--- /dev/null
+/****************************************************************************
+**
+** Copyright (C) 2015 Intel Corporation
+**
+** Permission is hereby granted, free of charge, to any person obtaining a copy
+** of this software and associated documentation files (the "Software"), to deal
+** in the Software without restriction, including without limitation the rights
+** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+** copies of the Software, and to permit persons to whom the Software is
+** furnished to do so, subject to the following conditions:
+**
+** The above copyright notice and this permission notice shall be included in
+** all copies or substantial portions of the Software.
+**
+** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+** OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+** THE SOFTWARE.
+**
+****************************************************************************/
+
+#define _BSD_SOURCE 1
+#define _DEFAULT_SOURCE 1
+#define _GNU_SOURCE 1
+
+#include <sys/types.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if defined(__unix__) || defined(__APPLE__)
+# include <unistd.h>
+#endif
+#ifdef __APPLE__
+typedef int RetType;
+typedef int LenType;
+#elif __GLIBC__
+typedef ssize_t RetType;
+typedef size_t LenType;
+#else
+# error "Cannot implement open_memstream!"
+#endif
+
+#include "compilersupport_p.h"
+
+struct Buffer
+{
+ char **ptr;
+ size_t *len;
+ size_t alloc;
+};
+
+static RetType write_to_buffer(void *cookie, const char *data, LenType len)
+{
+ struct Buffer *b = (struct Buffer *)cookie;
+ char *ptr = *b->ptr;
+ size_t newsize;
+
+ errno = EFBIG;
+ if (unlikely(add_check_overflow(*b->len, len, &newsize)))
+ return -1;
+
+ if (newsize >= b->alloc) { // NB! one extra byte is needed to avoid buffer overflow at close_buffer
+ // make room
+ size_t newalloc = newsize + newsize / 2 + 1; // give 50% more room
+ ptr = realloc(ptr, newalloc);
+ if (ptr == NULL)
+ return -1;
+ b->alloc = newalloc;
+ *b->ptr = ptr;
+ }
+
+ memcpy(ptr + *b->len, data, len);
+ *b->len = newsize;
+ return len;
+}
+
+static int close_buffer(void *cookie)
+{
+ struct Buffer *b = (struct Buffer *)cookie;
+ if (*b->ptr)
+ (*b->ptr)[*b->len] = '\0';
+ free(b);
+ return 0;
+}
+
+FILE *open_memstream(char **bufptr, size_t *lenptr)
+{
+ struct Buffer *b = (struct Buffer *)malloc(sizeof(struct Buffer));
+ if (b == NULL)
+ return NULL;
+ b->alloc = 0;
+ b->len = lenptr;
+ b->ptr = bufptr;
+ *bufptr = NULL;
+ *lenptr = 0;
+
+#ifdef __APPLE__
+ return funopen(b, NULL, write_to_buffer, NULL, close_buffer);
+#elif __GLIBC__
+ static const cookie_io_functions_t vtable = {
+ NULL,
+ write_to_buffer,
+ NULL,
+ close_buffer
+ };
+ return fopencookie(b, "w", vtable);
+#endif
+}
+