kgiusti commented on a change in pull request #1452: URL: https://github.com/apache/qpid-dispatch/pull/1452#discussion_r768876300
########## File path: src/buffer_field_api.h ########## @@ -0,0 +1,311 @@ +#ifndef __dispatch_buffer_field_api_h__ +#define __dispatch_buffer_field_api_h__ 1 +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +/** @file + * Inline API for common operations on buffer_fields + * @internal + * @{ + */ + +#include "qpid/dispatch/buffer_field.h" +#include "qpid/dispatch/iterator.h" + +/* qd_buffer_field_memcpy + * + * Copy up to n octets from bfield to dest, advance bfield by the number of + * octets copied + * + * @return total of octets copied - may be < n if len(bfield) < n + */ +static inline size_t qd_buffer_field_memcpy(qd_buffer_field_t *bfield, uint8_t *dest, size_t n) +{ + const uint8_t *start = dest; + size_t count = MIN(n, bfield->length); + if (bfield->buffer) { + while (count) { + size_t avail = qd_buffer_cursor(bfield->buffer) - bfield->cursor; + if (count < avail) { + // fastpath: no need to adjust buffer pointers + memcpy(dest, bfield->cursor, count); + dest += count; + bfield->cursor += count; + bfield->length -= count; + return dest - start; + } + + // count is >= what is available in the current buffer + memcpy(dest, bfield->cursor, avail); + dest += avail; + count -= avail; + bfield->length -= avail; + bfield->cursor += avail; + if (bfield->length) { + bfield->buffer = DEQ_NEXT(bfield->buffer); + if (bfield->buffer) { + bfield->cursor = (const uint8_t *)qd_buffer_base(bfield->buffer); + } else { + // DISPATCH-1394: field is truncated (length is inaccurate!) + bfield->length = 0; + count = 0; + assert(false); // TODO(KAG): is this fixed? + } + } + } while (count); + + return dest - start; + + } else { // string/binary data Review comment: Here's the problem (which is totally non-obvious) - qd_iterator_t (from which the qd_buffer_field_t api was copied) supports buffer fields that don't actually have an associated qd_buffer_list_t! When an iterator is created via qd_iterator_string() or qd_iterator_binary() there's no qd_buffer_t involved at all. I didn't realize that until parse tests started failing since the code was attempting to parse out an iterator that was created on a string/binary non-buffer. So I had to carry this over to minimize the patch. I agree this is non-obvious and messy. To remove the non-buffer code from the qd_buffer_field_t will require modifying parse() to check the iterator parameter for a buffer. If not present parse() _could_ copy the iterator's content into a temp buffer list. That may not be as bad as it sounds if it only occurs for non-message parsing - I'll take a look at that. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
