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// Copyright 2014 PDFium Authors. All rights reserved.
// 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/fpdfapi/parser/fpdf_parser_decode.h"
#include <limits.h>
#include <algorithm>
#include <sstream>
#include <utility>
#include <vector>
#include "constants/stream_dict_common.h"
#include "core/fpdfapi/cpdf_modulemgr.h"
#include "core/fpdfapi/parser/cpdf_array.h"
#include "core/fpdfapi/parser/cpdf_dictionary.h"
#include "core/fpdfapi/parser/fpdf_parser_utility.h"
#include "core/fxcodec/codec/ccodec_faxmodule.h"
#include "core/fxcodec/codec/ccodec_flatemodule.h"
#include "core/fxcodec/codec/ccodec_scanlinedecoder.h"
#include "core/fxcodec/fx_codec.h"
#include "core/fxcrt/fx_extension.h"
#include "third_party/base/numerics/safe_math.h"
namespace {
const uint32_t kMaxStreamSize = 20 * 1024 * 1024;
uint16_t GetUnicodeFromBytes(const uint8_t* bytes, bool bBE) {
return bBE ? (bytes[0] << 8 | bytes[1]) : (bytes[1] << 8 | bytes[0]);
}
bool CheckFlateDecodeParams(int Colors, int BitsPerComponent, int Columns) {
if (Colors < 0 || BitsPerComponent < 0 || Columns < 0)
return false;
pdfium::base::CheckedNumeric<int> check = Columns;
check *= Colors;
check *= BitsPerComponent;
if (!check.IsValid())
return false;
return check.ValueOrDie() <= INT_MAX - 7;
}
} // namespace
const uint16_t PDFDocEncoding[256] = {
0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008,
0x0009, 0x000a, 0x000b, 0x000c, 0x000d, 0x000e, 0x000f, 0x0010, 0x0011,
0x0012, 0x0013, 0x0014, 0x0015, 0x0016, 0x0017, 0x02d8, 0x02c7, 0x02c6,
0x02d9, 0x02dd, 0x02db, 0x02da, 0x02dc, 0x0020, 0x0021, 0x0022, 0x0023,
0x0024, 0x0025, 0x0026, 0x0027, 0x0028, 0x0029, 0x002a, 0x002b, 0x002c,
0x002d, 0x002e, 0x002f, 0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035,
0x0036, 0x0037, 0x0038, 0x0039, 0x003a, 0x003b, 0x003c, 0x003d, 0x003e,
0x003f, 0x0040, 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047,
0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x004f, 0x0050,
0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, 0x0058, 0x0059,
0x005a, 0x005b, 0x005c, 0x005d, 0x005e, 0x005f, 0x0060, 0x0061, 0x0062,
0x0063, 0x0064, 0x0065, 0x0066, 0x0067, 0x0068, 0x0069, 0x006a, 0x006b,
0x006c, 0x006d, 0x006e, 0x006f, 0x0070, 0x0071, 0x0072, 0x0073, 0x0074,
0x0075, 0x0076, 0x0077, 0x0078, 0x0079, 0x007a, 0x007b, 0x007c, 0x007d,
0x007e, 0x0000, 0x2022, 0x2020, 0x2021, 0x2026, 0x2014, 0x2013, 0x0192,
0x2044, 0x2039, 0x203a, 0x2212, 0x2030, 0x201e, 0x201c, 0x201d, 0x2018,
0x2019, 0x201a, 0x2122, 0xfb01, 0xfb02, 0x0141, 0x0152, 0x0160, 0x0178,
0x017d, 0x0131, 0x0142, 0x0153, 0x0161, 0x017e, 0x0000, 0x20ac, 0x00a1,
0x00a2, 0x00a3, 0x00a4, 0x00a5, 0x00a6, 0x00a7, 0x00a8, 0x00a9, 0x00aa,
0x00ab, 0x00ac, 0x0000, 0x00ae, 0x00af, 0x00b0, 0x00b1, 0x00b2, 0x00b3,
0x00b4, 0x00b5, 0x00b6, 0x00b7, 0x00b8, 0x00b9, 0x00ba, 0x00bb, 0x00bc,
0x00bd, 0x00be, 0x00bf, 0x00c0, 0x00c1, 0x00c2, 0x00c3, 0x00c4, 0x00c5,
0x00c6, 0x00c7, 0x00c8, 0x00c9, 0x00ca, 0x00cb, 0x00cc, 0x00cd, 0x00ce,
0x00cf, 0x00d0, 0x00d1, 0x00d2, 0x00d3, 0x00d4, 0x00d5, 0x00d6, 0x00d7,
0x00d8, 0x00d9, 0x00da, 0x00db, 0x00dc, 0x00dd, 0x00de, 0x00df, 0x00e0,
0x00e1, 0x00e2, 0x00e3, 0x00e4, 0x00e5, 0x00e6, 0x00e7, 0x00e8, 0x00e9,
0x00ea, 0x00eb, 0x00ec, 0x00ed, 0x00ee, 0x00ef, 0x00f0, 0x00f1, 0x00f2,
0x00f3, 0x00f4, 0x00f5, 0x00f6, 0x00f7, 0x00f8, 0x00f9, 0x00fa, 0x00fb,
0x00fc, 0x00fd, 0x00fe, 0x00ff};
uint32_t A85Decode(const uint8_t* src_buf,
uint32_t src_size,
uint8_t** dest_buf,
uint32_t* dest_size) {
*dest_size = 0;
*dest_buf = nullptr;
if (src_size == 0)
return 0;
// Count legal characters and zeros.
uint32_t zcount = 0;
uint32_t pos = 0;
while (pos < src_size) {
uint8_t ch = src_buf[pos];
if (ch == 'z') {
zcount++;
} else if ((ch < '!' || ch > 'u') && !PDFCharIsLineEnding(ch) &&
ch != ' ' && ch != '\t') {
break;
}
pos++;
}
// No content to decode.
if (pos == 0)
return 0;
// Count the space needed to contain non-zero characters. The encoding ratio
// of Ascii85 is 4:5.
uint32_t space_for_non_zeroes = (pos - zcount) / 5 * 4 + 4;
if (zcount > (UINT_MAX - space_for_non_zeroes) / 4)
return FX_INVALID_OFFSET;
*dest_buf = FX_Alloc(uint8_t, zcount * 4 + space_for_non_zeroes);
size_t state = 0;
uint32_t res = 0;
pos = 0;
while (pos < src_size) {
uint8_t ch = src_buf[pos++];
if (PDFCharIsLineEnding(ch) || ch == ' ' || ch == '\t')
continue;
if (ch == 'z') {
memset(*dest_buf + *dest_size, 0, 4);
state = 0;
res = 0;
*dest_size += 4;
continue;
}
// Check for the end or illegal character.
if (ch < '!' || ch > 'u')
break;
res = res * 85 + ch - 33;
if (state < 4) {
++state;
continue;
}
for (size_t i = 0; i < 4; ++i) {
(*dest_buf)[(*dest_size)++] = static_cast<uint8_t>(res >> (3 - i) * 8);
}
state = 0;
res = 0;
}
// Handle partial group.
if (state) {
for (size_t i = state; i < 5; ++i)
res = res * 85 + 84;
for (size_t i = 0; i < state - 1; ++i)
(*dest_buf)[(*dest_size)++] = static_cast<uint8_t>(res >> (3 - i) * 8);
}
if (pos < src_size && src_buf[pos] == '>')
++pos;
return pos;
}
uint32_t HexDecode(const uint8_t* src_buf,
uint32_t src_size,
uint8_t** dest_buf,
uint32_t* dest_size) {
*dest_size = 0;
if (src_size == 0) {
*dest_buf = nullptr;
return 0;
}
uint32_t i = 0;
// Find the end of data.
while (i < src_size && src_buf[i] != '>')
++i;
*dest_buf = FX_Alloc(uint8_t, i / 2 + 1);
bool bFirst = true;
for (i = 0; i < src_size; ++i) {
uint8_t ch = src_buf[i];
if (PDFCharIsLineEnding(ch) || ch == ' ' || ch == '\t')
continue;
if (ch == '>') {
++i;
break;
}
if (!std::isxdigit(ch))
continue;
int digit = FXSYS_HexCharToInt(ch);
if (bFirst)
(*dest_buf)[*dest_size] = digit * 16;
else
(*dest_buf)[(*dest_size)++] += digit;
bFirst = !bFirst;
}
if (!bFirst)
++(*dest_size);
return i;
}
uint32_t RunLengthDecode(const uint8_t* src_buf,
uint32_t src_size,
uint8_t** dest_buf,
uint32_t* dest_size) {
uint32_t i = 0;
*dest_size = 0;
while (i < src_size) {
if (src_buf[i] == 128)
break;
uint32_t old = *dest_size;
if (src_buf[i] < 128) {
*dest_size += src_buf[i] + 1;
if (*dest_size < old)
return FX_INVALID_OFFSET;
i += src_buf[i] + 2;
} else {
*dest_size += 257 - src_buf[i];
if (*dest_size < old)
return FX_INVALID_OFFSET;
i += 2;
}
}
if (*dest_size >= kMaxStreamSize)
return FX_INVALID_OFFSET;
*dest_buf = FX_Alloc(uint8_t, *dest_size);
i = 0;
int dest_count = 0;
while (i < src_size) {
if (src_buf[i] == 128)
break;
if (src_buf[i] < 128) {
uint32_t copy_len = src_buf[i] + 1;
uint32_t buf_left = src_size - i - 1;
if (buf_left < copy_len) {
uint32_t delta = copy_len - buf_left;
copy_len = buf_left;
memset(*dest_buf + dest_count + copy_len, '\0', delta);
}
memcpy(*dest_buf + dest_count, src_buf + i + 1, copy_len);
dest_count += src_buf[i] + 1;
i += src_buf[i] + 2;
} else {
int fill = 0;
if (i < src_size - 1)
fill = src_buf[i + 1];
memset(*dest_buf + dest_count, fill, 257 - src_buf[i]);
dest_count += 257 - src_buf[i];
i += 2;
}
}
return std::min(i + 1, src_size);
}
std::unique_ptr<CCodec_ScanlineDecoder> FPDFAPI_CreateFaxDecoder(
const uint8_t* src_buf,
uint32_t src_size,
int width,
int height,
const CPDF_Dictionary* pParams) {
int K = 0;
bool EndOfLine = false;
bool ByteAlign = false;
bool BlackIs1 = false;
int Columns = 1728;
int Rows = 0;
if (pParams) {
K = pParams->GetIntegerFor("K");
EndOfLine = !!pParams->GetIntegerFor("EndOfLine");
ByteAlign = !!pParams->GetIntegerFor("EncodedByteAlign");
BlackIs1 = !!pParams->GetIntegerFor("BlackIs1");
Columns = pParams->GetIntegerFor("Columns", 1728);
Rows = pParams->GetIntegerFor("Rows");
if (Rows > USHRT_MAX)
Rows = 0;
}
return CPDF_ModuleMgr::Get()->GetFaxModule()->CreateDecoder(
src_buf, src_size, width, height, K, EndOfLine, ByteAlign, BlackIs1,
Columns, Rows);
}
std::unique_ptr<CCodec_ScanlineDecoder> FPDFAPI_CreateFlateDecoder(
const uint8_t* src_buf,
uint32_t src_size,
int width,
int height,
int nComps,
int bpc,
const CPDF_Dictionary* pParams) {
int predictor = 0;
int Colors = 0;
int BitsPerComponent = 0;
int Columns = 0;
if (pParams) {
predictor = pParams->GetIntegerFor("Predictor");
Colors = pParams->GetIntegerFor("Colors", 1);
BitsPerComponent = pParams->GetIntegerFor("BitsPerComponent", 8);
Columns = pParams->GetIntegerFor("Columns", 1);
if (!CheckFlateDecodeParams(Colors, BitsPerComponent, Columns))
return nullptr;
}
return CPDF_ModuleMgr::Get()->GetFlateModule()->CreateDecoder(
src_buf, src_size, width, height, nComps, bpc, predictor, Colors,
BitsPerComponent, Columns);
}
uint32_t FPDFAPI_FlateOrLZWDecode(bool bLZW,
const uint8_t* src_buf,
uint32_t src_size,
const CPDF_Dictionary* pParams,
uint32_t estimated_size,
uint8_t** dest_buf,
uint32_t* dest_size) {
int predictor = 0;
int Colors = 0;
int BitsPerComponent = 0;
int Columns = 0;
bool bEarlyChange = true;
if (pParams) {
predictor = pParams->GetIntegerFor("Predictor");
bEarlyChange = !!pParams->GetIntegerFor("EarlyChange", 1);
Colors = pParams->GetIntegerFor("Colors", 1);
BitsPerComponent = pParams->GetIntegerFor("BitsPerComponent", 8);
Columns = pParams->GetIntegerFor("Columns", 1);
if (!CheckFlateDecodeParams(Colors, BitsPerComponent, Columns))
return FX_INVALID_OFFSET;
}
return CPDF_ModuleMgr::Get()->GetFlateModule()->FlateOrLZWDecode(
bLZW, src_buf, src_size, bEarlyChange, predictor, Colors,
BitsPerComponent, Columns, estimated_size, dest_buf, dest_size);
}
bool PDF_DataDecode(const uint8_t* src_buf,
uint32_t src_size,
const CPDF_Dictionary* pDict,
uint32_t last_estimated_size,
bool bImageAcc,
uint8_t** dest_buf,
uint32_t* dest_size,
ByteString* ImageEncoding,
const CPDF_Dictionary** pImageParms) {
const CPDF_Object* pDecoder =
pDict ? pDict->GetDirectObjectFor("Filter") : nullptr;
if (!pDecoder || (!pDecoder->IsArray() && !pDecoder->IsName()))
return false;
const CPDF_Object* pParams =
pDict ? pDict->GetDirectObjectFor(pdfium::stream::kDecodeParms) : nullptr;
std::vector<std::pair<ByteString, const CPDF_Object*>> DecoderArray;
if (const CPDF_Array* pDecoders = pDecoder->AsArray()) {
const CPDF_Array* pParamsArray = ToArray(pParams);
for (size_t i = 0; i < pDecoders->GetCount(); ++i) {
DecoderArray.push_back(
{pDecoders->GetStringAt(i),
pParamsArray ? pParamsArray->GetDictAt(i) : nullptr});
}
} else {
DecoderArray.push_back(
{pDecoder->GetString(), pParams ? pParams->GetDict() : nullptr});
}
uint8_t* last_buf = const_cast<uint8_t*>(src_buf);
uint32_t last_size = src_size;
size_t nSize = DecoderArray.size();
for (size_t i = 0; i < nSize; ++i) {
int estimated_size = i == nSize - 1 ? last_estimated_size : 0;
ByteString decoder = DecoderArray[i].first;
const CPDF_Dictionary* pParam = ToDictionary(DecoderArray[i].second);
uint8_t* new_buf = nullptr;
uint32_t new_size = 0xFFFFFFFF;
uint32_t offset = FX_INVALID_OFFSET;
if (decoder == "Crypt")
continue;
if (decoder == "FlateDecode" || decoder == "Fl") {
if (bImageAcc && i == nSize - 1) {
*ImageEncoding = "FlateDecode";
*dest_buf = last_buf;
*dest_size = last_size;
*pImageParms = pParam;
return true;
}
offset = FPDFAPI_FlateOrLZWDecode(false, last_buf, last_size, pParam,
estimated_size, &new_buf, &new_size);
} else if (decoder == "LZWDecode" || decoder == "LZW") {
offset = FPDFAPI_FlateOrLZWDecode(true, last_buf, last_size, pParam,
estimated_size, &new_buf, &new_size);
} else if (decoder == "ASCII85Decode" || decoder == "A85") {
offset = A85Decode(last_buf, last_size, &new_buf, &new_size);
} else if (decoder == "ASCIIHexDecode" || decoder == "AHx") {
offset = HexDecode(last_buf, last_size, &new_buf, &new_size);
} else if (decoder == "RunLengthDecode" || decoder == "RL") {
if (bImageAcc && i == nSize - 1) {
*ImageEncoding = "RunLengthDecode";
*dest_buf = last_buf;
*dest_size = last_size;
*pImageParms = pParam;
return true;
}
offset = RunLengthDecode(last_buf, last_size, &new_buf, &new_size);
} else {
// If we get here, assume it's an image decoder.
if (decoder == "DCT")
decoder = "DCTDecode";
else if (decoder == "CCF")
decoder = "CCITTFaxDecode";
*ImageEncoding = decoder;
*pImageParms = pParam;
*dest_buf = last_buf;
*dest_size = last_size;
return true;
}
if (last_buf != src_buf)
FX_Free(last_buf);
if (offset == FX_INVALID_OFFSET) {
FX_Free(new_buf);
return false;
}
last_buf = new_buf;
last_size = new_size;
}
ImageEncoding->clear();
*pImageParms = nullptr;
*dest_buf = last_buf;
*dest_size = last_size;
return true;
}
WideString PDF_DecodeText(const uint8_t* src_data, uint32_t src_len) {
int dest_pos = 0;
WideString result;
if (src_len >= 2 && ((src_data[0] == 0xfe && src_data[1] == 0xff) ||
(src_data[0] == 0xff && src_data[1] == 0xfe))) {
uint32_t max_chars = (src_len - 2) / 2;
if (!max_chars)
return result;
pdfium::span<wchar_t> dest_buf = result.GetBuffer(max_chars);
bool bBE = src_data[0] == 0xfe || (src_data[0] == 0xff && !src_data[2]);
const uint8_t* uni_str = src_data + 2;
for (uint32_t i = 0; i < max_chars * 2; i += 2) {
uint16_t unicode = GetUnicodeFromBytes(uni_str + i, bBE);
if (unicode != 0x1b) {
dest_buf[dest_pos++] = unicode;
continue;
}
i += 2;
while (i < max_chars * 2) {
uint16_t unicode2 = GetUnicodeFromBytes(uni_str + i, bBE);
i += 2;
if (unicode2 == 0x1b)
break;
}
}
} else {
pdfium::span<wchar_t> dest_buf = result.GetBuffer(src_len);
for (uint32_t i = 0; i < src_len; ++i)
dest_buf[i] = PDFDocEncoding[src_data[i]];
dest_pos = src_len;
}
result.ReleaseBuffer(dest_pos);
return result;
}
WideString PDF_DecodeText(const ByteString& bstr) {
return PDF_DecodeText(reinterpret_cast<const uint8_t*>(bstr.c_str()),
bstr.GetLength());
}
ByteString PDF_EncodeText(const wchar_t* pString, int len) {
if (len == -1)
len = wcslen(pString);
int i;
ByteString result;
{
pdfium::span<char> dest_buf = result.GetBuffer(len);
for (i = 0; i < len; ++i) {
int code;
for (code = 0; code < 256; ++code) {
if (PDFDocEncoding[code] == pString[i])
break;
}
if (code == 256)
break;
dest_buf[i] = code;
}
}
result.ReleaseBuffer(i);
if (i == len)
return result;
if (len > INT_MAX / 2 - 1) {
result.ReleaseBuffer(0);
return result;
}
size_t dest_index = 0;
size_t encLen = len * 2 + 2;
{
pdfium::span<char> cspan = result.GetBuffer(encLen);
auto dest_buf = pdfium::make_span(reinterpret_cast<uint8_t*>(cspan.data()),
cspan.size());
dest_buf[dest_index++] = 0xfe;
dest_buf[dest_index++] = 0xff;
for (int j = 0; j < len; ++j) {
dest_buf[dest_index++] = pString[j] >> 8;
dest_buf[dest_index++] = static_cast<uint8_t>(pString[j]);
}
}
result.ReleaseBuffer(encLen);
return result;
}
ByteString PDF_EncodeText(const WideString& str) {
return PDF_EncodeText(str.c_str(), str.GetLength());
}
ByteString PDF_EncodeString(const ByteString& src, bool bHex) {
std::ostringstream result;
int srclen = src.GetLength();
if (bHex) {
result << '<';
for (int i = 0; i < srclen; ++i) {
char buf[2];
FXSYS_IntToTwoHexChars(src[i], buf);
result << buf[0];
result << buf[1];
}
result << '>';
return ByteString(result);
}
result << '(';
for (int i = 0; i < srclen; ++i) {
uint8_t ch = src[i];
if (ch == 0x0a) {
result << "\\n";
continue;
}
if (ch == 0x0d) {
result << "\\r";
continue;
}
if (ch == ')' || ch == '\\' || ch == '(')
result << '\\';
result << static_cast<char>(ch);
}
result << ')';
return ByteString(result);
}
bool FlateEncode(const uint8_t* src_buf,
uint32_t src_size,
uint8_t** dest_buf,
uint32_t* dest_size) {
CCodec_ModuleMgr* pEncoders = CPDF_ModuleMgr::Get()->GetCodecModule();
return pEncoders->GetFlateModule()->Encode(src_buf, src_size, dest_buf,
dest_size);
}
uint32_t FlateDecode(const uint8_t* src_buf,
uint32_t src_size,
uint8_t** dest_buf,
uint32_t* dest_size) {
CCodec_ModuleMgr* pEncoders = CPDF_ModuleMgr::Get()->GetCodecModule();
return pEncoders->GetFlateModule()->FlateOrLZWDecode(
false, src_buf, src_size, false, 0, 0, 0, 0, 0, dest_buf, dest_size);
}