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(_IO_vasprintf): Try to avoid memory fragmentation by allocating new memory at the end instead of reallocating.

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This commit is contained in:
Ulrich Drepper 2000-04-11 17:53:41 +00:00
parent 4a1a3c2158
commit 4100c5a0e6
1 changed files with 21 additions and 4 deletions
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25
libio/vasprintf.c
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@ -1,4 +1,4 @@
/* Copyright (C) 1995, 1997, 1999 Free Software Foundation, Inc.
/* Copyright (C) 1995, 1997, 1999, 2000 Free Software Foundation, Inc.
This file is part of the GNU IO Library.
This library is free software; you can redistribute it and/or
@ -43,6 +43,8 @@ _IO_vasprintf (result_ptr, format, args)
_IO_lock_t lock;
#endif
int ret;
_IO_size_t needed;
_IO_size_t allocated;
string = (char *) malloc (init_string_size);
if (string == NULL)
return -1;
@ -58,9 +60,24 @@ _IO_vasprintf (result_ptr, format, args)
ret = _IO_vfprintf ((_IO_FILE *) &sf, format, args);
if (ret < 0)
return ret;
*result_ptr = (char *) realloc (sf._sbf._f._IO_buf_base,
(sf._sbf._f._IO_write_ptr
- sf._sbf._f._IO_write_base) +1);
/* Only use realloc if the size we need is of the same order of
magnitude then the memory we allocated. */
needed = sf._sbf._f._IO_write_ptr - sf._sbf._f._IO_write_base + 1;
allocated = sf._sbf._f._IO_write_end - sf._sbf._f._IO_write_base;
if ((allocated << 1) <= needed)
*result_ptr = (char *) realloc (sf._sbf._f._IO_buf_base, needed);
else
{
*result_ptr = (char *) malloc (needed);
if (*result_ptr != NULL)
{
memcpy (*result_ptr, sf._sbf._f._IO_buf_base, needed);
free (sf._sbf._f._IO_buf_base);
}
else
/* We have no choice, use the buffer we already have. */
*result_ptr = (char *) realloc (sf._sbf._f._IO_buf_base, needed);
}
if (*result_ptr == NULL)
*result_ptr = sf._sbf._f._IO_buf_base;
(*result_ptr)[sf._sbf._f._IO_write_ptr-sf._sbf._f._IO_write_base] = '\0';