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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
 
// +build darwin freebsd linux netbsd openbsd
 
// Parse "zoneinfo" time zone file.
// This is a fairly standard file format used on OS X, Linux, BSD, Sun, and others.
// See tzfile(5), http://en.wikipedia.org/wiki/Zoneinfo,
// and ftp://munnari.oz.au/pub/oldtz/
 
package time
 
import (
        "errors"
        "syscall"
)
 
const (
        headerSize = 4 + 16 + 4*7
)
 
// Simple I/O interface to binary blob of data.
type data struct {
        p     []byte
        error bool
}
 
func (d *data) read(n int) []byte {
        if len(d.p) < n {
                d.p = nil
                d.error = true
                return nil
        }
        p := d.p[0:n]
        d.p = d.p[n:]
        return p
}
 
func (d *data) big4() (n uint32, ok bool) {
        p := d.read(4)
        if len(p) < 4 {
                d.error = true
                return 0, false
        }
        return uint32(p[0])<<24 | uint32(p[1])<<16 | uint32(p[2])<<8 | uint32(p[3]), true
}
 
func (d *data) byte() (n byte, ok bool) {
        p := d.read(1)
        if len(p) < 1 {
                d.error = true
                return 0, false
        }
        return p[0], true
}
 
// Make a string by stopping at the first NUL
func byteString(p []byte) string {
        for i := 0; i < len(p); i++ {
                if p[i] == 0 {
                        return string(p[0:i])
                }
        }
        return string(p)
}
 
var badData = errors.New("malformed time zone information")
 
func loadZoneData(bytes []byte) (l *Location, err error) {
        d := data{bytes, false}
 
        // 4-byte magic "TZif"
        if magic := d.read(4); string(magic) != "TZif" {
                return nil, badData
        }
 
        // 1-byte version, then 15 bytes of padding
        var p []byte
        if p = d.read(16); len(p) != 16 || p[0] != 0 && p[0] != '2' {
                return nil, badData
        }
 
        // six big-endian 32-bit integers:
        //      number of UTC/local indicators
        //      number of standard/wall indicators
        //      number of leap seconds
        //      number of transition times
        //      number of local time zones
        //      number of characters of time zone abbrev strings
        const (
                NUTCLocal = iota
                NStdWall
                NLeap
                NTime
                NZone
                NChar
        )
        var n [6]int
        for i := 0; i < 6; i++ {
                nn, ok := d.big4()
                if !ok {
                        return nil, badData
                }
                n[i] = int(nn)
        }
 
        // Transition times.
        txtimes := data{d.read(n[NTime] * 4), false}
 
        // Time zone indices for transition times.
        txzones := d.read(n[NTime])
 
        // Zone info structures
        zonedata := data{d.read(n[NZone] * 6), false}
 
        // Time zone abbreviations.
        abbrev := d.read(n[NChar])
 
        // Leap-second time pairs
        d.read(n[NLeap] * 8)
 
        // Whether tx times associated with local time types
        // are specified as standard time or wall time.
        isstd := d.read(n[NStdWall])
 
        // Whether tx times associated with local time types
        // are specified as UTC or local time.
        isutc := d.read(n[NUTCLocal])
 
        if d.error { // ran out of data
                return nil, badData
        }
 
        // If version == 2, the entire file repeats, this time using
        // 8-byte ints for txtimes and leap seconds.
        // We won't need those until 2106.
 
        // Now we can build up a useful data structure.
        // First the zone information.
        //      utcoff[4] isdst[1] nameindex[1]
        zone := make([]zone, n[NZone])
        for i := range zone {
                var ok bool
                var n uint32
                if n, ok = zonedata.big4(); !ok {
                        return nil, badData
                }
                zone[i].offset = int(n)
                var b byte
                if b, ok = zonedata.byte(); !ok {
                        return nil, badData
                }
                zone[i].isDST = b != 0
                if b, ok = zonedata.byte(); !ok || int(b) >= len(abbrev) {
                        return nil, badData
                }
                zone[i].name = byteString(abbrev[b:])
        }
 
        // Now the transition time info.
        tx := make([]zoneTrans, n[NTime])
        for i := range tx {
                var ok bool
                var n uint32
                if n, ok = txtimes.big4(); !ok {
                        return nil, badData
                }
                tx[i].when = int64(int32(n))
                if int(txzones[i]) >= len(zone) {
                        return nil, badData
                }
                tx[i].index = txzones[i]
                if i < len(isstd) {
                        tx[i].isstd = isstd[i] != 0
                }
                if i < len(isutc) {
                        tx[i].isutc = isutc[i] != 0
                }
        }
 
        // Commited to succeed.
        l = &Location{zone: zone, tx: tx}
 
        // Fill in the cache with information about right now,
        // since that will be the most common lookup.
        sec, _ := now()
        for i := range tx {
                if tx[i].when <= sec && (i+1 == len(tx) || sec < tx[i+1].when) {
                        l.cacheStart = tx[i].when
                        l.cacheEnd = 1<<63 - 1
                        if i+1 < len(tx) {
                                l.cacheEnd = tx[i+1].when
                        }
                        l.cacheZone = &l.zone[tx[i].index]
                }
        }
 
        return l, nil
}
 
func loadZoneFile(name string) (l *Location, err error) {
        buf, err := readFile(name)
        if err != nil {
                return
        }
        return loadZoneData(buf)
}
 
func initTestingZone() {
        syscall.Setenv("TZ", "America/Los_Angeles")
        initLocal()
}
 
// Many systems use /usr/share/zoneinfo, Solaris 2 has
// /usr/share/lib/zoneinfo, IRIX 6 has /usr/lib/locale/TZ.
var zoneDirs = []string{
        "/usr/share/zoneinfo/",
        "/usr/share/lib/zoneinfo/",
        "/usr/lib/locale/TZ/",
}
 
func initLocal() {
        // consult $TZ to find the time zone to use.
        // no $TZ means use the system default /etc/localtime.
        // $TZ="" means use UTC.
        // $TZ="foo" means use /usr/share/zoneinfo/foo.
 
        tz, ok := syscall.Getenv("TZ")
        switch {
        case !ok:
                z, err := loadZoneFile("/etc/localtime")
                if err == nil {
                        localLoc = *z
                        localLoc.name = "Local"
                        return
                }
        case tz != "" && tz != "UTC":
                if z, err := loadLocation(tz); err == nil {
                        localLoc = *z
                        return
                }
        }
 
        // Fall back to UTC.
        localLoc.name = "UTC"
}
 
func loadLocation(name string) (*Location, error) {
        for _, zoneDir := range zoneDirs {
                if z, err := loadZoneFile(zoneDir + name); err == nil {
                        z.name = name
                        return z, nil
                }
        }
        return nil, errors.New("unknown time zone " + name)
}

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Subversion Repositories openrisc

[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgo/] [go/] [time/] [zoneinfo_unix.go] - Blame information for rev 750

Line No.	Rev	Author	Line
1	747	jeremybenn	`// Copyright 2009 The Go Authors. All rights reserved.`
2			`// Use of this source code is governed by a BSD-style`
3			`// license that can be found in the LICENSE file.`
4
5			`// +build darwin freebsd linux netbsd openbsd`
6
7			`// Parse "zoneinfo" time zone file.`
8			`// This is a fairly standard file format used on OS X, Linux, BSD, Sun, and others.`
9			`// See tzfile(5), http://en.wikipedia.org/wiki/Zoneinfo,`
10			`// and ftp://munnari.oz.au/pub/oldtz/`
11
12			`package time`
13
14			`import (`
15			`"errors"`
16			`"syscall"`
17			`)`
18
19			`const (`
20			`headerSize = 4 + 16 + 4*7`
21			`)`
22
23			`// Simple I/O interface to binary blob of data.`
24			`type data struct {`
25			`p []byte`
26			`error bool`
27			`}`
28
29			`func (d *data) read(n int) []byte {`
30			`if len(d.p) < n {`
31			`d.p = nil`
32			`d.error = true`
33			`return nil`
34			`}`
35			`p := d.p[0:n]`
36			`d.p = d.p[n:]`
37			`return p`
38			`}`
39
40			`func (d *data) big4() (n uint32, ok bool) {`
41			`p := d.read(4)`
42			`if len(p) < 4 {`
43			`d.error = true`
44			`return 0, false`
45			`}`
46			`return uint32(p[0])<<24 \| uint32(p[1])<<16 \| uint32(p[2])<<8 \| uint32(p[3]), true`
47			`}`
48
49			`func (d *data) byte() (n byte, ok bool) {`
50			`p := d.read(1)`
51			`if len(p) < 1 {`
52			`d.error = true`
53			`return 0, false`
54			`}`
55			`return p[0], true`
56			`}`
57
58			`// Make a string by stopping at the first NUL`
59			`func byteString(p []byte) string {`
60			`for i := 0; i < len(p); i++ {`
61			`if p[i] == 0 {`
62			`return string(p[0:i])`
63			`}`
64			`}`
65			`return string(p)`
66			`}`
67
68			`var badData = errors.New("malformed time zone information")`
69
70			`func loadZoneData(bytes []byte) (l *Location, err error) {`
71			`d := data{bytes, false}`
72
73			`// 4-byte magic "TZif"`
74			`if magic := d.read(4); string(magic) != "TZif" {`
75			`return nil, badData`
76			`}`
77
78			`// 1-byte version, then 15 bytes of padding`
79			`var p []byte`
80			`if p = d.read(16); len(p) != 16 \|\| p[0] != 0 && p[0] != '2' {`
81			`return nil, badData`
82			`}`
83
84			`// six big-endian 32-bit integers:`
85			`// number of UTC/local indicators`
86			`// number of standard/wall indicators`
87			`// number of leap seconds`
88			`// number of transition times`
89			`// number of local time zones`
90			`// number of characters of time zone abbrev strings`
91			`const (`
92			`NUTCLocal = iota`
93			`NStdWall`
94			`NLeap`
95			`NTime`
96			`NZone`
97			`NChar`
98			`)`
99			`var n [6]int`
100			`for i := 0; i < 6; i++ {`
101			`nn, ok := d.big4()`
102			`if !ok {`
103			`return nil, badData`
104			`}`
105			`n[i] = int(nn)`
106			`}`
107
108			`// Transition times.`
109			`txtimes := data{d.read(n[NTime] * 4), false}`
110
111			`// Time zone indices for transition times.`
112			`txzones := d.read(n[NTime])`
113
114			`// Zone info structures`
115			`zonedata := data{d.read(n[NZone] * 6), false}`
116
117			`// Time zone abbreviations.`
118			`abbrev := d.read(n[NChar])`
119
120			`// Leap-second time pairs`
121			`d.read(n[NLeap] * 8)`
122
123			`// Whether tx times associated with local time types`
124			`// are specified as standard time or wall time.`
125			`isstd := d.read(n[NStdWall])`
126
127			`// Whether tx times associated with local time types`
128			`// are specified as UTC or local time.`
129			`isutc := d.read(n[NUTCLocal])`
130
131			`if d.error { // ran out of data`
132			`return nil, badData`
133			`}`
134
135			`// If version == 2, the entire file repeats, this time using`
136			`// 8-byte ints for txtimes and leap seconds.`
137			`// We won't need those until 2106.`
138
139			`// Now we can build up a useful data structure.`
140			`// First the zone information.`
141			`// utcoff[4] isdst[1] nameindex[1]`
142			`zone := make([]zone, n[NZone])`
143			`for i := range zone {`
144			`var ok bool`
145			`var n uint32`
146			`if n, ok = zonedata.big4(); !ok {`
147			`return nil, badData`
148			`}`
149			`zone[i].offset = int(n)`
150			`var b byte`
151			`if b, ok = zonedata.byte(); !ok {`
152			`return nil, badData`
153			`}`
154			`zone[i].isDST = b != 0`
155			`if b, ok = zonedata.byte(); !ok \|\| int(b) >= len(abbrev) {`
156			`return nil, badData`
157			`}`
158			`zone[i].name = byteString(abbrev[b:])`
159			`}`
160
161			`// Now the transition time info.`
162			`tx := make([]zoneTrans, n[NTime])`
163			`for i := range tx {`
164			`var ok bool`
165			`var n uint32`
166			`if n, ok = txtimes.big4(); !ok {`
167			`return nil, badData`
168			`}`
169			`tx[i].when = int64(int32(n))`
170			`if int(txzones[i]) >= len(zone) {`
171			`return nil, badData`
172			`}`
173			`tx[i].index = txzones[i]`
174			`if i < len(isstd) {`
175			`tx[i].isstd = isstd[i] != 0`
176			`}`
177			`if i < len(isutc) {`
178			`tx[i].isutc = isutc[i] != 0`
179			`}`
180			`}`
181
182			`// Commited to succeed.`
183			`l = &Location{zone: zone, tx: tx}`
184
185			`// Fill in the cache with information about right now,`
186			`// since that will be the most common lookup.`
187			`sec, _ := now()`
188			`for i := range tx {`
189			`if tx[i].when <= sec && (i+1 == len(tx) \|\| sec < tx[i+1].when) {`
190			`l.cacheStart = tx[i].when`
191			`l.cacheEnd = 1<<63 - 1`
192			`if i+1 < len(tx) {`
193			`l.cacheEnd = tx[i+1].when`
194			`}`
195			`l.cacheZone = &l.zone[tx[i].index]`
196			`}`
197			`}`
198
199			`return l, nil`
200			`}`
201
202			`func loadZoneFile(name string) (l *Location, err error) {`
203			`buf, err := readFile(name)`
204			`if err != nil {`
205			`return`
206			`}`
207			`return loadZoneData(buf)`
208			`}`
209
210			`func initTestingZone() {`
211			`syscall.Setenv("TZ", "America/Los_Angeles")`
212			`initLocal()`
213			`}`
214
215			`// Many systems use /usr/share/zoneinfo, Solaris 2 has`
216			`// /usr/share/lib/zoneinfo, IRIX 6 has /usr/lib/locale/TZ.`
217			`var zoneDirs = []string{`
218			`"/usr/share/zoneinfo/",`
219			`"/usr/share/lib/zoneinfo/",`
220			`"/usr/lib/locale/TZ/",`
221			`}`
222
223			`func initLocal() {`
224			`// consult $TZ to find the time zone to use.`
225			`// no $TZ means use the system default /etc/localtime.`
226			`// $TZ="" means use UTC.`
227			`// $TZ="foo" means use /usr/share/zoneinfo/foo.`
228
229			`tz, ok := syscall.Getenv("TZ")`
230			`switch {`
231			`case !ok:`
232			`z, err := loadZoneFile("/etc/localtime")`
233			`if err == nil {`
234			`localLoc = *z`
235			`localLoc.name = "Local"`
236			`return`
237			`}`
238			`case tz != "" && tz != "UTC":`
239			`if z, err := loadLocation(tz); err == nil {`
240			`localLoc = *z`
241			`return`
242			`}`
243			`}`
244
245			`// Fall back to UTC.`
246			`localLoc.name = "UTC"`
247			`}`
248
249			`func loadLocation(name string) (*Location, error) {`
250			`for _, zoneDir := range zoneDirs {`
251			`if z, err := loadZoneFile(zoneDir + name); err == nil {`
252			`z.name = name`
253			`return z, nil`
254			`}`
255			`}`
256			`return nil, errors.New("unknown time zone " + name)`
257			`}`