141 lines
2.9 KiB
C++
141 lines
2.9 KiB
C++
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#include "rle.h"
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static bool CheckOverflow(size_t total_size, int current_position, int read_size)
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{
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if (read_size > (int)total_size) // check separate to avoid overflow
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return true;
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if (((int)total_size - read_size) < current_position)
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return true;
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return false;
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}
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void RLE16(const uint8_t *rle, size_t rle_size_bytes, uint16_t *video_frame, size_t video_frame_size, int stride)
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{
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int input = 0;
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int output = 0;
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video_frame_size >>= 1; // divide by 2 since we're indexing as uint16_t
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int next_line = output + stride;
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while (input < (int)rle_size_bytes && output < (int)video_frame_size)
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{
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if (CheckOverflow(rle_size_bytes, input, 2)) // we always read at least two bytes
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break;
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uint8_t b0 = rle[input++];
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if (b0)
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{
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if (CheckOverflow(rle_size_bytes, input, 2))
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break;
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if (CheckOverflow(video_frame_size, output, b0))
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{
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b0 = (uint8_t)(video_frame_size - output);
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}
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uint16_t pixel = *(uint16_t *)(&rle[input]);
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input += 2;
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while (b0--)
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{
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memcpy(&video_frame[output], &pixel, 2);
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output++;
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}
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}
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else
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{
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uint8_t b1 = rle[input++];
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if (b1 == 0)
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{
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output = next_line;
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next_line = output + stride;
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}
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else if (b1 == 1)
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{
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return;
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}
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else if (b1 == 2)
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{
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if (CheckOverflow(rle_size_bytes, input, 2))
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break;
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uint8_t p1 = rle[input++];
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uint8_t p2 = rle[input++];
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output += p1;
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output += p2*stride;
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next_line += p2*stride;
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}
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else
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{
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if (CheckOverflow(rle_size_bytes, input, b1*2))
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break;
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if (CheckOverflow(video_frame_size, output, b1))
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break;
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for (uint8_t i=0;i!=b1;i++)
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{
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video_frame[output++] = *(uint16_t *)(&rle[input]);
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input+=2;
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}
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}
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}
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}
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}
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void RLE8(const uint8_t *rle, size_t rle_size_bytes, uint8_t *video_frame, size_t video_frame_size, int stride)
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{
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int input = 0;
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int output = 0;
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int next_line = output + stride;
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while (input < (int)rle_size_bytes && output < (int)video_frame_size)
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{
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if (CheckOverflow(rle_size_bytes, input, 2)) // we always read at least two bytes
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break;
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uint8_t b0 = rle[input++];
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if (b0)
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{
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if (CheckOverflow(video_frame_size, output, b0))
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{
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b0 = (uint8_t)(video_frame_size - output);
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}
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uint8_t pixel = rle[input++];
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memset(&video_frame[output], pixel, b0);
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output+=b0;
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}
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else
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{
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uint8_t b1 = rle[input++];
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if (b1 == 0)
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{
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output = next_line;
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next_line = output + stride;
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}
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else if (b1 == 1)
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{
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break;
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}
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else if (b1 == 2)
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{
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if (CheckOverflow(rle_size_bytes, input, 2))
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break;
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uint8_t p1 = rle[input++];
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uint8_t p2 = rle[input++];
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output += p1;
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output += p2*stride;
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next_line += p2*stride;
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}
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else
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{
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if (CheckOverflow(rle_size_bytes, input, b1))
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break;
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if (CheckOverflow(video_frame_size, output, b1))
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break;
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memcpy(&video_frame[output], &rle[input], b1);
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input += b1;
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output += b1;
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if (b1 & 1)
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input++;
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}
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}
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}
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}
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