avcodec/faxcompr: Factor decode_uncompressed() out

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

1 files changed, 85 insertions, 127 deletions

diff --git a/libavcodec/faxcompr.c b/libavcodec/faxcompr.c
index 01f3e2a949..afb3503794 100644
--- a/libavcodec/faxcompr.c
+++ b/libavcodec/faxcompr.c
@@ -122,6 +122,77 @@ av_cold void ff_ccitt_unpack_init(void)
     initialized = 1;
 }
 
+static int decode_uncompressed(AVCodecContext *avctx, GetBitContext *gb,
+                               unsigned int *pix_left, int **runs,
+                               const int *runend, int *mode)
+{
+    int eob = 0;
+    int newmode;
+    int saved_run = 0;
+
+    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)
+            return 1;
+        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;
+    }
+    return 0;
+}
 
 static int decode_group3_1d_line(AVCodecContext *avctx, GetBitContext *gb,
                                  unsigned int pix_left, int *runs,
@@ -150,72 +221,13 @@ static int decode_group3_1d_line(AVCodecContext *avctx, GetBitContext *gb,
             mode      = !mode;
         } else if ((int)t == -1) {
             if (show_bits(gb, 12) == 15) {
-                int eob = 0;
-                int newmode;
-                int saved_run = 0;
+                int ret;
                 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;
-                }
+                ret = decode_uncompressed(avctx, gb, &pix_left, &runs, runend, &mode);
+                if (ret < 0) {
+                    return ret;
+                } else if (ret)
+                    break;
             } else {
                 av_log(avctx, AV_LOG_ERROR, "Incorrect code\n");
                 return AVERROR_INVALIDDATA;
@@ -282,73 +294,19 @@ static int decode_group3_2d_line(AVCodecContext *avctx, GetBitContext *gb,
         } else if (cmode == 9 || cmode == 10) {
             int xxx = get_bits(gb, 3);
             if (cmode == 9 && xxx == 7) {
-                int eob = 0;
-                int newmode;
+                int ret;
+                int pix_left = width - offs;
 
                 if (saved_run) {
                     av_log(avctx, AV_LOG_ERROR, "saved run %d on entering uncompressed mode\n", saved_run);
                     return AVERROR_INVALIDDATA;
                 }
-
-                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;
-                                }
-                                offs += saved_run;
-                                if (offs > width || run > width) {
-                                    av_log(avctx, AV_LOG_ERROR, "uncompressed run went out of bounds\n");
-                                    return AVERROR_INVALIDDATA;
-                                }
-                                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;
-                }
-                offs += saved_run;
-                if (offs > width || run > width) {
-                    av_log(avctx, AV_LOG_ERROR, "uncompressed run went out of bounds\n");
-                    return AVERROR_INVALIDDATA;
-                }
-                saved_run = 0;
-                mode = !mode;
-                if (newmode != mode) { //FIXME CHECK
-                    *runs++ = 0;
-                    mode = newmode;
-                }
+                ret = decode_uncompressed(avctx, gb, &pix_left, &runs, runend, &mode);
+                offs = width - pix_left;
+                if (ret < 0) {
+                    return ret;
+                } else if (ret)
+                    break;
             } else {
                 avpriv_report_missing_feature(avctx, "Special mode %d xxx=%d support", cmode, xxx);
                 return AVERROR_PATCHWELCOME;