michael@0: /*
michael@0:  * Copyright 2013 The Android Open Source Project
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkErrorInternals.h"
michael@0: #include "SkImageDecoder.h"
michael@0: #include "SkStream.h"
michael@0: #include "SkTRegistry.h"
michael@0: 
michael@0: // This file is used for registration of SkImageDecoders. It also holds a function
michael@0: // for checking all the the registered SkImageDecoders for one that matches an
michael@0: // input SkStreamRewindable.
michael@0: 
michael@0: template SkImageDecoder_DecodeReg* SkImageDecoder_DecodeReg::gHead;
michael@0: 
michael@0: SkImageDecoder* image_decoder_from_stream(SkStreamRewindable*);
michael@0: 
michael@0: SkImageDecoder* image_decoder_from_stream(SkStreamRewindable* stream) {
michael@0:     SkImageDecoder* codec = NULL;
michael@0:     const SkImageDecoder_DecodeReg* curr = SkImageDecoder_DecodeReg::Head();
michael@0:     while (curr) {
michael@0:         codec = curr->factory()(stream);
michael@0:         // we rewind here, because we promise later when we call "decode", that
michael@0:         // the stream will be at its beginning.
michael@0:         bool rewindSuceeded = stream->rewind();
michael@0: 
michael@0:         // our image decoder's require that rewind is supported so we fail early
michael@0:         // if we are given a stream that does not support rewinding.
michael@0:         if (!rewindSuceeded) {
michael@0:             SkDEBUGF(("Unable to rewind the image stream."));
michael@0:             SkDELETE(codec);
michael@0:             return NULL;
michael@0:         }
michael@0: 
michael@0:         if (codec) {
michael@0:             return codec;
michael@0:         }
michael@0:         curr = curr->next();
michael@0:     }
michael@0:     return NULL;
michael@0: }
michael@0: 
michael@0: template SkImageDecoder_FormatReg* SkImageDecoder_FormatReg::gHead;
michael@0: 
michael@0: SkImageDecoder::Format SkImageDecoder::GetStreamFormat(SkStreamRewindable* stream) {
michael@0:     const SkImageDecoder_FormatReg* curr = SkImageDecoder_FormatReg::Head();
michael@0:     while (curr != NULL) {
michael@0:         Format format = curr->factory()(stream);
michael@0:         if (!stream->rewind()) {
michael@0:             SkErrorInternals::SetError(kInvalidOperation_SkError,
michael@0:                                        "Unable to rewind the image stream\n");
michael@0:             return kUnknown_Format;
michael@0:         }
michael@0:         if (format != kUnknown_Format) {
michael@0:             return format;
michael@0:         }
michael@0:         curr = curr->next();
michael@0:     }
michael@0:     return kUnknown_Format;
michael@0: }