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/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* include/k5-input.h - k5input helper functions */
/*
* Copyright (C) 2014 by the Massachusetts Institute of Technology.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef K5_INPUT_H
#define K5_INPUT_H
#include "k5-platform.h"
/*
* The k5input module defines helpers for safely consuming a fixed-sized block
* of memory. If an overrun or allocation failure occurs at any step,
* subsequent functions will return default values until the error is detected
* by looking at the status field.
*/
struct k5input {
const unsigned char *ptr;
size_t len;
int32_t status;
};
static inline void
k5_input_init(struct k5input *in, const void *ptr, size_t len)
{
in->ptr = ptr;
in->len = len;
in->status = 0;
}
/* Only set the status value of in if it hasn't already been set, so status
* reflects the first thing to go wrong. */
static inline void
k5_input_set_status(struct k5input *in, int32_t status)
{
if (!in->status)
in->status = status;
}
static inline const unsigned char *
k5_input_get_bytes(struct k5input *in, size_t len)
{
if (in->len < len)
k5_input_set_status(in, EINVAL);
if (in->status)
return NULL;
in->len -= len;
in->ptr += len;
return in->ptr - len;
}
static inline unsigned char
k5_input_get_byte(struct k5input *in)
{
const unsigned char *ptr = k5_input_get_bytes(in, 1);
return (ptr == NULL) ? '\0' : *ptr;
}
static inline uint16_t
k5_input_get_uint16_be(struct k5input *in)
{
const unsigned char *ptr = k5_input_get_bytes(in, 2);
return (ptr == NULL) ? 0 : load_16_be(ptr);
}
static inline uint16_t
k5_input_get_uint16_le(struct k5input *in)
{
const unsigned char *ptr = k5_input_get_bytes(in, 2);
return (ptr == NULL) ? 0 : load_16_le(ptr);
}
static inline uint16_t
k5_input_get_uint16_n(struct k5input *in)
{
const unsigned char *ptr = k5_input_get_bytes(in, 2);
return (ptr == NULL) ? 0 : load_16_n(ptr);
}
static inline uint32_t
k5_input_get_uint32_be(struct k5input *in)
{
const unsigned char *ptr = k5_input_get_bytes(in, 4);
return (ptr == NULL) ? 0 : load_32_be(ptr);
}
static inline uint32_t
k5_input_get_uint32_le(struct k5input *in)
{
const unsigned char *ptr = k5_input_get_bytes(in, 4);
return (ptr == NULL) ? 0 : load_32_le(ptr);
}
static inline uint32_t
k5_input_get_uint32_n(struct k5input *in)
{
const unsigned char *ptr = k5_input_get_bytes(in, 4);
return (ptr == NULL) ? 0 : load_32_n(ptr);
}
static inline uint64_t
k5_input_get_uint64_be(struct k5input *in)
{
const unsigned char *ptr = k5_input_get_bytes(in, 8);
return (ptr == NULL) ? 0 : load_64_be(ptr);
}
static inline uint64_t
k5_input_get_uint64_le(struct k5input *in)
{
const unsigned char *ptr = k5_input_get_bytes(in, 8);
return (ptr == NULL) ? 0 : load_64_le(ptr);
}
#endif /* K5_BUF_H */
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