From b1b8c0140feb4e21c1c0d8512cca0ac0861728c4 Mon Sep 17 00:00:00 2001
From: kayomn <kayomn@kayomn.net>
Date: Tue, 20 Dec 2022 17:04:39 +0000
Subject: [PATCH] Initial commit

---
 go.mod |  3 ++
 ini.go | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 101 insertions(+)
 create mode 100644 go.mod
 create mode 100644 ini.go

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..ea27136
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module sauce.pizzawednes.day/kayomn/ini-gusher
+
+go 1.19
diff --git a/ini.go b/ini.go
new file mode 100644
index 0000000..5166836
--- /dev/null
+++ b/ini.go
@@ -0,0 +1,98 @@
+package ini
+
+import (
+	"bufio"
+	"io"
+	"strings"
+)
+
+// Singular key-value pair under the given section within an INI file.
+type Entry struct {
+	Section string
+	Key     string
+	Value   string
+}
+
+// Returns the last error that occured during parsing.
+func (parser *Parser) Err() error {
+	return parser.err
+}
+
+// Creates and returns a new [Parser] by reference from `reader`
+func NewParser(reader io.Reader) *Parser {
+	return &Parser{
+		scanner: bufio.NewScanner(reader),
+	}
+}
+
+// Parses the next key-value pair in the `parser` stream, returning the parsed [Entry], or an empty
+// one if nothing was parsed, and a `bool` representing whether or not there is any further data
+// available to parse.
+//
+// Note that the `parser` does not guarantee any parse order for key-value pairs extracted from the
+// `parser` stream.
+func (parser *Parser) Parse() (Entry, bool) {
+	for parser.scanner.Scan() {
+		var line = strings.TrimSpace(parser.scanner.Text())
+		var lineLen = len(line)
+
+		if lineLen == 0 {
+			// Skip empty lines.
+			continue
+		}
+
+		if (line[0] == '#') || (line[0] == ';') {
+			// Skip comment lines.
+			continue
+		}
+
+		var lineTail = lineLen - 1
+
+		if (line[0] == '[') && (line[lineTail] == ']') {
+			// Section name.
+			parser.section = line[1:lineTail]
+
+			continue
+		}
+
+		if assignmentIndex := strings.Index(line, "="); assignmentIndex > -1 {
+			// Key with value.
+			var value = strings.TrimSpace(line[assignmentIndex+1:])
+			var valueLen = len(value)
+
+			if valueLen != 0 {
+				var valueTail = len(value) - 1
+
+				if (value[0] == '"') && (value[valueTail] == '"') {
+					value = value[1:valueTail]
+				}
+			}
+
+			return Entry{
+				Section: parser.section,
+				Key:     strings.TrimSpace(line[0:assignmentIndex]),
+				Value:   value,
+			}, true
+		}
+
+		// Key which is its own value.
+		var keyValue = line[1:lineTail]
+
+		return Entry{
+			Section: parser.section,
+			Key:     keyValue,
+			Value:   keyValue,
+		}, true
+	}
+
+	parser.err = parser.scanner.Err()
+
+	return Entry{}, false
+}
+
+// State machine for parsing streamable INI file sources.
+type Parser struct {
+	scanner *bufio.Scanner
+	err     error
+	section string
+}