mirror of
https://gitlab.com/sortix/sortix.git
synced 2023-02-13 20:55:38 -05:00
122 lines
3.4 KiB
C++
122 lines
3.4 KiB
C++
/*******************************************************************************
|
|
|
|
Copyright(C) Jonas 'Sortie' Termansen 2015.
|
|
|
|
This file is part of the Sortix C Library.
|
|
|
|
The Sortix C Library is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation, either version 3 of the License, or (at your
|
|
option) any later version.
|
|
|
|
The Sortix C Library is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
|
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
|
|
License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
libc/stdio/open_memstream.cpp
|
|
Open a memory stream.
|
|
|
|
*******************************************************************************/
|
|
|
|
#include <sys/types.h>
|
|
|
|
#include <errno.h>
|
|
#include <limits.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
struct memstream
|
|
{
|
|
char** string_out;
|
|
size_t* used_out;
|
|
char* string;
|
|
size_t offset;
|
|
size_t used;
|
|
size_t size;
|
|
};
|
|
|
|
static ssize_t memstream_write(void* ms_ptr, const void* src, size_t count)
|
|
{
|
|
struct memstream* ms = (struct memstream*) ms_ptr;
|
|
if ( (size_t) SSIZE_MAX < count )
|
|
count = SSIZE_MAX;
|
|
if ( ms->offset == SIZE_MAX && 1 <= count )
|
|
return errno = EOVERFLOW, -1;
|
|
if ( (size_t) SSIZE_MAX - ms->offset < count )
|
|
count = SIZE_MAX - ms->offset;
|
|
size_t required_size = ms->offset + count;
|
|
if ( ms->size < required_size )
|
|
{
|
|
// TODO: Multiplication overflow.
|
|
size_t new_size = 2 * ms->size;
|
|
if ( new_size < 16 )
|
|
new_size = 16;
|
|
if ( new_size < required_size )
|
|
new_size = required_size;
|
|
if ( SIZE_MAX - new_size < 1 )
|
|
return errno = EOVERFLOW, -1;
|
|
char* new_string = (char*) realloc(ms->string, new_size + 1);
|
|
if ( !new_string )
|
|
return -1;
|
|
ms->string = new_string;
|
|
ms->size = new_size;
|
|
}
|
|
memcpy(ms->string + ms->offset, src, count);
|
|
ms->offset += count;
|
|
if ( ms->used < required_size )
|
|
{
|
|
ms->used = required_size;
|
|
ms->string[ms->used] = '\0';
|
|
}
|
|
*ms->string_out = ms->string;
|
|
*ms->used_out = ms->used;
|
|
return count;
|
|
}
|
|
|
|
static off_t memstream_seek(void* ms_ptr, off_t offset, int whence)
|
|
{
|
|
struct memstream* ms = (struct memstream*) ms_ptr;
|
|
off_t base;
|
|
switch ( whence )
|
|
{
|
|
case SEEK_SET: base = 0; break;
|
|
case SEEK_CUR: base = (off_t) ms->offset; break;
|
|
case SEEK_END: base = (off_t) ms->used; break;
|
|
default: return errno = EINVAL, -1;
|
|
}
|
|
if ( offset < -base || base - SSIZE_MAX < offset )
|
|
return errno = EOVERFLOW, -1;
|
|
return (off_t) (ms->offset = (size_t) (base + offset));
|
|
}
|
|
|
|
extern "C" FILE* open_memstream(char** string_out, size_t* used_out)
|
|
{
|
|
char* string = (char*) malloc(1);
|
|
if ( !string )
|
|
return NULL;
|
|
string[0] = '\0';
|
|
struct memstream* ms = (struct memstream*) malloc(sizeof(struct memstream));
|
|
if ( !ms )
|
|
return free(string), (FILE*) NULL;
|
|
FILE* fp = fnewfile();
|
|
if ( !fp )
|
|
return free(ms), free(string), (FILE*) NULL;
|
|
ms->string_out = string_out;
|
|
ms->used_out = used_out;
|
|
ms->string= string;
|
|
ms->offset = 0;
|
|
ms->used = 0;
|
|
ms->size = 0;
|
|
fp->flags |= _FILE_WRITABLE;
|
|
fp->user = ms;
|
|
fp->write_func = memstream_write;
|
|
fp->seek_func = memstream_seek;
|
|
*string_out = ms->string;
|
|
*used_out = ms->used;
|
|
return fp;
|
|
}
|