diff options
Diffstat (limited to 'libio/vasprintf.c')
| -rw-r--r-- | libio/vasprintf.c | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/libio/vasprintf.c b/libio/vasprintf.c index a656961167..0889a3151e 100644 --- a/libio/vasprintf.c +++ b/libio/vasprintf.c @@ -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'; |