/*
  * SGI RLE 8-bit decoder
  * Copyright (c) 2012 Peter Ross
  *
  * 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
  */
 
 /**
  * @file
  * SGI RLE 8-bit decoder
  */
 
 #include "libavutil/intreadwrite.h"
 #include "avcodec.h"
 #include "bytestream.h"
 
 static av_cold int sgirle_decode_init(AVCodecContext *avctx)
 {
     avctx->pix_fmt = AV_PIX_FMT_BGR8;
     avctx->coded_frame = avcodec_alloc_frame();
     if (!avctx->coded_frame)
         return AVERROR(ENOMEM);
     return 0;
 }
 
 /**
  * Convert SGI RGB332 pixel into PIX_FMT_BGR8
  * SGI RGB332 is packed RGB 3:3:2, 8bpp, (msb)3R 2B 3G(lsb)
  */
 #define RGB332_TO_BGR8(x) (((x << 3) & 0xC0) | ((x << 3) & 0x38) | ((x >> 5) & 7))
 
 static av_always_inline void memcpy_rgb332_to_bgr8(uint8_t *dst, const uint8_t *src, int size)
 {
     int i;
     for (i = 0; i < size; i++)
         dst[i] = RGB332_TO_BGR8(src[i]);
 }
 
 /**
  * @param[out] dst Destination buffer
  * @param[in] src Source buffer
  * @param src_size Source buffer size (bytes)
  * @param width Width of destination buffer (pixels)
  * @param height Height of destination buffer (pixels)
  * @param linesize Line size of destination buffer (bytes)
  * @return <0 on error
  */
 static int decode_sgirle8(AVCodecContext *avctx, uint8_t *dst, const uint8_t *src, int src_size, int width, int height, int linesize)
 {
     const uint8_t *src_end = src + src_size;
     int x = 0, y = 0;
 
 #define INC_XY(n) \
     x += n; \
     if (x >= width) { \
         y++; \
         if (y >= height) \
             return 0; \
         x = 0; \
     }
 
     while (src_end - src >= 2) {
         uint8_t v = *src++;
         if (v > 0 && v < 0xC0) {
             do {
                 int length = FFMIN(v, width - x);
                 memset(dst + y*linesize + x, RGB332_TO_BGR8(*src), length);
                 INC_XY(length);
                 v   -= length;
             } while (v > 0);
             src++;
         } else if (v >= 0xC1) {
             v -= 0xC0;
             do {
                 int length = FFMIN3(v, width - x, src_end - src);
                 if (src_end - src < length)
                     break;
                 memcpy_rgb332_to_bgr8(dst + y*linesize + x, src, length);
                 INC_XY(length);
                 src += length;
                 v   -= length;
             } while (v > 0);
         } else {
             av_log_ask_for_sample(avctx, "unknown opcode\n");
             return AVERROR_PATCHWELCOME;
         }
     }
     return 0;
 }
 
 static int sgirle_decode_frame(AVCodecContext *avctx,
                             void *data, int *got_frame,
                             AVPacket *avpkt)
 {
     AVFrame *frame = avctx->coded_frame;
     int ret;
 
     frame->reference = 3;
     frame->buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE |
                           FF_BUFFER_HINTS_REUSABLE | FF_BUFFER_HINTS_READABLE;
     ret = avctx->reget_buffer(avctx, frame);
     if (ret < 0) {
         av_log (avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
         return ret;
     }
 
     ret = decode_sgirle8(avctx, frame->data[0], avpkt->data, avpkt->size, avctx->width, avctx->height, frame->linesize[0]);
     if (ret < 0)
         return ret;
 
     *got_frame      = 1;
     *(AVFrame*)data = *frame;
 
     return avpkt->size;
 }
 
 static av_cold int sgirle_decode_end(AVCodecContext *avctx)
 {
     if (avctx->coded_frame->data[0])
         avctx->release_buffer(avctx, avctx->coded_frame);
     av_freep(&avctx->coded_frame);
     return 0;
 }
 
 AVCodec ff_sgirle_decoder = {
     .name           = "sgirle",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_SGIRLE,
     .init           = sgirle_decode_init,
     .close          = sgirle_decode_end,
     .decode         = sgirle_decode_frame,
     .capabilities   = CODEC_CAP_DR1,
     .long_name      = NULL_IF_CONFIG_SMALL("SGI RLE 8-bit"),
 };