From a4f9bb228bb34f0cfa4b55b207c19604b1e36818 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Thu, 13 Aug 2015 17:01:11 +0200
Subject: [PATCH] avcodec/faxcompr: Support uncompressed escapes in
 decode_group3_1d_line()

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/faxcompr.c | 73 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 71 insertions(+), 2 deletions(-)

diff --git a/libavcodec/faxcompr.c b/libavcodec/faxcompr.c
index 8c17c6e106..01f3e2a949 100644
--- a/libavcodec/faxcompr.c
+++ b/libavcodec/faxcompr.c
@@ -149,8 +149,77 @@ static int decode_group3_1d_line(AVCodecContext *avctx, GetBitContext *gb,
             run       = 0;
             mode      = !mode;
         } else if ((int)t == -1) {
-            av_log(avctx, AV_LOG_ERROR, "Incorrect code\n");
-            return AVERROR_INVALIDDATA;
+            if (show_bits(gb, 12) == 15) {
+                int eob = 0;
+                int newmode;
+                int saved_run = 0;
+                skip_bits(gb, 12);
+
+                do {
+                    int cwi, k;
+                    int cw = 0;
+                    int codes[2];
+                    do {
+                        cwi = show_bits(gb, 11);
+                        if (!cwi) {
+                            av_log(avctx, AV_LOG_ERROR, "Invalid uncompressed codeword\n");
+                            return AVERROR_INVALIDDATA;
+                        }
+                        cwi = 10 - av_log2(cwi);
+                        skip_bits(gb, cwi + 1);
+                        if (cwi > 5) {
+                            newmode = get_bits1(gb);
+                            eob = 1;
+                            cwi -= 6;
+                        }
+                        cw += cwi;
+                    } while(cwi == 5);
+
+                    codes[0] = cw;
+                    codes[1] = !eob;
+
+                    for (k = 0; k < 2; k++) {
+                        if (codes[k]) {
+                            if (mode == k) {
+                                *runs++ = saved_run;
+                                if (runs >= runend) {
+                                    av_log(avctx, AV_LOG_ERROR, "uncompressed run overrun\n");
+                                    return AVERROR_INVALIDDATA;
+                                }
+                                if (pix_left <= saved_run) {
+                                    av_log(avctx, AV_LOG_ERROR, "uncompressed run went out of bounds\n");
+                                    return AVERROR_INVALIDDATA;
+                                }
+                                pix_left -= saved_run;
+                                saved_run = 0;
+                                mode = !mode;
+                            }
+                            saved_run += codes[k];
+                        }
+                    }
+                } while (!eob);
+                *runs++ = saved_run;
+                if (runs >= runend) {
+                    av_log(avctx, AV_LOG_ERROR, "uncompressed run overrun\n");
+                    return AVERROR_INVALIDDATA;
+                }
+                if (pix_left <= saved_run) {
+                    if (pix_left == saved_run)
+                        break;
+                    av_log(avctx, AV_LOG_ERROR, "uncompressed run went out of boundsE\n");
+                    return AVERROR_INVALIDDATA;
+                }
+                pix_left -= saved_run;
+                saved_run = 0;
+                mode = !mode;
+                if (newmode != mode) { //FIXME CHECK
+                    *runs++ = 0;
+                    mode = newmode;
+                }
+            } else {
+                av_log(avctx, AV_LOG_ERROR, "Incorrect code\n");
+                return AVERROR_INVALIDDATA;
+            }
         }
     }
     *runs++ = 0;