From a9fc07abae7537d51d65839ee094d2e991a6f386 Mon Sep 17 00:00:00 2001
From: CHIKAMATSU Naohiro <n.chika156@gmail.com>
Date: Thu, 5 Sep 2024 22:34:23 +0900
Subject: [PATCH] Add ascii tag

---
 README.md     |  1 +
 csv_test.go   | 30 ++++++++++++++++++++++++++++++
 errors.go     |  2 ++
 i18n/en.yaml  |  3 +++
 i18n/ja.yaml  |  3 +++
 i18n/ru.yaml  |  3 +++
 parser.go     |  2 ++
 tag.go        |  2 ++
 validation.go | 23 +++++++++++++++++++++++
 9 files changed, 69 insertions(+)

diff --git a/README.md b/README.md
index 45c6708..9db706e 100644
--- a/README.md
+++ b/README.md
@@ -127,6 +127,7 @@ You set the validation rules following the "validate:" tag according to the rule
 |-------------------|---------------------------------------------------|
 | alpha             | Check whether value is alphabetic or not           |
 | alphanumeric     | Check whether value is alphanumeric or not        |
+| ascii             | Check whether value is ASCII or not                |
 | boolean           | Check whether value is boolean or not.           |
 | lowercase         | Check whether value is lowercase or not           |
 | numeric           | Check whether value is numeric or not              |
diff --git a/csv_test.go b/csv_test.go
index 5c4595b..0ce6549 100644
--- a/csv_test.go
+++ b/csv_test.go
@@ -2,6 +2,7 @@ package csv
 
 import (
 	"bytes"
+	"fmt"
 	"os"
 	"path/filepath"
 	"testing"
@@ -498,4 +499,33 @@ ABC
 			}
 		}
 	})
+
+	t.Run("validate ascii", func(t *testing.T) {
+		t.Parallel()
+
+		input := fmt.Sprintf(
+			"name\n%s\n%s\n",
+			"\"!#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\`]^_abcdefghijklmnopqrstuvwxyz{|}~\"",
+			"あいう",
+		)
+
+		c, err := NewCSV(bytes.NewBufferString(input))
+		if err != nil {
+			t.Fatal(err)
+		}
+		type ascii struct {
+			Name string `validate:"ascii"`
+		}
+
+		asciis := make([]ascii, 0)
+		errs := c.Decode(&asciis)
+		for i, err := range errs {
+			switch i {
+			case 0:
+				if err.Error() != "line:3 column name: target is not an ASCII character: value=あいう" {
+					t.Errorf("CSV.Decode() got errors: %v", err)
+				}
+			}
+		}
+	})
 }
diff --git a/errors.go b/errors.go
index 8b77c7d..47f0dac 100644
--- a/errors.go
+++ b/errors.go
@@ -94,4 +94,6 @@ var (
 	ErrLowercaseID = "ErrLowercase"
 	// ErrUppercaseID is the error ID used when the target is not an uppercase character.
 	ErrUppercaseID = "ErrUppercase"
+	// ErrASCIIID is the error ID used when the target is not an ASCII character.
+	ErrASCIIID = "ErrASCII"
 )
diff --git a/i18n/en.yaml b/i18n/en.yaml
index b32bc9f..c6f6ba6 100644
--- a/i18n/en.yaml
+++ b/i18n/en.yaml
@@ -63,3 +63,6 @@
 
 - id: "ErrUppercase"
   translation: "target is not an uppercase character"
+
+- id: "ErrASCII"
+  translation: "target is not an ASCII character"
diff --git a/i18n/ja.yaml b/i18n/ja.yaml
index 1506ff4..c4024e4 100644
--- a/i18n/ja.yaml
+++ b/i18n/ja.yaml
@@ -69,3 +69,6 @@
 
 - id: "ErrUppercase"
   translation: "値が大文字ではありません"
+
+- id: "ErrASCII"
+  translation: "値がASCII文字ではありません"
diff --git a/i18n/ru.yaml b/i18n/ru.yaml
index 15ff4db..201c334 100644
--- a/i18n/ru.yaml
+++ b/i18n/ru.yaml
@@ -63,3 +63,6 @@
 
 - id: "ErrUppercase"
   translation: "целевое значение не является заглавным символом"
+
+- id: "ErrASCII"
+  translation: "целевое значение не является ASCII символом"
diff --git a/parser.go b/parser.go
index 2ec273d..789d530 100644
--- a/parser.go
+++ b/parser.go
@@ -131,6 +131,8 @@ func (c *CSV) parseValidateTag(tags string) (validators, error) {
 			validatorList = append(validatorList, newLowercaseValidator())
 		case strings.HasPrefix(t, uppercaseTagValue.String()):
 			validatorList = append(validatorList, newUppercaseValidator())
+		case strings.HasPrefix(t, asciiTagValue.String()):
+			validatorList = append(validatorList, newASCIIValidator())
 		}
 	}
 	return validatorList, nil
diff --git a/tag.go b/tag.go
index fc7f977..d43fe2e 100644
--- a/tag.go
+++ b/tag.go
@@ -46,6 +46,8 @@ const (
 	lowercaseTagValue tagValue = "lowercase"
 	// uppercaseTagValue is the struct tag name for uppercase fields.
 	uppercaseTagValue tagValue = "uppercase"
+	// asciiTagValue is the struct tag name for ascii fields.
+	asciiTagValue tagValue = "ascii"
 )
 
 // String returns the string representation of the tag.
diff --git a/validation.go b/validation.go
index b7cdfe5..48f2b98 100644
--- a/validation.go
+++ b/validation.go
@@ -450,3 +450,26 @@ func (u *uppercaseValidator) Do(localizer *i18n.Localizer, target any) error {
 	}
 	return nil
 }
+
+// asciiValidator is a struct that contains the validation rules for an ASCII column.
+type asciiValidator struct{}
+
+// newASCIIValidator returns a new asciiValidator.
+func newASCIIValidator() *asciiValidator {
+	return &asciiValidator{}
+}
+
+// Do validates the target is an ASCII string.
+func (a *asciiValidator) Do(localizer *i18n.Localizer, target any) error {
+	v, ok := target.(string)
+	if !ok {
+		return NewError(localizer, ErrASCIIID, fmt.Sprintf("value=%v", target))
+	}
+
+	for _, r := range v {
+		if r > 127 {
+			return NewError(localizer, ErrASCIIID, fmt.Sprintf("value=%v", target))
+		}
+	}
+	return nil
+}