diff --git a/dec/decode.c b/dec/decode.c
index 4f8b7d9..d184f24 100644
--- a/dec/decode.c
+++ b/dec/decode.c
@@ -170,7 +170,7 @@ static BROTLI_NOINLINE BrotliErrorCode DecodeVarLenUint8(BrotliState* s,
       return BROTLI_SUCCESS;
 
     default:
-      return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE_1);
+      return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE);
   }
 }
 
@@ -287,7 +287,7 @@ static BrotliErrorCode BROTLI_NOINLINE DecodeMetaBlockLength(
         return BROTLI_SUCCESS;
 
       default:
-        return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE_2);
+        return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE);
     }
   }
 }
@@ -786,7 +786,7 @@ Complex: /* Decode Huffman-coded code lengths. */
     }
 
     default:
-      return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE_3);
+      return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE);
   }
 }
 
@@ -1019,7 +1019,7 @@ rleCode:
       return BROTLI_SUCCESS;
     }
     default:
-      return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE_4);
+      return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE);
   }
 }
 
@@ -1546,7 +1546,7 @@ static BROTLI_INLINE BrotliErrorCode ProcessCommandsInternal(int safe,
   } else if (s->state == BROTLI_STATE_COMMAND_POST_WRAP_COPY) {
     goto CommandPostWrapCopy;
   } else {
-    return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE_5);
+    return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE);
   }
 
 CommandBegin:
@@ -2141,7 +2141,7 @@ BrotliResult BrotliDecompressStream(size_t* available_in,
               break;
             default:
               return SaveErrorCode(s,
-                  BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE_6));
+                  BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE));
           }
           result = HuffmanTreeGroupDecode(hgroup, s);
         }
@@ -2245,6 +2245,18 @@ BrotliErrorCode BrotliGetErrorCode(const BrotliState* s) {
   return (BrotliErrorCode)s->error_code;
 }
 
+const char* BrotliErrorString(BrotliErrorCode c) {
+  switch (c) {
+#define _BROTLI_ERROR_CODE_CASE(PREFIX, NAME, CODE) \
+    case BROTLI ## PREFIX ## NAME: return #NAME;
+#define _BROTLI_NOTHING
+    BROTLI_ERROR_CODES_LIST(_BROTLI_ERROR_CODE_CASE, _BROTLI_NOTHING)
+#undef _BROTLI_ERROR_CODE_CASE
+#undef _BROTLI_NOTHING
+    default: return "INVALID";
+  }
+}
+
 #if defined(__cplusplus) || defined(c_plusplus)
 }  /* extern "C" */
 #endif
diff --git a/dec/decode.h b/dec/decode.h
index 4ce61f4..056a8b5 100644
--- a/dec/decode.h
+++ b/dec/decode.h
@@ -28,60 +28,56 @@ typedef enum {
   BROTLI_RESULT_NEEDS_MORE_OUTPUT = 3
 } BrotliResult;
 
-#define BROTLI_ERROR_CODES_LIST(BROTLI_ERROR_CODE, SEPARATOR)                  \
-  BROTLI_ERROR_CODE(BROTLI_NO_ERROR, 0) SEPARATOR                              \
-  /* Same as BrotliResult values */                                            \
-  BROTLI_ERROR_CODE(BROTLI_SUCCESS, 1) SEPARATOR                               \
-  BROTLI_ERROR_CODE(BROTLI_NEEDS_MORE_INPUT, 2) SEPARATOR                      \
-  BROTLI_ERROR_CODE(BROTLI_NEEDS_MORE_OUTPUT, 3) SEPARATOR                     \
-                                                                               \
-  /* Errors caused by invalid input */                                         \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_EXUBERANT_NIBBLE, -1) SEPARATOR        \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_RESERVED, -2) SEPARATOR                \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_EXUBERANT_META_NIBBLE, -3) SEPARATOR   \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_SIMPLE_HUFFMAN_ALPHABET, -4) SEPARATOR \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_SIMPLE_HUFFMAN_SAME, -5) SEPARATOR     \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_CL_SPACE, -6) SEPARATOR                \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_HUFFMAN_SPACE, -7) SEPARATOR           \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_CONTEXT_MAP_REPEAT, -8) SEPARATOR      \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_BLOCK_LENGTH_1, -9) SEPARATOR          \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_BLOCK_LENGTH_2, -10) SEPARATOR         \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_TRANSFORM, -11) SEPARATOR              \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_DICTIONARY, -12) SEPARATOR             \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_WINDOW_BITS, -13) SEPARATOR            \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_PADDING_1, -14) SEPARATOR              \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_FORMAT_PADDING_2, -15) SEPARATOR              \
-                                                                               \
-  /* -16..-20 codes are reserved */                                            \
-                                                                               \
-  /* Memory allocation problems */                                             \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_ALLOC_CONTEXT_MODES, -21) SEPARATOR           \
-  /* Literal, insert and distance trees together */                            \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_ALLOC_TREE_GROUPS, -22) SEPARATOR             \
-  /* -23..-24 codes are reserved for distinct tree groups */                   \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_ALLOC_CONTEXT_MAP, -25) SEPARATOR             \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_ALLOC_RING_BUFFER_1, -26) SEPARATOR           \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_ALLOC_RING_BUFFER_2, -27) SEPARATOR           \
-  /* -28..-29 codes are reserved for dynamic ringbuffer allocation */          \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_ALLOC_BLOCK_TYPE_TREES, -30) SEPARATOR        \
-                                                                               \
-  /* "Impossible" states */                                                    \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_UNREACHABLE_1, -31) SEPARATOR                 \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_UNREACHABLE_2, -32) SEPARATOR                 \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_UNREACHABLE_3, -33) SEPARATOR                 \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_UNREACHABLE_4, -34) SEPARATOR                 \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_UNREACHABLE_5, -35) SEPARATOR                 \
-  BROTLI_ERROR_CODE(BROTLI_ERROR_UNREACHABLE_6, -36)
+#define BROTLI_ERROR_CODES_LIST(BROTLI_ERROR_CODE, SEPARATOR)              \
+  BROTLI_ERROR_CODE(_, NO_ERROR, 0) SEPARATOR                              \
+  /* Same as BrotliResult values */                                        \
+  BROTLI_ERROR_CODE(_, SUCCESS, 1) SEPARATOR                               \
+  BROTLI_ERROR_CODE(_, NEEDS_MORE_INPUT, 2) SEPARATOR                      \
+  BROTLI_ERROR_CODE(_, NEEDS_MORE_OUTPUT, 3) SEPARATOR                     \
+                                                                           \
+  /* Errors caused by invalid input */                                     \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, EXUBERANT_NIBBLE, -1) SEPARATOR        \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, RESERVED, -2) SEPARATOR                \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, EXUBERANT_META_NIBBLE, -3) SEPARATOR   \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, SIMPLE_HUFFMAN_ALPHABET, -4) SEPARATOR \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, SIMPLE_HUFFMAN_SAME, -5) SEPARATOR     \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, CL_SPACE, -6) SEPARATOR                \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, HUFFMAN_SPACE, -7) SEPARATOR           \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, CONTEXT_MAP_REPEAT, -8) SEPARATOR      \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, BLOCK_LENGTH_1, -9) SEPARATOR          \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, BLOCK_LENGTH_2, -10) SEPARATOR         \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, TRANSFORM, -11) SEPARATOR              \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, DICTIONARY, -12) SEPARATOR             \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, WINDOW_BITS, -13) SEPARATOR            \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, PADDING_1, -14) SEPARATOR              \
+  BROTLI_ERROR_CODE(_ERROR_FORMAT_, PADDING_2, -15) SEPARATOR              \
+                                                                           \
+  /* -16..-20 codes are reserved */                                        \
+                                                                           \
+  /* Memory allocation problems */                                         \
+  BROTLI_ERROR_CODE(_ERROR_ALLOC_, CONTEXT_MODES, -21) SEPARATOR           \
+  /* Literal, insert and distance trees together */                        \
+  BROTLI_ERROR_CODE(_ERROR_ALLOC_, TREE_GROUPS, -22) SEPARATOR             \
+  /* -23..-24 codes are reserved for distinct tree groups */               \
+  BROTLI_ERROR_CODE(_ERROR_ALLOC_, CONTEXT_MAP, -25) SEPARATOR             \
+  BROTLI_ERROR_CODE(_ERROR_ALLOC_, RING_BUFFER_1, -26) SEPARATOR           \
+  BROTLI_ERROR_CODE(_ERROR_ALLOC_, RING_BUFFER_2, -27) SEPARATOR           \
+  /* -28..-29 codes are reserved for dynamic ringbuffer allocation */      \
+  BROTLI_ERROR_CODE(_ERROR_ALLOC_, BLOCK_TYPE_TREES, -30) SEPARATOR        \
+                                                                           \
+  /* "Impossible" states */                                                \
+  BROTLI_ERROR_CODE(_ERROR_, UNREACHABLE, -31)
 
 typedef enum {
-#define _BROTLI_COMMA /**/,
-#define _BROTLI_ERROR_CODE_ENUM_ITEM(NAME, CODE) NAME = CODE
+#define _BROTLI_COMMA ,
+#define _BROTLI_ERROR_CODE_ENUM_ITEM(PREFIX, NAME, CODE) \
+    BROTLI ## PREFIX ## NAME = CODE
   BROTLI_ERROR_CODES_LIST(_BROTLI_ERROR_CODE_ENUM_ITEM, _BROTLI_COMMA)
 #undef _BROTLI_ERROR_CODE_ENUM_ITEM
 #undef _BROTLI_COMMA
 } BrotliErrorCode;
 
-#define BROTLI_LAST_ERROR_CODE BROTLI_ERROR_UNREACHABLE_6
+#define BROTLI_LAST_ERROR_CODE BROTLI_ERROR_UNREACHABLE
 
 /* Creates the instance of BrotliState and initializes it. |alloc_func| and
    |free_func| MUST be both zero or both non-zero. In the case they are both
@@ -157,16 +153,7 @@ int BrotliStateIsStreamEnd(const BrotliState* s);
    BROTLI_RESULT_ERROR. */
 BrotliErrorCode BrotliGetErrorCode(const BrotliState* s);
 
-static const char* BrotliErrorString(BrotliErrorCode c) {
-  switch (c) {
-#define _BROTLI_ERROR_CODE_CASE(NAME, CODE) case NAME: return #NAME;
-#define _BROTLI_NOTHING
-    BROTLI_ERROR_CODES_LIST(_BROTLI_ERROR_CODE_CASE, _BROTLI_NOTHING)
-#undef _BROTLI_ERROR_CODE_CASE
-#undef _BROTLI_NOTHING
-    default: return "INVALID BrotliErrorCode";
-  }
-}
+const char* BrotliErrorString(BrotliErrorCode c);
 
 #if defined(__cplusplus) || defined(c_plusplus)
 } /* extern "C" */