imgutils.c

/*
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * misc image utilities
 */

#include "avassert.h"
#include "common.h"
#include "imgutils.h"
#include "internal.h"
#include "intreadwrite.h"
#include "log.h"
#include "pixdesc.h"

void av_image_fill_max_pixsteps(int max_pixsteps[4], int max_pixstep_comps[4],
                                const AVPixFmtDescriptor *pixdesc)
{
    int i;
    memset(max_pixsteps, 0, 4*sizeof(max_pixsteps[0]));
    if (max_pixstep_comps)
        memset(max_pixstep_comps, 0, 4*sizeof(max_pixstep_comps[0]));

    for (i = 0; i < 4; i++) {
        const AVComponentDescriptor *comp = &(pixdesc->comp[i]);
        if ((comp->step_minus1+1) > max_pixsteps[comp->plane]) {
            max_pixsteps[comp->plane] = comp->step_minus1+1;
            if (max_pixstep_comps)
                max_pixstep_comps[comp->plane] = i;
        }
    }
}

static inline
int image_get_linesize(int width, int plane,
                       int max_step, int max_step_comp,
                       const AVPixFmtDescriptor *desc)
{
    int s, shifted_w, linesize;

    if (!desc)
        return AVERROR(EINVAL);

    if (width < 0)
        return AVERROR(EINVAL);
    s = (max_step_comp == 1 || max_step_comp == 2) ? desc->log2_chroma_w : 0;
    shifted_w = ((width + (1 << s) - 1)) >> s;
    if (shifted_w && max_step > INT_MAX / shifted_w)
        return AVERROR(EINVAL);
    linesize = max_step * shifted_w;

    if (desc->flags & PIX_FMT_BITSTREAM)
        linesize = (linesize + 7) >> 3;
    return linesize;