Quelle  SkJPEGWriteUtility.cpp

/*
 * Copyright 2010 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#include "src/encode/SkJPEGWriteUtility.h"

#include "include/core/SkStream.h"
#include "src/codec/SkJpegPriv.h"

#include <csetjmp>
#include <cstddef>

extern "C" {
    #include "jerror.h"    // NO_G3_REWRITE
    #include "jpeglib.h"   // NO_G3_REWRITE
}

///////////////////////////////////////////////////////////////////////////////

static void sk_init_destination(j_compress_ptr cinfo) {
    skjpeg_destination_mgr* dest = (skjpeg_destination_mgr*)cinfo->dest;

    dest->next_output_byte = dest->fBuffer;
    dest->free_in_buffer = skjpeg_destination_mgr::kBufferSize;
}

static boolean sk_empty_output_buffer(j_compress_ptr cinfo) {
    skjpeg_destination_mgr* dest = (skjpeg_destination_mgr*)cinfo->dest;

//  if (!dest->fStream->write(dest->fBuffer, skjpeg_destination_mgr::kBufferSize - dest->free_in_buffer))
    if (!dest->fStream->write(dest->fBuffer,
            skjpeg_destination_mgr::kBufferSize)) {
        ERREXIT(cinfo, JERR_FILE_WRITE);
        return FALSE;
    }

    dest->next_output_byte = dest->fBuffer;
    dest->free_in_buffer = skjpeg_destination_mgr::kBufferSize;
    return TRUE;
}

static void sk_term_destination (j_compress_ptr cinfo) {
    skjpeg_destination_mgr* dest = (skjpeg_destination_mgr*)cinfo->dest;

    size_t size = skjpeg_destination_mgr::kBufferSize - dest->free_in_buffer;
    if (size > 0) {
        if (!dest->fStream->write(dest->fBuffer, size)) {
            ERREXIT(cinfo, JERR_FILE_WRITE);
            return;
        }
    }

    dest->fStream->flush();
}

skjpeg_destination_mgr::skjpeg_destination_mgr(SkWStream* stream) : fStream(stream) {
    this->init_destination = sk_init_destination;
    this->empty_output_buffer = sk_empty_output_buffer;
    this->term_destination = sk_term_destination;
}

void skjpeg_error_exit(j_common_ptr cinfo) {
    skjpeg_error_mgr* error = static_cast<skjpeg_error_mgr*>(cinfo->err);

    (*error->output_message)(cinfo);

    /* Let the memory manager delete any temp files before we die */
    jpeg_destroy(cinfo);

    if (error->fStack[0] == nullptr) {
        SK_ABORT("JPEG error with no jmp_buf set.");
    }
    longjmp(*error->fStack[0], -1);
}