From af0eb7e03872e759527e00a004df066a0b03a871 Mon Sep 17 00:00:00 2001
From: Shulhan <ms@kilabit.info>
Date: Sun, 9 Apr 2023 15:52:30 +0700
Subject: lib/bytes: return the number of skipped chars on
 Skip(Horizontal)Spaces

---
 lib/bytes/parser.go              | 21 ++++++++++++---------
 lib/bytes/parser_example_test.go | 38 ++++++++++++++++++++------------------
 2 files changed, 32 insertions(+), 27 deletions(-)

(limited to 'lib/bytes')

diff --git a/lib/bytes/parser.go b/lib/bytes/parser.go
index d6c9475d..70230622 100644
--- a/lib/bytes/parser.go
+++ b/lib/bytes/parser.go
@@ -194,17 +194,18 @@ func (bp *Parser) SkipN(n int) (c byte) {
 }
 
 // SkipHorizontalSpaces skip space (" "), tab ("\t"), carriage return
-// ("\r"), and form feed ("\f") characters; and return the first non-space
-// character or 0 if it reach end-of-content.
-func (bp *Parser) SkipHorizontalSpaces() (c byte) {
+// ("\r"), and form feed ("\f") characters; and return the number of space
+// skipped and first non-space character or 0 if it reach end-of-content.
+func (bp *Parser) SkipHorizontalSpaces() (n int, c byte) {
 	for ; bp.x < bp.size; bp.x++ {
 		c = bp.content[bp.x]
 		if c == ' ' || c == '\t' || c == '\r' || c == '\f' {
+			n++
 			continue
 		}
-		return c
+		return n, c
 	}
-	return 0
+	return n, 0
 }
 
 // SkipLine skip all characters until new line.
@@ -222,16 +223,18 @@ func (bp *Parser) SkipLine() (c byte) {
 }
 
 // SkipSpaces skip all spaces character (' ', '\f', '\n', '\r', '\t') and
-// return the first non-space character or 0 if it reach end-of-content.
-func (bp *Parser) SkipSpaces() (c byte) {
+// return the number of spaces skipped and first non-space character or 0 if
+// it reach end-of-content.
+func (bp *Parser) SkipSpaces() (n int, c byte) {
 	for ; bp.x < bp.size; bp.x++ {
 		c = bp.content[bp.x]
 		if ascii.IsSpace(c) {
+			n++
 			continue
 		}
-		return c
+		return n, c
 	}
-	return 0
+	return n, 0
 }
 
 // Stop the parser, return the remaining unparsed content and its last
diff --git a/lib/bytes/parser_example_test.go b/lib/bytes/parser_example_test.go
index 25ee6ba1..c62258fe 100644
--- a/lib/bytes/parser_example_test.go
+++ b/lib/bytes/parser_example_test.go
@@ -209,25 +209,26 @@ func ExampleParser_SkipHorizontalSpaces() {
 		content = []byte(" \t\r\fA. \nB.")
 		delims  = []byte{'.'}
 		parser  = libbytes.NewParser(content, delims)
+		n       int
 	)
 
-	parser.SkipHorizontalSpaces()
+	n, _ = parser.SkipHorizontalSpaces()
 	token, d := parser.Read()
-	fmt.Printf("token:%s delim:%c\n", token, d)
+	fmt.Printf("n:%d token:%s delim:%c\n", n, token, d)
 
-	parser.SkipHorizontalSpaces()
+	n, _ = parser.SkipHorizontalSpaces()
 	token, d = parser.Read() // The token include \n.
-	fmt.Printf("token:%s delim:%c\n", token, d)
+	fmt.Printf("n:%d token:%s delim:%c\n", n, token, d)
 
-	parser.SkipHorizontalSpaces()
+	n, _ = parser.SkipHorizontalSpaces()
 	token, d = parser.Read() // The token include \n.
-	fmt.Printf("token:%s delim:%d\n", token, d)
+	fmt.Printf("n:%d token:%s delim:%d\n", n, token, d)
 
 	// Output:
-	// token:A delim:.
-	// token:
+	// n:4 token:A delim:.
+	// n:1 token:
 	// B delim:.
-	// token: delim:0
+	// n:0 token: delim:0
 }
 
 func ExampleParser_SkipSpaces() {
@@ -235,24 +236,25 @@ func ExampleParser_SkipSpaces() {
 		content = []byte(" \t\r\fA. \nB.")
 		delims  = []byte{'.'}
 		parser  = libbytes.NewParser(content, delims)
+		n       int
 	)
 
-	parser.SkipSpaces()
+	n, _ = parser.SkipSpaces()
 	token, d := parser.Read()
-	fmt.Printf("token:%s delim:%c\n", token, d)
+	fmt.Printf("n:%d token:%s delim:%c\n", n, token, d)
 
-	parser.SkipSpaces()
+	n, _ = parser.SkipSpaces()
 	token, d = parser.Read() // The token include \n.
-	fmt.Printf("token:%s delim:%c\n", token, d)
+	fmt.Printf("n:%d token:%s delim:%c\n", n, token, d)
 
-	parser.SkipSpaces()
+	n, _ = parser.SkipSpaces()
 	token, d = parser.Read() // The token include \n.
-	fmt.Printf("token:%s delim:%d\n", token, d)
+	fmt.Printf("n:%d token:%s delim:%d\n", n, token, d)
 
 	// Output:
-	// token:A delim:.
-	// token:B delim:.
-	// token: delim:0
+	// n:4 token:A delim:.
+	// n:2 token:B delim:.
+	// n:0 token: delim:0
 }
 
 func ExampleParser_Stop() {
-- 
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