| /* |
| * |
| * Copyright 2015 gRPC authors. |
| * |
| * Licensed 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. |
| * |
| */ |
| |
| #include <grpc/support/port_platform.h> |
| |
| #ifdef GPR_POSIX_STRING |
| |
| #include <stdarg.h> |
| #include <stdio.h> |
| #include <string.h> |
| |
| #include <grpc/support/alloc.h> |
| #include <grpc/support/string_util.h> |
| |
| int gpr_asprintf(char** strp, const char* format, ...) { |
| va_list args; |
| int ret; |
| char buf[64]; |
| size_t strp_buflen; |
| |
| /* Use a constant-sized buffer to determine the length. */ |
| va_start(args, format); |
| ret = vsnprintf(buf, sizeof(buf), format, args); |
| va_end(args); |
| if (ret < 0) { |
| *strp = nullptr; |
| return -1; |
| } |
| |
| /* Allocate a new buffer, with space for the NUL terminator. */ |
| strp_buflen = static_cast<size_t>(ret) + 1; |
| if ((*strp = static_cast<char*>(gpr_malloc(strp_buflen))) == nullptr) { |
| /* This shouldn't happen, because gpr_malloc() calls abort(). */ |
| return -1; |
| } |
| |
| /* Return early if we have all the bytes. */ |
| if (strp_buflen <= sizeof(buf)) { |
| memcpy(*strp, buf, strp_buflen); |
| return ret; |
| } |
| |
| /* Try again using the larger buffer. */ |
| va_start(args, format); |
| ret = vsnprintf(*strp, strp_buflen, format, args); |
| va_end(args); |
| if (static_cast<size_t>(ret) == strp_buflen - 1) { |
| return ret; |
| } |
| |
| /* This should never happen. */ |
| gpr_free(*strp); |
| *strp = nullptr; |
| return -1; |
| } |
| |
| #endif /* GPR_POSIX_STRING */ |