*: add builtin string function SPACE (#1332)

pingcap · Jun 21, 2016 · b3bd0dc · b3bd0dc
1 parent dd6bfac
commit b3bd0dc
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Showing 6 changed files with 86 additions and 2 deletions.
diff --git a/evaluator/builtin.go b/evaluator/builtin.go
@@ -98,6 +98,7 @@ var Funcs = map[string]Func{
 	"replace":         {builtinReplace, 3, 3},
 	"reverse":         {builtinReverse, 1, 1},
 	"rtrim":           {trimFn(strings.TrimRight, spaceChars), 1, 1},
+	"space":           {builtinSpace, 1, 1},
 	"strcmp":          {builtinStrcmp, 2, 2},
 	"substring":       {builtinSubstring, 2, 3},
 	"substring_index": {builtinSubstringIndex, 3, 3},

diff --git a/evaluator/builtin_string.go b/evaluator/builtin_string.go
@@ -19,6 +19,8 @@ package evaluator
 
 import (
 	"fmt"
+	"math"
+	"strconv"
 	"strings"
 
 	"github.com/juju/errors"
@@ -186,6 +188,36 @@ func builtinReverse(args []types.Datum, _ context.Context) (d types.Datum, err e
 	}
 }
 
+// See: http://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_space
+func builtinSpace(args []types.Datum, _ context.Context) (d types.Datum, err error) {
+	x := args[0]
+	if x.IsNull() {
+		return d, nil
+	}
+
+	if x.Kind() == types.KindString || x.Kind() == types.KindBytes {
+		if _, e := strconv.ParseInt(x.GetString(), 10, 64); e != nil {
+			return d, errors.Trace(e)
+		}
+	}
+
+	v, err := x.ToInt64()
+	if err != nil {
+		return d, errors.Trace(err)
+	}
+
+	if v < 0 {
+		v = 0
+	}
+
+	if v > math.MaxInt32 {
+		d.SetNull()
+	} else {
+		d.SetString(strings.Repeat(" ", int(v)))
+	}
+	return d, nil
+}
+
 // See: https://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_upper
 func builtinUpper(args []types.Datum, _ context.Context) (d types.Datum, err error) {
 	x := args[0]

diff --git a/evaluator/builtin_string_test.go b/evaluator/builtin_string_test.go
@@ -472,6 +472,49 @@ func (s *testEvaluatorSuite) TestSubstringIndex(c *C) {
 	}
 }
 
+func (s *testEvaluatorSuite) TestSpace(c *C) {
+	defer testleak.AfterTest(c)()
+	d, err := builtinSpace(types.MakeDatums([]interface{}{nil}...), nil)
+	c.Assert(err, IsNil)
+	c.Assert(d.Kind(), Equals, types.KindNull)
+
+	d, err = builtinSpace(types.MakeDatums([]interface{}{8888888888}...), nil)
+	c.Assert(err, IsNil)
+	c.Assert(d.Kind(), Equals, types.KindNull)
+
+	tbl := []struct {
+		Input  interface{}
+		Expect string
+	}{
+		{5, "     "},
+		{0, ""},
+		{-1, ""},
+		{"5", "     "},
+	}
+
+	dtbl := tblToDtbl(tbl)
+
+	for _, t := range dtbl {
+		d, err = builtinSpace(t["Input"], nil)
+		c.Assert(err, IsNil)
+		c.Assert(d, testutil.DatumEquals, t["Expect"][0])
+	}
+
+	wrong := []struct {
+		Input string
+	}{
+		{"abc"},
+		{"3.3"},
+		{""},
+	}
+
+	dwrong := tblToDtbl(wrong)
+	for _, t := range dwrong {
+		_, err = builtinSpace(t["Input"], nil)
+		c.Assert(err, NotNil)
+	}
+}
+
 func (s *testEvaluatorSuite) TestLocate(c *C) {
 	defer testleak.AfterTest(c)()
 	tbl := []struct {

diff --git a/parser/parser.y b/parser/parser.y
@@ -269,6 +269,7 @@ import (
 	show		"SHOW"
 	signed		"SIGNED"
 	some 		"SOME"
+	space 		"SPACE"
 	start		"START"
 	status		"STATUS"
 	stringType	"string"
@@ -1954,7 +1955,7 @@ UnReservedKeyword:
 |	"COMMENT" | "AVG_ROW_LENGTH" | "CONNECTION" | "CHECKSUM" | "COMPRESSION" | "KEY_BLOCK_SIZE" | "MAX_ROWS" | "MIN_ROWS"
 |	"NATIONAL" | "ROW" | "ROW_FORMAT" | "QUARTER" | "ESCAPE" | "GRANTS" | "FIELDS" | "TRIGGERS" | "DELAY_KEY_WRITE"
 |	"ISOLATION" |	"REPEATABLE" | "COMMITTED" | "UNCOMMITTED" | "ONLY" | "SERIALIZABLE" | "LEVEL" | "VARIABLES"
-|	"SQL_CACHE" | "SQL_NO_CACHE" | "ACTION" | "DISABLE" | "ENABLE" | "REVERSE"
+|	"SQL_CACHE" | "SQL_NO_CACHE" | "ACTION" | "DISABLE" | "ENABLE" | "REVERSE" | "SPACE"
 
 NotKeywordToken:
 	"ABS" | "ADDDATE" | "ADMIN" | "COALESCE" | "CONCAT" | "CONCAT_WS" | "CONNECTION_ID" | "CUR_TIME"| "COUNT" | "DAY"
@@ -2647,6 +2648,10 @@ FunctionCallNonKeyword:
 	{
 		$$ = &ast.FuncCallExpr{FnName: model.NewCIStr($1.(string)), Args: []ast.ExprNode{$3.(ast.ExprNode)}}
 	}
+|	"SPACE" '(' Expression ')'
+	{
+		$$ = &ast.FuncCallExpr{FnName: model.NewCIStr($1.(string)), Args: []ast.ExprNode{$3.(ast.ExprNode)}}
+	}
 |	"STRCMP" '(' Expression ',' Expression ')'
 	{
 		$$ = &ast.FuncCallExpr{FnName: model.NewCIStr($1.(string)), Args: []ast.ExprNode{$3.(ast.ExprNode), $5.(ast.ExprNode)}}

diff --git a/parser/parser_test.go b/parser/parser_test.go
@@ -47,7 +47,7 @@ func (s *testParserSuite) TestSimple(c *C) {
 		"delay_key_write", "isolation", "repeatable", "committed", "uncommitted", "only", "serializable", "level",
 		"curtime", "variables", "dayname", "version", "btree", "hash", "row_format", "dynamic", "fixed", "compressed",
 		"compact", "redundant", "sql_no_cache sql_no_cache", "sql_cache sql_cache", "action", "round",
-		"enable", "disable", "reverse",
+		"enable", "disable", "reverse", "space",
 	}
 	for _, kw := range unreservedKws {
 		src := fmt.Sprintf("SELECT %s FROM tbl;", kw)

diff --git a/parser/scanner.l b/parser/scanner.l
@@ -470,6 +470,7 @@ set		{s}{e}{t}
 share		{s}{h}{a}{r}{e}
 show		{s}{h}{o}{w}
 some		{s}{o}{m}{e}
+space		{s}{p}{a}{c}{e}
 start		{s}{t}{a}{r}{t}
 status          {s}{t}{a}{t}{u}{s}
 subdate		{s}{u}{b}{d}{a}{t}{e}
@@ -972,6 +973,8 @@ redundant		lval.item = string(l.val)
 			return session
 {some}			lval.item = string(l.val)
 			return some
+{space}			lval.item = string(l.val)
+			return space
 {start}			lval.item = string(l.val)
 			return start
 {status}		lval.item = string(l.val)