Add a test for the HexDecode method.

I moved the declaration to be public, instead of having it implicit in one
file and defined in a seperate cpp file.

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1410873009 .

4 files changed, 83 insertions, 27 deletions

diff --git a/core/include/fpdfapi/fpdf_parser.h b/core/include/fpdfapi/fpdf_parser.h
index b1334e4c7a..6fec26d687 100644
--- a/core/include/fpdfapi/fpdf_parser.h
+++ b/core/include/fpdfapi/fpdf_parser.h
@@ -944,6 +944,24 @@ enum PDF_DATAAVAIL_STATUS {
   PDF_DATAAVAIL_TRAILER_APPEND
 };
 
+// Public for testing.
+FX_DWORD A85Decode(const uint8_t* src_buf,
+                   FX_DWORD src_size,
+                   uint8_t*& dest_buf,
+                   FX_DWORD& dest_size);
+// Public for testing.
+FX_DWORD HexDecode(const uint8_t* src_buf,
+                   FX_DWORD src_size,
+                   uint8_t*& dest_buf,
+                   FX_DWORD& dest_size);
+// Public for testing.
+FX_DWORD FPDFAPI_FlateOrLZWDecode(FX_BOOL bLZW,
+                                  const uint8_t* src_buf,
+                                  FX_DWORD src_size,
+                                  CPDF_Dictionary* pParams,
+                                  FX_DWORD estimated_size,
+                                  uint8_t*& dest_buf,
+                                  FX_DWORD& dest_size);
 FX_BOOL PDF_DataDecode(const uint8_t* src_buf,
                        FX_DWORD src_size,
                        const CPDF_Dictionary* pDict,
diff --git a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
index 1fa27e3805..187d6152e9 100644
--- a/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
+++ b/core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp
@@ -278,21 +278,7 @@ ICodec_ScanlineDecoder* FPDFAPI_CreateFaxDecoder(
     int width,
     int height,
     const CPDF_Dictionary* pParams);
-FX_DWORD _A85Decode(const uint8_t* src_buf,
-                    FX_DWORD src_size,
-                    uint8_t*& dest_buf,
-                    FX_DWORD& dest_size);
-FX_DWORD _HexDecode(const uint8_t* src_buf,
-                    FX_DWORD src_size,
-                    uint8_t*& dest_buf,
-                    FX_DWORD& dest_size);
-FX_DWORD FPDFAPI_FlateOrLZWDecode(FX_BOOL bLZW,
-                                  const uint8_t* src_buf,
-                                  FX_DWORD src_size,
-                                  CPDF_Dictionary* pParams,
-                                  FX_DWORD estimated_size,
-                                  uint8_t*& dest_buf,
-                                  FX_DWORD& dest_size);
+
 FX_DWORD PDF_DecodeInlineStream(const uint8_t* src_buf,
                                 FX_DWORD limit,
                                 int width,
@@ -307,10 +293,10 @@ FX_DWORD PDF_DecodeInlineStream(const uint8_t* src_buf,
     return _DecodeAllScanlines(pDecoder, dest_buf, dest_size);
   }
   if (decoder == FX_BSTRC("ASCII85Decode") || decoder == FX_BSTRC("A85")) {
-    return _A85Decode(src_buf, limit, dest_buf, dest_size);
+    return A85Decode(src_buf, limit, dest_buf, dest_size);
   }
   if (decoder == FX_BSTRC("ASCIIHexDecode") || decoder == FX_BSTRC("AHx")) {
-    return _HexDecode(src_buf, limit, dest_buf, dest_size);
+    return HexDecode(src_buf, limit, dest_buf, dest_size);
   }
   if (decoder == FX_BSTRC("FlateDecode") || decoder == FX_BSTRC("Fl")) {
     return FPDFAPI_FlateOrLZWDecode(FALSE, src_buf, limit, pParam, dest_size,
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
index 255d0ce29c..e68fcb6800 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
@@ -42,10 +42,10 @@ const FX_WORD PDFDocEncoding[256] = {
     0x00f3, 0x00f4, 0x00f5, 0x00f6, 0x00f7, 0x00f8, 0x00f9, 0x00fa, 0x00fb,
     0x00fc, 0x00fd, 0x00fe, 0x00ff};
 
-FX_DWORD _A85Decode(const uint8_t* src_buf,
-                    FX_DWORD src_size,
-                    uint8_t*& dest_buf,
-                    FX_DWORD& dest_size) {
+FX_DWORD A85Decode(const uint8_t* src_buf,
+                   FX_DWORD src_size,
+                   uint8_t*& dest_buf,
+                   FX_DWORD& dest_size) {
   dest_size = 0;
   dest_buf = NULL;
   if (src_size == 0) {
@@ -117,10 +117,10 @@ FX_DWORD _A85Decode(const uint8_t* src_buf,
   }
   return pos;
 }
-FX_DWORD _HexDecode(const uint8_t* src_buf,
-                    FX_DWORD src_size,
-                    uint8_t*& dest_buf,
-                    FX_DWORD& dest_size) {
+FX_DWORD HexDecode(const uint8_t* src_buf,
+                   FX_DWORD src_size,
+                   uint8_t*& dest_buf,
+                   FX_DWORD& dest_size) {
   FX_DWORD i;
   for (i = 0; i < src_size; i++)
     if (src_buf[i] == '>') {
@@ -380,10 +380,10 @@ FX_BOOL PDF_DataDecode(const uint8_t* src_buf,
                                         estimated_size, new_buf, new_size);
     } else if (decoder == FX_BSTRC("ASCII85Decode") ||
                decoder == FX_BSTRC("A85")) {
-      offset = _A85Decode(last_buf, last_size, new_buf, new_size);
+      offset = A85Decode(last_buf, last_size, new_buf, new_size);
     } else if (decoder == FX_BSTRC("ASCIIHexDecode") ||
                decoder == FX_BSTRC("AHx")) {
-      offset = _HexDecode(last_buf, last_size, new_buf, new_size);
+      offset = HexDecode(last_buf, last_size, new_buf, new_size);
     } else if (decoder == FX_BSTRC("RunLengthDecode") ||
                decoder == FX_BSTRC("RL")) {
       if (bImageAcc && i == DecoderList.GetSize() - 1) {
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp
new file mode 100644
index 0000000000..f01e21293c
--- /dev/null
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp
@@ -0,0 +1,52 @@
+// Copyright 2015 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+#include "../../../include/fpdfapi/fpdf_parser.h"
+
+TEST(fpdf_parser_decode, HexDecode) {
+  {
+    // Empty src string.
+    uint8_t* dest = nullptr;
+    FX_DWORD dest_size;
+    uint8_t src[] = "";
+    EXPECT_EQ(0, HexDecode(src, 0, dest, dest_size));
+    EXPECT_EQ(0, dest_size);
+    EXPECT_EQ('\0', dest[0]);
+  }
+
+  {
+    // Regular conversion.
+    uint8_t* dest = nullptr;
+    FX_DWORD dest_size;
+    uint8_t src[] = "12Ac>zzz";
+    EXPECT_EQ(5, HexDecode(src, 8, dest, dest_size));
+    EXPECT_EQ(2, dest_size);
+    EXPECT_EQ(18, dest[0]);
+    EXPECT_EQ(172, dest[1]);
+  }
+
+  {
+    // Non-multiple length.
+    uint8_t* dest = nullptr;
+    FX_DWORD dest_size;
+    uint8_t src[] = "12A>zzz";
+    EXPECT_EQ(4, HexDecode(src, 8, dest, dest_size));
+    EXPECT_EQ(2, dest_size);
+    EXPECT_EQ(18, dest[0]);
+    EXPECT_EQ(160, dest[1]);
+  }
+
+  {
+    // Skips unknown characters.
+    uint8_t* dest = nullptr;
+    FX_DWORD dest_size;
+    uint8_t src[] = "12tk  \tAc>zzz";
+    EXPECT_EQ(10, HexDecode(src, 13, dest, dest_size));
+    EXPECT_EQ(2, dest_size);
+    EXPECT_EQ(18, dest[0]);
+    EXPECT_EQ(172, dest[1]);
+  }
+}