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// Copyright (c) the JPEG XL Project Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "lib/jpegli/bit_writer.h"
#include "lib/jpegli/encode_internal.h"
namespace jpegli {
void JpegBitWriterInit(j_compress_ptr cinfo) {
jpeg_comp_master* m = cinfo->master;
JpegBitWriter* bw = &m->bw;
size_t buffer_size = m->blocks_per_iMCU_row * (DCTSIZE2 * 16 + 8) + (1 << 16);
bw->cinfo = cinfo;
bw->data = Allocate<uint8_t>(cinfo, buffer_size, JPOOL_IMAGE);
bw->len = buffer_size;
bw->pos = 0;
bw->output_pos = 0;
bw->put_buffer = 0;
bw->free_bits = 64;
bw->healthy = true;
}
bool EmptyBitWriterBuffer(JpegBitWriter* bw) {
while (bw->output_pos < bw->pos) {
j_compress_ptr cinfo = bw->cinfo;
if (cinfo->dest->free_in_buffer == 0 &&
!(*cinfo->dest->empty_output_buffer)(cinfo)) {
return false;
}
size_t buflen = bw->pos - bw->output_pos;
size_t copylen = std::min<size_t>(cinfo->dest->free_in_buffer, buflen);
memcpy(cinfo->dest->next_output_byte, bw->data + bw->output_pos, copylen);
bw->output_pos += copylen;
cinfo->dest->free_in_buffer -= copylen;
cinfo->dest->next_output_byte += copylen;
}
bw->output_pos = bw->pos = 0;
return true;
}
void JumpToByteBoundary(JpegBitWriter* bw) {
size_t n_bits = bw->free_bits & 7u;
if (n_bits > 0) {
WriteBits(bw, n_bits, (1u << n_bits) - 1);
}
bw->put_buffer <<= bw->free_bits;
while (bw->free_bits <= 56) {
int c = (bw->put_buffer >> 56) & 0xFF;
EmitByte(bw, c);
bw->put_buffer <<= 8;
bw->free_bits += 8;
}
bw->put_buffer = 0;
bw->free_bits = 64;
}
} // namespace jpegli
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