pngdec: decode and expose iCCP chunks as side data

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>

libavcodec/pngdec.c

@@ -836,6 +836,46 @@ static int decode_trns_chunk(AVCodecContext *avctx, PNGDecContext *s,
     return 0;
 }
 
+static int decode_iccp_chunk(PNGDecContext *s, int length, AVFrame *f)
+{
+    int ret, cnt = 0;
+    uint8_t *data, profile_name[82];
+    AVBPrint bp;
+    AVFrameSideData *sd;
+
+    while ((profile_name[cnt++] = bytestream2_get_byte(&s->gb)) && cnt < 81);
+    if (cnt > 80) {
+        av_log(s->avctx, AV_LOG_ERROR, "iCCP with invalid name!\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    length = FFMAX(length - cnt, 0);
+
+    if (bytestream2_get_byte(&s->gb) != 0) {
+        av_log(s->avctx, AV_LOG_ERROR, "iCCP with invalid compression!\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    length = FFMAX(length - 1, 0);
+
+    if ((ret = decode_zbuf(&bp, s->gb.buffer, s->gb.buffer + length) < 0))
+        return ret;
+
+    av_bprint_finalize(&bp, (char **)&data);
+
+    if (!(sd = av_frame_new_side_data(f, AV_FRAME_DATA_ICC_PROFILE, bp.len)))
+        return AVERROR(ENOMEM);
+
+    av_dict_set(&sd->metadata, "name", profile_name, 0);
+    memcpy(sd->data, data, bp.len);
+    av_free(data);
+
+    /* ICC compressed data and CRC */
+    bytestream2_skip(&s->gb, length + 4);
+
+    return 0;
+}
+
 static void handle_small_bpp(PNGDecContext *s, AVFrame *p)
 {
     if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE) {
@@ -1239,6 +1279,11 @@ static int decode_frame_common(AVCodecContext *avctx, PNGDecContext *s,
             bytestream2_skip(&s->gb, 4); /* crc */
             break;
         }
+        case MKTAG('i', 'C', 'C', 'P'): {
+            if (decode_iccp_chunk(s, length, p) < 0)
+                goto fail;
+            break;
+        }
         case MKTAG('I', 'E', 'N', 'D'):
             if (!(s->pic_state & PNG_ALLIMAGE))
                 av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");