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| author | thestig <thestig@chromium.org> | 2016-10-12 09:37:28 -0700 |
|---|---|---|
| committer | Commit bot <commit-bot@chromium.org> | 2016-10-12 09:37:28 -0700 |
| commit | 47cbc06ef6f528e4d30a869ec533d010ee79b064 (patch) | |
| tree | ebe4ee69194e32de371999268749cef7ef114305 | |
| parent | a30537f8b07492489e81414c9037af90c8b1448e (diff) | |
| download | pdfium-47cbc06ef6f528e4d30a869ec533d010ee79b064.tar.xz | |
Optimize roll operator in CPDF_PSEngine.
Rolling 0 times is a no-op.
Rolling 0 items is a no-op.
Rolling N items J times is the same as rolling N items J % N times.
This also avoids an integer overflow corner case.
BUG=chromium:648077
Review-Url: https://codereview.chromium.org/2412833002
| -rw-r--r-- | core/fpdfapi/page/fpdf_page_func.cpp | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/core/fpdfapi/page/fpdf_page_func.cpp b/core/fpdfapi/page/fpdf_page_func.cpp index bf44a1e7c5..6af787ea49 100644 --- a/core/fpdfapi/page/fpdf_page_func.cpp +++ b/core/fpdfapi/page/fpdf_page_func.cpp @@ -376,10 +376,12 @@ FX_BOOL CPDF_PSEngine::DoOperator(PDF_PSOP op) { case PSOP_ROLL: { int j = static_cast<int>(Pop()); int n = static_cast<int>(Pop()); - if (m_StackCount == 0) + if (j == 0 || n == 0 || m_StackCount == 0) break; if (n < 0 || n > static_cast<int>(m_StackCount)) break; + + j %= n; if (j < 0) { for (int i = 0; i < -j; i++) { FX_FLOAT first = m_Stack[m_StackCount - n]; |