XBM decoder

Signed-off-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

Changelog

@@ -15,7 +15,7 @@ version next:
 - libutvideo encoder wrapper (--enable-libutvideo)
 - swapuv filter
 - bbox filter
-- XBM encoder
+- XBM encoder and decoder
 - RealAudio Lossless decoder
 - ZeroCodec decoder
 - tile video filter

doc/general.texi

@@ -403,7 +403,7 @@ following image formats are supported:
     @tab YUV, JPEG and some extension is not supported yet.
 @item Truevision Targa  @tab X @tab X
     @tab Targa (.TGA) image format
-@item XBM  @tab X @tab
+@item XBM  @tab X @tab X
     @tab X BitMap image format
 @item XWD  @tab X @tab X
     @tab X Window Dump image format

libavcodec/Makefile

@@ -486,6 +486,7 @@ OBJS-$(CONFIG_XAN_DPCM_DECODER)        += dpcm.o
 OBJS-$(CONFIG_XAN_WC3_DECODER)         += xan.o
 OBJS-$(CONFIG_XAN_WC4_DECODER)         += xxan.o
 OBJS-$(CONFIG_XBIN_DECODER)            += bintext.o cga_data.o
+OBJS-$(CONFIG_XBM_DECODER)             += xbmdec.o
 OBJS-$(CONFIG_XBM_ENCODER)             += xbmenc.o
 OBJS-$(CONFIG_XL_DECODER)              += xl.o
 OBJS-$(CONFIG_XSUB_DECODER)            += xsubdec.o

libavcodec/allcodecs.c

@@ -249,7 +249,7 @@ void avcodec_register_all(void)
     REGISTER_DECODER (WNV1, wnv1);
     REGISTER_DECODER (XAN_WC3, xan_wc3);
     REGISTER_DECODER (XAN_WC4, xan_wc4);
-    REGISTER_ENCODER (XBM, xbm);
+    REGISTER_ENCDEC  (XBM, xbm);
     REGISTER_DECODER (XL, xl);
     REGISTER_ENCDEC  (XWD, xwd);
     REGISTER_ENCDEC  (Y41P, y41p);

libavcodec/xbmdec.c

@@ -0,0 +1,130 @@
+/*
+ * XBM image format
+ *
+ * Copyright (c) 2012 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
+ */
+
+#include "avcodec.h"
+#include "internal.h"
+
+static av_cold int xbm_decode_init(AVCodecContext *avctx)
+{
+    avctx->coded_frame = avcodec_alloc_frame();
+    if (!avctx->coded_frame)
+        return AVERROR(ENOMEM);
+
+    return 0;
+}
+
+static int convert(uint8_t x)
+{
+    if (x >= 'a')
+        x -= 87;
+    else if (x >= 'A')
+        x -= 55;
+    else
+        x -= '0';
+    return x;
+}
+
+static int xbm_decode_frame(AVCodecContext *avctx, void *data,
+                            int *data_size, AVPacket *avpkt)
+{
+    AVFrame *p = avctx->coded_frame;
+    const uint8_t *end, *ptr = avpkt->data;
+    uint8_t *dst;
+    int ret, linesize, i, j;
+
+    end = avpkt->data + avpkt->size;
+    while (!avctx->width || !avctx->height) {
+        char name[256];
+        int number, len;
+
+        ptr += strcspn(ptr, "#");
+        if (sscanf(ptr, "#define %256s %u", name, &number) != 2)
+            return AVERROR_INVALIDDATA;
+
+        len = strlen(name);
+        if ((len > 6) && !avctx->height && !memcmp(name + len - 7, "_height", 7)) {
+                avctx->height = number;
+        } else if ((len > 5) && !avctx->width && !memcmp(name + len - 6, "_width", 6)) {
+                avctx->width = number;
+        } else {
+            return AVERROR_INVALIDDATA;
+        }
+        ptr += strcspn(ptr, "\n\r") + 1;
+    }
+
+    avctx->pix_fmt = PIX_FMT_MONOWHITE;
+
+    if (p->data[0])
+        avctx->release_buffer(avctx, p);
+
+    p->reference = 0;
+    if ((ret = avctx->get_buffer(avctx, p)) < 0)
+        return ret;
+
+    linesize = (avctx->width + 7) / 8;
+    for (i = 0; i < avctx->height; i++) {
+        dst = p->data[0] + i * p->linesize[0];
+        for (j = 0; j < linesize; j++) {
+            uint8_t val;
+
+            ptr += strcspn(ptr, "x") + 1;
+            if (ptr < end && isxdigit(*ptr)) {
+                val = convert(*ptr);
+                ptr++;
+                if (isxdigit(*ptr))
+                    val = (val << 4) + convert(*ptr);
+                *dst++ = av_reverse[val];
+            } else {
+                return AVERROR_INVALIDDATA;
+            }
+        }
+    }
+
+    p->key_frame = 1;
+    p->pict_type = AV_PICTURE_TYPE_I;
+
+    *data_size       = sizeof(AVFrame);
+    *(AVFrame *)data = *p;
+
+    return avpkt->size;
+}
+
+static av_cold int xbm_decode_close(AVCodecContext *avctx)
+{
+    if (avctx->coded_frame->data[0])
+        avctx->release_buffer(avctx, avctx->coded_frame);
+
+    av_freep(&avctx->coded_frame);
+
+    return 0;
+}
+
+AVCodec ff_xbm_decoder = {
+    .name         = "xbm",
+    .type         = AVMEDIA_TYPE_VIDEO,
+    .id           = CODEC_ID_XBM,
+    .init         = xbm_decode_init,
+    .close        = xbm_decode_close,
+    .decode       = xbm_decode_frame,
+    .capabilities = CODEC_CAP_DR1,
+    .long_name    = NULL_IF_CONFIG_SMALL("XBM (X BitMap) image"),
+};