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author | Lei Zhang <thestig@chromium.org> | 2017-12-12 18:36:30 +0000 |
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committer | Chromium commit bot <commit-bot@chromium.org> | 2017-12-12 18:36:30 +0000 |
commit | 97c0aed963a0ebdce39fa59502be5ae127407dd0 (patch) | |
tree | 2cd2a08812938824055867538c614419db64bd22 | |
parent | 27a36690573db0e63b0f36cb250c6d9e92579bd7 (diff) | |
download | pdfium-97c0aed963a0ebdce39fa59502be5ae127407dd0.tar.xz |
Use early returns in pdf_parser_decode.cpp.
Also add a GetUnicodeFromBytes() helper function and use
FX_INVALID_OFFSET more often.
Change-Id: I3b0954e0cad31a600b0a990360ab370186c792d6
Reviewed-on: https://pdfium-review.googlesource.com/20850
Reviewed-by: Ryan Harrison <rharrison@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
-rw-r--r-- | core/fpdfapi/parser/fpdf_parser_decode.cpp | 68 |
1 files changed, 36 insertions, 32 deletions
diff --git a/core/fpdfapi/parser/fpdf_parser_decode.cpp b/core/fpdfapi/parser/fpdf_parser_decode.cpp index 3a8660f0a4..d7114b66c5 100644 --- a/core/fpdfapi/parser/fpdf_parser_decode.cpp +++ b/core/fpdfapi/parser/fpdf_parser_decode.cpp @@ -28,6 +28,10 @@ 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; @@ -104,7 +108,7 @@ uint32_t A85Decode(const uint8_t* src_buf, // 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 0xFFFFFFFF; + return FX_INVALID_OFFSET; *dest_buf = FX_Alloc(uint8_t, zcount * 4 + space_for_non_zeroes); size_t state = 0; @@ -120,21 +124,24 @@ uint32_t A85Decode(const uint8_t* src_buf, state = 0; res = 0; *dest_size += 4; - } else if (ch >= '!' && ch <= 'u') { - res = res * 85 + ch - 33; - state++; - if (state == 5) { - for (size_t i = 0; i < 4; ++i) { - (*dest_buf)[(*dest_size)++] = - static_cast<uint8_t>(res >> (3 - i) * 8); - } - state = 0; - res = 0; - } - } else { - // The end or illegal character. + 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) { @@ -316,7 +323,7 @@ uint32_t FPDFAPI_FlateOrLZWDecode(bool bLZW, BitsPerComponent = pParams->GetIntegerFor("BitsPerComponent", 8); Columns = pParams->GetIntegerFor("Columns", 1); if (!CheckFlateDecodeParams(Colors, BitsPerComponent, Columns)) - return 0xFFFFFFFF; + return FX_INVALID_OFFSET; } return CPDF_ModuleMgr::Get()->GetFlateModule()->FlateOrLZWDecode( bLZW, src_buf, src_size, bEarlyChange, predictor, Colors, @@ -360,7 +367,7 @@ bool PDF_DataDecode(const uint8_t* src_buf, CPDF_Dictionary* pParam = ToDictionary(DecoderArray[i].second); uint8_t* new_buf = nullptr; uint32_t new_size = 0xFFFFFFFF; - int offset = -1; + uint32_t offset = FX_INVALID_OFFSET; if (decoder == "Crypt") continue; if (decoder == "FlateDecode" || decoder == "Fl") { @@ -403,7 +410,7 @@ bool PDF_DataDecode(const uint8_t* src_buf, } if (last_buf != src_buf) FX_Free(last_buf); - if (offset == -1) { + if (offset == FX_INVALID_OFFSET) { FX_Free(new_buf); return false; } @@ -421,30 +428,27 @@ WideString PDF_DecodeText(const uint8_t* src_data, uint32_t src_len) { WideString result; if (src_len >= 2 && ((src_data[0] == 0xfe && src_data[1] == 0xff) || (src_data[0] == 0xff && src_data[1] == 0xfe))) { - bool bBE = src_data[0] == 0xfe; uint32_t max_chars = (src_len - 2) / 2; if (!max_chars) return result; - if (src_data[0] == 0xff) - bBE = !src_data[2]; + bool bBE = src_data[0] == 0xfe || (src_data[0] == 0xff && !src_data[2]); wchar_t* dest_buf = result.GetBuffer(max_chars); const uint8_t* uni_str = src_data + 2; int dest_pos = 0; for (uint32_t i = 0; i < max_chars * 2; i += 2) { - uint16_t unicode = bBE ? (uni_str[i] << 8 | uni_str[i + 1]) - : (uni_str[i + 1] << 8 | uni_str[i]); - if (unicode == 0x1b) { - i += 2; - while (i < max_chars * 2) { - uint16_t unicode2 = bBE ? (uni_str[i] << 8 | uni_str[i + 1]) - : (uni_str[i + 1] << 8 | uni_str[i]); - i += 2; - if (unicode2 == 0x1b) - break; - } - } else { + 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; } } result.ReleaseBuffer(dest_pos); |