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 */