avcodec: add XWD parser

libavcodec/Makefile

@@ -1170,6 +1170,7 @@ OBJS-$(CONFIG_VP9_PARSER)              += vp9_parser.o
 OBJS-$(CONFIG_WEBP_PARSER)             += webp_parser.o
 OBJS-$(CONFIG_XBM_PARSER)              += xbm_parser.o
 OBJS-$(CONFIG_XMA_PARSER)              += xma_parser.o
+OBJS-$(CONFIG_XWD_PARSER)              += xwd_parser.o
 
 # bitstream filters
 OBJS-$(CONFIG_AAC_ADTSTOASC_BSF)          += aac_adtstoasc_bsf.o

libavcodec/parsers.c

@@ -76,6 +76,7 @@ extern const AVCodecParser ff_vp9_parser;
 extern const AVCodecParser ff_webp_parser;
 extern const AVCodecParser ff_xbm_parser;
 extern const AVCodecParser ff_xma_parser;
+extern const AVCodecParser ff_xwd_parser;
 
 #include "libavcodec/parser_list.c"
 

libavcodec/xwd_parser.c

@@ -0,0 +1,103 @@
+/*
+ * XWD parser
+ * Copyright (c) 2022 Paul B Mahol
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * XWD parser
+ **/
+
+#include "libavutil/intreadwrite.h"
+#include "parser.h"
+#include "xwd.h"
+
+typedef struct XWDParseContext {
+    ParseContext  pc;
+    int           left;
+    int           idx;
+    uint8_t       hdr[XWD_HEADER_SIZE];
+} XWDParseContext;
+
+static int xwd_parse(AVCodecParserContext *s, AVCodecContext *avctx,
+                     const uint8_t **poutbuf, int *poutbuf_size,
+                     const uint8_t *buf, int buf_size)
+{
+    XWDParseContext *t = s->priv_data;
+    ParseContext *pc   = &t->pc;
+    int next           = END_NOT_FOUND;
+
+    s->pict_type = AV_PICTURE_TYPE_NONE;
+
+    *poutbuf      = NULL;
+    *poutbuf_size = 0;
+
+    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
+        next = buf_size;
+    } else {
+        for (int i = 0; i < buf_size; i++) {
+            if (t->left > 0) {
+                t->left--;
+                if (t->left == 0) {
+                    next = i;
+                    break;
+                }
+                continue;
+            }
+
+            if (t->idx >= 100) {
+                t->idx = 99;
+                memmove(&t->hdr[0], &t->hdr[1], XWD_HEADER_SIZE-1);
+            }
+
+            t->hdr[t->idx++] = buf[i];
+
+            if (t->idx >= 100 && AV_RB32(t->hdr + 4) == XWD_VERSION) {
+                uint32_t header_size  = AV_RB32(t->hdr + 0);
+                uint32_t height       = AV_RB32(t->hdr + 20);
+                uint32_t lsize        = AV_RB32(t->hdr + 48);
+                uint32_t ncolors      = AV_RB32(t->hdr + 76);
+                uint32_t size         = header_size + ncolors * XWD_CMAP_SIZE + height * lsize;
+                pc->frame_start_found = 1;
+                t->left               = size - XWD_HEADER_SIZE + 1;
+                t->idx                = 0;
+                memset(t->hdr, 0, sizeof(t->hdr));
+            }
+        }
+
+        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0)
+            return buf_size;
+    }
+
+    *poutbuf      = buf;
+    *poutbuf_size = buf_size;
+
+    s->pict_type = AV_PICTURE_TYPE_I;
+    s->key_frame = 1;
+    s->duration  = 1;
+
+    return next;
+}
+
+const AVCodecParser ff_xwd_parser = {
+    .codec_ids      = { AV_CODEC_ID_XWD },
+    .priv_data_size = sizeof(XWDParseContext),
+    .parser_parse   = xwd_parse,
+    .parser_close   = ff_parse_close,
+};