
} else {
value = dt.FieldValueByName(row, fieldName)
}
if strings.TrimSpace(value) == "" {
continue
}
switch f.Kind() {
default:
return errors.Errorf("unsupported type '%s' for database table schema, use dash to omit", f.Type())
case reflect.String:
f.SetString(value)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
intValue, err := strconv.ParseInt(value, 0, f.Type().Bits())
if err != nil {
// Sometimes ints are formatted as floats
floatValue, err := strconv.ParseFloat(value, 64)
if err != nil {
return fmt.Errorf("fail to parse field '%s' type: %s value: %s",
fieldName, f.Type().String(), value)
}
intValue = int64(floatValue)
}
f.SetInt(intValue)
case reflect.Bool:
if value == "T" || value == "t" || value == "Y" || value == "y" {
f.SetBool(true)
} else {
f.SetBool(false)
}
case reflect.Float32, reflect.Float64:
floatValue, err := strconv.ParseFloat(value, f.Type().Bits())
if err != nil {
return errors.Errorf("fail to parse field '%s' type: %s value: %s",
fieldName, f.Type().String(), value)
}
f.SetFloat(floatValue)
case reflect.Struct:
if f.Type() != reflect.TypeOf(time.Time{}) {
return errors.Errorf("unsupported type '%s' for database table schema, use dash to omit", f.Type())
}
date, err := time.Parse("20060102", value)
if err != nil {
return errors.Errorf("fail to parse field '%s' type: %s value: %s",
fieldName, f.Type().String(), value)
}
f.Set(reflect.ValueOf(date))
}
}
}
return nil
}