chunked-encoding: provide a readable error string for chunked errors

lib/http_chunks.c

@@ -361,4 +361,25 @@ CHUNKcode Curl_httpchunk_read(struct connectdata *conn,
   }
   return CHUNKE_OK;
 }
+
+const char *Curl_chunked_strerror(CHUNKcode code)
+{
+  switch (code) {
+  default:
+    return "OK";
+  case CHUNKE_TOO_LONG_HEX:
+    return "Too long hexadecimal number";
+  case CHUNKE_ILLEGAL_HEX:
+    return "Illegal or missing hexadecimal sequence";
+  case CHUNKE_BAD_CHUNK:
+    return "Malformed encoding found";
+  case CHUNKE_WRITE_ERROR:
+    return "Write error";
+  case CHUNKE_BAD_ENCODING:
+    return "Bad content-encoding found";
+  case CHUNKE_OUT_OF_MEMORY:
+    return "Out of memory";
+  }
+}
+
 #endif /* CURL_DISABLE_HTTP */

lib/http_chunks.h

@@ -72,12 +72,13 @@ typedef enum {
   CHUNKE_ILLEGAL_HEX,
   CHUNKE_BAD_CHUNK,
   CHUNKE_WRITE_ERROR,
-  CHUNKE_STATE_ERROR,
   CHUNKE_BAD_ENCODING,
   CHUNKE_OUT_OF_MEMORY,
   CHUNKE_LAST
 } CHUNKcode;
 
+const char *Curl_chunked_strerror(CHUNKcode code);
+
 struct Curl_chunker {
   char hexbuffer[ MAXNUM_SIZE + 1];
   int hexindex;

lib/transfer.c

@@ -611,7 +611,7 @@ static CURLcode readwrite_data(struct SessionHandle *data,
             failf(data, "Failed writing data");
             return CURLE_WRITE_ERROR;
           }
-          failf(data, "Problem (%d) in the Chunked-Encoded data", (int)res);
+          failf(data, "%s in chunked-encoding", Curl_chunked_strerror(res));
           return CURLE_RECV_ERROR;
         }
         else if(CHUNKE_STOP == res) {