Prevent buffer underflow in CPDF_TextObject::CalcPositionData
R=tsepez@chromium.org
BUG=554115
Review URL: https://codereview.chromium.org/1435473004 .
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
index eaa8ef1..3777cd0 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page.cpp
@@ -409,11 +409,11 @@
for (int i = 0; i < m_nChars; ++i) {
FX_DWORD charcode =
m_nChars == 1 ? (FX_DWORD)(uintptr_t)m_pCharCodes : m_pCharCodes[i];
- if (charcode == (FX_DWORD)-1) {
- curpos -= FXSYS_Mul(m_pCharPos[i - 1], fontsize) / 1000;
- continue;
- }
- if (i) {
+ if (i > 0) {
+ if (charcode == (FX_DWORD)-1) {
+ curpos -= FXSYS_Mul(m_pCharPos[i - 1], fontsize) / 1000;
+ continue;
+ }
m_pCharPos[i - 1] = curpos;
}
FX_RECT char_rect;
