libavcodec/pgxdec: Add PGX decoder

This patch adds a pgx decoder.

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

1 files changed, 168 insertions, 0 deletions

diff --git a/libavcodec/pgxdec.c b/libavcodec/pgxdec.c
new file mode 100644
index 0000000000..93b9f4e7a0
--- /dev/null
+++ b/libavcodec/pgxdec.c
@@ -0,0 +1,168 @@
+/*
+ * PGX image format
+ * Copyright (c) 2020 Gautam Ramakrishnan
+ *
+ * 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"
+#include "bytestream.h"
+#include "libavutil/imgutils.h"
+
+static int pgx_get_number(AVCodecContext *avctx, GetByteContext *g, int *number) {
+    int ret = AVERROR_INVALIDDATA;
+    char digit;
+
+    *number = 0;
+    while (1) {
+        uint64_t temp;
+        if (!bytestream2_get_bytes_left(g))
+            return AVERROR_INVALIDDATA;
+        digit = bytestream2_get_byte(g);
+        if (digit == ' ' || digit == 0xA || digit == 0xD)
+            break;
+        else if (digit < '0' || digit > '9')
+            return AVERROR_INVALIDDATA;
+
+        temp = (uint64_t)10 * (*number) + (digit - '0');
+        if (temp > INT_MAX)
+            return AVERROR_INVALIDDATA;
+        *number = temp;
+        ret = 0;
+    }
+
+    return ret;
+}
+
+static int pgx_decode_header(AVCodecContext *avctx, GetByteContext *g,
+                             int *depth, int *width, int *height,
+                             int *sign)
+{
+    int byte;
+
+    if (bytestream2_get_bytes_left(g) < 6) {
+        return AVERROR_INVALIDDATA;
+    }
+
+    bytestream2_skip(g, 6);
+
+    // Is the component signed?
+    byte = bytestream2_peek_byte(g);
+    if (byte == '+') {
+        *sign = 0;
+        bytestream2_skip(g, 1);
+    } else if (byte == '-') {
+        *sign = 1;
+        bytestream2_skip(g, 1);
+    } else if (byte == 0)
+        goto error;
+
+    byte = bytestream2_peek_byte(g);
+    if (byte == ' ')
+        bytestream2_skip(g, 1);
+    else if (byte == 0)
+        goto error;
+
+    if (pgx_get_number(avctx, g, depth))
+        goto error;
+    if (pgx_get_number(avctx, g, width))
+        goto error;
+    if (pgx_get_number(avctx, g, height))
+        goto error;
+
+    if (bytestream2_peek_byte(g) == 0xA)
+        bytestream2_skip(g, 1);
+    return 0;
+
+error:
+    av_log(avctx, AV_LOG_ERROR, "Error in decoding header.\n");
+    return AVERROR_INVALIDDATA;
+}
+
+#define WRITE_FRAME(D, PIXEL, suffix)                                                       \
+    static inline void write_frame_ ##D(AVPacket *avpkt, AVFrame *frame, GetByteContext *g, \
+                                        int width, int height, int sign, int depth)         \
+    {                                                                                       \
+        int i, j;                                                                           \
+        for (i = 0; i < height; i++) {                                                      \
+            PIXEL *line = (PIXEL*)frame->data[0] + i*frame->linesize[0]/sizeof(PIXEL);      \
+            for (j = 0; j < width; j++) {                                                   \
+                int val;                                                                    \
+                if (sign)                                                                   \
+                    val = (PIXEL)bytestream2_get_ ##suffix(g) + (1 << (depth - 1));         \
+                else                                                                        \
+                    val = bytestream2_get_ ##suffix(g);                                     \
+                val <<= (D - depth);                                                        \
+                *(line + j) = val;                                                          \
+            }                                                                               \
+        }                                                                                   \
+    }                                                                                       \
+
+WRITE_FRAME(8, int8_t, byte)
+WRITE_FRAME(16, int16_t, be16)
+
+static int pgx_decode_frame(AVCodecContext *avctx, void *data,
+                            int *got_frame, AVPacket *avpkt)
+{
+    AVFrame *p = data;
+    int ret;
+    int bpp;
+    int width, height, depth;
+    int sign = 0;
+    GetByteContext g;
+    bytestream2_init(&g, avpkt->data, avpkt->size);
+
+    if ((ret = pgx_decode_header(avctx, &g, &depth, &width, &height, &sign)) < 0)
+        return ret;
+
+    if ((ret = ff_set_dimensions(avctx, width, height)) < 0)
+        return ret;
+
+    if (depth <= 8) {
+        avctx->pix_fmt = AV_PIX_FMT_GRAY8;
+        bpp = 8;
+    } else if (depth <= 16) {
+        avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
+        bpp = 16;
+    } else {
+        av_log(avctx, AV_LOG_ERROR, "Maximum depth of 16 bits supported.\n");
+        return AVERROR_PATCHWELCOME;
+    }
+    if (bytestream2_get_bytes_left(&g) < width * height * (bpp >> 3))
+        return AVERROR_INVALIDDATA;
+    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
+        return ret;
+    p->pict_type = AV_PICTURE_TYPE_I;
+    p->key_frame = 1;
+    avctx->bits_per_raw_sample = depth;
+    if (bpp == 8)
+        write_frame_8(avpkt, p, &g, width, height, sign, depth);
+    else if (bpp == 16)
+        write_frame_16(avpkt, p, &g, width, height, sign, depth);
+    *got_frame = 1;
+    return 0;
+}
+
+AVCodec ff_pgx_decoder = {
+    .name           = "pgx",
+    .long_name      = NULL_IF_CONFIG_SMALL("PGX (JPEG2000 Test Format)"),
+    .type           = AVMEDIA_TYPE_VIDEO,
+    .id             = AV_CODEC_ID_PGX,
+    .decode         = pgx_decode_frame,
+    .capabilities   = AV_CODEC_CAP_DR1,
+};