/libavcodec/pcx.c

  1/*
  2 * PC Paintbrush PCX (.pcx) image decoder
  3 * Copyright (c) 2007, 2008 Ivo van Poorten
  4 *
  5 * This decoder does not support CGA palettes. I am unable to find samples
  6 * and Netpbm cannot generate them.
  7 *
  8 * This file is part of FFmpeg.
  9 *
 10 * FFmpeg is free software; you can redistribute it and/or
 11 * modify it under the terms of the GNU Lesser General Public
 12 * License as published by the Free Software Foundation; either
 13 * version 2.1 of the License, or (at your option) any later version.
 14 *
 15 * FFmpeg is distributed in the hope that it will be useful,
 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 18 * Lesser General Public License for more details.
 19 *
 20 * You should have received a copy of the GNU Lesser General Public
 21 * License along with FFmpeg; if not, write to the Free Software
 22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 23 */
 24
 25#include "libavutil/imgutils.h"
 26#include "avcodec.h"
 27#include "bytestream.h"
 28#include "get_bits.h"
 29#include "internal.h"
 30
 31#define PCX_HEADER_SIZE 128
 32
 33static int pcx_rle_decode(GetByteContext *gb,
 34                           uint8_t *dst,
 35                           unsigned int bytes_per_scanline,
 36                           int compressed)
 37{
 38    unsigned int i = 0;
 39    unsigned char run, value;
 40
 41    if (bytestream2_get_bytes_left(gb) < 1)
 42        return AVERROR_INVALIDDATA;
 43
 44    if (compressed) {
 45        while (i < bytes_per_scanline && bytestream2_get_bytes_left(gb)>0) {
 46            run   = 1;
 47            value = bytestream2_get_byte(gb);
 48            if (value >= 0xc0 && bytestream2_get_bytes_left(gb)>0) {
 49                run   = value & 0x3f;
 50                value = bytestream2_get_byte(gb);
 51            }
 52            while (i < bytes_per_scanline && run--)
 53                dst[i++] = value;
 54        }
 55    } else {
 56        bytestream2_get_buffer(gb, dst, bytes_per_scanline);
 57    }
 58    return 0;
 59}
 60
 61static void pcx_palette(GetByteContext *gb, uint32_t *dst, int pallen)
 62{
 63    int i;
 64
 65    pallen = FFMIN(pallen, bytestream2_get_bytes_left(gb) / 3);
 66    for (i = 0; i < pallen; i++)
 67        *dst++ = 0xFF000000 | bytestream2_get_be24u(gb);
 68    if (pallen < 256)
 69        memset(dst, 0, (256 - pallen) * sizeof(*dst));
 70}
 71
 72static int pcx_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
 73                            AVPacket *avpkt)
 74{
 75    GetByteContext gb;
 76    AVFrame * const p  = data;
 77    int compressed, xmin, ymin, xmax, ymax;
 78    int ret;
 79    unsigned int w, h, bits_per_pixel, bytes_per_line, nplanes, stride, y, x,
 80                 bytes_per_scanline;
 81    uint8_t *ptr, *scanline;
 82
 83    if (avpkt->size < PCX_HEADER_SIZE) {
 84        av_log(avctx, AV_LOG_ERROR, "Packet too small\n");
 85        return AVERROR_INVALIDDATA;
 86    }
 87
 88    bytestream2_init(&gb, avpkt->data, avpkt->size);
 89
 90    if (bytestream2_get_byteu(&gb) != 0x0a || bytestream2_get_byteu(&gb) > 5) {
 91        av_log(avctx, AV_LOG_ERROR, "this is not PCX encoded data\n");
 92        return AVERROR_INVALIDDATA;
 93    }
 94
 95    compressed                     = bytestream2_get_byteu(&gb);
 96    bits_per_pixel                 = bytestream2_get_byteu(&gb);
 97    xmin                           = bytestream2_get_le16u(&gb);
 98    ymin                           = bytestream2_get_le16u(&gb);
 99    xmax                           = bytestream2_get_le16u(&gb);
100    ymax                           = bytestream2_get_le16u(&gb);
101    avctx->sample_aspect_ratio.num = bytestream2_get_le16u(&gb);
102    avctx->sample_aspect_ratio.den = bytestream2_get_le16u(&gb);
103
104    if (xmax < xmin || ymax < ymin) {
105        av_log(avctx, AV_LOG_ERROR, "invalid image dimensions\n");
106        return AVERROR_INVALIDDATA;
107    }
108
109    w = xmax - xmin + 1;
110    h = ymax - ymin + 1;
111
112    bytestream2_skipu(&gb, 49);
113    nplanes            = bytestream2_get_byteu(&gb);
114    bytes_per_line     = bytestream2_get_le16u(&gb);
115    bytes_per_scanline = nplanes * bytes_per_line;
116
117    if (bytes_per_scanline < (w * bits_per_pixel * nplanes + 7) / 8 ||
118        (!compressed && bytes_per_scanline > bytestream2_get_bytes_left(&gb) / h)) {
119        av_log(avctx, AV_LOG_ERROR, "PCX data is corrupted\n");
120        return AVERROR_INVALIDDATA;
121    }
122
123    switch ((nplanes << 8) + bits_per_pixel) {
124    case 0x0308:
125        avctx->pix_fmt = AV_PIX_FMT_RGB24;
126        break;
127    case 0x0108:
128    case 0x0104:
129    case 0x0102:
130    case 0x0101:
131    case 0x0401:
132    case 0x0301:
133    case 0x0201:
134        avctx->pix_fmt = AV_PIX_FMT_PAL8;
135        break;
136    default:
137        av_log(avctx, AV_LOG_ERROR, "invalid PCX file\n");
138        return AVERROR_INVALIDDATA;
139    }
140
141    bytestream2_skipu(&gb, 60);
142
143    if ((ret = ff_set_dimensions(avctx, w, h)) < 0)
144        return ret;
145
146    if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
147        return ret;
148
149    p->pict_type = AV_PICTURE_TYPE_I;
150
151    ptr    = p->data[0];
152    stride = p->linesize[0];
153
154    scanline = av_malloc(bytes_per_scanline + AV_INPUT_BUFFER_PADDING_SIZE);
155    if (!scanline)
156        return AVERROR(ENOMEM);
157
158    if (nplanes == 3 && bits_per_pixel == 8) {
159        for (y = 0; y < h; y++) {
160            ret = pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
161            if (ret < 0)
162                goto end;
163
164            for (x = 0; x < w; x++) {
165                ptr[3 * x]     = scanline[x];
166                ptr[3 * x + 1] = scanline[x + bytes_per_line];
167                ptr[3 * x + 2] = scanline[x + (bytes_per_line << 1)];
168            }
169
170            ptr += stride;
171        }
172    } else if (nplanes == 1 && bits_per_pixel == 8) {
173        int palstart = avpkt->size - 769;
174
175        if (avpkt->size < 769) {
176            av_log(avctx, AV_LOG_ERROR, "File is too short\n");
177            ret = avctx->err_recognition & AV_EF_EXPLODE ?
178                  AVERROR_INVALIDDATA : avpkt->size;
179            goto end;
180        }
181
182        for (y = 0; y < h; y++, ptr += stride) {
183            ret = pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
184            if (ret < 0)
185                goto end;
186            memcpy(ptr, scanline, w);
187        }
188
189        if (bytestream2_tell(&gb) != palstart) {
190            av_log(avctx, AV_LOG_WARNING, "image data possibly corrupted\n");
191            bytestream2_seek(&gb, palstart, SEEK_SET);
192        }
193        if (bytestream2_get_byte(&gb) != 12) {
194            av_log(avctx, AV_LOG_ERROR, "expected palette after image data\n");
195            ret = avctx->err_recognition & AV_EF_EXPLODE ?
196                  AVERROR_INVALIDDATA : avpkt->size;
197            goto end;
198        }
199    } else if (nplanes == 1) {   /* all packed formats, max. 16 colors */
200        GetBitContext s;
201
202        for (y = 0; y < h; y++) {
203            init_get_bits8(&s, scanline, bytes_per_scanline);
204
205            ret = pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
206            if (ret < 0)
207                goto end;
208
209            for (x = 0; x < w; x++)
210                ptr[x] = get_bits(&s, bits_per_pixel);
211            ptr += stride;
212        }
213    } else {    /* planar, 4, 8 or 16 colors */
214        int i;
215
216        for (y = 0; y < h; y++) {
217            ret = pcx_rle_decode(&gb, scanline, bytes_per_scanline, compressed);
218            if (ret < 0)
219                goto end;
220
221            for (x = 0; x < w; x++) {
222                int m = 0x80 >> (x & 7), v = 0;
223                for (i = nplanes - 1; i >= 0; i--) {
224                    v <<= 1;
225                    v  += !!(scanline[i * bytes_per_line + (x >> 3)] & m);
226                }
227                ptr[x] = v;
228            }
229            ptr += stride;
230        }
231    }
232
233    ret = bytestream2_tell(&gb);
234    if (nplanes == 1 && bits_per_pixel == 8) {
235        pcx_palette(&gb, (uint32_t *)p->data[1], 256);
236        ret += 256 * 3;
237    } else if (bits_per_pixel * nplanes == 1) {
238        AV_WN32A(p->data[1]  , 0xFF000000);
239        AV_WN32A(p->data[1]+4, 0xFFFFFFFF);
240    } else if (bits_per_pixel < 8) {
241        bytestream2_seek(&gb, 16, SEEK_SET);
242        pcx_palette(&gb, (uint32_t *)p->data[1], 16);
243    }
244
245    *got_frame = 1;
246
247end:
248    av_free(scanline);
249    return ret;
250}
251
252AVCodec ff_pcx_decoder = {
253    .name         = "pcx",
254    .long_name    = NULL_IF_CONFIG_SMALL("PC Paintbrush PCX image"),
255    .type         = AVMEDIA_TYPE_VIDEO,
256    .id           = AV_CODEC_ID_PCX,
257    .decode       = pcx_decode_frame,
258    .capabilities = AV_CODEC_CAP_DR1,
259};