7a9389330e
gcc/: * gcc.c (default_compilers): Add entry for ".go". * common.opt: Add -static-libgo as a driver option. * doc/install.texi (Configuration): Mention libgo as an option for --enable-shared. Mention go as an option for --enable-languages. * doc/invoke.texi (Overall Options): Mention .go as a file name suffix. Mention go as a -x option. * doc/frontends.texi (G++ and GCC): Mention Go as a supported language. * doc/sourcebuild.texi (Top Level): Mention libgo. * doc/standards.texi (Standards): Add section on Go language. Move references for other languages into their own section. * doc/contrib.texi (Contributors): Mention that I contributed the Go frontend. gcc/testsuite/: * lib/go.exp: New file. * lib/go-dg.exp: New file. * lib/go-torture.exp: New file. * lib/target-supports.exp (check_compile): Match // Go. From-SVN: r167407
87 lines
2.5 KiB
Go
87 lines
2.5 KiB
Go
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package image
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import (
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"bufio"
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"io"
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"os"
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)
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// An UnknownFormatErr indicates that decoding encountered an unknown format.
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var UnknownFormatErr = os.NewError("image: unknown format")
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// A format holds an image format's name, magic header and how to decode it.
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type format struct {
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name, magic string
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decode func(io.Reader) (Image, os.Error)
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decodeConfig func(io.Reader) (Config, os.Error)
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}
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// Formats is the list of registered formats.
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var formats []format
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// RegisterFormat registers an image format for use by Decode.
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// Name is the name of the format, like "jpeg" or "png".
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// Magic is the magic prefix that identifies the format's encoding.
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// Decode is the function that decodes the encoded image.
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// DecodeConfig is the function that decodes just its configuration.
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func RegisterFormat(name, magic string, decode func(io.Reader) (Image, os.Error), decodeConfig func(io.Reader) (Config, os.Error)) {
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formats = append(formats, format{name, magic, decode, decodeConfig})
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}
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// A reader is an io.Reader that can also peek ahead.
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type reader interface {
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io.Reader
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Peek(int) ([]byte, os.Error)
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}
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// AsReader converts an io.Reader to a reader.
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func asReader(r io.Reader) reader {
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if rr, ok := r.(reader); ok {
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return rr
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}
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return bufio.NewReader(r)
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}
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// sniff determines the format of r's data.
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func sniff(r reader) format {
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for _, f := range formats {
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s, err := r.Peek(len(f.magic))
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if err == nil && string(s) == f.magic {
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return f
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}
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}
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return format{}
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}
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// Decode decodes an image that has been encoded in a registered format.
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// The string returned is the format name used during format registration.
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// Format registration is typically done by the init method of the codec-
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// specific package.
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func Decode(r io.Reader) (Image, string, os.Error) {
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rr := asReader(r)
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f := sniff(rr)
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if f.decode == nil {
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return nil, "", UnknownFormatErr
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}
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m, err := f.decode(rr)
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return m, f.name, err
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}
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// DecodeConfig decodes the color model and dimensions of an image that has
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// been encoded in a registered format. The string returned is the format name
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// used during format registration. Format registration is typically done by
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// the init method of the codec-specific package.
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func DecodeConfig(r io.Reader) (Config, string, os.Error) {
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rr := asReader(r)
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f := sniff(rr)
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if f.decodeConfig == nil {
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return Config{}, "", UnknownFormatErr
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}
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c, err := f.decodeConfig(rr)
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return c, f.name, err
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}
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