Remove strange integral constants for "true", "false", "%PDF".

Compilers have good inline memcmp nowadays, so we don't
have to resort to old tricks.

Remove FXDWORD_FROM_LSBFIRST and FXDWORD_FROM_MSBFIRST
while we're at it. MSBFIRST was technically wrong due
to promotion to int.

R=dsinclair@chromium.org

Review URL: https://codereview.chromium.org/1834553002 .

1 files changed, 2 insertions, 8 deletions

diff --git a/core/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp b/core/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
index a4cc85ae7d..caffb6861b 100644
--- a/core/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
+++ b/core/fpdfapi/fpdf_parser/fpdf_parser_utility.cpp
@@ -69,20 +69,14 @@ const char PDF_CharType[256] = {
     'R', 'R', 'R', 'R', 'R', 'R', 'R', 'W'};
 
 int32_t GetHeaderOffset(IFX_FileRead* pFile) {
-  // TODO(dsinclair): This is a complicated way of saying %PDF, simplify?
-  const FX_DWORD tag = FXDWORD_FROM_LSBFIRST(0x46445025);
-
   const size_t kBufSize = 4;
   uint8_t buf[kBufSize];
-  int32_t offset = 0;
-  while (offset <= 1024) {
+  for (int32_t offset = 0; offset <= 1024; ++offset) {
     if (!pFile->ReadBlock(buf, offset, kBufSize))
       return -1;
 
-    if (*(FX_DWORD*)buf == tag)
+    if (memcmp(buf, "%PDF", 4) == 0)
       return offset;
-
-    ++offset;
   }
   return -1;
 }