From 54d9cbc743e9294fe1720f67533dfbfc229d1956 Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Wed, 5 Apr 2017 07:54:41 -0500
Subject: [PATCH] Add pgtype.Varbit

---
 pgtype/pgtype.go      |   1 +
 pgtype/varbit.go      | 141 ++++++++++++++++++++++++++++++++++++++++++
 pgtype/varbit_test.go |  25 ++++++++
 v3.md                 |   7 ---
 4 files changed, 167 insertions(+), 7 deletions(-)
 create mode 100644 pgtype/varbit.go
 create mode 100644 pgtype/varbit_test.go

diff --git a/pgtype/pgtype.go b/pgtype/pgtype.go
index 5de07b7d..338afc9b 100644
--- a/pgtype/pgtype.go
+++ b/pgtype/pgtype.go
@@ -263,6 +263,7 @@ func init() {
 		"tstzrange":    &Tstzrange{},
 		"unknown":      &Unknown{},
 		"uuid":         &Uuid{},
+		"varbit":       &Varbit{},
 		"varchar":      &Varchar{},
 		"xid":          &Xid{},
 	}
diff --git a/pgtype/varbit.go b/pgtype/varbit.go
new file mode 100644
index 00000000..d28e95cd
--- /dev/null
+++ b/pgtype/varbit.go
@@ -0,0 +1,141 @@
+package pgtype
+
+import (
+	"database/sql/driver"
+	"encoding/binary"
+	"fmt"
+	"io"
+
+	"github.com/jackc/pgx/pgio"
+)
+
+type Varbit struct {
+	Bytes  []byte
+	Len    int32 // Number of bits
+	Status Status
+}
+
+func (dst *Varbit) Set(src interface{}) error {
+	return fmt.Errorf("cannot convert %v to Varbit", src)
+}
+
+func (dst *Varbit) Get() interface{} {
+	switch dst.Status {
+	case Present:
+		return dst
+	case Null:
+		return nil
+	default:
+		return dst.Status
+	}
+}
+
+func (src *Varbit) AssignTo(dst interface{}) error {
+	return fmt.Errorf("cannot assign %v to %T", src, dst)
+}
+
+func (dst *Varbit) DecodeText(ci *ConnInfo, src []byte) error {
+	if src == nil {
+		*dst = Varbit{Status: Null}
+		return nil
+	}
+
+	bitLen := len(src)
+	byteLen := bitLen / 8
+	if bitLen%8 > 0 {
+		byteLen++
+	}
+	buf := make([]byte, byteLen)
+
+	for i, b := range src {
+		if b == '1' {
+			byteIdx := i / 8
+			bitIdx := uint(i % 8)
+			buf[byteIdx] = buf[byteIdx] | (128 >> bitIdx)
+		}
+	}
+
+	*dst = Varbit{Bytes: buf, Len: int32(bitLen), Status: Present}
+	return nil
+}
+
+func (dst *Varbit) DecodeBinary(ci *ConnInfo, src []byte) error {
+	if src == nil {
+		*dst = Varbit{Status: Null}
+		return nil
+	}
+
+	if len(src) < 4 {
+		return fmt.Errorf("invalid length for varbit: %v", len(src))
+	}
+
+	bitLen := int32(binary.BigEndian.Uint32(src))
+	rp := 4
+
+	buf := make([]byte, len(src[rp:]))
+	copy(buf, src[rp:])
+
+	*dst = Varbit{Bytes: buf, Len: bitLen, Status: Present}
+	return nil
+}
+
+func (src *Varbit) EncodeText(ci *ConnInfo, w io.Writer) (bool, error) {
+	switch src.Status {
+	case Null:
+		return true, nil
+	case Undefined:
+		return false, errUndefined
+	}
+
+	buf := make([]byte, int(src.Len))
+	for i, _ := range buf {
+		byteIdx := i / 8
+		bitMask := byte(128 >> byte(i%8))
+		char := byte('0')
+		if src.Bytes[byteIdx]&bitMask > 0 {
+			char = '1'
+		}
+		buf[i] = char
+	}
+
+	_, err := w.Write(buf)
+	return false, err
+}
+
+func (src *Varbit) EncodeBinary(ci *ConnInfo, w io.Writer) (bool, error) {
+	switch src.Status {
+	case Null:
+		return true, nil
+	case Undefined:
+		return false, errUndefined
+	}
+
+	if _, err := pgio.WriteInt32(w, src.Len); err != nil {
+		return false, err
+	}
+
+	_, err := w.Write(src.Bytes)
+	return false, err
+}
+
+// Scan implements the database/sql Scanner interface.
+func (dst *Varbit) Scan(src interface{}) error {
+	if src == nil {
+		*dst = Varbit{Status: Null}
+		return nil
+	}
+
+	switch src := src.(type) {
+	case string:
+		return dst.DecodeText(nil, []byte(src))
+	case []byte:
+		return dst.DecodeText(nil, src)
+	}
+
+	return fmt.Errorf("cannot scan %T", src)
+}
+
+// Value implements the database/sql/driver Valuer interface.
+func (src *Varbit) Value() (driver.Value, error) {
+	return encodeValueText(src)
+}
diff --git a/pgtype/varbit_test.go b/pgtype/varbit_test.go
new file mode 100644
index 00000000..cd146d26
--- /dev/null
+++ b/pgtype/varbit_test.go
@@ -0,0 +1,25 @@
+package pgtype_test
+
+import (
+	"testing"
+
+	"github.com/jackc/pgx/pgtype"
+)
+
+func TestVarbitTranscode(t *testing.T) {
+	testSuccessfulTranscode(t, "varbit", []interface{}{
+		&pgtype.Varbit{Bytes: []byte{}, Len: 0, Status: pgtype.Present},
+		&pgtype.Varbit{Bytes: []byte{0, 1, 128, 254, 255}, Len: 40, Status: pgtype.Present},
+		&pgtype.Varbit{Bytes: []byte{0, 1, 128, 254, 128}, Len: 33, Status: pgtype.Present},
+		&pgtype.Varbit{Status: pgtype.Null},
+	})
+}
+
+func TestVarbitNormalize(t *testing.T) {
+	testSuccessfulNormalize(t, []normalizeTest{
+		{
+			sql:   "select B'111111111'",
+			value: &pgtype.Varbit{Bytes: []byte{255, 128}, Len: 9, Status: pgtype.Present},
+		},
+	})
+}
diff --git a/v3.md b/v3.md
index f522825d..20038938 100644
--- a/v3.md
+++ b/v3.md
@@ -42,14 +42,10 @@ Or maybe double-down on conn/pool coupling and improve connpool
 
 Add auto-idle pinging to conns in pool
 
-Extract types Null* and Hstore to separate package
-
 Remove names from prepared statements - use database/sql style objects
 
 Better way of handling text/binary protocol choice than pgx.DefaultTypeFormats or manually editing a PreparedStatement. Possibly an optional part of preparing a statement is specifying the format and/or a decoder. Or maybe it is part of a QueryEx call... Could be very interesting to make encoding and decoding possible without being a method of the type. This could drastically clean up those huge type switches.
 
-Also maybe support binary and text for everything possible
-
 dValueReader / msgReader cleanup
 
 Make easier / possible to mock Conn or ConnPool (https://github.com/jackc/pgx/pull/162)
@@ -66,6 +62,3 @@ Keep ability to change logging while running
 consider test to ensure that AssignTo makes copy of reference types
 something like:
 select array[1,2,3], array[4,5,6,7]
-
-pgtype TODO:
-varbit