pngdec.c 53.5 KB
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/*
 * PNG image format
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 * Copyright (c) 2003 Fabrice Bellard
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 *
 * 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
 */
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//#define DEBUG

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#include "libavutil/avassert.h"
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#include "libavutil/bprint.h"
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#include "libavutil/imgutils.h"
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#include "libavutil/stereo3d.h"
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#include "avcodec.h"
#include "bytestream.h"
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#include "internal.h"
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#include "apng.h"
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#include "png.h"
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#include "pngdsp.h"
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#include "thread.h"
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#include <zlib.h>

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enum PNGHeaderState {
    PNG_IHDR = 1 << 0,
    PNG_PLTE = 1 << 1,
};

enum PNGImageState {
    PNG_IDAT     = 1 << 0,
    PNG_ALLIMAGE = 1 << 1,
};

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typedef struct PNGDecContext {
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    PNGDSPContext dsp;
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    AVCodecContext *avctx;
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    GetByteContext gb;
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    ThreadFrame previous_picture;
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    ThreadFrame last_picture;
    ThreadFrame picture;
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    enum PNGHeaderState hdr_state;
    enum PNGImageState pic_state;
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    int width, height;
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    int cur_w, cur_h;
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    int last_w, last_h;
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    int x_offset, y_offset;
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    int last_x_offset, last_y_offset;
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    uint8_t dispose_op, blend_op;
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    uint8_t last_dispose_op;
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    int bit_depth;
    int color_type;
    int compression_type;
    int interlace_type;
    int filter_type;
    int channels;
    int bits_per_pixel;
    int bpp;
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    int has_trns;
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    uint8_t transparent_color_be[6];
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    uint8_t *image_buf;
    int image_linesize;
    uint32_t palette[256];
    uint8_t *crow_buf;
    uint8_t *last_row;
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    unsigned int last_row_size;
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    uint8_t *tmp_row;
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    unsigned int tmp_row_size;
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    uint8_t *buffer;
    int buffer_size;
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    int pass;
    int crow_size; /* compressed row size (include filter type) */
    int row_size; /* decompressed row size */
    int pass_row_size; /* decompress row size of the current pass */
    int y;
    z_stream zstream;
} PNGDecContext;

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/* Mask to determine which pixels are valid in a pass */
static const uint8_t png_pass_mask[NB_PASSES] = {
    0x01, 0x01, 0x11, 0x11, 0x55, 0x55, 0xff,
};

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/* Mask to determine which y pixels can be written in a pass */
static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
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    0xff, 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
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};

/* Mask to determine which pixels to overwrite while displaying */
static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
    0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
};

/* NOTE: we try to construct a good looking image at each pass. width
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 * is the original image width. We also do pixel format conversion at
 * this stage */
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static void png_put_interlaced_row(uint8_t *dst, int width,
                                   int bits_per_pixel, int pass,
                                   int color_type, const uint8_t *src)
{
    int x, mask, dsp_mask, j, src_x, b, bpp;
    uint8_t *d;
    const uint8_t *s;

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    mask     = png_pass_mask[pass];
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    dsp_mask = png_pass_dsp_mask[pass];
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    switch (bits_per_pixel) {
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    case 1:
        src_x = 0;
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        for (x = 0; x < width; x++) {
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            j = (x & 7);
            if ((dsp_mask << j) & 0x80) {
                b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
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                dst[x >> 3] &= 0xFF7F>>j;
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                dst[x >> 3] |= b << (7 - j);
            }
            if ((mask << j) & 0x80)
                src_x++;
        }
        break;
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    case 2:
        src_x = 0;
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        for (x = 0; x < width; x++) {
            int j2 = 2 * (x & 3);
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            j = (x & 7);
            if ((dsp_mask << j) & 0x80) {
                b = (src[src_x >> 2] >> (6 - 2*(src_x & 3))) & 3;
                dst[x >> 2] &= 0xFF3F>>j2;
                dst[x >> 2] |= b << (6 - j2);
            }
            if ((mask << j) & 0x80)
                src_x++;
        }
        break;
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    case 4:
        src_x = 0;
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        for (x = 0; x < width; x++) {
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            int j2 = 4*(x&1);
            j = (x & 7);
            if ((dsp_mask << j) & 0x80) {
                b = (src[src_x >> 1] >> (4 - 4*(src_x & 1))) & 15;
                dst[x >> 1] &= 0xFF0F>>j2;
                dst[x >> 1] |= b << (4 - j2);
            }
            if ((mask << j) & 0x80)
                src_x++;
        }
        break;
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    default:
        bpp = bits_per_pixel >> 3;
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        d   = dst;
        s   = src;
            for (x = 0; x < width; x++) {
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                j = x & 7;
                if ((dsp_mask << j) & 0x80) {
                    memcpy(d, s, bpp);
                }
                d += bpp;
                if ((mask << j) & 0x80)
                    s += bpp;
            }
        break;
    }
}

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void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top,
                                 int w, int bpp)
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{
    int i;
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    for (i = 0; i < w; i++) {
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        int a, b, c, p, pa, pb, pc;

        a = dst[i - bpp];
        b = top[i];
        c = top[i - bpp];

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        p  = b - c;
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        pc = a - c;

        pa = abs(p);
        pb = abs(pc);
        pc = abs(p + pc);

        if (pa <= pb && pa <= pc)
            p = a;
        else if (pb <= pc)
            p = b;
        else
            p = c;
        dst[i] = p + src[i];
    }
}

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#define UNROLL1(bpp, op)                                                      \
    {                                                                         \
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        r = dst[0];                                                           \
        if (bpp >= 2)                                                         \
            g = dst[1];                                                       \
        if (bpp >= 3)                                                         \
            b = dst[2];                                                       \
        if (bpp >= 4)                                                         \
            a = dst[3];                                                       \
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        for (; i <= size - bpp; i += bpp) {                                   \
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            dst[i + 0] = r = op(r, src[i + 0], last[i + 0]);                  \
            if (bpp == 1)                                                     \
                continue;                                                     \
            dst[i + 1] = g = op(g, src[i + 1], last[i + 1]);                  \
            if (bpp == 2)                                                     \
                continue;                                                     \
            dst[i + 2] = b = op(b, src[i + 2], last[i + 2]);                  \
            if (bpp == 3)                                                     \
                continue;                                                     \
            dst[i + 3] = a = op(a, src[i + 3], last[i + 3]);                  \
        }                                                                     \
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    }
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#define UNROLL_FILTER(op)                                                     \
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    if (bpp == 1) {                                                           \
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        UNROLL1(1, op)                                                        \
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    } else if (bpp == 2) {                                                    \
        UNROLL1(2, op)                                                        \
    } else if (bpp == 3) {                                                    \
        UNROLL1(3, op)                                                        \
    } else if (bpp == 4) {                                                    \
        UNROLL1(4, op)                                                        \
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    }                                                                         \
    for (; i < size; i++) {                                                   \
        dst[i] = op(dst[i - bpp], src[i], last[i]);                           \
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    }
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/* NOTE: 'dst' can be equal to 'last' */
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static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
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                           uint8_t *src, uint8_t *last, int size, int bpp)
{
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    int i, p, r, g, b, a;
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    switch (filter_type) {
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    case PNG_FILTER_VALUE_NONE:
        memcpy(dst, src, size);
        break;
    case PNG_FILTER_VALUE_SUB:
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        for (i = 0; i < bpp; i++)
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            dst[i] = src[i];
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        if (bpp == 4) {
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            p = *(int *)dst;
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            for (; i < size; i += bpp) {
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                unsigned s = *(int *)(src + i);
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                p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
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                *(int *)(dst + i) = p;
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            }
        } else {
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#define OP_SUB(x, s, l) ((x) + (s))
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            UNROLL_FILTER(OP_SUB);
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        }
        break;
    case PNG_FILTER_VALUE_UP:
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        dsp->add_bytes_l2(dst, src, last, size);
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        break;
    case PNG_FILTER_VALUE_AVG:
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        for (i = 0; i < bpp; i++) {
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            p      = (last[i] >> 1);
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            dst[i] = p + src[i];
        }
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#define OP_AVG(x, s, l) (((((x) + (l)) >> 1) + (s)) & 0xff)
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        UNROLL_FILTER(OP_AVG);
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        break;
    case PNG_FILTER_VALUE_PAETH:
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        for (i = 0; i < bpp; i++) {
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            p      = last[i];
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            dst[i] = p + src[i];
        }
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        if (bpp > 2 && size > 4) {
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            /* would write off the end of the array if we let it process
             * the last pixel with bpp=3 */
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            int w = (bpp & 3) ? size - 3 : size;

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            if (w > i) {
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                dsp->add_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
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                i = w;
            }
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        }
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        ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
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        break;
    }
}

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/* This used to be called "deloco" in FFmpeg
 * and is actually an inverse reversible colorspace transformation */
#define YUV2RGB(NAME, TYPE) \
static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
{ \
    int i; \
    for (i = 0; i < size; i += 3 + alpha) { \
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        int g = dst [i + 1]; \
        dst[i + 0] += g; \
        dst[i + 2] += g; \
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    } \
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}

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YUV2RGB(rgb8, uint8_t)
YUV2RGB(rgb16, uint16_t)
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/* process exactly one decompressed row */
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static void png_handle_row(PNGDecContext *s)
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{
    uint8_t *ptr, *last_row;
    int got_line;

    if (!s->interlace_type) {
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        ptr = s->image_buf + s->image_linesize * (s->y + s->y_offset) + s->x_offset * s->bpp;
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        if (s->y == 0)
            last_row = s->last_row;
        else
            last_row = ptr - s->image_linesize;
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        png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
                       last_row, s->row_size, s->bpp);
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        /* loco lags by 1 row so that it doesn't interfere with top prediction */
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        if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
            if (s->bit_depth == 16) {
                deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
                             s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
            } else {
                deloco_rgb8(ptr - s->image_linesize, s->row_size,
                            s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
            }
        }
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        s->y++;
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        if (s->y == s->cur_h) {
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            s->pic_state |= PNG_ALLIMAGE;
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            if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
                if (s->bit_depth == 16) {
                    deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
                                 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
                } else {
                    deloco_rgb8(ptr, s->row_size,
                                s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
                }
            }
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        }
    } else {
        got_line = 0;
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        for (;;) {
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            ptr = s->image_buf + s->image_linesize * (s->y + s->y_offset) + s->x_offset * s->bpp;
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            if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
                /* if we already read one row, it is time to stop to
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                 * wait for the next one */
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                if (got_line)
                    break;
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                png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
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                               s->last_row, s->pass_row_size, s->bpp);
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                FFSWAP(uint8_t *, s->last_row, s->tmp_row);
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                FFSWAP(unsigned int, s->last_row_size, s->tmp_row_size);
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                got_line = 1;
            }
            if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
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                png_put_interlaced_row(ptr, s->cur_w, s->bits_per_pixel, s->pass,
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                                       s->color_type, s->last_row);
            }
            s->y++;
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            if (s->y == s->cur_h) {
380
                memset(s->last_row, 0, s->row_size);
381
                for (;;) {
382
                    if (s->pass == NB_PASSES - 1) {
383
                        s->pic_state |= PNG_ALLIMAGE;
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                        goto the_end;
                    } else {
                        s->pass++;
                        s->y = 0;
                        s->pass_row_size = ff_png_pass_row_size(s->pass,
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                                                                s->bits_per_pixel,
390
                                                                s->cur_w);
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                        s->crow_size = s->pass_row_size + 1;
                        if (s->pass_row_size != 0)
                            break;
                        /* skip pass if empty row */
                    }
                }
            }
        }
399
the_end:;
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    }
}

403
static int png_decode_idat(PNGDecContext *s, int length)
404 405
{
    int ret;
406
    s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
407
    s->zstream.next_in  = (unsigned char *)s->gb.buffer;
408
    bytestream2_skip(&s->gb, length);
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    /* decode one line if possible */
    while (s->zstream.avail_in > 0) {
        ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
        if (ret != Z_OK && ret != Z_STREAM_END) {
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            av_log(s->avctx, AV_LOG_ERROR, "inflate returned error %d\n", ret);
            return AVERROR_EXTERNAL;
416 417
        }
        if (s->zstream.avail_out == 0) {
418
            if (!(s->pic_state & PNG_ALLIMAGE)) {
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                png_handle_row(s);
            }
            s->zstream.avail_out = s->crow_size;
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            s->zstream.next_out  = s->crow_buf;
423
        }
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        if (ret == Z_STREAM_END && s->zstream.avail_in > 0) {
425 426
            av_log(NULL, AV_LOG_WARNING,
                   "%d undecompressed bytes left in buffer\n", s->zstream.avail_in);
427 428
            return 0;
        }
429 430 431 432
    }
    return 0;
}

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static int decode_zbuf(AVBPrint *bp, const uint8_t *data,
                       const uint8_t *data_end)
{
    z_stream zstream;
    unsigned char *buf;
    unsigned buf_size;
    int ret;

    zstream.zalloc = ff_png_zalloc;
    zstream.zfree  = ff_png_zfree;
    zstream.opaque = NULL;
    if (inflateInit(&zstream) != Z_OK)
        return AVERROR_EXTERNAL;
    zstream.next_in  = (unsigned char *)data;
    zstream.avail_in = data_end - data;
    av_bprint_init(bp, 0, -1);

    while (zstream.avail_in > 0) {
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        av_bprint_get_buffer(bp, 2, &buf, &buf_size);
        if (buf_size < 2) {
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            ret = AVERROR(ENOMEM);
            goto fail;
        }
        zstream.next_out  = buf;
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        zstream.avail_out = buf_size - 1;
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        ret = inflate(&zstream, Z_PARTIAL_FLUSH);
        if (ret != Z_OK && ret != Z_STREAM_END) {
            ret = AVERROR_EXTERNAL;
            goto fail;
        }
        bp->len += zstream.next_out - buf;
        if (ret == Z_STREAM_END)
            break;
    }
    inflateEnd(&zstream);
    bp->str[bp->len] = 0;
    return 0;

fail:
    inflateEnd(&zstream);
    av_bprint_finalize(bp, NULL);
    return ret;
}

static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
{
    size_t extra = 0, i;
    uint8_t *out, *q;

    for (i = 0; i < size_in; i++)
        extra += in[i] >= 0x80;
    if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
        return NULL;
    q = out = av_malloc(size_in + extra + 1);
    if (!out)
        return NULL;
    for (i = 0; i < size_in; i++) {
        if (in[i] >= 0x80) {
            *(q++) = 0xC0 | (in[i] >> 6);
            *(q++) = 0x80 | (in[i] & 0x3F);
        } else {
            *(q++) = in[i];
        }
    }
    *(q++) = 0;
    return out;
}

static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
                             AVDictionary **dict)
{
    int ret, method;
    const uint8_t *data        = s->gb.buffer;
    const uint8_t *data_end    = data + length;
    const uint8_t *keyword     = data;
    const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
    uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
    unsigned text_len;
    AVBPrint bp;

    if (!keyword_end)
        return AVERROR_INVALIDDATA;
    data = keyword_end + 1;

    if (compressed) {
        if (data == data_end)
            return AVERROR_INVALIDDATA;
        method = *(data++);
        if (method)
            return AVERROR_INVALIDDATA;
        if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
            return ret;
        text_len = bp.len;
        av_bprint_finalize(&bp, (char **)&text);
        if (!text)
            return AVERROR(ENOMEM);
    } else {
        text = (uint8_t *)data;
        text_len = data_end - text;
    }

    kw_utf8  = iso88591_to_utf8(keyword, keyword_end - keyword);
    txt_utf8 = iso88591_to_utf8(text, text_len);
    if (text != data)
        av_free(text);
    if (!(kw_utf8 && txt_utf8)) {
        av_free(kw_utf8);
        av_free(txt_utf8);
        return AVERROR(ENOMEM);
    }

    av_dict_set(dict, kw_utf8, txt_utf8,
                AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
    return 0;
}

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static int decode_ihdr_chunk(AVCodecContext *avctx, PNGDecContext *s,
                             uint32_t length)
{
    if (length != 13)
        return AVERROR_INVALIDDATA;
554

555
    if (s->pic_state & PNG_IDAT) {
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        av_log(avctx, AV_LOG_ERROR, "IHDR after IDAT\n");
        return AVERROR_INVALIDDATA;
    }

560
    if (s->hdr_state & PNG_IHDR) {
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        av_log(avctx, AV_LOG_ERROR, "Multiple IHDR\n");
        return AVERROR_INVALIDDATA;
    }

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    s->width  = s->cur_w = bytestream2_get_be32(&s->gb);
    s->height = s->cur_h = bytestream2_get_be32(&s->gb);
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    if (av_image_check_size(s->width, s->height, 0, avctx)) {
568
        s->cur_w = s->cur_h = s->width = s->height = 0;
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        av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
        return AVERROR_INVALIDDATA;
    }
    s->bit_depth        = bytestream2_get_byte(&s->gb);
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    if (s->bit_depth != 1 && s->bit_depth != 2 && s->bit_depth != 4 &&
        s->bit_depth != 8 && s->bit_depth != 16) {
        av_log(avctx, AV_LOG_ERROR, "Invalid bit depth\n");
        goto error;
    }
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    s->color_type       = bytestream2_get_byte(&s->gb);
    s->compression_type = bytestream2_get_byte(&s->gb);
    s->filter_type      = bytestream2_get_byte(&s->gb);
    s->interlace_type   = bytestream2_get_byte(&s->gb);
    bytestream2_skip(&s->gb, 4); /* crc */
583
    s->hdr_state |= PNG_IHDR;
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    if (avctx->debug & FF_DEBUG_PICT_INFO)
        av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
                "compression_type=%d filter_type=%d interlace_type=%d\n",
                s->width, s->height, s->bit_depth, s->color_type,
                s->compression_type, s->filter_type, s->interlace_type);
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    return 0;
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error:
    s->cur_w = s->cur_h = s->width = s->height = 0;
    s->bit_depth = 8;
    return AVERROR_INVALIDDATA;
595 596 597 598
}

static int decode_phys_chunk(AVCodecContext *avctx, PNGDecContext *s)
{
599
    if (s->pic_state & PNG_IDAT) {
600 601 602 603 604 605 606 607 608 609
        av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
        return AVERROR_INVALIDDATA;
    }
    avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
    avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
    if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
        avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
    bytestream2_skip(&s->gb, 1); /* unit specifier */
    bytestream2_skip(&s->gb, 4); /* crc */

610 611 612
    return 0;
}

613 614 615 616
static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s,
                             uint32_t length, AVFrame *p)
{
    int ret;
617
    size_t byte_depth = s->bit_depth > 8 ? 2 : 1;
618

619
    if (!(s->hdr_state & PNG_IHDR)) {
620 621 622
        av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
        return AVERROR_INVALIDDATA;
    }
623
    if (!(s->pic_state & PNG_IDAT)) {
624
        /* init image info */
625 626 627
        ret = ff_set_dimensions(avctx, s->width, s->height);
        if (ret < 0)
            return ret;
628 629 630 631

        s->channels       = ff_png_get_nb_channels(s->color_type);
        s->bits_per_pixel = s->bit_depth * s->channels;
        s->bpp            = (s->bits_per_pixel + 7) >> 3;
632
        s->row_size       = (s->cur_w * s->bits_per_pixel + 7) >> 3;
633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654

        if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
                s->color_type == PNG_COLOR_TYPE_RGB) {
            avctx->pix_fmt = AV_PIX_FMT_RGB24;
        } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
                s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
            avctx->pix_fmt = AV_PIX_FMT_RGBA;
        } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
                s->color_type == PNG_COLOR_TYPE_GRAY) {
            avctx->pix_fmt = AV_PIX_FMT_GRAY8;
        } else if (s->bit_depth == 16 &&
                s->color_type == PNG_COLOR_TYPE_GRAY) {
            avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
        } else if (s->bit_depth == 16 &&
                s->color_type == PNG_COLOR_TYPE_RGB) {
            avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
        } else if (s->bit_depth == 16 &&
                s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
            avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
        } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
                s->color_type == PNG_COLOR_TYPE_PALETTE) {
            avctx->pix_fmt = AV_PIX_FMT_PAL8;
655
        } else if (s->bit_depth == 1 && s->bits_per_pixel == 1 && avctx->codec_id != AV_CODEC_ID_APNG) {
656 657 658 659 660 661 662 663 664 665 666 667 668 669
            avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
        } else if (s->bit_depth == 8 &&
                s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
            avctx->pix_fmt = AV_PIX_FMT_YA8;
        } else if (s->bit_depth == 16 &&
                s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
            avctx->pix_fmt = AV_PIX_FMT_YA16BE;
        } else {
            av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
                    "and color type %d\n",
                    s->bit_depth, s->color_type);
            return AVERROR_INVALIDDATA;
        }

670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688
        if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE) {
            switch (avctx->pix_fmt) {
            case AV_PIX_FMT_RGB24:
                avctx->pix_fmt = AV_PIX_FMT_RGBA;
                break;

            case AV_PIX_FMT_RGB48BE:
                avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
                break;

            case AV_PIX_FMT_GRAY8:
                avctx->pix_fmt = AV_PIX_FMT_YA8;
                break;

            case AV_PIX_FMT_GRAY16BE:
                avctx->pix_fmt = AV_PIX_FMT_YA16BE;
                break;

            default:
689 690 691 692
                avpriv_request_sample(avctx, "bit depth %d "
                        "and color type %d with TRNS",
                        s->bit_depth, s->color_type);
                return AVERROR_INVALIDDATA;
693 694 695 696 697
            }

            s->bpp += byte_depth;
        }

698 699
        if ((ret = ff_thread_get_buffer(avctx, &s->picture, AV_GET_BUFFER_FLAG_REF)) < 0)
            return ret;
700 701 702 703 704
        if (avctx->codec_id == AV_CODEC_ID_APNG && s->last_dispose_op != APNG_DISPOSE_OP_PREVIOUS) {
            ff_thread_release_buffer(avctx, &s->previous_picture);
            if ((ret = ff_thread_get_buffer(avctx, &s->previous_picture, AV_GET_BUFFER_FLAG_REF)) < 0)
                return ret;
        }
705 706 707 708
        p->pict_type        = AV_PICTURE_TYPE_I;
        p->key_frame        = 1;
        p->interlaced_frame = !!s->interlace_type;

709 710
        ff_thread_finish_setup(avctx);

711 712 713 714 715 716 717
        /* compute the compressed row size */
        if (!s->interlace_type) {
            s->crow_size = s->row_size + 1;
        } else {
            s->pass          = 0;
            s->pass_row_size = ff_png_pass_row_size(s->pass,
                    s->bits_per_pixel,
718
                    s->cur_w);
719 720
            s->crow_size = s->pass_row_size + 1;
        }
721
        ff_dlog(avctx, "row_size=%d crow_size =%d\n",
722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747
                s->row_size, s->crow_size);
        s->image_buf      = p->data[0];
        s->image_linesize = p->linesize[0];
        /* copy the palette if needed */
        if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
            memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
        /* empty row is used if differencing to the first row */
        av_fast_padded_mallocz(&s->last_row, &s->last_row_size, s->row_size);
        if (!s->last_row)
            return AVERROR_INVALIDDATA;
        if (s->interlace_type ||
                s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
            av_fast_padded_malloc(&s->tmp_row, &s->tmp_row_size, s->row_size);
            if (!s->tmp_row)
                return AVERROR_INVALIDDATA;
        }
        /* compressed row */
        av_fast_padded_malloc(&s->buffer, &s->buffer_size, s->row_size + 16);
        if (!s->buffer)
            return AVERROR(ENOMEM);

        /* we want crow_buf+1 to be 16-byte aligned */
        s->crow_buf          = s->buffer + 15;
        s->zstream.avail_out = s->crow_size;
        s->zstream.next_out  = s->crow_buf;
    }
748

749
    s->pic_state |= PNG_IDAT;
750 751 752 753 754 755 756 757 758 759 760

    /* set image to non-transparent bpp while decompressing */
    if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE)
        s->bpp -= byte_depth;

    ret = png_decode_idat(s, length);

    if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE)
        s->bpp += byte_depth;

    if (ret < 0)
761
        return ret;
762

763 764 765 766 767
    bytestream2_skip(&s->gb, 4); /* crc */

    return 0;
}

768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784
static int decode_plte_chunk(AVCodecContext *avctx, PNGDecContext *s,
                             uint32_t length)
{
    int n, i, r, g, b;

    if ((length % 3) != 0 || length > 256 * 3)
        return AVERROR_INVALIDDATA;
    /* read the palette */
    n = length / 3;
    for (i = 0; i < n; i++) {
        r = bytestream2_get_byte(&s->gb);
        g = bytestream2_get_byte(&s->gb);
        b = bytestream2_get_byte(&s->gb);
        s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
    }
    for (; i < 256; i++)
        s->palette[i] = (0xFFU << 24);
785
    s->hdr_state |= PNG_PLTE;
786 787 788 789 790
    bytestream2_skip(&s->gb, 4);     /* crc */

    return 0;
}

791 792 793 794 795
static int decode_trns_chunk(AVCodecContext *avctx, PNGDecContext *s,
                             uint32_t length)
{
    int v, i;

796
    if (!(s->hdr_state & PNG_IHDR)) {
797 798 799 800
        av_log(avctx, AV_LOG_ERROR, "trns before IHDR\n");
        return AVERROR_INVALIDDATA;
    }

801
    if (s->pic_state & PNG_IDAT) {
802 803 804 805
        av_log(avctx, AV_LOG_ERROR, "trns after IDAT\n");
        return AVERROR_INVALIDDATA;
    }

806
    if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
807
        if (length > 256 || !(s->hdr_state & PNG_PLTE))
808 809 810
            return AVERROR_INVALIDDATA;

        for (i = 0; i < length; i++) {
811
            unsigned v = bytestream2_get_byte(&s->gb);
812 813 814 815
            s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
        }
    } else if (s->color_type == PNG_COLOR_TYPE_GRAY || s->color_type == PNG_COLOR_TYPE_RGB) {
        if ((s->color_type == PNG_COLOR_TYPE_GRAY && length != 2) ||
816 817
            (s->color_type == PNG_COLOR_TYPE_RGB && length != 6) ||
            s->bit_depth == 1)
818 819 820 821
            return AVERROR_INVALIDDATA;

        for (i = 0; i < length / 2; i++) {
            /* only use the least significant bits */
822
            v = av_mod_uintp2(bytestream2_get_be16(&s->gb), s->bit_depth);
823 824 825 826 827 828 829

            if (s->bit_depth > 8)
                AV_WB16(&s->transparent_color_be[2 * i], v);
            else
                s->transparent_color_be[i] = v;
        }
    } else {
830 831 832
        return AVERROR_INVALIDDATA;
    }

833
    bytestream2_skip(&s->gb, 4); /* crc */
834 835
    s->has_trns = 1;

836 837 838
    return 0;
}

839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911
static void handle_small_bpp(PNGDecContext *s, AVFrame *p)
{
    if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE) {
        int i, j, k;
        uint8_t *pd = p->data[0];
        for (j = 0; j < s->height; j++) {
            i = s->width / 8;
            for (k = 7; k >= 1; k--)
                if ((s->width&7) >= k)
                    pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
            for (i--; i >= 0; i--) {
                pd[8*i + 7]=  pd[i]     & 1;
                pd[8*i + 6]= (pd[i]>>1) & 1;
                pd[8*i + 5]= (pd[i]>>2) & 1;
                pd[8*i + 4]= (pd[i]>>3) & 1;
                pd[8*i + 3]= (pd[i]>>4) & 1;
                pd[8*i + 2]= (pd[i]>>5) & 1;
                pd[8*i + 1]= (pd[i]>>6) & 1;
                pd[8*i + 0]=  pd[i]>>7;
            }
            pd += s->image_linesize;
        }
    } else if (s->bits_per_pixel == 2) {
        int i, j;
        uint8_t *pd = p->data[0];
        for (j = 0; j < s->height; j++) {
            i = s->width / 4;
            if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
                if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
                if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
                if ((s->width&3) >= 1) pd[4*i + 0]=  pd[i] >> 6;
                for (i--; i >= 0; i--) {
                    pd[4*i + 3]=  pd[i]     & 3;
                    pd[4*i + 2]= (pd[i]>>2) & 3;
                    pd[4*i + 1]= (pd[i]>>4) & 3;
                    pd[4*i + 0]=  pd[i]>>6;
                }
            } else {
                if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
                if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
                if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6     )*0x55;
                for (i--; i >= 0; i--) {
                    pd[4*i + 3]= ( pd[i]     & 3)*0x55;
                    pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
                    pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
                    pd[4*i + 0]= ( pd[i]>>6     )*0x55;
                }
            }
            pd += s->image_linesize;
        }
    } else if (s->bits_per_pixel == 4) {
        int i, j;
        uint8_t *pd = p->data[0];
        for (j = 0; j < s->height; j++) {
            i = s->width/2;
            if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
                if (s->width&1) pd[2*i+0]= pd[i]>>4;
                for (i--; i >= 0; i--) {
                    pd[2*i + 1] = pd[i] & 15;
                    pd[2*i + 0] = pd[i] >> 4;
                }
            } else {
                if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
                for (i--; i >= 0; i--) {
                    pd[2*i + 1] = (pd[i] & 15) * 0x11;
                    pd[2*i + 0] = (pd[i] >> 4) * 0x11;
                }
            }
            pd += s->image_linesize;
        }
    }
}

912 913 914
static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s,
                             uint32_t length)
{
915
    uint32_t sequence_number;
916
    int cur_w, cur_h, x_offset, y_offset, dispose_op, blend_op;
917 918 919 920

    if (length != 26)
        return AVERROR_INVALIDDATA;

921
    if (!(s->hdr_state & PNG_IHDR)) {
922 923 924 925
        av_log(avctx, AV_LOG_ERROR, "fctl before IHDR\n");
        return AVERROR_INVALIDDATA;
    }

926 927 928 929 930 931
    s->last_w = s->cur_w;
    s->last_h = s->cur_h;
    s->last_x_offset = s->x_offset;
    s->last_y_offset = s->y_offset;
    s->last_dispose_op = s->dispose_op;

932
    sequence_number = bytestream2_get_be32(&s->gb);
933 934 935 936
    cur_w           = bytestream2_get_be32(&s->gb);
    cur_h           = bytestream2_get_be32(&s->gb);
    x_offset        = bytestream2_get_be32(&s->gb);
    y_offset        = bytestream2_get_be32(&s->gb);
937
    bytestream2_skip(&s->gb, 4); /* delay_num (2), delay_den (2) */
938 939
    dispose_op      = bytestream2_get_byte(&s->gb);
    blend_op        = bytestream2_get_byte(&s->gb);
940 941 942
    bytestream2_skip(&s->gb, 4); /* crc */

    if (sequence_number == 0 &&
943 944 945 946 947 948 949
        (cur_w != s->width ||
         cur_h != s->height ||
         x_offset != 0 ||
         y_offset != 0) ||
        cur_w <= 0 || cur_h <= 0 ||
        x_offset < 0 || y_offset < 0 ||
        cur_w > s->width - x_offset|| cur_h > s->height - y_offset)
950
            return AVERROR_INVALIDDATA;
951

952 953 954 955 956
    if (blend_op != APNG_BLEND_OP_OVER && blend_op != APNG_BLEND_OP_SOURCE) {
        av_log(avctx, AV_LOG_ERROR, "Invalid blend_op %d\n", blend_op);
        return AVERROR_INVALIDDATA;
    }

957 958
    if ((sequence_number == 0 || !s->previous_picture.f->data[0]) &&
        dispose_op == APNG_DISPOSE_OP_PREVIOUS) {
959 960
        // No previous frame to revert to for the first frame
        // Spec says to just treat it as a APNG_DISPOSE_OP_BACKGROUND
961
        dispose_op = APNG_DISPOSE_OP_BACKGROUND;
962 963
    }

964
    if (blend_op == APNG_BLEND_OP_OVER && !s->has_trns && (
965 966 967 968 969 970 971
            avctx->pix_fmt == AV_PIX_FMT_RGB24 ||
            avctx->pix_fmt == AV_PIX_FMT_RGB48BE ||
            avctx->pix_fmt == AV_PIX_FMT_PAL8 ||
            avctx->pix_fmt == AV_PIX_FMT_GRAY8 ||
            avctx->pix_fmt == AV_PIX_FMT_GRAY16BE ||
            avctx->pix_fmt == AV_PIX_FMT_MONOBLACK
        )) {
972 973
        // APNG_BLEND_OP_OVER is the same as APNG_BLEND_OP_SOURCE when there is no alpha channel
        blend_op = APNG_BLEND_OP_SOURCE;
974 975
    }

976 977 978 979 980 981 982
    s->cur_w      = cur_w;
    s->cur_h      = cur_h;
    s->x_offset   = x_offset;
    s->y_offset   = y_offset;
    s->dispose_op = dispose_op;
    s->blend_op   = blend_op;

983 984 985
    return 0;
}

986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001
static void handle_p_frame_png(PNGDecContext *s, AVFrame *p)
{
    int i, j;
    uint8_t *pd      = p->data[0];
    uint8_t *pd_last = s->last_picture.f->data[0];
    int ls = FFMIN(av_image_get_linesize(p->format, s->width, 0), s->width * s->bpp);

    ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
    for (j = 0; j < s->height; j++) {
        for (i = 0; i < ls; i++)
            pd[i] += pd_last[i];
        pd      += s->image_linesize;
        pd_last += s->image_linesize;
    }
}

1002 1003 1004 1005 1006 1007 1008
// divide by 255 and round to nearest
// apply a fast variant: (X+127)/255 = ((X+127)*257+257)>>16 = ((X+128)*257)>>16
#define FAST_DIV255(x) ((((x) + 128) * 257) >> 16)

static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
                               AVFrame *p)
{
1009
    size_t x, y;
1010
    uint8_t *buffer;
1011

1012
    if (s->blend_op == APNG_BLEND_OP_OVER &&
1013
        avctx->pix_fmt != AV_PIX_FMT_RGBA &&
1014 1015
        avctx->pix_fmt != AV_PIX_FMT_GRAY8A &&
        avctx->pix_fmt != AV_PIX_FMT_PAL8) {
1016 1017 1018 1019 1020
        avpriv_request_sample(avctx, "Blending with pixel format %s",
                              av_get_pix_fmt_name(avctx->pix_fmt));
        return AVERROR_PATCHWELCOME;
    }

1021
    buffer = av_malloc_array(s->image_linesize, s->height);
1022 1023 1024 1025
    if (!buffer)
        return AVERROR(ENOMEM);


1026
    // Do the disposal operation specified by the last frame on the frame
1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037
    if (s->last_dispose_op != APNG_DISPOSE_OP_PREVIOUS) {
        ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
        memcpy(buffer, s->last_picture.f->data[0], s->image_linesize * s->height);

        if (s->last_dispose_op == APNG_DISPOSE_OP_BACKGROUND)
            for (y = s->last_y_offset; y < s->last_y_offset + s->last_h; ++y)
                memset(buffer + s->image_linesize * y + s->bpp * s->last_x_offset, 0, s->bpp * s->last_w);

        memcpy(s->previous_picture.f->data[0], buffer, s->image_linesize * s->height);
        ff_thread_report_progress(&s->previous_picture, INT_MAX, 0);
    } else {
1038
        ff_thread_await_progress(&s->previous_picture, INT_MAX, 0);
1039
        memcpy(buffer, s->previous_picture.f->data[0], s->image_linesize * s->height);
1040 1041
    }

1042 1043 1044 1045 1046
    // Perform blending
    if (s->blend_op == APNG_BLEND_OP_SOURCE) {
        for (y = s->y_offset; y < s->y_offset + s->cur_h; ++y) {
            size_t row_start = s->image_linesize * y + s->bpp * s->x_offset;
            memcpy(buffer + row_start, p->data[0] + row_start, s->bpp * s->cur_w);
1047
        }
1048 1049 1050 1051 1052 1053 1054
    } else { // APNG_BLEND_OP_OVER
        for (y = s->y_offset; y < s->y_offset + s->cur_h; ++y) {
            uint8_t *foreground = p->data[0] + s->image_linesize * y + s->bpp * s->x_offset;
            uint8_t *background = buffer + s->image_linesize * y + s->bpp * s->x_offset;
            for (x = s->x_offset; x < s->x_offset + s->cur_w; ++x, foreground += s->bpp, background += s->bpp) {
                size_t b;
                uint8_t foreground_alpha, background_alpha, output_alpha;
1055
                uint8_t output[10];
1056 1057 1058 1059 1060 1061 1062 1063 1064

                // Since we might be blending alpha onto alpha, we use the following equations:
                // output_alpha = foreground_alpha + (1 - foreground_alpha) * background_alpha
                // output = (foreground_alpha * foreground + (1 - foreground_alpha) * background_alpha * background) / output_alpha

                switch (avctx->pix_fmt) {
                case AV_PIX_FMT_RGBA:
                    foreground_alpha = foreground[3];
                    background_alpha = background[3];
1065
                    break;
1066 1067 1068 1069 1070

                case AV_PIX_FMT_GRAY8A:
                    foreground_alpha = foreground[1];
                    background_alpha = background[1];
                    break;
1071 1072 1073 1074 1075

                case AV_PIX_FMT_PAL8:
                    foreground_alpha = s->palette[foreground[0]] >> 24;
                    background_alpha = s->palette[background[0]] >> 24;
                    break;
1076
                }
1077 1078 1079 1080 1081 1082 1083 1084 1085

                if (foreground_alpha == 0)
                    continue;

                if (foreground_alpha == 255) {
                    memcpy(background, foreground, s->bpp);
                    continue;
                }

1086 1087 1088 1089 1090 1091 1092
                if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {
                    // TODO: Alpha blending with PAL8 will likely need the entire image converted over to RGBA first
                    avpriv_request_sample(avctx, "Alpha blending palette samples");
                    background[0] = foreground[0];
                    continue;
                }

1093 1094
                output_alpha = foreground_alpha + FAST_DIV255((255 - foreground_alpha) * background_alpha);

1095 1096
                av_assert0(s->bpp <= 10);

1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107
                for (b = 0; b < s->bpp - 1; ++b) {
                    if (output_alpha == 0) {
                        output[b] = 0;
                    } else if (background_alpha == 255) {
                        output[b] = FAST_DIV255(foreground_alpha * foreground[b] + (255 - foreground_alpha) * background[b]);
                    } else {
                        output[b] = (255 * foreground_alpha * foreground[b] + (255 - foreground_alpha) * background_alpha * background[b]) / (255 * output_alpha);
                    }
                }
                output[b] = output_alpha;
                memcpy(background, output, s->bpp);
1108
            }
1109
        }
1110
    }
1111

1112 1113 1114
    // Copy blended buffer into the frame and free
    memcpy(p->data[0], buffer, s->image_linesize * s->height);
    av_free(buffer);
1115 1116 1117 1118

    return 0;
}

1119 1120
static int decode_frame_common(AVCodecContext *avctx, PNGDecContext *s,
                               AVFrame *p, AVPacket *avpkt)
1121
{
1122
    AVDictionary **metadatap = NULL;
1123
    uint32_t tag, length;
1124
    int decode_next_dat = 0;
1125
    int ret;
1126

1127
    for (;;) {
1128 1129
        length = bytestream2_get_bytes_left(&s->gb);
        if (length <= 0) {
1130 1131 1132 1133 1134 1135

            if (avctx->codec_id == AV_CODEC_ID_PNG &&
                avctx->skip_frame == AVDISCARD_ALL) {
                return 0;
            }

1136
            if (CONFIG_APNG_DECODER && avctx->codec_id == AV_CODEC_ID_APNG && length == 0) {
1137
                if (!(s->pic_state & PNG_IDAT))
1138 1139 1140 1141 1142
                    return 0;
                else
                    goto exit_loop;
            }
            av_log(avctx, AV_LOG_ERROR, "%d bytes left\n", length);
1143
            if (   s->pic_state & PNG_ALLIMAGE
1144 1145
                && avctx->strict_std_compliance <= FF_COMPLIANCE_NORMAL)
                goto exit_loop;
1146
            ret = AVERROR_INVALIDDATA;
1147
            goto fail;
1148
        }
1149

1150
        length = bytestream2_get_be32(&s->gb);
1151
        if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb)) {
1152
            av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
1153
            ret = AVERROR_INVALIDDATA;
1154
            goto fail;
1155
        }
1156
        tag = bytestream2_get_le32(&s->gb);
1157
        if (avctx->debug & FF_DEBUG_STARTCODE)
1158 1159
            av_log(avctx, AV_LOG_DEBUG, "png: tag=%s length=%u\n",
                   av_fourcc2str(tag), length);
1160 1161 1162 1163 1164 1165 1166 1167

        if (avctx->codec_id == AV_CODEC_ID_PNG &&
            avctx->skip_frame == AVDISCARD_ALL) {
            switch(tag) {
            case MKTAG('I', 'H', 'D', 'R'):
            case MKTAG('p', 'H', 'Y', 's'):
            case MKTAG('t', 'E', 'X', 't'):
            case MKTAG('I', 'D', 'A', 'T'):
1168
            case MKTAG('t', 'R', 'N', 'S'):
1169 1170 1171 1172 1173 1174
                break;
            default:
                goto skip_tag;
            }
        }

1175
        metadatap = &p->metadata;
1176
        switch (tag) {
1177
        case MKTAG('I', 'H', 'D', 'R'):
1178
            if ((ret = decode_ihdr_chunk(avctx, s, length)) < 0)
1179 1180
                goto fail;
            break;
1181
        case MKTAG('p', 'H', 'Y', 's'):
1182
            if ((ret = decode_phys_chunk(avctx, s)) < 0)
1183 1184
                goto fail;
            break;
1185
        case MKTAG('f', 'c', 'T', 'L'):
1186
            if (!CONFIG_APNG_DECODER || avctx->codec_id != AV_CODEC_ID_APNG)
1187 1188 1189 1190 1191 1192
                goto skip_tag;
            if ((ret = decode_fctl_chunk(avctx, s, length)) < 0)
                goto fail;
            decode_next_dat = 1;
            break;
        case MKTAG('f', 'd', 'A', 'T'):
1193
            if (!CONFIG_APNG_DECODER || avctx->codec_id != AV_CODEC_ID_APNG)
1194
                goto skip_tag;
1195 1196
            if (!decode_next_dat) {
                ret = AVERROR_INVALIDDATA;
1197
                goto fail;
1198
            }
1199 1200 1201
            bytestream2_get_be32(&s->gb);
            length -= 4;
            /* fallthrough */
1202
        case MKTAG('I', 'D', 'A', 'T'):
1203
            if (CONFIG_APNG_DECODER && avctx->codec_id == AV_CODEC_ID_APNG && !decode_next_dat)
1204
                goto skip_tag;
1205
            if ((ret = decode_idat_chunk(avctx, s, length, p)) < 0)
1206 1207 1208
                goto fail;
            break;
        case MKTAG('P', 'L', 'T', 'E'):
1209
            if (decode_plte_chunk(avctx, s, length) < 0)
1210
                goto skip_tag;
1211
            break;
1212
        case MKTAG('t', 'R', 'N', 'S'):
1213
            if (decode_trns_chunk(avctx, s, length) < 0)
1214
                goto skip_tag;
1215
            break;
1216
        case MKTAG('t', 'E', 'X', 't'):
1217
            if (decode_text_chunk(s, length, 0, metadatap) < 0)
1218 1219 1220 1221
                av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
            bytestream2_skip(&s->gb, length + 4);
            break;
        case MKTAG('z', 'T', 'X', 't'):
1222
            if (decode_text_chunk(s, length, 1, metadatap) < 0)
1223 1224 1225
                av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
            bytestream2_skip(&s->gb, length + 4);
            break;
1226
        case MKTAG('s', 'T', 'E', 'R'): {
1227
            int mode = bytestream2_get_byte(&s->gb);
1228
            AVStereo3D *stereo3d = av_stereo3d_create_side_data(p);
1229
            if (!stereo3d)
1230
                goto fail;
1231 1232

            if (mode == 0 || mode == 1) {
1233
                stereo3d->type  = AV_STEREO3D_SIDEBYSIDE;
1234
                stereo3d->flags = mode ? 0 : AV_STEREO3D_FLAG_INVERT;
1235
            } else {
1236 1237
                 av_log(avctx, AV_LOG_WARNING,
                        "Unknown value in sTER chunk (%d)\n", mode);
1238
            }
1239
            bytestream2_skip(&s->gb, 4); /* crc */
1240 1241
            break;
        }
1242
        case MKTAG('I', 'E', 'N', 'D'):
1243
            if (!(s->pic_state & PNG_ALLIMAGE))
1244
                av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
1245
            if (!(s->pic_state & (PNG_ALLIMAGE|PNG_IDAT))) {
1246
                ret = AVERROR_INVALIDDATA;
1247
                goto fail;
1248
            }
1249
            bytestream2_skip(&s->gb, 4); /* crc */
1250 1251 1252
            goto exit_loop;
        default:
            /* skip tag */
1253
skip_tag:
1254
            bytestream2_skip(&s->gb, length + 4);
1255 1256 1257
            break;
        }
    }
1258
exit_loop:
1259

1260 1261 1262 1263
    if (avctx->codec_id == AV_CODEC_ID_PNG &&
        avctx->skip_frame == AVDISCARD_ALL) {
        return 0;
    }
1264

1265 1266
    if (s->bits_per_pixel <= 4)
        handle_small_bpp(s, p);
1267

1268 1269 1270 1271 1272 1273
    /* apply transparency if needed */
    if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE) {
        size_t byte_depth = s->bit_depth > 8 ? 2 : 1;
        size_t raw_bpp = s->bpp - byte_depth;
        unsigned x, y;

1274 1275
        av_assert0(s->bit_depth > 1);

1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292
        for (y = 0; y < s->height; ++y) {
            uint8_t *row = &s->image_buf[s->image_linesize * y];

            /* since we're updating in-place, we have to go from right to left */
            for (x = s->width; x > 0; --x) {
                uint8_t *pixel = &row[s->bpp * (x - 1)];
                memmove(pixel, &row[raw_bpp * (x - 1)], raw_bpp);

                if (!memcmp(pixel, s->transparent_color_be, raw_bpp)) {
                    memset(&pixel[raw_bpp], 0, byte_depth);
                } else {
                    memset(&pixel[raw_bpp], 0xff, byte_depth);
                }
            }
        }
    }

1293
    /* handle P-frames only if a predecessor frame is available */
1294
    if (s->last_picture.f->data[0]) {
1295
        if (   !(avpkt->flags & AV_PKT_FLAG_KEY) && avctx->codec_tag != AV_RL32("MPNG")
1296 1297 1298
            && s->last_picture.f->width == p->width
            && s->last_picture.f->height== p->height
            && s->last_picture.f->format== p->format
1299
         ) {
1300
            if (CONFIG_PNG_DECODER && avctx->codec_id != AV_CODEC_ID_APNG)
1301
                handle_p_frame_png(s, p);
1302 1303 1304 1305
            else if (CONFIG_APNG_DECODER &&
                     avctx->codec_id == AV_CODEC_ID_APNG &&
                     (ret = handle_p_frame_apng(avctx, s, p)) < 0)
                goto fail;
1306 1307
        }
    }
1308
    ff_thread_report_progress(&s->picture, INT_MAX, 0);
1309
    ff_thread_report_progress(&s->previous_picture, INT_MAX, 0);
1310

1311 1312 1313 1314
    return 0;

fail:
    ff_thread_report_progress(&s->picture, INT_MAX, 0);
1315
    ff_thread_report_progress(&s->previous_picture, INT_MAX, 0);
1316
    return ret;
1317 1318
}

1319
#if CONFIG_PNG_DECODER
1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340
static int decode_frame_png(AVCodecContext *avctx,
                        void *data, int *got_frame,
                        AVPacket *avpkt)
{
    PNGDecContext *const s = avctx->priv_data;
    const uint8_t *buf     = avpkt->data;
    int buf_size           = avpkt->size;
    AVFrame *p;
    int64_t sig;
    int ret;

    ff_thread_release_buffer(avctx, &s->last_picture);
    FFSWAP(ThreadFrame, s->picture, s->last_picture);
    p = s->picture.f;

    bytestream2_init(&s->gb, buf, buf_size);

    /* check signature */
    sig = bytestream2_get_be64(&s->gb);
    if (sig != PNGSIG &&
        sig != MNGSIG) {
1341
        av_log(avctx, AV_LOG_ERROR, "Invalid PNG signature 0x%08"PRIX64".\n", sig);
1342 1343 1344
        return AVERROR_INVALIDDATA;
    }

1345 1346 1347
    s->y = s->has_trns = 0;
    s->hdr_state = 0;
    s->pic_state = 0;
1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360

    /* init the zlib */
    s->zstream.zalloc = ff_png_zalloc;
    s->zstream.zfree  = ff_png_zfree;
    s->zstream.opaque = NULL;
    ret = inflateInit(&s->zstream);
    if (ret != Z_OK) {
        av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
        return AVERROR_EXTERNAL;
    }

    if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
        goto the_end;
1361

1362 1363 1364 1365 1366 1367
    if (avctx->skip_frame == AVDISCARD_ALL) {
        *got_frame = 0;
        ret = bytestream2_tell(&s->gb);
        goto the_end;
    }

1368 1369
    if ((ret = av_frame_ref(data, s->picture.f)) < 0)
        return ret;
1370

1371
    *got_frame = 1;
1372

1373
    ret = bytestream2_tell(&s->gb);
1374
the_end:
1375
    inflateEnd(&s->zstream);
1376
    s->crow_buf = NULL;
1377 1378
    return ret;
}
1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389
#endif

#if CONFIG_APNG_DECODER
static int decode_frame_apng(AVCodecContext *avctx,
                        void *data, int *got_frame,
                        AVPacket *avpkt)
{
    PNGDecContext *const s = avctx->priv_data;
    int ret;
    AVFrame *p;

1390 1391
    ff_thread_release_buffer(avctx, &s->last_picture);
    FFSWAP(ThreadFrame, s->picture, s->last_picture);
1392 1393
    p = s->picture.f;

1394
    if (!(s->hdr_state & PNG_IHDR)) {
1395
        if (!avctx->extradata_size)
1396 1397 1398 1399 1400 1401
            return AVERROR_INVALIDDATA;

        /* only init fields, there is no zlib use in extradata */
        s->zstream.zalloc = ff_png_zalloc;
        s->zstream.zfree  = ff_png_zfree;

1402
        bytestream2_init(&s->gb, avctx->extradata, avctx->extradata_size);
1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413
        if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
            goto end;
    }

    /* reset state for a new frame */
    if ((ret = inflateInit(&s->zstream)) != Z_OK) {
        av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
        ret = AVERROR_EXTERNAL;
        goto end;
    }
    s->y = 0;
1414
    s->pic_state = 0;
1415 1416 1417 1418
    bytestream2_init(&s->gb, avpkt->data, avpkt->size);
    if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
        goto end;

1419
    if (!(s->pic_state & PNG_ALLIMAGE))
1420
        av_log(avctx, AV_LOG_WARNING, "Frame did not contain a complete image\n");
1421
    if (!(s->pic_state & (PNG_ALLIMAGE|PNG_IDAT))) {
1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435
        ret = AVERROR_INVALIDDATA;
        goto end;
    }
    if ((ret = av_frame_ref(data, s->picture.f)) < 0)
        goto end;

    *got_frame = 1;
    ret = bytestream2_tell(&s->gb);

end:
    inflateEnd(&s->zstream);
    return ret;
}
#endif
1436

1437
#if HAVE_THREADS
1438 1439 1440 1441
static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src)
{
    PNGDecContext *psrc = src->priv_data;
    PNGDecContext *pdst = dst->priv_data;
1442
    int ret;
1443 1444 1445 1446 1447

    if (dst == src)
        return 0;

    ff_thread_release_buffer(dst, &pdst->picture);
1448 1449 1450 1451
    if (psrc->picture.f->data[0] &&
        (ret = ff_thread_ref_frame(&pdst->picture, &psrc->picture)) < 0)
        return ret;
    if (CONFIG_APNG_DECODER && dst->codec_id == AV_CODEC_ID_APNG) {
1452 1453 1454 1455 1456 1457 1458
        pdst->width             = psrc->width;
        pdst->height            = psrc->height;
        pdst->bit_depth         = psrc->bit_depth;
        pdst->color_type        = psrc->color_type;
        pdst->compression_type  = psrc->compression_type;
        pdst->interlace_type    = psrc->interlace_type;
        pdst->filter_type       = psrc->filter_type;
1459 1460 1461 1462
        pdst->cur_w = psrc->cur_w;
        pdst->cur_h = psrc->cur_h;
        pdst->x_offset = psrc->x_offset;
        pdst->y_offset = psrc->y_offset;
1463
        pdst->has_trns = psrc->has_trns;
1464
        memcpy(pdst->transparent_color_be, psrc->transparent_color_be, sizeof(pdst->transparent_color_be));
1465

1466 1467
        pdst->dispose_op = psrc->dispose_op;

1468 1469
        memcpy(pdst->palette, psrc->palette, sizeof(pdst->palette));

1470
        pdst->hdr_state |= psrc->hdr_state;
1471

1472
        ff_thread_release_buffer(dst, &pdst->last_picture);
1473 1474 1475 1476 1477 1478 1479 1480
        if (psrc->last_picture.f->data[0] &&
            (ret = ff_thread_ref_frame(&pdst->last_picture, &psrc->last_picture)) < 0)
            return ret;

        ff_thread_release_buffer(dst, &pdst->previous_picture);
        if (psrc->previous_picture.f->data[0] &&
            (ret = ff_thread_ref_frame(&pdst->previous_picture, &psrc->previous_picture)) < 0)
            return ret;
1481
    }
1482 1483 1484

    return 0;
}
1485
#endif
1486

1487 1488
static av_cold int png_dec_init(AVCodecContext *avctx)
{
1489 1490
    PNGDecContext *s = avctx->priv_data;

1491 1492
    avctx->color_range = AVCOL_RANGE_JPEG;

1493
    s->avctx = avctx;
1494
    s->previous_picture.f = av_frame_alloc();
1495 1496
    s->last_picture.f = av_frame_alloc();
    s->picture.f = av_frame_alloc();
1497 1498 1499 1500
    if (!s->previous_picture.f || !s->last_picture.f || !s->picture.f) {
        av_frame_free(&s->previous_picture.f);
        av_frame_free(&s->last_picture.f);
        av_frame_free(&s->picture.f);
1501
        return AVERROR(ENOMEM);
1502
    }
1503

1504 1505 1506 1507
    if (!avctx->internal->is_copy) {
        avctx->internal->allocate_progress = 1;
        ff_pngdsp_init(&s->dsp);
    }
1508

1509 1510 1511
    return 0;
}

1512 1513 1514 1515
static av_cold int png_dec_end(AVCodecContext *avctx)
{
    PNGDecContext *s = avctx->priv_data;

1516 1517
    ff_thread_release_buffer(avctx, &s->previous_picture);
    av_frame_free(&s->previous_picture.f);
1518 1519 1520 1521
    ff_thread_release_buffer(avctx, &s->last_picture);
    av_frame_free(&s->last_picture.f);
    ff_thread_release_buffer(avctx, &s->picture);
    av_frame_free(&s->picture.f);
1522 1523 1524 1525
    av_freep(&s->buffer);
    s->buffer_size = 0;
    av_freep(&s->last_row);
    s->last_row_size = 0;
1526 1527
    av_freep(&s->tmp_row);
    s->tmp_row_size = 0;
1528 1529 1530 1531

    return 0;
}

1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543
#if CONFIG_APNG_DECODER
AVCodec ff_apng_decoder = {
    .name           = "apng",
    .long_name      = NULL_IF_CONFIG_SMALL("APNG (Animated Portable Network Graphics) image"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_APNG,
    .priv_data_size = sizeof(PNGDecContext),
    .init           = png_dec_init,
    .close          = png_dec_end,
    .decode         = decode_frame_apng,
    .init_thread_copy = ONLY_IF_THREADS_ENABLED(png_dec_init),
    .update_thread_context = ONLY_IF_THREADS_ENABLED(update_thread_context),
1544
    .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS /*| AV_CODEC_CAP_DRAW_HORIZ_BAND*/,
1545
    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
1546 1547 1548 1549
};
#endif

#if CONFIG_PNG_DECODER
1550
AVCodec ff_png_decoder = {
1551
    .name           = "png",
1552
    .long_name      = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
1553
    .type           = AVMEDIA_TYPE_VIDEO,
1554
    .id             = AV_CODEC_ID_PNG,
1555 1556 1557
    .priv_data_size = sizeof(PNGDecContext),
    .init           = png_dec_init,
    .close          = png_dec_end,
1558
    .decode         = decode_frame_png,
1559 1560
    .init_thread_copy = ONLY_IF_THREADS_ENABLED(png_dec_init),
    .update_thread_context = ONLY_IF_THREADS_ENABLED(update_thread_context),
1561
    .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS /*| AV_CODEC_CAP_DRAW_HORIZ_BAND*/,
1562
    .caps_internal  = FF_CODEC_CAP_SKIP_FRAME_FILL_PARAM | FF_CODEC_CAP_INIT_THREADSAFE,
1563
};
1564
#endif