/*
  * PNG image format

  * Copyright (c) 2003 Fabrice Bellard

  *
  * 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
  */

 
 //#define DEBUG
 

 #include "libavutil/imgutils.h"

 #include "avcodec.h"
 #include "bytestream.h"
 #include "png.h"
 
 /* TODO:
  * - add 2, 4 and 16 bit depth support
  */
 
 #include <zlib.h>
 
 /* Mask to determine which y pixels can be written in a pass */
 static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
     0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55,
 };
 
 /* 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

    is the original image width. We also do pixel format conversion at

    this stage */
 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;
 
     mask = ff_png_pass_mask[pass];
     dsp_mask = png_pass_dsp_mask[pass];
     switch(bits_per_pixel) {
     case 1:
         /* we must initialize the line to zero before writing to it */
         if (pass == 0)
             memset(dst, 0, (width + 7) >> 3);
         src_x = 0;
         for(x = 0; x < width; x++) {
             j = (x & 7);
             if ((dsp_mask << j) & 0x80) {
                 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
                 dst[x >> 3] |= b << (7 - j);
             }
             if ((mask << j) & 0x80)
                 src_x++;
         }
         break;
     default:
         bpp = bits_per_pixel >> 3;
         d = dst;
         s = src;
         if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
             for(x = 0; x < width; x++) {
                 j = x & 7;
                 if ((dsp_mask << j) & 0x80) {
                     *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2];
                 }
                 d += bpp;
                 if ((mask << j) & 0x80)
                     s += bpp;
             }
         } else {
             for(x = 0; x < width; x++) {
                 j = x & 7;
                 if ((dsp_mask << j) & 0x80) {
                     memcpy(d, s, bpp);
                 }
                 d += bpp;
                 if ((mask << j) & 0x80)
                     s += bpp;
             }
         }
         break;
     }
 }
 

 // 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
 #define pb_7f (~0UL/255 * 0x7f)
 #define pb_80 (~0UL/255 * 0x80)
 
 static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
 {
     long i;
     for(i=0; i<=w-sizeof(long); i+=sizeof(long)){
         long a = *(long*)(src1+i);
         long b = *(long*)(src2+i);
         *(long*)(dst+i) = ((a&pb_7f) + (b&pb_7f)) ^ ((a^b)&pb_80);
     }
     for(; i<w; i++)
         dst[i] = src1[i]+src2[i];
 }
 
 static void add_paeth_prediction_c(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)

 {
     int i;
     for(i = 0; i < w; i++) {
         int a, b, c, p, pa, pb, pc;
 
         a = dst[i - bpp];
         b = top[i];
         c = top[i - bpp];
 
         p = b - c;
         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];
     }
 }
 
 #define UNROLL1(bpp, op) {\
                  r = dst[0];\
     if(bpp >= 2) g = dst[1];\
     if(bpp >= 3) b = dst[2];\
     if(bpp >= 4) a = dst[3];\
     for(; i < size; i+=bpp) {\
         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]);\
     }\
 }
 
 #define UNROLL_FILTER(op)\
          if(bpp == 1) UNROLL1(1, op)\
     else if(bpp == 2) UNROLL1(2, op)\
     else if(bpp == 3) UNROLL1(3, op)\
     else if(bpp == 4) UNROLL1(4, op)\

     else {\
         for (; i < size; i += bpp) {\
             int j;\
             for (j = 0; j < bpp; j++)\
                 dst[i+j] = op(dst[i+j-bpp], src[i+j], last[i+j]);\
         }\
     }

 /* NOTE: 'dst' can be equal to 'last' */

 static void png_filter_row(PNGDecContext *s, uint8_t *dst, int filter_type,

                            uint8_t *src, uint8_t *last, int size, int bpp)
 {

     int i, p, r, g, b, a;

 
     switch(filter_type) {
     case PNG_FILTER_VALUE_NONE:
         memcpy(dst, src, size);
         break;
     case PNG_FILTER_VALUE_SUB:
         for(i = 0; i < bpp; i++) {
             dst[i] = src[i];
         }

         if(bpp == 4) {
             p = *(int*)dst;
             for(; i < size; i+=bpp) {
                 int s = *(int*)(src+i);
                 p = ((s&0x7f7f7f7f) + (p&0x7f7f7f7f)) ^ ((s^p)&0x80808080);
                 *(int*)(dst+i) = p;
             }
         } else {
 #define OP_SUB(x,s,l) x+s
             UNROLL_FILTER(OP_SUB);

         }
         break;
     case PNG_FILTER_VALUE_UP:

         s->add_bytes_l2(dst, src, last, size);

         break;
     case PNG_FILTER_VALUE_AVG:
         for(i = 0; i < bpp; i++) {
             p = (last[i] >> 1);
             dst[i] = p + src[i];
         }

 #define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff
         UNROLL_FILTER(OP_AVG);

         break;
     case PNG_FILTER_VALUE_PAETH:
         for(i = 0; i < bpp; i++) {
             p = last[i];
             dst[i] = p + src[i];
         }

         if(bpp > 1 && size > 4) {
             // would write off the end of the array if we let it process the last pixel with bpp=3
             int w = bpp==4 ? size : size-3;

             s->add_paeth_prediction(dst+i, src+i, last+i, w-i, bpp);

             i = w;

         }

         add_paeth_prediction_c(dst+i, src+i, last+i, size-i, bpp);

         break;
     }
 }
 

 static av_always_inline void convert_to_rgb32_loco(uint8_t *dst, const uint8_t *src, int width, int loco)

 {
     int j;
     unsigned int r, g, b, a;
 
     for(j = 0;j < width; j++) {
         r = src[0];
         g = src[1];
         b = src[2];
         a = src[3];

         if(loco) {
             r = (r+g)&0xff;
             b = (b+g)&0xff;
         }

         *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b;
         dst += 4;
         src += 4;
     }
 }
 

 static void convert_to_rgb32(uint8_t *dst, const uint8_t *src, int width, int loco)
 {
     if(loco)
         convert_to_rgb32_loco(dst, src, width, 1);
     else
         convert_to_rgb32_loco(dst, src, width, 0);
 }
 
 static void deloco_rgb24(uint8_t *dst, int size)
 {
     int i;
     for(i=0; i<size; i+=3) {
         int g = dst[i+1];
         dst[i+0] += g;
         dst[i+2] += g;
     }
 }
 

 /* process exactly one decompressed row */

 static void png_handle_row(PNGDecContext *s)

 {
     uint8_t *ptr, *last_row;
     int got_line;
 
     if (!s->interlace_type) {
         ptr = s->image_buf + s->image_linesize * s->y;
         /* need to swap bytes correctly for RGB_ALPHA */
         if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {

             png_filter_row(s, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,

                            s->last_row, s->row_size, s->bpp);

             convert_to_rgb32(ptr, s->tmp_row, s->width, s->filter_type == PNG_FILTER_TYPE_LOCO);

             FFSWAP(uint8_t*, s->last_row, s->tmp_row);

         } else {
             /* in normal case, we avoid one copy */
             if (s->y == 0)
                 last_row = s->last_row;
             else
                 last_row = ptr - s->image_linesize;
 

             png_filter_row(s, ptr, s->crow_buf[0], s->crow_buf + 1,

                            last_row, s->row_size, s->bpp);
         }

         /* loco lags by 1 row so that it doesn't interfere with top prediction */
         if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
             s->color_type == PNG_COLOR_TYPE_RGB && s->y > 0)
             deloco_rgb24(ptr - s->image_linesize, s->row_size);

         s->y++;
         if (s->y == s->height) {
             s->state |= PNG_ALLIMAGE;

             if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
                 s->color_type == PNG_COLOR_TYPE_RGB)
                 deloco_rgb24(ptr, s->row_size);

         }
     } else {
         got_line = 0;
         for(;;) {
             ptr = s->image_buf + s->image_linesize * s->y;
             if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
                 /* if we already read one row, it is time to stop to
                    wait for the next one */
                 if (got_line)
                     break;

                 png_filter_row(s, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,

                                s->last_row, s->pass_row_size, s->bpp);

                 FFSWAP(uint8_t*, s->last_row, s->tmp_row);

                 got_line = 1;
             }
             if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
                 /* NOTE: RGB32 is handled directly in png_put_interlaced_row */
                 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
                                        s->color_type, s->last_row);
             }
             s->y++;
             if (s->y == s->height) {
                 for(;;) {
                     if (s->pass == NB_PASSES - 1) {
                         s->state |= PNG_ALLIMAGE;
                         goto the_end;
                     } else {
                         s->pass++;
                         s->y = 0;
                         s->pass_row_size = ff_png_pass_row_size(s->pass,
                                                              s->bits_per_pixel,
                                                              s->width);
                         s->crow_size = s->pass_row_size + 1;
                         if (s->pass_row_size != 0)
                             break;
                         /* skip pass if empty row */
                     }
                 }
             }
         }
     the_end: ;
     }
 }
 

 static int png_decode_idat(PNGDecContext *s, int length)

 {
     int ret;
     s->zstream.avail_in = length;
     s->zstream.next_in = s->bytestream;
     s->bytestream += length;
 
     if(s->bytestream > s->bytestream_end)
         return -1;
 
     /* 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) {
             return -1;
         }
         if (s->zstream.avail_out == 0) {
             if (!(s->state & PNG_ALLIMAGE)) {
                 png_handle_row(s);
             }
             s->zstream.avail_out = s->crow_size;
             s->zstream.next_out = s->crow_buf;
         }
     }
     return 0;
 }
 
 static int decode_frame(AVCodecContext *avctx,
                         void *data, int *data_size,

                         AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     PNGDecContext * const s = avctx->priv_data;

     AVFrame *picture = data;

     AVFrame *p;

     uint8_t *crow_buf_base = NULL;

     uint32_t tag, length;

     int ret;

     FFSWAP(AVFrame *, s->current_picture, s->last_picture);
     avctx->coded_frame= s->current_picture;
     p = s->current_picture;
 

     s->bytestream_start=
     s->bytestream= buf;
     s->bytestream_end= buf + buf_size;
 
     /* check signature */

     if (memcmp(s->bytestream, ff_pngsig, 8) != 0 &&
         memcmp(s->bytestream, ff_mngsig, 8) != 0)

         return -1;
     s->bytestream+= 8;
     s->y=
     s->state=0;

 //    memset(s, 0, sizeof(PNGDecContext));

     /* 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)
         return -1;
     for(;;) {
         int tag32;
         if (s->bytestream >= s->bytestream_end)
             goto fail;
         length = bytestream_get_be32(&s->bytestream);
         if (length > 0x7fffffff)
             goto fail;
         tag32 = bytestream_get_be32(&s->bytestream);

         tag = av_bswap32(tag32);

         av_dlog(avctx, "png: tag=%c%c%c%c length=%u\n",

                 (tag & 0xff),
                 ((tag >> 8) & 0xff),
                 ((tag >> 16) & 0xff),
                 ((tag >> 24) & 0xff), length);

         switch(tag) {
         case MKTAG('I', 'H', 'D', 'R'):
             if (length != 13)
                 goto fail;
             s->width = bytestream_get_be32(&s->bytestream);
             s->height = bytestream_get_be32(&s->bytestream);

             if(av_image_check_size(s->width, s->height, 0, avctx)){

                 s->width= s->height= 0;
                 goto fail;
             }
             s->bit_depth = *s->bytestream++;
             s->color_type = *s->bytestream++;
             s->compression_type = *s->bytestream++;
             s->filter_type = *s->bytestream++;
             s->interlace_type = *s->bytestream++;

             s->bytestream += 4; /* crc */

             s->state |= PNG_IHDR;

             av_dlog(avctx, "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);

             break;
         case MKTAG('I', 'D', 'A', 'T'):
             if (!(s->state & PNG_IHDR))
                 goto fail;
             if (!(s->state & PNG_IDAT)) {
                 /* init image info */
                 avctx->width = s->width;
                 avctx->height = s->height;
 
                 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;
                 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
 
                 if (s->bit_depth == 8 &&
                     s->color_type == PNG_COLOR_TYPE_RGB) {
                     avctx->pix_fmt = PIX_FMT_RGB24;
                 } else if (s->bit_depth == 8 &&
                            s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
                     avctx->pix_fmt = PIX_FMT_RGB32;
                 } else if (s->bit_depth == 8 &&
                            s->color_type == PNG_COLOR_TYPE_GRAY) {
                     avctx->pix_fmt = PIX_FMT_GRAY8;
                 } else if (s->bit_depth == 16 &&
                            s->color_type == PNG_COLOR_TYPE_GRAY) {
                     avctx->pix_fmt = PIX_FMT_GRAY16BE;

                 } else if (s->bit_depth == 16 &&
                            s->color_type == PNG_COLOR_TYPE_RGB) {
                     avctx->pix_fmt = PIX_FMT_RGB48BE;

                 } else if (s->bit_depth == 1) {

                     avctx->pix_fmt = PIX_FMT_MONOBLACK;
                 } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
                     avctx->pix_fmt = PIX_FMT_PAL8;

                 } else if (s->bit_depth == 8 &&
                            s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {

                     avctx->pix_fmt = PIX_FMT_GRAY8A;

                 } else {
                     goto fail;
                 }
                 if(p->data[0])
                     avctx->release_buffer(avctx, p);
 
                 p->reference= 0;
                 if(avctx->get_buffer(avctx, p) < 0){
                     av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
                     goto fail;
                 }

                 p->pict_type= AV_PICTURE_TYPE_I;

                 p->key_frame= 1;
                 p->interlaced_frame = !!s->interlace_type;
 
                 /* 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,
                                                          s->width);
                     s->crow_size = s->pass_row_size + 1;
                 }

                 av_dlog(avctx, "row_size=%d crow_size =%d\n",

                         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 == PIX_FMT_PAL8)

                     memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
                 /* empty row is used if differencing to the first row */
                 s->last_row = av_mallocz(s->row_size);
                 if (!s->last_row)
                     goto fail;
                 if (s->interlace_type ||
                     s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
                     s->tmp_row = av_malloc(s->row_size);
                     if (!s->tmp_row)
                         goto fail;
                 }
                 /* compressed row */

                 crow_buf_base = av_malloc(s->row_size + 16);
                 if (!crow_buf_base)

                     goto fail;

 
                 /* we want crow_buf+1 to be 16-byte aligned */
                 s->crow_buf = crow_buf_base + 15;

                 s->zstream.avail_out = s->crow_size;
                 s->zstream.next_out = s->crow_buf;
             }
             s->state |= PNG_IDAT;
             if (png_decode_idat(s, length) < 0)
                 goto fail;

             s->bytestream += 4; /* crc */

             break;
         case MKTAG('P', 'L', 'T', 'E'):
             {
                 int n, i, r, g, b;
 
                 if ((length % 3) != 0 || length > 256 * 3)
                     goto skip_tag;
                 /* read the palette */
                 n = length / 3;
                 for(i=0;i<n;i++) {
                     r = *s->bytestream++;
                     g = *s->bytestream++;
                     b = *s->bytestream++;
                     s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
                 }
                 for(;i<256;i++) {
                     s->palette[i] = (0xff << 24);
                 }
                 s->state |= PNG_PLTE;

                 s->bytestream += 4; /* crc */

             }
             break;
         case MKTAG('t', 'R', 'N', 'S'):
             {
                 int v, i;
 
                 /* read the transparency. XXX: Only palette mode supported */
                 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
                     length > 256 ||
                     !(s->state & PNG_PLTE))
                     goto skip_tag;
                 for(i=0;i<length;i++) {
                     v = *s->bytestream++;
                     s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
                 }

                 s->bytestream += 4; /* crc */

             }
             break;
         case MKTAG('I', 'E', 'N', 'D'):
             if (!(s->state & PNG_ALLIMAGE))
                 goto fail;

             s->bytestream += 4; /* crc */

             goto exit_loop;
         default:
             /* skip tag */
         skip_tag:
             s->bytestream += length + 4;
             break;
         }
     }
  exit_loop:

      /* handle p-frames only if a predecessor frame is available */
      if(s->last_picture->data[0] != NULL) {

          if(!(avpkt->flags & AV_PKT_FLAG_KEY)) {

             int i, j;
             uint8_t *pd = s->current_picture->data[0];
             uint8_t *pd_last = s->last_picture->data[0];
 
             for(j=0; j < s->height; j++) {
                 for(i=0; i < s->width * s->bpp; i++) {
                     pd[i] += pd_last[i];
                 }
                 pd += s->image_linesize;
                 pd_last += s->image_linesize;
             }
         }
     }
 
     *picture= *s->current_picture;

     *data_size = sizeof(AVFrame);

 
     ret = s->bytestream - s->bytestream_start;
  the_end:
     inflateEnd(&s->zstream);

     av_free(crow_buf_base);
     s->crow_buf = NULL;

     av_freep(&s->last_row);
     av_freep(&s->tmp_row);
     return ret;
  fail:
     ret = -1;
     goto the_end;
 }
 

 static av_cold int png_dec_init(AVCodecContext *avctx)
 {

     PNGDecContext *s = avctx->priv_data;
 

     s->current_picture = &s->picture1;
     s->last_picture = &s->picture2;
     avcodec_get_frame_defaults(&s->picture1);
     avcodec_get_frame_defaults(&s->picture2);

 #if HAVE_MMX

     ff_png_init_mmx(s);

 #endif

 
     if (!s->add_paeth_prediction)
         s->add_paeth_prediction = add_paeth_prediction_c;
     if (!s->add_bytes_l2)
         s->add_bytes_l2 = add_bytes_l2_c;

 
     return 0;
 }
 

 static av_cold int png_dec_end(AVCodecContext *avctx)
 {
     PNGDecContext *s = avctx->priv_data;
 
     if (s->picture1.data[0])
         avctx->release_buffer(avctx, &s->picture1);
     if (s->picture2.data[0])
         avctx->release_buffer(avctx, &s->picture2);
 
     return 0;
 }
 

 AVCodec ff_png_decoder = {

     "png",

     AVMEDIA_TYPE_VIDEO,

     CODEC_ID_PNG,

     sizeof(PNGDecContext),
     png_dec_init,

     NULL,

     png_dec_end,

     decode_frame,

     CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/,

     NULL,

     .long_name = NULL_IF_CONFIG_SMALL("PNG image"),

 };