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// Copyright 2014 The PDFium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
#include "core/fxcodec/fax/faxmodule.h"
#include <stdint.h>
#include <algorithm>
#include <array>
#include <iterator>
#include <memory>
#include <utility>
#include "build/build_config.h"
#include "core/fxcodec/scanlinedecoder.h"
#include "core/fxcrt/binary_buffer.h"
#include "core/fxcrt/check.h"
#include "core/fxcrt/check_op.h"
#include "core/fxcrt/compiler_specific.h"
#include "core/fxcrt/data_vector.h"
#include "core/fxcrt/fx_2d_size.h"
#include "core/fxcrt/fx_memcpy_wrappers.h"
#include "core/fxcrt/fx_memory.h"
#include "core/fxcrt/numerics/safe_conversions.h"
#include "core/fxcrt/raw_span.h"
#include "core/fxcrt/span.h"
#include "core/fxcrt/span_util.h"
#include "core/fxcrt/stl_util.h"
#include "core/fxge/calculate_pitch.h"
#if BUILDFLAG(IS_WIN)
#include "core/fxge/dib/cfx_dibbase.h"
#endif
namespace fxcodec {
namespace {
constexpr std::array<const uint8_t, 256> kOneLeadPos = {{
8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3,
3, 3, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
}};
// Limit of image dimension. Use the same limit as the JBIG2 codecs.
constexpr int kFaxMaxImageDimension = 65535;
constexpr int kFaxBpc = 1;
constexpr int kFaxComps = 1;
int FindBit(pdfium::span<const uint8_t> data_buf,
int max_pos,
int start_pos,
bool bit) {
DCHECK(start_pos >= 0);
if (start_pos >= max_pos)
return max_pos;
const uint8_t bit_xor = bit ? 0x00 : 0xff;
int bit_offset = start_pos % 8;
if (bit_offset) {
const int byte_pos = start_pos / 8;
uint8_t data = (data_buf[byte_pos] ^ bit_xor) & (0xff >> bit_offset);
if (data) {
return byte_pos * 8 + kOneLeadPos[data];
}
start_pos += 7;
}
const int max_byte = (max_pos + 7) / 8;
int byte_pos = start_pos / 8;
// Try reading in bigger chunks in case there are long runs to be skipped.
static constexpr int kBulkReadSize = 8;
if (max_byte >= kBulkReadSize && byte_pos < max_byte - kBulkReadSize) {
static constexpr uint8_t skip_block_0[kBulkReadSize] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
static constexpr uint8_t skip_block_1[kBulkReadSize] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
const uint8_t* skip_block = bit ? skip_block_0 : skip_block_1;
while (byte_pos < max_byte - kBulkReadSize &&
memcmp(data_buf.subspan(byte_pos).data(), skip_block,
kBulkReadSize) == 0) {
byte_pos += kBulkReadSize;
}
}
while (byte_pos < max_byte) {
uint8_t data = data_buf[byte_pos] ^ bit_xor;
if (data) {
return std::min(byte_pos * 8 + kOneLeadPos[data], max_pos);
}
++byte_pos;
}
return max_pos;
}
void FaxG4FindB1B2(pdfium::span<const uint8_t> ref_buf,
int columns,
int a0,
bool a0color,
int* b1,
int* b2) {
bool first_bit = a0 < 0 || (ref_buf[a0 / 8] & (1 << (7 - a0 % 8))) != 0;
*b1 = FindBit(ref_buf, columns, a0 + 1, !first_bit);
if (*b1 >= columns) {
*b1 = *b2 = columns;
return;
}
if (first_bit == !a0color) {
*b1 = FindBit(ref_buf, columns, *b1 + 1, first_bit);
first_bit = !first_bit;
}
if (*b1 >= columns) {
*b1 = *b2 = columns;
return;
}
*b2 = FindBit(ref_buf, columns, *b1 + 1, first_bit);
}
void FaxFillBits(uint8_t* dest_buf, int columns, int startpos, int endpos) {
startpos = std::max(startpos, 0);
endpos = std::clamp(endpos, 0, columns);
if (startpos >= endpos) {
return;
}
int first_byte = startpos / 8;
int last_byte = (endpos - 1) / 8;
if (first_byte == last_byte) {
for (int i = startpos % 8; i <= (endpos - 1) % 8; ++i) {
UNSAFE_TODO(dest_buf[first_byte] -= 1 << (7 - i));
}
return;
}
for (int i = startpos % 8; i < 8; ++i) {
UNSAFE_TODO(dest_buf[first_byte] -= 1 << (7 - i));
}
for (int i = 0; i <= (endpos - 1) % 8; ++i) {
UNSAFE_TODO(dest_buf[last_byte] -= 1 << (7 - i));
}
if (last_byte > first_byte + 1) {
UNSAFE_TODO(
FXSYS_memset(dest_buf + first_byte + 1, 0, last_byte - first_byte - 1));
}
}
inline bool NextBit(const uint8_t* src_buf, int* bitpos) {
int pos = (*bitpos)++;
return !!UNSAFE_TODO((src_buf[pos / 8] & (1 << (7 - pos % 8))));
}
const uint8_t kFaxBlackRunIns[] = {
0, 2, 0x02, 3, 0, 0x03,
2, 0, 2, 0x02, 1, 0,
0x03, 4, 0, 2, 0x02, 6,
0, 0x03, 5, 0, 1, 0x03,
7, 0, 2, 0x04, 9, 0,
0x05, 8, 0, 3, 0x04, 10,
0, 0x05, 11, 0, 0x07, 12,
0, 2, 0x04, 13, 0, 0x07,
14, 0, 1, 0x18, 15, 0,
5, 0x08, 18, 0, 0x0f, 64,
0, 0x17, 16, 0, 0x18, 17,
0, 0x37, 0, 0, 10, 0x08,
0x00, 0x07, 0x0c, 0x40, 0x07, 0x0d,
0x80, 0x07, 0x17, 24, 0, 0x18,
25, 0, 0x28, 23, 0, 0x37,
22, 0, 0x67, 19, 0, 0x68,
20, 0, 0x6c, 21, 0, 54,
0x12, 1984 % 256, 1984 / 256, 0x13, 2048 % 256, 2048 / 256,
0x14, 2112 % 256, 2112 / 256, 0x15, 2176 % 256, 2176 / 256,
0x16, 2240 % 256, 2240 / 256, 0x17, 2304 % 256, 2304 / 256,
0x1c, 2368 % 256, 2368 / 256, 0x1d, 2432 % 256, 2432 / 256,
0x1e, 2496 % 256, 2496 / 256, 0x1f, 2560 % 256, 2560 / 256,
0x24, 52, 0, 0x27, 55, 0,
0x28, 56, 0, 0x2b, 59, 0,
0x2c, 60, 0, 0x33, 320 % 256, 320 / 256,
0x34, 384 % 256, 384 / 256, 0x35, 448 % 256, 448 / 256,
0x37, 53, 0, 0x38, 54, 0,
0x52, 50, 0, 0x53, 51, 0,
0x54, 44, 0, 0x55, 45, 0,
0x56, 46, 0, 0x57, 47, 0,
0x58, 57, 0, 0x59, 58, 0,
0x5a, 61, 0, 0x5b, 256 % 256, 256 / 256,
0x64, 48, 0, 0x65, 49, 0,
0x66, 62, 0, 0x67, 63, 0,
0x68, 30, 0, 0x69, 31, 0,
0x6a, 32, 0, 0x6b, 33, 0,
0x6c, 40, 0, 0x6d, 41, 0,
0xc8, 128, 0, 0xc9, 192, 0,
0xca, 26, 0, 0xcb, 27, 0,
0xcc, 28, 0, 0xcd, 29, 0,
0xd2, 34, 0, 0xd3, 35, 0,
0xd4, 36, 0, 0xd5, 37, 0,
0xd6, 38, 0, 0xd7, 39, 0,
0xda, 42, 0, 0xdb, 43, 0,
20, 0x4a, 640 % 256, 640 / 256, 0x4b, 704 % 256,
704 / 256, 0x4c, 768 % 256, 768 / 256, 0x4d, 832 % 256,
832 / 256, 0x52, 1280 % 256, 1280 / 256, 0x53, 1344 % 256,
1344 / 256, 0x54, 1408 % 256, 1408 / 256, 0x55, 1472 % 256,
1472 / 256, 0x5a, 1536 % 256, 1536 / 256, 0x5b, 1600 % 256,
1600 / 256, 0x64, 1664 % 256, 1664 / 256, 0x65, 1728 % 256,
1728 / 256, 0x6c, 512 % 256, 512 / 256, 0x6d, 576 % 256,
576 / 256, 0x72, 896 % 256, 896 / 256, 0x73, 960 % 256,
960 / 256, 0x74, 1024 % 256, 1024 / 256, 0x75, 1088 % 256,
1088 / 256, 0x76, 1152 % 256, 1152 / 256, 0x77, 1216 % 256,
1216 / 256, 0xff};
const uint8_t kFaxWhiteRunIns[] = {
0, 0, 0, 6, 0x07, 2,
0, 0x08, 3, 0, 0x0B, 4,
0, 0x0C, 5, 0, 0x0E, 6,
0, 0x0F, 7, 0, 6, 0x07,
10, 0, 0x08, 11, 0, 0x12,
128, 0, 0x13, 8, 0, 0x14,
9, 0, 0x1b, 64, 0, 9,
0x03, 13, 0, 0x07, 1, 0,
0x08, 12, 0, 0x17, 192, 0,
0x18, 1664 % 256, 1664 / 256, 0x2a, 16, 0,
0x2B, 17, 0, 0x34, 14, 0,
0x35, 15, 0, 12, 0x03, 22,
0, 0x04, 23, 0, 0x08, 20,
0, 0x0c, 19, 0, 0x13, 26,
0, 0x17, 21, 0, 0x18, 28,
0, 0x24, 27, 0, 0x27, 18,
0, 0x28, 24, 0, 0x2B, 25,
0, 0x37, 256 % 256, 256 / 256, 42, 0x02,
29, 0, 0x03, 30, 0, 0x04,
45, 0, 0x05, 46, 0, 0x0a,
47, 0, 0x0b, 48, 0, 0x12,
33, 0, 0x13, 34, 0, 0x14,
35, 0, 0x15, 36, 0, 0x16,
37, 0, 0x17, 38, 0, 0x1a,
31, 0, 0x1b, 32, 0, 0x24,
53, 0, 0x25, 54, 0, 0x28,
39, 0, 0x29, 40, 0, 0x2a,
41, 0, 0x2b, 42, 0, 0x2c,
43, 0, 0x2d, 44, 0, 0x32,
61, 0, 0x33, 62, 0, 0x34,
63, 0, 0x35, 0, 0, 0x36,
320 % 256, 320 / 256, 0x37, 384 % 256, 384 / 256, 0x4a,
59, 0, 0x4b, 60, 0, 0x52,
49, 0, 0x53, 50, 0, 0x54,
51, 0, 0x55, 52, 0, 0x58,
55, 0, 0x59, 56, 0, 0x5a,
57, 0, 0x5b, 58, 0, 0x64,
448 % 256, 448 / 256, 0x65, 512 % 256, 512 / 256, 0x67,
640 % 256, 640 / 256, 0x68, 576 % 256, 576 / 256, 16,
0x98, 1472 % 256, 1472 / 256, 0x99, 1536 % 256, 1536 / 256,
0x9a, 1600 % 256, 1600 / 256, 0x9b, 1728 % 256, 1728 / 256,
0xcc, 704 % 256, 704 / 256, 0xcd, 768 % 256, 768 / 256,
0xd2, 832 % 256, 832 / 256, 0xd3, 896 % 256, 896 / 256,
0xd4, 960 % 256, 960 / 256, 0xd5, 1024 % 256, 1024 / 256,
0xd6, 1088 % 256, 1088 / 256, 0xd7, 1152 % 256, 1152 / 256,
0xd8, 1216 % 256, 1216 / 256, 0xd9, 1280 % 256, 1280 / 256,
0xda, 1344 % 256, 1344 / 256, 0xdb, 1408 % 256, 1408 / 256,
0, 3, 0x08, 1792 % 256, 1792 / 256, 0x0c,
1856 % 256, 1856 / 256, 0x0d, 1920 % 256, 1920 / 256, 10,
0x12, 1984 % 256, 1984 / 256, 0x13, 2048 % 256, 2048 / 256,
0x14, 2112 % 256, 2112 / 256, 0x15, 2176 % 256, 2176 / 256,
0x16, 2240 % 256, 2240 / 256, 0x17, 2304 % 256, 2304 / 256,
0x1c, 2368 % 256, 2368 / 256, 0x1d, 2432 % 256, 2432 / 256,
0x1e, 2496 % 256, 2496 / 256, 0x1f, 2560 % 256, 2560 / 256,
0xff,
};
int FaxGetRun(pdfium::span<const uint8_t> ins_array,
const uint8_t* src_buf,
int* bitpos,
int bitsize) {
uint32_t code = 0;
int ins_off = 0;
while (true) {
uint8_t ins = ins_array[ins_off++];
if (ins == 0xff)
return -1;
if (*bitpos >= bitsize)
return -1;
code <<= 1;
UNSAFE_TODO({
if (src_buf[*bitpos / 8] & (1 << (7 - *bitpos % 8))) {
++code;
}
});
++(*bitpos);
int next_off = ins_off + ins * 3;
for (; ins_off < next_off; ins_off += 3) {
if (ins_array[ins_off] == code)
return ins_array[ins_off + 1] + ins_array[ins_off + 2] * 256;
}
}
}
void FaxG4GetRow(const uint8_t* src_buf,
int bitsize,
int* bitpos,
uint8_t* dest_buf,
pdfium::span<const uint8_t> ref_buf,
int columns) {
int a0 = -1;
bool a0color = true;
while (true) {
if (*bitpos >= bitsize)
return;
int a1;
int a2;
int b1;
int b2;
FaxG4FindB1B2(ref_buf, columns, a0, a0color, &b1, &b2);
int v_delta = 0;
if (!NextBit(src_buf, bitpos)) {
if (*bitpos >= bitsize)
return;
bool bit1 = NextBit(src_buf, bitpos);
if (*bitpos >= bitsize)
return;
bool bit2 = NextBit(src_buf, bitpos);
if (bit1) {
v_delta = bit2 ? 1 : -1;
} else if (bit2) {
int run_len1 = 0;
while (true) {
int run = FaxGetRun(a0color ? pdfium::make_span(kFaxWhiteRunIns)
: pdfium::make_span(kFaxBlackRunIns),
src_buf, bitpos, bitsize);
run_len1 += run;
if (run < 64)
break;
}
if (a0 < 0)
++run_len1;
if (run_len1 < 0)
return;
a1 = a0 + run_len1;
if (!a0color)
FaxFillBits(dest_buf, columns, a0, a1);
int run_len2 = 0;
while (true) {
int run = FaxGetRun(a0color ? pdfium::make_span(kFaxBlackRunIns)
: pdfium::make_span(kFaxWhiteRunIns),
src_buf, bitpos, bitsize);
run_len2 += run;
if (run < 64)
break;
}
if (run_len2 < 0)
return;
a2 = a1 + run_len2;
if (a0color)
FaxFillBits(dest_buf, columns, a1, a2);
a0 = a2;
if (a0 < columns)
continue;
return;
} else {
if (*bitpos >= bitsize)
return;
if (NextBit(src_buf, bitpos)) {
if (!a0color)
FaxFillBits(dest_buf, columns, a0, b2);
if (b2 >= columns)
return;
a0 = b2;
continue;
}
if (*bitpos >= bitsize)
return;
bool next_bit1 = NextBit(src_buf, bitpos);
if (*bitpos >= bitsize)
return;
bool next_bit2 = NextBit(src_buf, bitpos);
if (next_bit1) {
v_delta = next_bit2 ? 2 : -2;
} else if (next_bit2) {
if (*bitpos >= bitsize)
return;
v_delta = NextBit(src_buf, bitpos) ? 3 : -3;
} else {
if (*bitpos >= bitsize)
return;
if (NextBit(src_buf, bitpos)) {
*bitpos += 3;
continue;
}
*bitpos += 5;
return;
}
}
}
a1 = b1 + v_delta;
if (!a0color)
FaxFillBits(dest_buf, columns, a0, a1);
if (a1 >= columns)
return;
// The position of picture element must be monotonic increasing.
if (a0 >= a1)
return;
a0 = a1;
a0color = !a0color;
}
}
void FaxSkipEOL(const uint8_t* src_buf, int bitsize, int* bitpos) {
int startbit = *bitpos;
while (*bitpos < bitsize) {
if (!NextBit(src_buf, bitpos))
continue;
if (*bitpos - startbit <= 11)
*bitpos = startbit;
return;
}
}
void FaxGet1DLine(const uint8_t* src_buf,
int bitsize,
int* bitpos,
uint8_t* dest_buf,
int columns) {
bool color = true;
int startpos = 0;
while (true) {
if (*bitpos >= bitsize)
return;
int run_len = 0;
while (true) {
int run = FaxGetRun(color ? pdfium::make_span(kFaxWhiteRunIns)
: pdfium::make_span(kFaxBlackRunIns),
src_buf, bitpos, bitsize);
if (run < 0) {
while (*bitpos < bitsize) {
if (NextBit(src_buf, bitpos))
return;
}
return;
}
run_len += run;
if (run < 64)
break;
}
if (!color)
FaxFillBits(dest_buf, columns, startpos, startpos + run_len);
startpos += run_len;
if (startpos >= columns)
break;
color = !color;
}
}
class FaxDecoder final : public ScanlineDecoder {
public:
FaxDecoder(pdfium::span<const uint8_t> src_span,
int width,
int height,
int K,
bool EndOfLine,
bool EncodedByteAlign,
bool BlackIs1);
~FaxDecoder() override;
// ScanlineDecoder:
bool Rewind() override;
pdfium::span<uint8_t> GetNextLine() override;
uint32_t GetSrcOffset() override;
private:
void InvertBuffer();
const int m_Encoding;
int m_bitpos = 0;
bool m_bByteAlign = false;
const bool m_bEndOfLine;
const bool m_bBlack;
const pdfium::raw_span<const uint8_t> m_SrcSpan;
DataVector<uint8_t> m_ScanlineBuf;
DataVector<uint8_t> m_RefBuf;
};
FaxDecoder::FaxDecoder(pdfium::span<const uint8_t> src_span,
int width,
int height,
int K,
bool EndOfLine,
bool EncodedByteAlign,
bool BlackIs1)
: ScanlineDecoder(width,
height,
width,
height,
kFaxComps,
kFaxBpc,
fxge::CalculatePitch32OrDie(kFaxBpc, width)),
m_Encoding(K),
m_bByteAlign(EncodedByteAlign),
m_bEndOfLine(EndOfLine),
m_bBlack(BlackIs1),
m_SrcSpan(src_span),
m_ScanlineBuf(m_Pitch),
m_RefBuf(m_Pitch) {}
FaxDecoder::~FaxDecoder() {
// Span in superclass can't outlive our buffer.
m_pLastScanline = pdfium::span<uint8_t>();
}
bool FaxDecoder::Rewind() {
fxcrt::Fill(m_RefBuf, 0xff);
m_bitpos = 0;
return true;
}
pdfium::span<uint8_t> FaxDecoder::GetNextLine() {
int bitsize = pdfium::checked_cast<int>(m_SrcSpan.size() * 8);
FaxSkipEOL(m_SrcSpan.data(), bitsize, &m_bitpos);
if (m_bitpos >= bitsize)
return pdfium::span<uint8_t>();
fxcrt::Fill(m_ScanlineBuf, 0xff);
if (m_Encoding < 0) {
FaxG4GetRow(m_SrcSpan.data(), bitsize, &m_bitpos, m_ScanlineBuf.data(),
m_RefBuf, m_OrigWidth);
m_RefBuf = m_ScanlineBuf;
} else if (m_Encoding == 0) {
FaxGet1DLine(m_SrcSpan.data(), bitsize, &m_bitpos, m_ScanlineBuf.data(),
m_OrigWidth);
} else {
if (NextBit(m_SrcSpan.data(), &m_bitpos)) {
FaxGet1DLine(m_SrcSpan.data(), bitsize, &m_bitpos, m_ScanlineBuf.data(),
m_OrigWidth);
} else {
FaxG4GetRow(m_SrcSpan.data(), bitsize, &m_bitpos, m_ScanlineBuf.data(),
m_RefBuf, m_OrigWidth);
}
m_RefBuf = m_ScanlineBuf;
}
if (m_bEndOfLine)
FaxSkipEOL(m_SrcSpan.data(), bitsize, &m_bitpos);
if (m_bByteAlign && m_bitpos < bitsize) {
int bitpos0 = m_bitpos;
int bitpos1 = FxAlignToBoundary<8>(m_bitpos);
while (m_bByteAlign && bitpos0 < bitpos1) {
int bit = m_SrcSpan[bitpos0 / 8] & (1 << (7 - bitpos0 % 8));
if (bit != 0)
m_bByteAlign = false;
else
++bitpos0;
}
if (m_bByteAlign)
m_bitpos = bitpos1;
}
if (m_bBlack)
InvertBuffer();
return m_ScanlineBuf;
}
uint32_t FaxDecoder::GetSrcOffset() {
return pdfium::checked_cast<uint32_t>(
std::min<size_t>((m_bitpos + 7) / 8, m_SrcSpan.size()));
}
void FaxDecoder::InvertBuffer() {
auto byte_span = pdfium::make_span(m_ScanlineBuf);
auto data = fxcrt::reinterpret_span<uint32_t>(byte_span);
for (auto& datum : data) {
datum = ~datum;
}
}
} // namespace
// static
std::unique_ptr<ScanlineDecoder> FaxModule::CreateDecoder(
pdfium::span<const uint8_t> src_span,
int width,
int height,
int K,
bool EndOfLine,
bool EncodedByteAlign,
bool BlackIs1,
int Columns,
int Rows) {
int actual_width = Columns ? Columns : width;
int actual_height = Rows ? Rows : height;
// Reject invalid values.
if (actual_width <= 0 || actual_height <= 0)
return nullptr;
// Reject unreasonable large input.
if (actual_width > kFaxMaxImageDimension ||
actual_height > kFaxMaxImageDimension) {
return nullptr;
}
return std::make_unique<FaxDecoder>(src_span, actual_width, actual_height, K,
EndOfLine, EncodedByteAlign, BlackIs1);
}
// static
int FaxModule::FaxG4Decode(pdfium::span<const uint8_t> src_span,
int starting_bitpos,
int width,
int height,
int pitch,
uint8_t* dest_buf) {
DCHECK(pitch != 0);
const uint8_t* src_buf = src_span.data();
uint32_t src_size = pdfium::checked_cast<uint32_t>(src_span.size());
DataVector<uint8_t> ref_buf(pitch, 0xff);
int bitpos = starting_bitpos;
for (int iRow = 0; iRow < height; ++iRow) {
uint8_t* line_buf = UNSAFE_TODO(dest_buf + iRow * pitch);
UNSAFE_TODO(FXSYS_memset(line_buf, 0xff, pitch));
FaxG4GetRow(src_buf, src_size << 3, &bitpos, line_buf, ref_buf, width);
UNSAFE_TODO(FXSYS_memcpy(ref_buf.data(), line_buf, pitch));
}
return bitpos;
}
#if BUILDFLAG(IS_WIN)
namespace {
const uint8_t BlackRunTerminator[128] = {
0x37, 10, 0x02, 3, 0x03, 2, 0x02, 2, 0x03, 3, 0x03, 4, 0x02, 4,
0x03, 5, 0x05, 6, 0x04, 6, 0x04, 7, 0x05, 7, 0x07, 7, 0x04, 8,
0x07, 8, 0x18, 9, 0x17, 10, 0x18, 10, 0x08, 10, 0x67, 11, 0x68, 11,
0x6c, 11, 0x37, 11, 0x28, 11, 0x17, 11, 0x18, 11, 0xca, 12, 0xcb, 12,
0xcc, 12, 0xcd, 12, 0x68, 12, 0x69, 12, 0x6a, 12, 0x6b, 12, 0xd2, 12,
0xd3, 12, 0xd4, 12, 0xd5, 12, 0xd6, 12, 0xd7, 12, 0x6c, 12, 0x6d, 12,
0xda, 12, 0xdb, 12, 0x54, 12, 0x55, 12, 0x56, 12, 0x57, 12, 0x64, 12,
0x65, 12, 0x52, 12, 0x53, 12, 0x24, 12, 0x37, 12, 0x38, 12, 0x27, 12,
0x28, 12, 0x58, 12, 0x59, 12, 0x2b, 12, 0x2c, 12, 0x5a, 12, 0x66, 12,
0x67, 12,
};
const uint8_t BlackRunMarkup[80] = {
0x0f, 10, 0xc8, 12, 0xc9, 12, 0x5b, 12, 0x33, 12, 0x34, 12, 0x35, 12,
0x6c, 13, 0x6d, 13, 0x4a, 13, 0x4b, 13, 0x4c, 13, 0x4d, 13, 0x72, 13,
0x73, 13, 0x74, 13, 0x75, 13, 0x76, 13, 0x77, 13, 0x52, 13, 0x53, 13,
0x54, 13, 0x55, 13, 0x5a, 13, 0x5b, 13, 0x64, 13, 0x65, 13, 0x08, 11,
0x0c, 11, 0x0d, 11, 0x12, 12, 0x13, 12, 0x14, 12, 0x15, 12, 0x16, 12,
0x17, 12, 0x1c, 12, 0x1d, 12, 0x1e, 12, 0x1f, 12,
};
const uint8_t WhiteRunTerminator[128] = {
0x35, 8, 0x07, 6, 0x07, 4, 0x08, 4, 0x0B, 4, 0x0C, 4, 0x0E, 4, 0x0F, 4,
0x13, 5, 0x14, 5, 0x07, 5, 0x08, 5, 0x08, 6, 0x03, 6, 0x34, 6, 0x35, 6,
0x2a, 6, 0x2B, 6, 0x27, 7, 0x0c, 7, 0x08, 7, 0x17, 7, 0x03, 7, 0x04, 7,
0x28, 7, 0x2B, 7, 0x13, 7, 0x24, 7, 0x18, 7, 0x02, 8, 0x03, 8, 0x1a, 8,
0x1b, 8, 0x12, 8, 0x13, 8, 0x14, 8, 0x15, 8, 0x16, 8, 0x17, 8, 0x28, 8,
0x29, 8, 0x2a, 8, 0x2b, 8, 0x2c, 8, 0x2d, 8, 0x04, 8, 0x05, 8, 0x0a, 8,
0x0b, 8, 0x52, 8, 0x53, 8, 0x54, 8, 0x55, 8, 0x24, 8, 0x25, 8, 0x58, 8,
0x59, 8, 0x5a, 8, 0x5b, 8, 0x4a, 8, 0x4b, 8, 0x32, 8, 0x33, 8, 0x34, 8,
};
const uint8_t WhiteRunMarkup[80] = {
0x1b, 5, 0x12, 5, 0x17, 6, 0x37, 7, 0x36, 8, 0x37, 8, 0x64, 8,
0x65, 8, 0x68, 8, 0x67, 8, 0xcc, 9, 0xcd, 9, 0xd2, 9, 0xd3, 9,
0xd4, 9, 0xd5, 9, 0xd6, 9, 0xd7, 9, 0xd8, 9, 0xd9, 9, 0xda, 9,
0xdb, 9, 0x98, 9, 0x99, 9, 0x9a, 9, 0x18, 6, 0x9b, 9, 0x08, 11,
0x0c, 11, 0x0d, 11, 0x12, 12, 0x13, 12, 0x14, 12, 0x15, 12, 0x16, 12,
0x17, 12, 0x1c, 12, 0x1d, 12, 0x1e, 12, 0x1f, 12,
};
class FaxEncoder {
public:
explicit FaxEncoder(RetainPtr<const CFX_DIBBase> src);
~FaxEncoder();
DataVector<uint8_t> Encode();
private:
void FaxEncode2DLine(pdfium::span<const uint8_t> src_span);
void FaxEncodeRun(int run, bool bWhite);
void AddBitStream(int data, int bitlen);
// Must outlive `m_RefLineSpan`.
RetainPtr<const CFX_DIBBase> const m_Src;
int m_DestBitpos = 0;
const int m_Cols;
const int m_Rows;
const int m_Pitch;
BinaryBuffer m_DestBuf;
// Must outlive `m_RefLineSpan`.
const DataVector<uint8_t> m_InitialRefLine;
DataVector<uint8_t> m_LineBuf;
pdfium::raw_span<const uint8_t> m_RefLineSpan;
};
FaxEncoder::FaxEncoder(RetainPtr<const CFX_DIBBase> src)
: m_Src(std::move(src)),
m_Cols(m_Src->GetWidth()),
m_Rows(m_Src->GetHeight()),
m_Pitch(m_Src->GetPitch()),
m_InitialRefLine(m_Pitch, 0xff),
m_LineBuf(Fx2DSizeOrDie(8, m_Pitch)),
m_RefLineSpan(m_InitialRefLine) {
DCHECK_EQ(1, m_Src->GetBPP());
m_DestBuf.SetAllocStep(10240);
}
FaxEncoder::~FaxEncoder() = default;
void FaxEncoder::AddBitStream(int data, int bitlen) {
for (int i = bitlen - 1; i >= 0; --i, ++m_DestBitpos) {
if (data & (1 << i))
m_LineBuf[m_DestBitpos / 8] |= 1 << (7 - m_DestBitpos % 8);
}
}
void FaxEncoder::FaxEncodeRun(int run, bool bWhite) {
while (run >= 2560) {
AddBitStream(0x1f, 12);
run -= 2560;
}
UNSAFE_TODO({
if (run >= 64) {
int markup = run - run % 64;
const uint8_t* p = bWhite ? WhiteRunMarkup : BlackRunMarkup;
p += (markup / 64 - 1) * 2;
AddBitStream(*p, p[1]);
}
run %= 64;
const uint8_t* p = bWhite ? WhiteRunTerminator : BlackRunTerminator;
p += run * 2;
AddBitStream(*p, p[1]);
});
}
void FaxEncoder::FaxEncode2DLine(pdfium::span<const uint8_t> src_span) {
int a0 = -1;
bool a0color = true;
while (1) {
int a1 = FindBit(src_span, m_Cols, a0 + 1, !a0color);
int b1;
int b2;
FaxG4FindB1B2(m_RefLineSpan, m_Cols, a0, a0color, &b1, &b2);
if (b2 < a1) {
m_DestBitpos += 3;
m_LineBuf[m_DestBitpos / 8] |= 1 << (7 - m_DestBitpos % 8);
++m_DestBitpos;
a0 = b2;
} else if (a1 - b1 <= 3 && b1 - a1 <= 3) {
int delta = a1 - b1;
switch (delta) {
case 0:
m_LineBuf[m_DestBitpos / 8] |= 1 << (7 - m_DestBitpos % 8);
break;
case 1:
case 2:
case 3:
m_DestBitpos += delta == 1 ? 1 : delta + 2;
m_LineBuf[m_DestBitpos / 8] |= 1 << (7 - m_DestBitpos % 8);
++m_DestBitpos;
m_LineBuf[m_DestBitpos / 8] |= 1 << (7 - m_DestBitpos % 8);
break;
case -1:
case -2:
case -3:
m_DestBitpos += delta == -1 ? 1 : -delta + 2;
m_LineBuf[m_DestBitpos / 8] |= 1 << (7 - m_DestBitpos % 8);
++m_DestBitpos;
break;
}
++m_DestBitpos;
a0 = a1;
a0color = !a0color;
} else {
int a2 = FindBit(src_span, m_Cols, a1 + 1, a0color);
++m_DestBitpos;
++m_DestBitpos;
m_LineBuf[m_DestBitpos / 8] |= 1 << (7 - m_DestBitpos % 8);
++m_DestBitpos;
if (a0 < 0)
a0 = 0;
FaxEncodeRun(a1 - a0, a0color);
FaxEncodeRun(a2 - a1, !a0color);
a0 = a2;
}
if (a0 >= m_Cols)
return;
}
}
DataVector<uint8_t> FaxEncoder::Encode() {
m_DestBitpos = 0;
uint8_t last_byte = 0;
for (int i = 0; i < m_Rows; ++i) {
fxcrt::Fill(m_LineBuf, 0);
m_LineBuf[0] = last_byte;
pdfium::span<const uint8_t> scan_line = m_Src->GetScanline(i);
FaxEncode2DLine(scan_line);
m_DestBuf.AppendSpan(pdfium::make_span(m_LineBuf).first(m_DestBitpos / 8));
last_byte = m_LineBuf[m_DestBitpos / 8];
m_DestBitpos %= 8;
m_RefLineSpan = scan_line;
}
if (m_DestBitpos)
m_DestBuf.AppendUint8(last_byte);
return m_DestBuf.DetachBuffer();
}
} // namespace
// static
DataVector<uint8_t> FaxModule::FaxEncode(RetainPtr<const CFX_DIBBase> src) {
DCHECK_EQ(1, src->GetBPP());
FaxEncoder encoder(std::move(src));
return encoder.Encode();
}
#endif // BUILDFLAG(IS_WIN)
} // namespace fxcodec