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/****************************************************************************
**
** Copyright (C) 2016 Intel Corporation
**
** Permission is hereby granted, free of charge, to any person obtaining a copy
** of this software and associated documentation files (the "Software"), to deal
** in the Software without restriction, including without limitation the rights
** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
** copies of the Software, and to permit persons to whom the Software is
** furnished to do so, subject to the following conditions:
**
** The above copyright notice and this permission notice shall be included in
** all copies or substantial portions of the Software.
**
** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
** OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
** THE SOFTWARE.
**
****************************************************************************/
#ifndef _BSD_SOURCE
#define _BSD_SOURCE 1
#endif
#ifndef _DEFAULT_SOURCE
#define _DEFAULT_SOURCE 1
#endif
#ifndef __STDC_LIMIT_MACROS
# define __STDC_LIMIT_MACROS 1
#endif
#include "cbor.h"
#include "cborinternal_p.h"
#include "compilersupport_p.h"
#include <stdlib.h>
#include <string.h>
/**
* \defgroup CborEncoding Encoding to CBOR
* \brief Group of functions used to encode data to CBOR.
*
* CborEncoder is used to encode data into a CBOR stream. The outermost
* CborEncoder is initialized by calling cbor_encoder_init(), with the buffer
* where the CBOR stream will be stored. The outermost CborEncoder is usually
* used to encode exactly one item, most often an array or map. It is possible
* to encode more than one item, but care must then be taken on the decoder
* side to ensure the state is reset after each item was decoded.
*
* Nested CborEncoder objects are created using cbor_encoder_create_array() and
* cbor_encoder_create_map(), later closed with cbor_encoder_close_container()
* or cbor_encoder_close_container_checked(). The pairs of creation and closing
* must be exactly matched and their parameters are always the same.
*
* CborEncoder writes directly to the user-supplied buffer, without extra
* buffering. CborEncoder does not allocate memory and CborEncoder objects are
* usually created on the stack of the encoding functions.
*
* The example below initializes a CborEncoder object with a buffer and encodes
* a single integer.
*
* \code
* uint8_t buf[16];
* CborEncoder encoder;
* cbor_encoder_init(&encoder, buf, sizeof(buf), 0);
* cbor_encode_int(&encoder, some_value);
* \endcode
*
* As explained before, usually the outermost CborEncoder object is used to add
* one array or map, which in turn contains multiple elements. The example
* below creates a CBOR map with one element: a key "foo" and a boolean value.
*
* \code
* uint8_t buf[16];
* CborEncoder encoder, mapEncoder;
* cbor_encoder_init(&encoder, buf, sizeof(buf), 0);
* cbor_encoder_create_map(&encoder, &mapEncoder, 1);
* cbor_encode_text_stringz(&mapEncoder, "foo");
* cbor_encode_boolean(&mapEncoder, some_value);
* cbor_encoder_close_container(&encoder, &mapEncoder);
* \endcode
*
* <h3 class="groupheader">Error checking and buffer size</h3>
*
* All functions operating on CborEncoder return a condition of type CborError.
* If the encoding was successful, they return CborNoError. Some functions do
* extra checking on the input provided and may return some other error
* conditions (for example, cbor_encode_simple_value() checks that the type is
* of the correct type).
*
* In addition, all functions check whether the buffer has enough bytes to
* encode the item being appended. If that is not possible, they return
* CborErrorOutOfMemory.
*
* It is possible to continue with the encoding of data past the first function
* that returns CborErrorOutOfMemory. CborEncoder functions will not overrun
* the buffer, but will instead count how many more bytes are needed to
* complete the encoding. At the end, you can obtain that count by calling
* cbor_encoder_get_extra_bytes_needed().
*
* \section1 Finalizing the encoding
*
* Once all items have been appended and the containers have all been properly
* closed, the user-supplied buffer will contain the CBOR stream and may be
* immediately used. To obtain the size of the buffer, call
* cbor_encoder_get_buffer_size() with the original buffer pointer.
*
* The example below illustrates how one can encode an item with error checking
* and then pass on the buffer for network sending.
*
* \code
* uint8_t buf[16];
* CborError err;
* CborEncoder encoder, mapEncoder;
* cbor_encoder_init(&encoder, buf, sizeof(buf), 0);
* err = cbor_encoder_create_map(&encoder, &mapEncoder, 1);
* if (err)
* return err;
* err = cbor_encode_text_stringz(&mapEncoder, "foo");
* if (err)
* return err;
* err = cbor_encode_boolean(&mapEncoder, some_value);
* if (err)
* return err;
* err = cbor_encoder_close_container_checked(&encoder, &mapEncoder);
* if (err)
* return err;
*
* size_t len = cbor_encoder_get_buffer_size(&encoder, buf);
* send_payload(buf, len);
* return CborNoError;
* \endcode
*
* Finally, the example below expands on the one above and also
* deals with dynamically growing the buffer if the initial allocation wasn't
* big enough. Note the two places where the error checking was replaced with
* an cbor_assertion, showing where the author assumes no error can occur.
*
* \code
* uint8_t *encode_string_array(const char **strings, int n, size_t *bufsize)
* {
* CborError err;
* CborEncoder encoder, arrayEncoder;
* size_t size = 256;
* uint8_t *buf = NULL;
*
* while (1) {
* int i;
* size_t more_bytes;
* uint8_t *nbuf = realloc(buf, size);
* if (nbuf == NULL)
* goto error;
* buf = nbuf;
*
* cbor_encoder_init(&encoder, buf, size, 0);
* err = cbor_encoder_create_array(&encoder, &arrayEncoder, n);
* cbor_assert(!err); // can't fail, the buffer is always big enough
*
* for (i = 0; i < n; ++i) {
* err = cbor_encode_text_stringz(&arrayEncoder, strings[i]);
* if (err && err != CborErrorOutOfMemory)
* goto error;
* }
*
* err = cbor_encoder_close_container_checked(&encoder, &arrayEncoder);
* cbor_assert(!err); // shouldn't fail!
*
* more_bytes = cbor_encoder_get_extra_bytes_needed(encoder);
* if (more_size) {
* // buffer wasn't big enough, try again
* size += more_bytes;
* continue;
* }
*
* *bufsize = cbor_encoder_get_buffer_size(encoder, buf);
* return buf;
* }
* error:
* free(buf);
* return NULL;
* }
* \endcode
*/
/**
* \addtogroup CborEncoding
* @{
*/
/**
* \struct CborEncoder
* Structure used to encode to CBOR.
*/
/**
* Initializes a CborEncoder structure \a encoder by pointing it to buffer \a
* buffer of size \a size. The \a flags field is currently unused and must be
* zero.
*/
void cbor_encoder_init(CborEncoder *encoder, uint8_t *buffer, size_t size, int flags)
{
encoder->data.ptr = buffer;
encoder->end = buffer + size;
encoder->remaining = 2;
encoder->flags = flags;
}
static inline void put16(void *where, uint16_t v)
{
uint16_t v_be = cbor_htons(v);
memcpy(where, &v_be, sizeof(v_be));
}
/* Note: Since this is currently only used in situations where OOM is the only
* valid error, we KNOW this to be true. Thus, this function now returns just 'true',
* but if in the future, any function starts returning a non-OOM error, this will need
* to be changed to the test. At the moment, this is done to prevent more branches
* being created in the tinycbor output */
static inline bool isOomError(CborError err)
{
(void) err;
return true;
}
static inline void put32(void *where, uint32_t v)
{
uint32_t v_be = cbor_htonl(v);
memcpy(where, &v_be, sizeof(v_be));
}
static inline void put64(void *where, uint64_t v)
{
uint64_t v_be = cbor_htonll(v);
memcpy(where, &v_be, sizeof(v_be));
}
static inline bool would_overflow(CborEncoder *encoder, size_t len)
{
ptrdiff_t remaining = (ptrdiff_t)encoder->end;
remaining -= remaining ? (ptrdiff_t)encoder->data.ptr : encoder->data.bytes_needed;
remaining -= (ptrdiff_t)len;
return unlikely(remaining < 0);
}
static inline void advance_ptr(CborEncoder *encoder, size_t n)
{
if (encoder->end)
encoder->data.ptr += n;
else
encoder->data.bytes_needed += n;
}
static inline CborError append_to_buffer(CborEncoder *encoder, const void *data, size_t len)
{
if (would_overflow(encoder, len)) {
if (encoder->end != NULL) {
len -= encoder->end - encoder->data.ptr;
encoder->end = NULL;
encoder->data.bytes_needed = 0;
}
advance_ptr(encoder, len);
return CborErrorOutOfMemory;
}
memcpy(encoder->data.ptr, data, len);
encoder->data.ptr += len;
return CborNoError;
}
static inline CborError append_byte_to_buffer(CborEncoder *encoder, uint8_t byte)
{
return append_to_buffer(encoder, &byte, 1);
}
static inline CborError encode_number_no_update(CborEncoder *encoder, uint64_t ui, uint8_t shiftedMajorType)
{
/* Little-endian would have been so much more convenient here:
* We could just write at the beginning of buf but append_to_buffer
* only the necessary bytes.
* Since it has to be big endian, do it the other way around:
* write from the end. */
uint64_t buf[2];
uint8_t *const bufend = (uint8_t *)buf + sizeof(buf);
uint8_t *bufstart = bufend - 1;
put64(buf + 1, ui); /* we probably have a bunch of zeros in the beginning */
if (ui < Value8Bit) {
*bufstart += shiftedMajorType;
} else {
uint8_t more = 0;
if (ui > 0xffU)
++more;
if (ui > 0xffffU)
++more;
if (ui > 0xffffffffU)
++more;
bufstart -= (size_t)1 << more;
*bufstart = shiftedMajorType + Value8Bit + more;
}
return append_to_buffer(encoder, bufstart, bufend - bufstart);
}
static inline void saturated_decrement(CborEncoder *encoder)
{
if (encoder->remaining)
--encoder->remaining;
}
static inline CborError encode_number(CborEncoder *encoder, uint64_t ui, uint8_t shiftedMajorType)
{
saturated_decrement(encoder);
return encode_number_no_update(encoder, ui, shiftedMajorType);
}
/**
* Appends the unsigned 64-bit integer \a value to the CBOR stream provided by
* \a encoder.
*
* \sa cbor_encode_negative_int, cbor_encode_int
*/
CborError cbor_encode_uint(CborEncoder *encoder, uint64_t value)
{
return encode_number(encoder, value, UnsignedIntegerType << MajorTypeShift);
}
/**
* Appends the negative 64-bit integer whose absolute value is \a
* absolute_value to the CBOR stream provided by \a encoder.
*
* If the value \a absolute_value is zero, this function encodes -2^64.
*
* \sa cbor_encode_uint, cbor_encode_int
*/
CborError cbor_encode_negative_int(CborEncoder *encoder, uint64_t absolute_value)
{
return encode_number(encoder, absolute_value - 1, NegativeIntegerType << MajorTypeShift);
}
/**
* Appends the signed 64-bit integer \a value to the CBOR stream provided by
* \a encoder.
*
* \sa cbor_encode_negative_int, cbor_encode_uint
*/
CborError cbor_encode_int(CborEncoder *encoder, int64_t value)
{
/* adapted from code in RFC 7049 appendix C (pseudocode) */
uint64_t ui = value >> 63; /* extend sign to whole length */
uint8_t majorType = ui & 0x20; /* extract major type */
ui ^= value; /* complement negatives */
return encode_number(encoder, ui, majorType);
}
/**
* Appends the CBOR Simple Type of value \a value to the CBOR stream provided by
* \a encoder.
*
* This function may return error CborErrorIllegalSimpleType if the \a value
* variable contains a number that is not a valid simple type.
*/
CborError cbor_encode_simple_value(CborEncoder *encoder, uint8_t value)
{
#ifndef CBOR_ENCODER_NO_CHECK_USER
/* check if this is a valid simple type */
if (value >= HalfPrecisionFloat && value <= Break)
return CborErrorIllegalSimpleType;
#endif
return encode_number(encoder, value, SimpleTypesType << MajorTypeShift);
}
/**
* Appends the floating-point value of type \a fpType and pointed to by \a
* value to the CBOR stream provided by \a encoder. The value of \a fpType must
* be one of CborHalfFloatType, CborFloatType or CborDoubleType, otherwise the
* behavior of this function is undefined.
*
* This function is useful for code that needs to pass through floating point
* values but does not wish to have the actual floating-point code.
*
* \sa cbor_encode_half_float, cbor_encode_float, cbor_encode_double
*/
CborError cbor_encode_floating_point(CborEncoder *encoder, CborType fpType, const void *value)
{
unsigned size;
uint8_t buf[1 + sizeof(uint64_t)];
cbor_assert(fpType == CborHalfFloatType || fpType == CborFloatType || fpType == CborDoubleType);
buf[0] = fpType;
size = 2U << (fpType - CborHalfFloatType);
if (size == 8)
put64(buf + 1, *(const uint64_t*)value);
else if (size == 4)
put32(buf + 1, *(const uint32_t*)value);
else
put16(buf + 1, *(const uint16_t*)value);
saturated_decrement(encoder);
return append_to_buffer(encoder, buf, size + 1);
}
/**
* Appends the CBOR tag \a tag to the CBOR stream provided by \a encoder.
*
* \sa CborTag
*/
CborError cbor_encode_tag(CborEncoder *encoder, CborTag tag)
{
/* tags don't count towards the number of elements in an array or map */
return encode_number_no_update(encoder, tag, TagType << MajorTypeShift);
}
static CborError encode_string(CborEncoder *encoder, size_t length, uint8_t shiftedMajorType, const void *string)
{
CborError err = encode_number(encoder, length, shiftedMajorType);
if (err && !isOomError(err))
return err;
return append_to_buffer(encoder, string, length);
}
/**
* \fn CborError cbor_encode_text_stringz(CborEncoder *encoder, const char *string)
*
* Appends the null-terminated text string \a string to the CBOR stream
* provided by \a encoder. CBOR requires that \a string be valid UTF-8, but
* TinyCBOR makes no verification of correctness. The terminating null is not
* included in the stream.
*
* \sa cbor_encode_text_string, cbor_encode_byte_string
*/
/**
* Appends the byte string \a string of length \a length to the CBOR stream
* provided by \a encoder. CBOR byte strings are arbitrary raw data.
*
* \sa cbor_encode_text_stringz, cbor_encode_text_string
*/
CborError cbor_encode_byte_string(CborEncoder *encoder, const uint8_t *string, size_t length)
{
return encode_string(encoder, length, ByteStringType << MajorTypeShift, string);
}
/**
* Appends the text string \a string of length \a length to the CBOR stream
* provided by \a encoder. CBOR requires that \a string be valid UTF-8, but
* TinyCBOR makes no verification of correctness.
*
* \sa CborError cbor_encode_text_stringz, cbor_encode_byte_string
*/
CborError cbor_encode_text_string(CborEncoder *encoder, const char *string, size_t length)
{
return encode_string(encoder, length, TextStringType << MajorTypeShift, string);
}
#ifdef __GNUC__
__attribute__((noinline))
#endif
static CborError create_container(CborEncoder *encoder, CborEncoder *container, size_t length, uint8_t shiftedMajorType)
{
CborError err;
container->data.ptr = encoder->data.ptr;
container->end = encoder->end;
saturated_decrement(encoder);
container->remaining = length + 1; /* overflow ok on CborIndefiniteLength */
cbor_static_assert(((MapType << MajorTypeShift) & CborIteratorFlag_ContainerIsMap) == CborIteratorFlag_ContainerIsMap);
cbor_static_assert(((ArrayType << MajorTypeShift) & CborIteratorFlag_ContainerIsMap) == 0);
container->flags = shiftedMajorType & CborIteratorFlag_ContainerIsMap;
if (length == CborIndefiniteLength) {
container->flags |= CborIteratorFlag_UnknownLength;
err = append_byte_to_buffer(container, shiftedMajorType + IndefiniteLength);
} else {
if (shiftedMajorType & CborIteratorFlag_ContainerIsMap)
container->remaining += length;
err = encode_number_no_update(container, length, shiftedMajorType);
}
return err;
}
/**
* Creates a CBOR array in the CBOR stream provided by \a parentEncoder and
* initializes \a arrayEncoder so that items can be added to the array using
* the CborEncoder functions. The array must be terminated by calling either
* cbor_encoder_close_container() or cbor_encoder_close_container_checked()
* with the same \a encoder and \a arrayEncoder parameters.
*
* The number of items inserted into the array must be exactly \a length items,
* otherwise the stream is invalid. If the number of items is not known when
* creating the array, the constant \ref CborIndefiniteLength may be passed as
* length instead.
*
* \sa cbor_encoder_create_map
*/
CborError cbor_encoder_create_array(CborEncoder *parentEncoder, CborEncoder *arrayEncoder, size_t length)
{
return create_container(parentEncoder, arrayEncoder, length, ArrayType << MajorTypeShift);
}
/**
* Creates a CBOR map in the CBOR stream provided by \a parentEncoder and
* initializes \a mapEncoder so that items can be added to the map using
* the CborEncoder functions. The map must be terminated by calling either
* cbor_encoder_close_container() or cbor_encoder_close_container_checked()
* with the same \a encoder and \a mapEncoder parameters.
*
* The number of pair of items inserted into the map must be exactly \a length
* items, otherwise the stream is invalid. If the number is not known
* when creating the map, the constant \ref CborIndefiniteLength may be passed as
* length instead, and an indefinite length map is created.
*
* \b{Implementation limitation:} TinyCBOR cannot encode more than SIZE_MAX/2
* key-value pairs in the stream. If the length \a length is larger than this
* value (and is not \ref CborIndefiniteLength), this function returns error
* CborErrorDataTooLarge.
*
* \sa cbor_encoder_create_array
*/
CborError cbor_encoder_create_map(CborEncoder *parentEncoder, CborEncoder *mapEncoder, size_t length)
{
if (length != CborIndefiniteLength && length > SIZE_MAX / 2)
return CborErrorDataTooLarge;
return create_container(parentEncoder, mapEncoder, length, MapType << MajorTypeShift);
}
/**
* Closes the CBOR container (array or map) provided by \a containerEncoder and
* updates the CBOR stream provided by \a encoder. Both parameters must be the
* same as were passed to cbor_encoder_create_array() or
* cbor_encoder_create_map().
*
* Since version 0.5, this function verifies that the number of items (or pairs
* of items, in the case of a map) was correct. It is no longer necessary to call
* cbor_encoder_close_container_checked() instead.
*
* \sa cbor_encoder_create_array(), cbor_encoder_create_map()
*/
CborError cbor_encoder_close_container(CborEncoder *parentEncoder, const CborEncoder *containerEncoder)
{
// synchronise buffer state with that of the container
parentEncoder->end = containerEncoder->end;
parentEncoder->data = containerEncoder->data;
if (containerEncoder->flags & CborIteratorFlag_UnknownLength)
return append_byte_to_buffer(parentEncoder, BreakByte);
if (containerEncoder->remaining != 1)
return containerEncoder->remaining == 0 ? CborErrorTooManyItems : CborErrorTooFewItems;
if (!parentEncoder->end)
return CborErrorOutOfMemory; /* keep the state */
return CborNoError;
}
/**
* \fn CborError cbor_encode_boolean(CborEncoder *encoder, bool value)
*
* Appends the boolean value \a value to the CBOR stream provided by \a encoder.
*/
/**
* \fn CborError cbor_encode_null(CborEncoder *encoder)
*
* Appends the CBOR type representing a null value to the CBOR stream provided
* by \a encoder.
*
* \sa cbor_encode_undefined()
*/
/**
* \fn CborError cbor_encode_undefined(CborEncoder *encoder)
*
* Appends the CBOR type representing an undefined value to the CBOR stream
* provided by \a encoder.
*
* \sa cbor_encode_null()
*/
/**
* \fn CborError cbor_encode_half_float(CborEncoder *encoder, const void *value)
*
* Appends the IEEE 754 half-precision (16-bit) floating point value pointed to
* by \a value to the CBOR stream provided by \a encoder.
*
* \sa cbor_encode_floating_point(), cbor_encode_float(), cbor_encode_double()
*/
/**
* \fn CborError cbor_encode_float(CborEncoder *encoder, float value)
*
* Appends the IEEE 754 single-precision (32-bit) floating point value \a value
* to the CBOR stream provided by \a encoder.
*
* \sa cbor_encode_floating_point(), cbor_encode_half_float(), cbor_encode_double()
*/
/**
* \fn CborError cbor_encode_double(CborEncoder *encoder, double value)
*
* Appends the IEEE 754 double-precision (64-bit) floating point value \a value
* to the CBOR stream provided by \a encoder.
*
* \sa cbor_encode_floating_point(), cbor_encode_half_float(), cbor_encode_float()
*/
/**
* \fn size_t cbor_encoder_get_buffer_size(const CborEncoder *encoder, const uint8_t *buffer)
*
* Returns the total size of the buffer starting at \a buffer after the
* encoding finished without errors. The \a encoder and \a buffer arguments
* must be the same as supplied to cbor_encoder_init().
*
* If the encoding process had errors, the return value of this function is
* meaningless. If the only errors were CborErrorOutOfMemory, instead use
* cbor_encoder_get_extra_bytes_needed() to find out by how much to grow the
* buffer before encoding again.
*
* See \ref CborEncoding for an example of using this function.
*
* \sa cbor_encoder_init(), cbor_encoder_get_extra_bytes_needed(), CborEncoding
*/
/**
* \fn size_t cbor_encoder_get_extra_bytes_needed(const CborEncoder *encoder)
*
* Returns how many more bytes the original buffer supplied to
* cbor_encoder_init() needs to be extended by so that no CborErrorOutOfMemory
* condition will happen for the encoding. If the buffer was big enough, this
* function returns 0. The \a encoder must be the original argument as passed
* to cbor_encoder_init().
*
* This function is usually called after an encoding sequence ended with one or
* more CborErrorOutOfMemory errors, but no other error. If any other error
* happened, the return value of this function is meaningless.
*
* See \ref CborEncoding for an example of using this function.
*
* \sa cbor_encoder_init(), cbor_encoder_get_buffer_size(), CborEncoding
*/
/** @} */