Implement searching

cmd/micro/buffer/search.go

@@ -0,0 +1,93 @@
+package buffer
+
+import (
+	"regexp"
+	"unicode/utf8"
+
+	"github.com/zyedidia/micro/cmd/micro/util"
+)
+
+func (b *Buffer) findDown(r *regexp.Regexp, start, end Loc) ([2]Loc, bool) {
+	start.Y = util.Clamp(start.Y, 0, b.LinesNum()-1)
+
+	for i := start.Y; i <= end.Y; i++ {
+		l := b.LineBytes(i)
+		charpos := 0
+
+		if i == start.Y {
+			nchars := utf8.RuneCount(l)
+			start.X = util.Clamp(start.X, 0, nchars-1)
+			l = util.SliceEnd(l, start.X)
+			charpos = start.X
+		}
+
+		match := r.FindIndex(l)
+
+		if match != nil {
+			start := Loc{charpos + util.RunePos(l, match[0]), i}
+			end := Loc{charpos + util.RunePos(l, match[1]), i}
+			return [2]Loc{start, end}, true
+		}
+	}
+	return [2]Loc{}, false
+}
+
+func (b *Buffer) findUp(r *regexp.Regexp, start, end Loc) ([2]Loc, bool) {
+	start.Y = util.Clamp(start.Y, 0, b.LinesNum()-1)
+
+	for i := start.Y; i >= end.Y; i-- {
+		l := b.LineBytes(i)
+
+		if i == start.Y {
+			nchars := utf8.RuneCount(l)
+			start.X = util.Clamp(start.X, 0, nchars-1)
+			l = util.SliceStart(l, start.X)
+		}
+
+		match := r.FindIndex(l)
+
+		if match != nil {
+			start := Loc{util.RunePos(l, match[0]), i}
+			end := Loc{util.RunePos(l, match[1]), i}
+			return [2]Loc{start, end}, true
+		}
+	}
+	return [2]Loc{}, false
+}
+
+// FindNext finds the next occurrence of a given string in the buffer
+// It returns the start and end location of the match (if found) and
+// a boolean indicating if it was found
+// May also return an error if the search regex is invalid
+func (b *Buffer) FindNext(s string, from Loc, down bool) ([2]Loc, bool, error) {
+	if s == "" {
+		return [2]Loc{}, false, nil
+	}
+
+	var r *regexp.Regexp
+	var err error
+	if b.Settings["ignorecase"].(bool) {
+		r, err = regexp.Compile("(?i)" + s)
+	} else {
+		r, err = regexp.Compile(s)
+	}
+
+	if err != nil {
+		return [2]Loc{}, false, err
+	}
+
+	found := false
+	var l [2]Loc
+	if down {
+		l, found = b.findDown(r, from, b.End())
+		if !found {
+			l, found = b.findDown(r, b.Start(), from)
+		}
+	} else {
+		l, found = b.findUp(r, from, b.Start())
+		if !found {
+			l, found = b.findUp(r, b.End(), from)
+		}
+	}
+	return l, found, nil
+}