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sgirledec.c
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1 /*
2  * SGI RLE 8-bit decoder
3  * Copyright (c) 2012 Peter Ross
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * SGI RLE 8-bit decoder
25  */
26 
27 #include "avcodec.h"
28 #include "internal.h"
29 
30 typedef struct SGIRLEContext {
33 
35 {
36  SGIRLEContext *s = avctx->priv_data;
37  avctx->pix_fmt = AV_PIX_FMT_BGR8;
38  s->frame = av_frame_alloc();
39  if (!s->frame)
40  return AVERROR(ENOMEM);
41  return 0;
42 }
43 
44 /**
45  * Convert SGI RGB332 pixel into AV_PIX_FMT_BGR8
46  * SGI RGB332 is packed RGB 3:3:2, 8bpp, (msb)3R 2B 3G(lsb)
47  */
48 #define RGB332_TO_BGR8(x) (((x << 3) & 0xC0) | ((x << 3) & 0x38) | ((x >> 5) & 7))
49 
51 {
52  int i;
53  for (i = 0; i < size; i++)
54  dst[i] = RGB332_TO_BGR8(src[i]);
55 }
56 
57 /**
58  * @param[out] dst Destination buffer
59  * @param[in] src Source buffer
60  * @param src_size Source buffer size (bytes)
61  * @param width Width of destination buffer (pixels)
62  * @param height Height of destination buffer (pixels)
63  * @param linesize Line size of destination buffer (bytes)
64  * @return <0 on error
65  */
66 static int decode_sgirle8(AVCodecContext *avctx, uint8_t *dst, const uint8_t *src, int src_size, int width, int height, int linesize)
67 {
68  const uint8_t *src_end = src + src_size;
69  int x = 0, y = 0;
70 
71 #define INC_XY(n) \
72  x += n; \
73  if (x >= width) { \
74  y++; \
75  if (y >= height) \
76  return 0; \
77  x = 0; \
78  }
79 
80  while (src_end - src >= 2) {
81  uint8_t v = *src++;
82  if (v > 0 && v < 0xC0) {
83  do {
84  int length = FFMIN(v, width - x);
85  if (length <= 0)
86  break;
87  memset(dst + y*linesize + x, RGB332_TO_BGR8(*src), length);
88  INC_XY(length);
89  v -= length;
90  } while (v > 0);
91  src++;
92  } else if (v >= 0xC1) {
93  v -= 0xC0;
94  do {
95  int length = FFMIN3(v, width - x, src_end - src);
96  if (src_end - src < length || length <= 0)
97  break;
98  memcpy_rgb332_to_bgr8(dst + y*linesize + x, src, length);
99  INC_XY(length);
100  src += length;
101  v -= length;
102  } while (v > 0);
103  } else {
104  avpriv_request_sample(avctx, "opcode %d", v);
105  return AVERROR_PATCHWELCOME;
106  }
107  }
108  return 0;
109 }
110 
112  void *data, int *got_frame,
113  AVPacket *avpkt)
114 {
115  SGIRLEContext *s = avctx->priv_data;
116  int ret;
117 
118  if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
119  return ret;
120 
121  ret = decode_sgirle8(avctx, s->frame->data[0], avpkt->data, avpkt->size, avctx->width, avctx->height, s->frame->linesize[0]);
122  if (ret < 0)
123  return ret;
124 
125  *got_frame = 1;
126  if ((ret = av_frame_ref(data, s->frame)) < 0)
127  return ret;
128 
129  return avpkt->size;
130 }
131 
133 {
134  SGIRLEContext *s = avctx->priv_data;
135 
136  av_frame_free(&s->frame);
137 
138  return 0;
139 }
140 
142  .name = "sgirle",
143  .long_name = NULL_IF_CONFIG_SMALL("SGI RLE 8-bit"),
144  .type = AVMEDIA_TYPE_VIDEO,
145  .id = AV_CODEC_ID_SGIRLE,
146  .priv_data_size = sizeof(SGIRLEContext),
150  .capabilities = CODEC_CAP_DR1,
151 };