Handle non-printing characters at beginning of extraction region
Currently if a text extraction region begins on a non-printing
character then "" will be returned. This is the incorrect behaviour,
instead the call should scan ahead until a printing character is
found and start extracting from there. Also proactively adds a
similar check and scan for the end of the extraction region.
BUG=pdfium:1139
Change-Id: Ia2001ac89740f3d31d2bb69e8000773f8b01091b
Reviewed-on: https://pdfium-review.googlesource.com/41532
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>
diff --git a/core/fpdftext/cpdf_textpage.cpp b/core/fpdftext/cpdf_textpage.cpp
index 5465297..8c110b6 100644
--- a/core/fpdftext/cpdf_textpage.cpp
+++ b/core/fpdftext/cpdf_textpage.cpp
@@ -510,15 +510,36 @@
return L"";
}
+ const int count_chars = CountChars();
int text_start = TextIndexFromCharIndex(start);
- if (text_start < 0)
- return L"";
- count = std::min(count, CountChars() - start);
+ // If the character at |start| is a non-printing character, then
+ // TextIndexFromCharIndex will return -1, so scan ahead to the first printing
+ // character.
+ while (text_start < 0) {
+ if (start >= count_chars)
+ return L"";
+ start++;
+ text_start = TextIndexFromCharIndex(start);
+ }
+
+ count = std::min(count, count_chars - start);
int last = start + count - 1;
int text_last = TextIndexFromCharIndex(last);
- if (text_last < 0 || text_last < text_start)
+
+ // If the character at |last| is a non-printing character, then
+ // TextIndexFromCharIndex will return -1, so scan back to the last printing
+ // character.
+ while (text_last < 0) {
+ if (last < text_start)
+ return L"";
+
+ last--;
+ text_last = TextIndexFromCharIndex(last);
+ }
+
+ if (text_last < text_start)
return L"";
int text_count = text_last - text_start + 1;
diff --git a/fpdfsdk/fpdf_text_embeddertest.cpp b/fpdfsdk/fpdf_text_embeddertest.cpp
index 83b43d9..1f29589 100644
--- a/fpdfsdk/fpdf_text_embeddertest.cpp
+++ b/fpdfsdk/fpdf_text_embeddertest.cpp
@@ -944,3 +944,26 @@
UnloadPage(page);
}
}
+
+TEST_F(FPDFTextEmbeddertest, Bug_1139) {
+ ASSERT_TRUE(OpenDocument("bug_1139.pdf"));
+ FPDF_PAGE page = LoadPage(0);
+ ASSERT_TRUE(page);
+
+ FPDF_TEXTPAGE text_page = FPDFText_LoadPage(page);
+ ASSERT_TRUE(text_page);
+
+ // -1 for CountChars not including the \0, but +1 for the extra control
+ // character.
+ EXPECT_EQ(kHelloGoodbyeTextSize, FPDFText_CountChars(text_page));
+
+ // There is an extra control character at the beginning of the string, but it
+ // should not appear in the output nor prevent extracting the text.
+ unsigned short buffer[128];
+ int num_chars = FPDFText_GetText(text_page, 0, 128, buffer);
+ ASSERT_EQ(kHelloGoodbyeTextSize, num_chars);
+ EXPECT_TRUE(
+ check_unsigned_shorts(kHelloGoodbyeText, buffer, kHelloGoodbyeTextSize));
+ FPDFText_ClosePage(text_page);
+ UnloadPage(page);
+}
diff --git a/testing/resources/bug_1139.in b/testing/resources/bug_1139.in
new file mode 100644
index 0000000..d5603f0
--- /dev/null
+++ b/testing/resources/bug_1139.in
@@ -0,0 +1,55 @@
+{{header}}
+{{object 1 0}} <<
+ /Type /Catalog
+ /Pages 2 0 R
+>>
+endobj
+{{object 2 0}} <<
+ /Type /Pages
+ /MediaBox [ 0 0 200 200 ]
+ /Count 1
+ /Kids [ 3 0 R ]
+>>
+endobj
+{{object 3 0}} <<
+ /Type /Page
+ /Parent 2 0 R
+ /Resources <<
+ /Font <<
+ /F1 4 0 R
+ /F2 5 0 R
+ >>
+ >>
+ /Contents 6 0 R
+>>
+endobj
+{{object 4 0}} <<
+ /Type /Font
+ /Subtype /Type1
+ /BaseFont /Times-Roman
+>>
+endobj
+{{object 5 0}} <<
+ /Type /Font
+ /Subtype /Type1
+ /BaseFont /Helvetica
+>>
+endobj
+{{object 6 0}} <<
+>>
+stream
+stream
+BT
+20 50 Td
+/F1 12 Tf
+(\003Hello, world!) Tj
+0 50 Td
+/F2 16 Tf
+(Goodbye, world!) Tj
+ET
+endstream
+endobj
+{{xref}}
+{{trailer}}
+{{startxref}}
+%%EOF
diff --git a/testing/resources/bug_1139.pdf b/testing/resources/bug_1139.pdf
new file mode 100644
index 0000000..d89695e
--- /dev/null
+++ b/testing/resources/bug_1139.pdf
@@ -0,0 +1,68 @@
+%PDF-1.7
+% ò¤ô
+1 0 obj <<
+ /Type /Catalog
+ /Pages 2 0 R
+>>
+endobj
+2 0 obj <<
+ /Type /Pages
+ /MediaBox [ 0 0 200 200 ]
+ /Count 1
+ /Kids [ 3 0 R ]
+>>
+endobj
+3 0 obj <<
+ /Type /Page
+ /Parent 2 0 R
+ /Resources <<
+ /Font <<
+ /F1 4 0 R
+ /F2 5 0 R
+ >>
+ >>
+ /Contents 6 0 R
+>>
+endobj
+4 0 obj <<
+ /Type /Font
+ /Subtype /Type1
+ /BaseFont /Times-Roman
+>>
+endobj
+5 0 obj <<
+ /Type /Font
+ /Subtype /Type1
+ /BaseFont /Helvetica
+>>
+endobj
+6 0 obj <<
+>>
+stream
+stream
+BT
+20 50 Td
+/F1 12 Tf
+(\003Hello, world!) Tj
+0 50 Td
+/F2 16 Tf
+(Goodbye, world!) Tj
+ET
+endstream
+endobj
+xref
+0 7
+0000000000 65535 f
+0000000015 00000 n
+0000000068 00000 n
+0000000161 00000 n
+0000000303 00000 n
+0000000381 00000 n
+0000000457 00000 n
+trailer <<
+ /Root 1 0 R
+ /Size 7
+>>
+startxref
+589
+%%EOF
