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/* See LICENSE file for copyright and license details. */
#include "liblss16.h"
#include <stdlib.h>
#include <string.h>
#if defined(__clang__)
# pragma clang diagnostic ignored "-Wimplicit-fallthrough"
# pragma clang diagnostic ignored "-Wunsafe-buffer-usage"
#endif
static size_t
flush_buffer(struct liblss16_encoder *encoder, uint8_t *buffer, size_t size)
{
size_t i = 0, j = 0;
for (; size && encoder->nbuffered - i > 1U; i += 2U, size--)
buffer[j++] = (uint8_t)(encoder->buffered[i + 0] | (encoder->buffered[i + 1] << 4));
memmove(&encoder->buffered[0], &encoder->buffered[i], encoder->nbuffered -= (uint8_t)i);
return j;
}
enum liblss16_encode_state
liblss16_encode_from_colour_index(struct liblss16_encoder *encoder, void *buffer_, size_t size, size_t *written_out,
const uint8_t *pixels, size_t npixels, size_t *nconsumed_out)
{
uint8_t *buffer = buffer_;
size_t n;
unsigned value;
*written_out = 0;
*nconsumed_out = 0;
switch (encoder->header_position) {
case 0:
if (!size--)
return LIBLSS16_ENCODE_RUNNING;
*buffer++ = (uint8_t)0x3DU;
++*written_out;
encoder->header_position++;
/* fall through */
case 1:
if (!size--)
return LIBLSS16_ENCODE_RUNNING;
*buffer++ = (uint8_t)0xF3U;
++*written_out;
encoder->header_position++;
/* fall through */
case 2:
if (!size--)
return LIBLSS16_ENCODE_RUNNING;
*buffer++ = (uint8_t)0x13U;
++*written_out;
encoder->header_position++;
/* fall through */
case 3:
if (!size--)
return LIBLSS16_ENCODE_RUNNING;
*buffer++ = (uint8_t)0x14U;
++*written_out;
encoder->header_position++;
/* fall through */
case 4:
if (!size--)
return LIBLSS16_ENCODE_RUNNING;
*buffer++ = (uint8_t)encoder->header.width;
++*written_out;
encoder->header_position++;
/* fall through */
case 5:
if (!size--)
return LIBLSS16_ENCODE_RUNNING;
*buffer++ = (uint8_t)(encoder->header.width >> 8);
++*written_out;
encoder->header_position++;
/* fall through */
case 6:
if (!size--)
return LIBLSS16_ENCODE_RUNNING;
*buffer++ = (uint8_t)encoder->header.height;
++*written_out;
encoder->header_position++;
/* fall through */
case 7:
if (!size--)
return LIBLSS16_ENCODE_RUNNING;
*buffer++ = (uint8_t)(encoder->header.height >> 8);
++*written_out;
encoder->header_position++;
/* fall through */
default:
break;
}
while (encoder->header_position < 8U + 16U * 3U) {
if (!size--)
return LIBLSS16_ENCODE_RUNNING;
*buffer++ = ((const uint8_t *)encoder->header.colour_map)[encoder->header_position - 8U];
++*written_out;
encoder->header_position++;
}
if (encoder->nbuffered > 1U) {
n = flush_buffer(encoder, buffer, size);
buffer = &buffer[n];
size -= n;
*written_out += n;
if (encoder->nbuffered > 1U)
return LIBLSS16_ENCODE_RUNNING;
if (!encoder->y_rem) {
if (encoder->nbuffered)
abort();
return LIBLSS16_ENCODE_DONE;
}
}
if (!encoder->x_rem)
goto end_of_image;
while (npixels--) {
if (*pixels == encoder->previous) {
if (encoder->repetition == 255U + 16U) {
encoder->buffered[encoder->nbuffered++] = encoder->previous;
encoder->buffered[encoder->nbuffered++] = 0;
encoder->buffered[encoder->nbuffered++] = (uint8_t)15U;
encoder->buffered[encoder->nbuffered++] = (uint8_t)15U;
n = flush_buffer(encoder, buffer, size);
buffer = &buffer[n];
size -= n;
*written_out += n;
encoder->repetition = 0U;
}
encoder->repetition++;
} else {
if (!encoder->repetition) {
/* do nothing */
} else if (encoder->repetition < 16U) {
encoder->buffered[encoder->nbuffered++] = encoder->previous;
encoder->buffered[encoder->nbuffered++] = (uint8_t)encoder->repetition;
} else {
value = encoder->repetition - 16U;
encoder->buffered[encoder->nbuffered++] = encoder->previous;
encoder->buffered[encoder->nbuffered++] = 0;
encoder->buffered[encoder->nbuffered++] = (uint8_t)(value & 15U);
encoder->buffered[encoder->nbuffered++] = (uint8_t)(value >> 4);
}
encoder->buffered[encoder->nbuffered++] = *pixels;
encoder->previous = *pixels;
encoder->repetition = 0;
n = flush_buffer(encoder, buffer, size);
buffer = &buffer[n];
size -= n;
*written_out += n;
}
++pixels;
++*nconsumed_out;
--encoder->x_rem;
if (encoder->nbuffered > 1U)
return LIBLSS16_ENCODE_RUNNING;
if (!encoder->x_rem) {
end_of_image:
if (!encoder->repetition) {
/* do nothing */
} else if (encoder->repetition < 16U) {
encoder->buffered[encoder->nbuffered++] = encoder->previous;
encoder->buffered[encoder->nbuffered++] = (uint8_t)encoder->repetition;
} else {
value = encoder->repetition - 16U;
encoder->buffered[encoder->nbuffered++] = encoder->previous;
encoder->buffered[encoder->nbuffered++] = 0;
encoder->buffered[encoder->nbuffered++] = (uint8_t)(value & 15U);
encoder->buffered[encoder->nbuffered++] = (uint8_t)(value >> 4);
}
encoder->previous = 0;
encoder->repetition = 0;
encoder->x_rem = encoder->header.width;
encoder->y_rem--;
if (encoder->nbuffered & 1)
encoder->buffered[encoder->nbuffered++] = 0;
n = flush_buffer(encoder, buffer, size);
buffer = &buffer[n];
size -= n;
*written_out += n;
if (encoder->nbuffered > 1U)
return LIBLSS16_ENCODE_RUNNING;
else if (encoder->nbuffered)
abort();
if (!encoder->y_rem)
return LIBLSS16_ENCODE_DONE;
}
}
return LIBLSS16_ENCODE_RUNNING;
}
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