2 files changed, 18 insertions, 7 deletions
diff --git a/fpdfsdk/fpdftext.cpp b/fpdfsdk/fpdftext.cpp
index 6df593f710..6a030b8ebd 100644
--- a/fpdfsdk/fpdftext.cpp
+++ b/fpdfsdk/fpdftext.cpp
@@ -29,6 +29,8 @@
 
 namespace {
 
+constexpr size_t kBytesPerCharacter = sizeof(unsigned short);
+
 CPDF_TextPage* CPDFTextPageFromFPDFTextPage(FPDF_TEXTPAGE text_page) {
   return static_cast<CPDF_TextPage*>(text_page);
 }
@@ -169,19 +171,19 @@ FPDF_EXPORT int FPDF_CALLCONV FPDFText_GetText(FPDF_TEXTPAGE text_page,
   if (start >= textpage->CountChars())
     return 0;
 
-  CFX_WideString str = textpage->GetPageText(start, count);
+  CFX_WideString str = textpage->GetPageText(start, count - 1);
   if (str.GetLength() <= 0)
     return 0;
 
   // UFT16LE_Encode doesn't handle surrogate pairs properly, so it is expected
   // the number of items to stay the same.
   CFX_ByteString cbUTF16str = str.UTF16LE_Encode();
-  ASSERT(cbUTF16str.GetLength() / sizeof(unsigned short) <=
+  ASSERT(cbUTF16str.GetLength() / kBytesPerCharacter <=
          static_cast<size_t>(count));
   memcpy(result, cbUTF16str.GetBuffer(cbUTF16str.GetLength()),
          cbUTF16str.GetLength());
 
-  return cbUTF16str.GetLength() / sizeof(unsigned short);
+  return cbUTF16str.GetLength() / kBytesPerCharacter;
 }
 
 FPDF_EXPORT int FPDF_CALLCONV FPDFText_CountRects(FPDF_TEXTPAGE text_page,
diff --git a/fpdfsdk/fpdftext_embeddertest.cpp b/fpdfsdk/fpdftext_embeddertest.cpp
index a83ffe7c29..7e8e033ae0 100644
--- a/fpdfsdk/fpdftext_embeddertest.cpp
+++ b/fpdfsdk/fpdftext_embeddertest.cpp
@@ -16,13 +16,12 @@ namespace {
 bool check_unsigned_shorts(const char* expected,
                            const unsigned short* actual,
                            size_t length) {
-  if (length > strlen(expected) + 1) {
+  if (length > strlen(expected) + 1)
     return false;
-  }
+
   for (size_t i = 0; i < length; ++i) {
-    if (actual[i] != static_cast<unsigned short>(expected[i])) {
+    if (actual[i] != static_cast<unsigned short>(expected[i]))
       return false;
-    }
   }
   return true;
 }
@@ -64,6 +63,16 @@ TEST_F(FPDFTextEmbeddertest, Text) {
         << " at " << i;
   }
 
+  // Extracting using a buffer that will be completely filled. Small buffer is
+  // 12 elements long, since it will need 2 locations per displayed character in
+  // the expected string, plus 2 more for the terminating character.
+  static const char small_expected[] = "Hello";
+  unsigned short small_buffer[12];
+  memset(fixed_buffer, 0xbd, sizeof(fixed_buffer));
+  EXPECT_EQ(6, FPDFText_GetText(textpage, 0, 6, small_buffer));
+  EXPECT_TRUE(check_unsigned_shorts(small_expected, small_buffer,
+                                    sizeof(small_expected)));
+
   EXPECT_EQ(12.0, FPDFText_GetFontSize(textpage, 0));
   EXPECT_EQ(16.0, FPDFText_GetFontSize(textpage, 15));