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/*
*
* 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>
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 = NULL;
return -1;
}
/* Allocate a new buffer, with space for the NUL terminator. */
strp_buflen = (size_t)ret + 1;
if ((*strp = (char *)gpr_malloc(strp_buflen)) == NULL) {
/* 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 ((size_t)ret == strp_buflen - 1) {
return ret;
}
/* This should never happen. */
gpr_free(*strp);
*strp = NULL;
return -1;
}
#endif /* GPR_POSIX_STRING */
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