chore: csvparser module layout

csvparser/columns.go

@@ -0,0 +1,66 @@
+package csvparser
+
+type (
+	Col[T any] interface {
+		Parse(data []byte, item *T) error
+		//Compile(x T, writer io.Writer) error
+	}
+
+	StringColumn[T any] struct {
+		inner  StringType
+		setter func(x *T, v string)
+		getter func(x T) string
+	}
+
+	IntColumn[T any] struct {
+		inner  IntegerType
+		setter func(x *T, v int)
+		getter func(x T) int
+	}
+
+	BoolColumn[T any] struct {
+		inner  StringType
+		setter func(x T, v bool)
+		getter func(x T) bool
+	}
+)
+
+func (s StringColumn[T]) Parse(data []byte, item *T) error {
+	val, err := s.inner.Parse(data)
+	if err != nil {
+		return err
+	}
+	s.setter(item, val)
+	return nil
+}
+
+func (c IntColumn[T]) Parse(data []byte, item *T) error {
+	val, err := c.inner.Parse(data)
+	if err != nil {
+		return err
+	}
+	c.setter(item, val)
+	return nil
+}
+
+func StringCol[T any](
+	quoted bool,
+	getter func(T) string,
+	setter func(*T, string),
+) Col[T] {
+	return StringColumn[T]{
+		inner:  StrType(quoted),
+		getter: getter, setter: setter,
+	}
+}
+
+func IntCol[T any](
+	quoted bool,
+	getter func(T) int,
+	setter func(*T, int),
+) Col[T] {
+	return IntColumn[T]{
+		inner:  IntType(quoted),
+		getter: getter, setter: setter,
+	}
+}

csvparser/parser.go

@@ -0,0 +1,65 @@
+package csvparser
+
+import (
+	"github.com/pkg/errors"
+	"github.com/sonirico/stadio/slices"
+)
+
+var (
+	quote = []byte{byte('"')}
+
+	SeparatorComma     byte = ','
+	SeparatorSemicolon byte = ';'
+	SeparatorTab       byte = '\t'
+)
+
+type (
+	Parser[T any] struct {
+		separator byte
+		columns   []Col[T]
+	}
+)
+
+func (p Parser[T]) Parse(data []byte, item *T) (err error) {
+	counter := 0
+	for _, col := range p.columns {
+		pos := slices.IndexOf[byte](
+			data,
+			func(x byte) bool {
+				return x == p.separator
+			},
+		)
+
+		lastCol := counter == len(p.columns)-1
+
+		if pos == -1 && !lastCol {
+			// Only if no more separators have been found, and current column is not the last one, yield error
+			err = errors.Wrapf(
+				ErrColumnMismatch,
+				"want %d, have %d",
+				len(p.columns),
+				counter,
+			)
+		}
+
+		payload := data
+		if !lastCol {
+			payload = data[:pos]
+		}
+
+		if err = col.Parse(payload, item); err != nil {
+			return err
+		}
+
+		counter++
+
+		if !lastCol {
+			data = data[pos+1:]
+		}
+	}
+	return nil
+}
+
+func NewParser[T any](sep byte, cols ...Col[T]) Parser[T] {
+	return Parser[T]{separator: sep, columns: cols}
+}