X-Bitmap decoder

[ffmpeg] / libavcodec / xbmdec.c

diff --git a/libavcodec/xbmdec.c b/libavcodec/xbmdec.c
new file mode 100644 (file)
index 0000000..c26f343
--- /dev/null
+++ b/libavcodec/xbmdec.c
@@ -0,0 +1,122 @@
+/*
+ * XBM image format
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/avstring.h"
+
+#include "avcodec.h"
+#include "internal.h"
+#include "mathops.h"
+
+static int xbm_decode_frame(AVCodecContext *avctx, void *data,
+                            int *got_frame, AVPacket *avpkt)
+{
+    AVFrame *p = data;
+    int ret, linesize, i;
+    int width  = 0;
+    int height = 0;
+    const uint8_t *ptr = avpkt->data;
+    uint8_t *dst;
+
+    avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
+    while (!width || !height) {
+        ptr += strcspn(ptr, "#");
+        if (ptr >= avpkt->data + avpkt->size) {
+            av_log(avctx, AV_LOG_ERROR, "End of file reached.\n");
+            return AVERROR_INVALIDDATA;
+        }
+        if (strncmp(ptr, "#define", 7) != 0) {
+            av_log(avctx, AV_LOG_ERROR,
+                   "Unexpected preprocessor directive.\n");
+            return AVERROR_INVALIDDATA;
+        }
+        // skip the name
+        ptr += strcspn(ptr, "_") + 1;
+        // get width or height
+        if (strncmp(ptr, "width", 5) == 0) {
+            ptr += strcspn(ptr, " ");
+            width = strtol(ptr, NULL, 10);
+        } else if (strncmp(ptr, "height", 6) == 0) {
+            ptr += strcspn(ptr, " ");
+            height = strtol(ptr, NULL, 10);
+        } else {
+            // skip offset and unknown variables
+            av_log(avctx, AV_LOG_VERBOSE,
+                   "Ignoring preprocessor directive.\n");
+        }
+    }
+
+    if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
+        return ret;
+
+    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
+        return ret;
+
+    // go to start of image data
+    ptr += strcspn(ptr, "{");
+
+    linesize = (avctx->width + 7) / 8;
+    for (i = 0; i < avctx->height; i++) {
+        int eol = 0, e = 0;
+        dst = p->data[0] + i * p->linesize[0];
+        if (ptr >= avpkt->data + avpkt->size) {
+            av_log(avctx, AV_LOG_ERROR, "End of file reached.\n");
+            return AVERROR_INVALIDDATA;
+        }
+        do {
+            int val;
+            uint8_t *endptr;
+
+            ptr += strcspn(ptr, "x") - 1; // -1 to get 0x
+            val = strtol(ptr, (char **)&endptr, 16);
+
+            if (endptr - ptr == 4) {
+                // XBM X11 format
+                *dst++ = ff_reverse[val];
+                eol = linesize;
+            } else if (endptr - ptr == 6) {
+                // XBM X10 format
+                *dst++ = ff_reverse[val >> 8];
+                *dst++ = ff_reverse[val & 0xFF];
+                eol = linesize / 2; // 2 bytes read
+            } else {
+                av_log(avctx, AV_LOG_ERROR,
+                       "Unexpected data at %.8s.\n", ptr);
+                return AVERROR_INVALIDDATA;
+            }
+            ptr = endptr;
+        } while (++e < eol);
+    }
+
+    p->key_frame = 1;
+    p->pict_type = AV_PICTURE_TYPE_I;
+
+    *got_frame = 1;
+
+    return avpkt->size;
+}
+
+AVCodec ff_xbm_decoder = {
+    .name         = "xbm",
+    .long_name    = NULL_IF_CONFIG_SMALL("XBM (X BitMap) image"),
+    .type         = AVMEDIA_TYPE_VIDEO,
+    .id           = AV_CODEC_ID_XBM,
+    .decode       = xbm_decode_frame,
+    .capabilities = CODEC_CAP_DR1,
+};