Change FPDF_GetText to return "" when asked to get 0 characters
BUG=chromium:788103
Change-Id: I8ebdbc78eb14c358d7ac019b96de4828e6071b79
Reviewed-on: https://pdfium-review.googlesource.com/19350
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
diff --git a/core/fxcrt/widestring.h b/core/fxcrt/widestring.h
index f48c323..14621ec 100644
--- a/core/fxcrt/widestring.h
+++ b/core/fxcrt/widestring.h
@@ -182,6 +182,10 @@
size_t Remove(wchar_t ch);
ByteString UTF8Encode() const;
+
+ // This method will add \0\0 to the end of the string to represent the
+ // wide string terminator. These values are in the string, not just the data,
+ // so GetLength() will include them.
ByteString UTF16LE_Encode() const;
protected:
diff --git a/fpdfsdk/fpdftext.cpp b/fpdfsdk/fpdftext.cpp
index ae6841f..9d7d563 100644
--- a/fpdfsdk/fpdftext.cpp
+++ b/fpdfsdk/fpdftext.cpp
@@ -164,29 +164,26 @@
int start,
int count,
unsigned short* result) {
- if (start < 0 || count < 1 || !result || !text_page)
+ if (start < 0 || count < 0 || !result || !text_page)
return 0;
CPDF_TextPage* textpage = CPDFTextPageFromFPDFTextPage(text_page);
if (start >= textpage->CountChars())
return 0;
- WideString str = textpage->GetPageText(start, count - 1);
- if (str.GetLength() <= 0)
- return 0;
-
+ WideString str = textpage->GetPageText(start, count);
if (str.GetLength() > static_cast<size_t>(count))
str = str.Left(static_cast<size_t>(count));
// UFT16LE_Encode doesn't handle surrogate pairs properly, so it is expected
// the number of items to stay the same.
- ByteString cbUTF16str = str.UTF16LE_Encode();
- ASSERT(cbUTF16str.GetLength() / kBytesPerCharacter <=
- static_cast<size_t>(count));
- memcpy(result, cbUTF16str.GetBuffer(cbUTF16str.GetLength()),
- cbUTF16str.GetLength());
-
- return cbUTF16str.GetLength() / kBytesPerCharacter;
+ ByteString byte_str = str.UTF16LE_Encode();
+ ASSERT((byte_str.GetLength()) / kBytesPerCharacter <=
+ static_cast<size_t>(count + 1)); // +1 to account for the string
+ // terminator
+ memcpy(result, byte_str.GetBuffer(byte_str.GetLength()),
+ byte_str.GetLength());
+ return (byte_str.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 a443109..4b82dc0 100644
--- a/fpdfsdk/fpdftext_embeddertest.cpp
+++ b/fpdfsdk/fpdftext_embeddertest.cpp
@@ -42,11 +42,12 @@
unsigned short fixed_buffer[128];
memset(fixed_buffer, 0xbd, sizeof(fixed_buffer));
- // Check that unreasonable inputs are handled gracefully
+ // Check that edge cases are handled gracefully
EXPECT_EQ(0, FPDFText_GetText(textpage, 0, 128, nullptr));
EXPECT_EQ(0, FPDFText_GetText(textpage, -1, 128, fixed_buffer));
- EXPECT_EQ(0, FPDFText_GetText(textpage, 0, 0, fixed_buffer));
EXPECT_EQ(0, FPDFText_GetText(textpage, 0, -1, fixed_buffer));
+ EXPECT_EQ(1, FPDFText_GetText(textpage, 0, 0, fixed_buffer));
+ EXPECT_EQ(0, fixed_buffer[0]);
// Check includes the terminating NUL that is provided.
int num_chars = FPDFText_GetText(textpage, 0, 128, fixed_buffer);
@@ -69,7 +70,7 @@
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_EQ(6, FPDFText_GetText(textpage, 0, 5, small_buffer));
EXPECT_TRUE(check_unsigned_shorts(small_expected, small_buffer,
sizeof(small_expected)));
@@ -515,7 +516,7 @@
unsigned short buffer[FX_ArraySize(kData) + 1];
memset(buffer, 0xbd, sizeof(buffer));
int count =
- FPDFText_GetText(textpage, kStartIndex, FX_ArraySize(buffer), buffer);
+ FPDFText_GetText(textpage, kStartIndex, FX_ArraySize(kData), buffer);
ASSERT_GT(count, 0);
ASSERT_EQ(FX_ArraySize(kData) + 1, static_cast<size_t>(count));
for (size_t i = 0; i < FX_ArraySize(kData); ++i)
@@ -542,13 +543,12 @@
0x0056, 0x0065, 0x0072, 0x0069, 0x0074, 0x0061, 0xfffe,
0x0073, 0x0065, 0x0072, 0x0075, 0x006D, 0x0000};
{
- constexpr int expected_count = FX_ArraySize(soft_expected);
- unsigned short buffer[expected_count];
+ constexpr int count = FX_ArraySize(soft_expected) - 1;
+ unsigned short buffer[FX_ArraySize(soft_expected)];
memset(buffer, 0, sizeof(buffer));
- EXPECT_EQ(expected_count,
- FPDFText_GetText(textpage, 0, expected_count, buffer));
- for (int i = 0; i < expected_count; i++)
+ EXPECT_EQ(count + 1, FPDFText_GetText(textpage, 0, count, buffer));
+ for (int i = 0; i < count; i++)
EXPECT_EQ(soft_expected[i], buffer[i]);
}
@@ -562,12 +562,11 @@
constexpr unsigned short hard_expected[] = {
0x0055, 0x0073, 0x0065, 0x0072, 0x2010, 0x000d, 0x000a, 0x0067, 0x0065,
0x006e, 0x0065, 0x0072, 0x0061, 0x0074, 0x0065, 0x0064, 0x0000};
- constexpr int expected_count = FX_ArraySize(hard_expected);
- unsigned short buffer[expected_count];
+ constexpr int count = FX_ArraySize(hard_expected) - 1;
+ unsigned short buffer[FX_ArraySize(hard_expected)];
- EXPECT_EQ(expected_count,
- FPDFText_GetText(textpage, offset, expected_count, buffer));
- for (int i = 0; i < expected_count; i++)
+ EXPECT_EQ(count + 1, FPDFText_GetText(textpage, offset, count, buffer));
+ for (int i = 0; i < count; i++)
EXPECT_EQ(hard_expected[i], buffer[i]);
}
