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sortix--sortix/libc/stdio/vsscanf.c
Jonas 'Sortie' Termansen 221fa7d954 Rewrite scanf(3) to be standards compliant.
This change adds missing features:

* %[ for pattern matching with a scanset.
* %m for allocation of strings.
* %p for pointers.
* Field width for integers.

The following features remain unimplemented, like with printf(3):

* Floating point support.
* Wide character support.
* %n$ positional parameters.

The code has been completely refactored to be much more maintainable.

The implemented features should now be standards compliant. A large number
of edge cases have been fixed.

The vscanf_callback(3) function has been renamed to vcbscanf(3) and a new
cbscanf(3) function has been added.
2020-03-07 23:31:05 +01:00

58 lines
1.6 KiB
C

/*
* Copyright (c) 2012, 2014 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* stdio/vsscanf.c
* Input format conversion.
*/
#include <assert.h>
#include <stdio.h>
struct vsscanf_input
{
union
{
const char* str;
const unsigned char* ustr;
};
size_t offset;
};
static int vsscanf_fgetc(void* fp)
{
struct vsscanf_input* input = (struct vsscanf_input*) fp;
if ( !input->ustr[input->offset] )
return EOF;
return (int) input->ustr[input->offset++];
}
static int vsscanf_ungetc(int c, void* fp)
{
struct vsscanf_input* input = (struct vsscanf_input*) fp;
if ( c == EOF && !input->ustr[input->offset] )
return c;
assert(input->offset);
input->offset--;
assert(input->ustr[input->offset] == (unsigned char) c);
return c;
}
int vsscanf(const char* str, const char* format, va_list ap)
{
struct vsscanf_input input;
input.str = str;
input.offset = 0;
return vcbscanf(&input, vsscanf_fgetc, vsscanf_ungetc, format, ap);
}