Clean up fx_codec_fax.cpp.

core/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp

 // 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/fpdf_parser/include/fpdf_parser_decode.h"
 
 #include <limits.h>
+
+#include <algorithm>
 #include <utility>
 #include <vector>
 
 #include "core/fpdfapi/fpdf_parser/fpdf_parser_utility.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_dictionary.h"
 #include "core/fpdfapi/include/cpdf_modulemgr.h"
 #include "core/fxcodec/include/fx_codec.h"
 #include "core/fxcrt/include/fx_ext.h"
 #include "third_party/base/stl_util.h"
@@ skipping 147 matching lines @@
 }
 
 uint32_t RunLengthDecode(const uint8_t* src_buf,
                          uint32_t src_size,
                          uint8_t*& dest_buf,
                          uint32_t& dest_size) {
   uint32_t i = 0;
   uint32_t old;
   dest_size = 0;
   while (i < src_size) {
+    if (src_buf[i] == 128)
+      break;
+
     if (src_buf[i] < 128) {
       old = dest_size;
       dest_size += src_buf[i] + 1;
       if (dest_size < old)

[Tom Sepez, 2016/09/23 21:55:48]

note: OK, unsigned type.

         return FX_INVALID_OFFSET;
       i += src_buf[i] + 2;

[Tom Sepez, 2016/09/23 21:55:48]

note: there's one value where this can overflow, even if dest_size didn't. let's
just ignore it?

[Lei Zhang, 2016/09/26 22:50:59]

Sure.

-    } else if (src_buf[i] > 128) {
+    } else {
       old = dest_size;
       dest_size += 257 - src_buf[i];
       if (dest_size < old)
         return FX_INVALID_OFFSET;
       i += 2;
-    } else {
-      break;
     }
   }
   if (dest_size >= _STREAM_MAX_SIZE_)
     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;
         FXSYS_memset(dest_buf + dest_count + copy_len, '\0', delta);
       }
       FXSYS_memcpy(dest_buf + dest_count, src_buf + i + 1, copy_len);
       dest_count += src_buf[i] + 1;
       i += src_buf[i] + 2;
-    } else if (src_buf[i] > 128) {
+    } else {
       int fill = 0;
       if (i < src_size - 1) {
         fill = src_buf[i + 1];
       }
       FXSYS_memset(dest_buf + dest_count, fill, 257 - src_buf[i]);
       dest_count += 257 - src_buf[i];
       i += 2;
-    } else {
-      break;
     }
   }
-  uint32_t ret = i + 1;
-  if (ret > src_size) {
-    ret = src_size;
-  }
-  return ret;
+
+  return std::min(i + 1, src_size);
 }
 
 CCodec_ScanlineDecoder* FPDFAPI_CreateFaxDecoder(
     const uint8_t* src_buf,
     uint32_t src_size,
     int width,
     int height,
     const CPDF_Dictionary* pParams) {
   int K = 0;
-  FX_BOOL EndOfLine = FALSE;
-  FX_BOOL ByteAlign = FALSE;
-  FX_BOOL BlackIs1 = FALSE;
+  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");
+    EndOfLine = !!pParams->GetIntegerFor("EndOfLine");

[Tom Sepez, 2016/09/23 21:55:48]

Yay, another not assigning 0 or 1 to FX_BOOL !!!

[Lei Zhang, 2016/09/26 22:50:59]

Acknowledged.

+    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);
 }
@@ skipping 313 matching lines @@
                      uint32_t src_size,
                      uint8_t*& dest_buf,
                      uint32_t& dest_size) {
   CCodec_ModuleMgr* pEncoders = CPDF_ModuleMgr::Get()->GetCodecModule();
   if (pEncoders) {
     return pEncoders->GetFlateModule()->FlateOrLZWDecode(
         FALSE, src_buf, src_size, FALSE, 0, 0, 0, 0, 0, dest_buf, dest_size);
   }
   return 0;
 }