diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
index 5fbcf63..d3ef4d7 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp
@@ -50,34 +50,34 @@
                    FX_DWORD& dest_size) {
   dest_size = 0;
   dest_buf = nullptr;
-  if (src_size == 0) {
+  if (src_size == 0)
     return 0;
-  }
+
+  // Count legal characters and zeros.
   FX_DWORD zcount = 0;
   FX_DWORD pos = 0;
   while (pos < src_size) {
     uint8_t ch = src_buf[pos];
-    if (ch < '!' && ch != '\n' && ch != '\r' && ch != ' ' && ch != '\t') {
-      break;
-    }
     if (ch == 'z') {
       zcount++;
-    } else if (ch > 'u') {
+    } else if ((ch < '!' || ch > 'u') && !PDFCharIsLineEnding(ch) &&
+               ch != ' ' && ch != '\t') {
       break;
     }
     pos++;
   }
-  if (pos == 0) {
+  // No content to decode.
+  if (pos == 0)
     return 0;
-  }
-  if (zcount > UINT_MAX / 4) {
+
+  // Count the space needed to contain non-zero characters. The encoding ratio
+  // of Ascii85 is 4:5.
+  FX_DWORD space_for_non_zeroes = (pos - zcount) / 5 * 4 + 4;
+  if (zcount > (UINT_MAX - space_for_non_zeroes) / 4) {
     return (FX_DWORD)-1;
   }
-  if (zcount * 4 > UINT_MAX - (pos - zcount)) {
-    return (FX_DWORD)-1;
-  }
-  dest_buf = FX_Alloc(uint8_t, zcount * 4 + (pos - zcount));
-  int state = 0;
+  dest_buf = FX_Alloc(uint8_t, zcount * 4 + space_for_non_zeroes);
+  size_t state = 0;
   uint32_t res = 0;
   pos = dest_size = 0;
   while (pos < src_size) {
@@ -90,46 +90,49 @@
       state = 0;
       res = 0;
       dest_size += 4;
-    } else {
-      if (ch < '!' || ch > 'u') {
-        break;
-      }
+    } else if (ch >= '!' && ch <= 'u') {
       res = res * 85 + ch - 33;
       state++;
       if (state == 5) {
-        for (int i = 0; i < 4; i++) {
+        for (size_t i = 0; i < 4; i++) {
           dest_buf[dest_size++] = (uint8_t)(res >> (3 - i) * 8);
         }
         state = 0;
         res = 0;
       }
+    } else {
+      // The end or illegal character.
+      break;
     }
   }
+  // Handle partial group.
   if (state) {
-    int i;
-    for (i = state; i < 5; i++) {
+    for (size_t i = state; i < 5; i++)
       res = res * 85 + 84;
-    }
-    for (i = 0; i < state - 1; i++) {
+    for (size_t i = 0; i < state - 1; i++)
       dest_buf[dest_size++] = (uint8_t)(res >> (3 - i) * 8);
-    }
   }
-  if (pos < src_size && src_buf[pos] == '>') {
+  if (pos < src_size && src_buf[pos] == '>')
     pos++;
-  }
   return pos;
 }
+
 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] == '>') {
-      break;
-    }
-  dest_buf = FX_Alloc(uint8_t, i / 2 + 1);
   dest_size = 0;
+  if (src_size == 0) {
+    dest_buf = nullptr;
+    return 0;
+  }
+
+  FX_DWORD i = 0;
+  // Find the end of data.
+  while (i < src_size && src_buf[i] != '>')
+    i++;
+
+  dest_buf = FX_Alloc(uint8_t, i / 2 + 1);
   bool bFirst = true;
   for (i = 0; i < src_size; i++) {
     uint8_t ch = src_buf[i];
@@ -218,6 +221,7 @@
   }
   return ret;
 }
+
 ICodec_ScanlineDecoder* FPDFAPI_CreateFaxDecoder(
     const uint8_t* src_buf,
     FX_DWORD src_size,
@@ -248,6 +252,7 @@
       src_buf, src_size, width, height, K, EndOfLine, ByteAlign, BlackIs1,
       Columns, Rows);
 }
+
 static FX_BOOL CheckFlateDecodeParams(int Colors,
                                       int BitsPerComponent,
                                       int Columns) {
@@ -269,6 +274,7 @@
   }
   return TRUE;
 }
+
 ICodec_ScanlineDecoder* FPDFAPI_CreateFlateDecoder(
     const uint8_t* src_buf,
     FX_DWORD src_size,
@@ -292,6 +298,7 @@
       src_buf, src_size, width, height, nComps, bpc, predictor, Colors,
       BitsPerComponent, Columns);
 }
+
 FX_DWORD FPDFAPI_FlateOrLZWDecode(FX_BOOL bLZW,
                                   const uint8_t* src_buf,
                                   FX_DWORD src_size,
@@ -316,6 +323,7 @@
       bLZW, src_buf, src_size, bEarlyChange, predictor, Colors,
       BitsPerComponent, Columns, estimated_size, dest_buf, dest_size);
 }
+
 FX_BOOL PDF_DataDecode(const uint8_t* src_buf,
                        FX_DWORD src_size,
                        const CPDF_Dictionary* pDict,
@@ -417,6 +425,7 @@
   dest_size = last_size;
   return TRUE;
 }
+
 CFX_WideString PDF_DecodeText(const uint8_t* src_data,
                               FX_DWORD src_len,
                               CFX_CharMap* pCharMap) {
@@ -464,6 +473,7 @@
   }
   return result;
 }
+
 CFX_ByteString PDF_EncodeText(const FX_WCHAR* pString,
                               int len,
                               CFX_CharMap* pCharMap) {
@@ -509,6 +519,7 @@
   result.ReleaseBuffer(encLen);
   return result;
 }
+
 CFX_ByteString PDF_EncodeString(const CFX_ByteString& src, FX_BOOL bHex) {
   CFX_ByteTextBuf result;
   int srclen = src.GetLength();
@@ -538,6 +549,7 @@
   result.AppendChar(')');
   return result.GetByteString();
 }
+
 void FlateEncode(const uint8_t* src_buf,
                  FX_DWORD src_size,
                  uint8_t*& dest_buf,
@@ -547,6 +559,7 @@
     pEncoders->GetFlateModule()->Encode(src_buf, src_size, dest_buf, dest_size);
   }
 }
+
 void FlateEncode(const uint8_t* src_buf,
                  FX_DWORD src_size,
                  int predictor,
@@ -562,6 +575,7 @@
                                         dest_size);
   }
 }
+
 FX_DWORD FlateDecode(const uint8_t* src_buf,
                      FX_DWORD src_size,
                      uint8_t*& dest_buf,
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_embeddertest.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_embeddertest.cpp
index c807703..4b2e686 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_embeddertest.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_embeddertest.cpp
@@ -10,30 +10,20 @@
 #include "testing/embedder_test.h"
 #include "testing/fx_string_testhelpers.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "testing/test_support.h"
 
 class FPDFParserDecodeEmbeddertest : public EmbedderTest {};
 
 // NOTE: python's zlib.compress() and zlib.decompress() may be useful for
 // external validation of the FlateEncode/FlateDecode test cases.
 
-#define TEST_CASE(input_literal, expected_literal)                           \
-  {                                                                          \
-    (const unsigned char*) input_literal, sizeof(input_literal) - 1,         \
-        (const unsigned char*)expected_literal, sizeof(expected_literal) - 1 \
-  }
-
 TEST_F(FPDFParserDecodeEmbeddertest, FlateEncode) {
-  struct FlateEncodeCase {
-    const unsigned char* input;
-    unsigned int input_size;
-    const unsigned char* expected;
-    unsigned int expected_size;
-  } flate_encode_cases[] = {
-      TEST_CASE("", "\x78\x9c\x03\x00\x00\x00\x00\x01"),
-      TEST_CASE(" ", "\x78\x9c\x53\x00\x00\x00\x21\x00\x21"),
-      TEST_CASE("123", "\x78\x9c\x33\x34\x32\x06\x00\01\x2d\x00\x97"),
-      TEST_CASE("\x00\xff", "\x78\x9c\x63\xf8\x0f\x00\x01\x01\x01\x00"),
-      TEST_CASE(
+  pdfium::StrFuncTestData flate_encode_cases[] = {
+      STR_TEST_CASE("", "\x78\x9c\x03\x00\x00\x00\x00\x01"),
+      STR_TEST_CASE(" ", "\x78\x9c\x53\x00\x00\x00\x21\x00\x21"),
+      STR_TEST_CASE("123", "\x78\x9c\x33\x34\x32\x06\x00\01\x2d\x00\x97"),
+      STR_TEST_CASE("\x00\xff", "\x78\x9c\x63\xf8\x0f\x00\x01\x01\x01\x00"),
+      STR_TEST_CASE(
           "1 0 0 -1 29 763 cm\n0 0 555 735 re\nW n\nq\n0 0 555 734.394 re\n"
           "W n\nq\n0.8009 0 0 0.8009 0 0 cm\n1 1 1 RG 1 1 1 rg\n/G0 gs\n"
           "0 0 693 917 re\nf\nQ\nQ\n",
@@ -46,12 +36,12 @@
   };
 
   for (size_t i = 0; i < FX_ArraySize(flate_encode_cases); ++i) {
-    FlateEncodeCase* ptr = &flate_encode_cases[i];
+    const pdfium::StrFuncTestData& data = flate_encode_cases[i];
     unsigned char* result;
     unsigned int result_size;
-    FlateEncode(ptr->input, ptr->input_size, result, result_size);
+    FlateEncode(data.input, data.input_size, result, result_size);
     ASSERT_TRUE(result);
-    EXPECT_EQ(std::string((const char*)ptr->expected, ptr->expected_size),
+    EXPECT_EQ(std::string((const char*)data.expected, data.expected_size),
               std::string((const char*)result, result_size))
         << " for case " << i;
     FX_Free(result);
@@ -59,18 +49,16 @@
 }
 
 TEST_F(FPDFParserDecodeEmbeddertest, FlateDecode) {
-  struct FlateDecodeCase {
-    const unsigned char* input;
-    unsigned int input_size;
-    const unsigned char* expected;
-    unsigned int expected_size;
-  } flate_decode_cases[] = {
-      TEST_CASE("", ""), TEST_CASE("preposterous nonsense", ""),
-      TEST_CASE("\x78\x9c\x03\x00\x00\x00\x00\x01", ""),
-      TEST_CASE("\x78\x9c\x53\x00\x00\x00\x21\x00\x21", " "),
-      TEST_CASE("\x78\x9c\x33\x34\x32\x06\x00\01\x2d\x00\x97", "123"),
-      TEST_CASE("\x78\x9c\x63\xf8\x0f\x00\x01\x01\x01\x00", "\x00\xff"),
-      TEST_CASE(
+  pdfium::DecodeTestData flate_decode_cases[] = {
+      DECODE_TEST_CASE("", "", 0),
+      DECODE_TEST_CASE("preposterous nonsense", "", 2),
+      DECODE_TEST_CASE("\x78\x9c\x03\x00\x00\x00\x00\x01", "", 8),
+      DECODE_TEST_CASE("\x78\x9c\x53\x00\x00\x00\x21\x00\x21", " ", 9),
+      DECODE_TEST_CASE("\x78\x9c\x33\x34\x32\x06\x00\01\x2d\x00\x97", "123",
+                       11),
+      DECODE_TEST_CASE("\x78\x9c\x63\xf8\x0f\x00\x01\x01\x01\x00", "\x00\xff",
+                       10),
+      DECODE_TEST_CASE(
           "\x78\x9c\x33\x54\x30\x00\x42\x5d\x43\x05\x23\x4b\x05\x73\x33\x63"
           "\x85\xe4\x5c\x2e\x90\x80\xa9\xa9\xa9\x82\xb9\xb1\xa9\x42\x51\x2a"
           "\x57\xb8\x42\x1e\x57\x21\x92\xa0\x89\x9e\xb1\xa5\x09\x92\x84\x9e"
@@ -79,16 +67,19 @@
           "\x2b\x58\x1a\x9a\x83\x8c\x49\xe3\x0a\x04\x42\x00\x37\x4c\x1b\x42",
           "1 0 0 -1 29 763 cm\n0 0 555 735 re\nW n\nq\n0 0 555 734.394 re\n"
           "W n\nq\n0.8009 0 0 0.8009 0 0 cm\n1 1 1 RG 1 1 1 rg\n/G0 gs\n"
-          "0 0 693 917 re\nf\nQ\nQ\n"),
+          "0 0 693 917 re\nf\nQ\nQ\n",
+          96),
   };
 
   for (size_t i = 0; i < FX_ArraySize(flate_decode_cases); ++i) {
-    FlateDecodeCase* ptr = &flate_decode_cases[i];
+    const pdfium::DecodeTestData& data = flate_decode_cases[i];
     unsigned char* result;
     unsigned int result_size;
-    FlateDecode(ptr->input, ptr->input_size, result, result_size);
+    EXPECT_EQ(data.processed_size,
+              FlateDecode(data.input, data.input_size, result, result_size))
+        << " for case " << i;
     ASSERT_TRUE(result);
-    EXPECT_EQ(std::string((const char*)ptr->expected, ptr->expected_size),
+    EXPECT_EQ(std::string((const char*)data.expected, data.expected_size),
               std::string((const char*)result, result_size))
         << " for case " << i;
     FX_Free(result);
@@ -115,4 +106,3 @@
   UnloadPage(page);
 }
 
-#undef TEST_CASE
diff --git a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp
index 3318bcd..3064a24 100644
--- a/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp
+++ b/core/src/fpdfapi/fpdf_parser/fpdf_parser_decode_unittest.cpp
@@ -4,52 +4,74 @@
 
 #include "core/include/fpdfapi/fpdf_parser.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "testing/test_support.h"
+
+TEST(fpdf_parser_decode, A85Decode) {
+  pdfium::DecodeTestData test_data[] = {
+      // Empty src string.
+      DECODE_TEST_CASE("", "", 0),
+      // Empty content in src string.
+      DECODE_TEST_CASE("~>", "", 0),
+      // Regular conversion.
+      DECODE_TEST_CASE("FCfN8~>", "test", 7),
+      // End at the ending mark.
+      DECODE_TEST_CASE("FCfN8~>FCfN8", "test", 7),
+      // Skip whitespaces.
+      DECODE_TEST_CASE("\t F C\r\n \tf N 8 ~>", "test", 17),
+      // No ending mark.
+      DECODE_TEST_CASE("@3B0)DJj_BF*)>@Gp#-s", "a funny story :)", 20),
+      // Non-multiple length.
+      DECODE_TEST_CASE("12A", "2k", 3),
+      // Stop at unknown characters.
+      DECODE_TEST_CASE("FCfN8FCfN8vw", "testtest", 11),
+  };
+  for (size_t i = 0; i < FX_ArraySize(test_data); ++i) {
+    pdfium::DecodeTestData* ptr = &test_data[i];
+    uint8_t* result = nullptr;
+    FX_DWORD result_size;
+    EXPECT_EQ(ptr->processed_size,
+              A85Decode(ptr->input, ptr->input_size, result, result_size))
+        << "for case " << i;
+    ASSERT_EQ(ptr->expected_size, result_size);
+    for (size_t j = 0; j < result_size; ++j) {
+      EXPECT_EQ(ptr->expected[j], result[j]) << "for case " << i << " char "
+                                             << j;
+    }
+    FX_Free(result);
+  }
+}
 
 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]);
-    FX_Free(dest);
-  }
-
-  {
-    // 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]);
-    FX_Free(dest);
-  }
-
-  {
-    // 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]);
-    FX_Free(dest);
-  }
-
-  {
-    // 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]);
-    FX_Free(dest);
+  pdfium::DecodeTestData test_data[] = {
+      // Empty src string.
+      DECODE_TEST_CASE("", "", 0),
+      // Empty content in src string.
+      DECODE_TEST_CASE(">", "", 1),
+      // Only whitespaces in src string.
+      DECODE_TEST_CASE("\t   \r\n>", "", 7),
+      // Regular conversion.
+      DECODE_TEST_CASE("12Ac>zzz", "\x12\xac", 5),
+      // Skip whitespaces.
+      DECODE_TEST_CASE("12 Ac\t02\r\nBF>zzz>", "\x12\xac\x02\xbf", 13),
+      // Non-multiple length.
+      DECODE_TEST_CASE("12A>zzz", "\x12\xa0", 4),
+      // Skips unknown characters.
+      DECODE_TEST_CASE("12tk  \tAc>zzz", "\x12\xac", 10),
+      // No ending mark.
+      DECODE_TEST_CASE("12AcED3c3456", "\x12\xac\xed\x3c\x34\x56", 12),
+  };
+  for (size_t i = 0; i < FX_ArraySize(test_data); ++i) {
+    pdfium::DecodeTestData* ptr = &test_data[i];
+    uint8_t* result = nullptr;
+    FX_DWORD result_size;
+    EXPECT_EQ(ptr->processed_size,
+              HexDecode(ptr->input, ptr->input_size, result, result_size))
+        << "for case " << i;
+    ASSERT_EQ(ptr->expected_size, result_size);
+    for (size_t j = 0; j < result_size; ++j) {
+      EXPECT_EQ(ptr->expected[j], result[j]) << "for case " << i << " char "
+                                             << j;
+    }
+    FX_Free(result);
   }
 }
diff --git a/testing/test_support.h b/testing/test_support.h
index f59d544..3c7ffe5 100644
--- a/testing/test_support.h
+++ b/testing/test_support.h
@@ -18,6 +18,35 @@
 
 namespace pdfium {
 
+#define STR_TEST_CASE(input_literal, expected_literal)                       \
+  {                                                                          \
+    (const unsigned char*) input_literal, sizeof(input_literal) - 1,         \
+        (const unsigned char*)expected_literal, sizeof(expected_literal) - 1 \
+  }
+
+#define DECODE_TEST_CASE(input_literal, expected_literal, processed_size)     \
+  {                                                                           \
+    (const unsigned char*) input_literal, sizeof(input_literal) - 1,          \
+        (const unsigned char*)expected_literal, sizeof(expected_literal) - 1, \
+        processed_size                                                        \
+  }
+
+struct StrFuncTestData {
+  const unsigned char* input;
+  unsigned int input_size;
+  const unsigned char* expected;
+  unsigned int expected_size;
+};
+
+struct DecodeTestData {
+  const unsigned char* input;
+  unsigned int input_size;
+  const unsigned char* expected;
+  unsigned int expected_size;
+  // The size of input string being processed.
+  unsigned int processed_size;
+};
+
 // Used with std::unique_ptr to free() objects that can't be deleted.
 struct FreeDeleter {
   inline void operator()(void* ptr) const { free(ptr); }