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9be2cfe968b4223f9d416aecd483f3b999bbab71
nanopb/pb_encode.c
Petteri Aimonen 9be2cfe968 Get rid of pb_bytes_ptr_t, just allocate pb_bytes_array_t dynamically. 
This makes the internal logic much simpler, and also keeps the datatypes
more similar between STATIC/POINTER cases. It will still be a bit cumbersome
to use because of variable length array member. Macros PB_BYTES_ARRAY_T(n) and
PB_BYTES_ARRAY_T_ALLOCSIZE(n) have been added to make life a bit easier.

This has the drawback that it is no longer as easy to use externally allocated
byte array as input for bytes field in pointer mode. However, this is still
easy to do using callbacks, so it shouldn't be a large issue.
2014-03-15 08:45:58 +02:00

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/* pb_encode.c -- encode a protobuf using minimal resources
*
* 2011 Petteri Aimonen <jpa@kapsi.fi>
*/
#define NANOPB_INTERNALS
#include "pb.h"
#include "pb_encode.h"
/* Use the GCC warn_unused_result attribute to check that all return values
* are propagated correctly. On other compilers and gcc before 3.4.0 just
* ignore the annotation.
*/
#if !defined(__GNUC__) || ( __GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 4)
#define checkreturn
#else
#define checkreturn __attribute__((warn_unused_result))
#endif
/**************************************
* Declarations internal to this file *
**************************************/
typedef bool (*pb_encoder_t)(pb_ostream_t *stream, const pb_field_t *field, const void *src) checkreturn;
static bool checkreturn buf_write(pb_ostream_t *stream, const uint8_t *buf, size_t count);
static bool checkreturn encode_array(pb_ostream_t *stream, const pb_field_t *field, const void *pData, size_t count, pb_encoder_t func);
static bool checkreturn encode_field(pb_ostream_t *stream, const pb_field_t *field, const void *pData);
static bool checkreturn default_extension_encoder(pb_ostream_t *stream, const pb_extension_t *extension);
static bool checkreturn encode_extension_field(pb_ostream_t *stream, const pb_field_t *field, const void *pData);
static bool checkreturn pb_enc_varint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
static bool checkreturn pb_enc_uvarint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
static bool checkreturn pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
static bool checkreturn pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src);
static bool checkreturn pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src);
static bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src);
static bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src);
static bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src);
/* --- Function pointers to field encoders ---
* Order in the array must match pb_action_t LTYPE numbering.
*/
static const pb_encoder_t PB_ENCODERS[PB_LTYPES_COUNT] = {
&pb_enc_varint,
&pb_enc_uvarint,
&pb_enc_svarint,
&pb_enc_fixed32,
&pb_enc_fixed64,
&pb_enc_bytes,
&pb_enc_string,
&pb_enc_submessage,
NULL /* extensions */
};
/*******************************
* pb_ostream_t implementation *
*******************************/
static bool checkreturn buf_write(pb_ostream_t *stream, const uint8_t *buf, size_t count)
{
uint8_t *dest = (uint8_t*)stream->state;
stream->state = dest + count;
while (count--)
*dest++ = *buf++;
return true;
}
pb_ostream_t pb_ostream_from_buffer(uint8_t *buf, size_t bufsize)
{
pb_ostream_t stream;
#ifdef PB_BUFFER_ONLY
stream.callback = (void*)1; /* Just a marker value */
#else
stream.callback = &buf_write;
#endif
stream.state = buf;
stream.max_size = bufsize;
stream.bytes_written = 0;
#ifndef PB_NO_ERRMSG
stream.errmsg = NULL;
#endif
return stream;
}
bool checkreturn pb_write(pb_ostream_t *stream, const uint8_t *buf, size_t count)
{
if (stream->callback != NULL)
{
if (stream->bytes_written + count > stream->max_size)
PB_RETURN_ERROR(stream, "stream full");
#ifdef PB_BUFFER_ONLY
if (!buf_write(stream, buf, count))
PB_RETURN_ERROR(stream, "io error");
#else
if (!stream->callback(stream, buf, count))
PB_RETURN_ERROR(stream, "io error");
#endif
}
stream->bytes_written += count;
return true;
}
/*************************
* Encode a single field *
*************************/
/* Encode a static array. Handles the size calculations and possible packing. */
static bool checkreturn encode_array(pb_ostream_t *stream, const pb_field_t *field,
const void *pData, size_t count, pb_encoder_t func)
{
size_t i;
const void *p;
size_t size;
if (count == 0)
return true;
if (PB_ATYPE(field->type) != PB_ATYPE_POINTER && count > field->array_size)
PB_RETURN_ERROR(stream, "array max size exceeded");
/* We always pack arrays if the datatype allows it. */
if (PB_LTYPE(field->type) <= PB_LTYPE_LAST_PACKABLE)
{
if (!pb_encode_tag(stream, PB_WT_STRING, field->tag))
return false;
/* Determine the total size of packed array. */
if (PB_LTYPE(field->type) == PB_LTYPE_FIXED32)
{
size = 4 * count;
}
else if (PB_LTYPE(field->type) == PB_LTYPE_FIXED64)
{
size = 8 * count;
}
else
{
pb_ostream_t sizestream = PB_OSTREAM_SIZING;
p = pData;
for (i = 0; i < count; i++)
{
if (!func(&sizestream, field, p))
return false;
p = (const char*)p + field->data_size;
}
size = sizestream.bytes_written;
}
if (!pb_encode_varint(stream, (uint64_t)size))
return false;
if (stream->callback == NULL)
return pb_write(stream, NULL, size); /* Just sizing.. */
/* Write the data */
p = pData;
for (i = 0; i < count; i++)
{
if (!func(stream, field, p))
return false;
p = (const char*)p + field->data_size;
}
}
else
{
p = pData;
for (i = 0; i < count; i++)
{
if (!pb_encode_tag_for_field(stream, field))
return false;
/* Normally the data is stored directly in the array entries, but
* for pointer-type string and bytes fields, the array entries are
* actually pointers themselves also. So we have to dereference once
* more to get to the actual data. */
if (PB_ATYPE(field->type) == PB_ATYPE_POINTER &&
(PB_LTYPE(field->type) == PB_LTYPE_STRING ||
PB_LTYPE(field->type) == PB_LTYPE_BYTES))
{
if (!func(stream, field, *(const void* const*)p))
return false;
}
else
{
if (!func(stream, field, p))
return false;
}
p = (const char*)p + field->data_size;
}
}
return true;
}
/* Encode a field with static or pointer allocation, i.e. one whose data
* is available to the encoder directly. */
static bool checkreturn encode_basic_field(pb_ostream_t *stream,
const pb_field_t *field, const void *pData)
{
pb_encoder_t func;
const void *pSize;
bool implicit_has = true;
func = PB_ENCODERS[PB_LTYPE(field->type)];
if (field->size_offset)
pSize = (const char*)pData + field->size_offset;
else
pSize = &implicit_has;
if (PB_ATYPE(field->type) == PB_ATYPE_POINTER)
{
/* pData is a pointer to the field, which contains pointer to
* the data. If the 2nd pointer is NULL, it is interpreted as if
* the has_field was false.
*/
pData = *(const void* const*)pData;
implicit_has = (pData != NULL);
}
switch (PB_HTYPE(field->type))
{
case PB_HTYPE_REQUIRED:
if (!pData)
PB_RETURN_ERROR(stream, "missing required field");
if (!pb_encode_tag_for_field(stream, field))
return false;
if (!func(stream, field, pData))
return false;
break;
case PB_HTYPE_OPTIONAL:
if (*(const bool*)pSize)
{
if (!pb_encode_tag_for_field(stream, field))
return false;
if (!func(stream, field, pData))
return false;
}
break;
case PB_HTYPE_REPEATED:
if (!encode_array(stream, field, pData, *(const size_t*)pSize, func))
return false;
break;
default:
PB_RETURN_ERROR(stream, "invalid field type");
}
return true;
}
/* Encode a field with callback semantics. This means that a user function is
* called to provide and encode the actual data. */
static bool checkreturn encode_callback_field(pb_ostream_t *stream,
const pb_field_t *field, const void *pData)
{
const pb_callback_t *callback = (const pb_callback_t*)pData;
#ifdef PB_OLD_CALLBACK_STYLE
const void *arg = callback->arg;
#else
void * const *arg = &(callback->arg);
#endif
if (callback->funcs.encode != NULL)
{
if (!callback->funcs.encode(stream, field, arg))
PB_RETURN_ERROR(stream, "callback error");
}
return true;
}
/* Encode a single field of any callback or static type. */
static bool checkreturn encode_field(pb_ostream_t *stream,
const pb_field_t *field, const void *pData)
{
switch (PB_ATYPE(field->type))
{
case PB_ATYPE_STATIC:
case PB_ATYPE_POINTER:
return encode_basic_field(stream, field, pData);
case PB_ATYPE_CALLBACK:
return encode_callback_field(stream, field, pData);
default:
PB_RETURN_ERROR(stream, "invalid field type");
}
}
/* Default handler for extension fields. Expects to have a pb_field_t
* pointer in the extension->type->arg field. */
static bool checkreturn default_extension_encoder(pb_ostream_t *stream,
const pb_extension_t *extension)
{
const pb_field_t *field = (const pb_field_t*)extension->type->arg;
return encode_field(stream, field, extension->dest);
}
/* Walk through all the registered extensions and give them a chance
* to encode themselves. */
static bool checkreturn encode_extension_field(pb_ostream_t *stream,
const pb_field_t *field, const void *pData)
{
const pb_extension_t *extension = *(const pb_extension_t* const *)pData;
UNUSED(field);
while (extension)
{
bool status;
if (extension->type->encode)
status = extension->type->encode(stream, extension);
else
status = default_extension_encoder(stream, extension);
if (!status)
return false;
extension = extension->next;
}
return true;
}
/*********************
* Encode all fields *
*********************/
bool checkreturn pb_encode(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
{
const pb_field_t *field = fields;
const void *pData = src_struct;
size_t prev_size = 0;
while (field->tag != 0)
{
pData = (const char*)pData + prev_size + field->data_offset;
if (PB_ATYPE(field->type) == PB_ATYPE_POINTER)
prev_size = sizeof(const void*);
else
prev_size = field->data_size;
/* Special case for static arrays */
if (PB_ATYPE(field->type) == PB_ATYPE_STATIC &&
PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
{
prev_size *= field->array_size;
}
if (PB_LTYPE(field->type) == PB_LTYPE_EXTENSION)
{
/* Special case for the extension field placeholder */
if (!encode_extension_field(stream, field, pData))
return false;
}
else
{
/* Regular field */
if (!encode_field(stream, field, pData))
return false;
}
field++;
}
return true;
}
bool pb_encode_delimited(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
{
return pb_encode_submessage(stream, fields, src_struct);
}
/********************
* Helper functions *
********************/
bool checkreturn pb_encode_varint(pb_ostream_t *stream, uint64_t value)
{
uint8_t buffer[10];
size_t i = 0;
if (value == 0)
return pb_write(stream, (uint8_t*)&value, 1);
while (value)
{
buffer[i] = (uint8_t)((value & 0x7F) | 0x80);
value >>= 7;
i++;
}
buffer[i-1] &= 0x7F; /* Unset top bit on last byte */
return pb_write(stream, buffer, i);
}
bool checkreturn pb_encode_svarint(pb_ostream_t *stream, int64_t value)
{
uint64_t zigzagged;
if (value < 0)
zigzagged = (uint64_t)(~(value << 1));
else
zigzagged = (uint64_t)(value << 1);
return pb_encode_varint(stream, zigzagged);
}
bool checkreturn pb_encode_fixed32(pb_ostream_t *stream, const void *value)
{
#ifdef __BIG_ENDIAN__
const uint8_t *bytes = value;
uint8_t lebytes[4];
lebytes[0] = bytes[3];
lebytes[1] = bytes[2];
lebytes[2] = bytes[1];
lebytes[3] = bytes[0];
return pb_write(stream, lebytes, 4);
#else
return pb_write(stream, (const uint8_t*)value, 4);
#endif
}
bool checkreturn pb_encode_fixed64(pb_ostream_t *stream, const void *value)
{
#ifdef __BIG_ENDIAN__
const uint8_t *bytes = value;
uint8_t lebytes[8];
lebytes[0] = bytes[7];
lebytes[1] = bytes[6];
lebytes[2] = bytes[5];
lebytes[3] = bytes[4];
lebytes[4] = bytes[3];
lebytes[5] = bytes[2];
lebytes[6] = bytes[1];
lebytes[7] = bytes[0];
return pb_write(stream, lebytes, 8);
#else
return pb_write(stream, (const uint8_t*)value, 8);
#endif
}
bool checkreturn pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, uint32_t field_number)
{
uint64_t tag = wiretype | (field_number << 3);
return pb_encode_varint(stream, tag);
}
bool checkreturn pb_encode_tag_for_field(pb_ostream_t *stream, const pb_field_t *field)
{
pb_wire_type_t wiretype;
switch (PB_LTYPE(field->type))
{
case PB_LTYPE_VARINT:
case PB_LTYPE_UVARINT:
case PB_LTYPE_SVARINT:
wiretype = PB_WT_VARINT;
break;
case PB_LTYPE_FIXED32:
wiretype = PB_WT_32BIT;
break;
case PB_LTYPE_FIXED64:
wiretype = PB_WT_64BIT;
break;
case PB_LTYPE_BYTES:
case PB_LTYPE_STRING:
case PB_LTYPE_SUBMESSAGE:
wiretype = PB_WT_STRING;
break;
default:
PB_RETURN_ERROR(stream, "invalid field type");
}
return pb_encode_tag(stream, wiretype, field->tag);
}
bool checkreturn pb_encode_string(pb_ostream_t *stream, const uint8_t *buffer, size_t size)
{
if (!pb_encode_varint(stream, (uint64_t)size))
return false;
return pb_write(stream, buffer, size);
}
bool checkreturn pb_encode_submessage(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
{
/* First calculate the message size using a non-writing substream. */
pb_ostream_t substream = PB_OSTREAM_SIZING;
size_t size;
bool status;
if (!pb_encode(&substream, fields, src_struct))
{
#ifndef PB_NO_ERRMSG
stream->errmsg = substream.errmsg;
#endif
return false;
}
size = substream.bytes_written;
if (!pb_encode_varint(stream, (uint64_t)size))
return false;
if (stream->callback == NULL)
return pb_write(stream, NULL, size); /* Just sizing */
if (stream->bytes_written + size > stream->max_size)
PB_RETURN_ERROR(stream, "stream full");
/* Use a substream to verify that a callback doesn't write more than
* what it did the first time. */
substream.callback = stream->callback;
substream.state = stream->state;
substream.max_size = size;
substream.bytes_written = 0;
#ifndef PB_NO_ERRMSG
substream.errmsg = NULL;
#endif
status = pb_encode(&substream, fields, src_struct);
stream->bytes_written += substream.bytes_written;
stream->state = substream.state;
#ifndef PB_NO_ERRMSG
stream->errmsg = substream.errmsg;
#endif
if (substream.bytes_written != size)
PB_RETURN_ERROR(stream, "submsg size changed");
return status;
}
/* Field encoders */
bool checkreturn pb_enc_varint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
{
int64_t value = 0;
/* Cases 1 and 2 are for compilers that have smaller types for bool
* or enums. */
switch (field->data_size)
{
case 1: value = *(const int8_t*)src; break;
case 2: value = *(const int16_t*)src; break;
case 4: value = *(const int32_t*)src; break;
case 8: value = *(const int64_t*)src; break;
default: PB_RETURN_ERROR(stream, "invalid data_size");
}
return pb_encode_varint(stream, (uint64_t)value);
}
bool checkreturn pb_enc_uvarint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
{
uint64_t value = 0;
switch (field->data_size)
{
case 4: value = *(const uint32_t*)src; break;
case 8: value = *(const uint64_t*)src; break;
default: PB_RETURN_ERROR(stream, "invalid data_size");
}
return pb_encode_varint(stream, value);
}
bool checkreturn pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
{
int64_t value = 0;
switch (field->data_size)
{
case 4: value = *(const int32_t*)src; break;
case 8: value = *(const int64_t*)src; break;
default: PB_RETURN_ERROR(stream, "invalid data_size");
}
return pb_encode_svarint(stream, value);
}
bool checkreturn pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src)
{
UNUSED(field);
return pb_encode_fixed64(stream, src);
}
bool checkreturn pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src)
{
UNUSED(field);
return pb_encode_fixed32(stream, src);
}
bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src)
{
const pb_bytes_array_t *bytes = (const pb_bytes_array_t*)src;
if (src == NULL)
{
/* Threat null pointer as an empty bytes field */
return pb_encode_string(stream, NULL, 0);
}
if (PB_ATYPE(field->type) == PB_ATYPE_STATIC &&
PB_BYTES_ARRAY_T_ALLOCSIZE(bytes->size) > field->data_size)
{
PB_RETURN_ERROR(stream, "bytes size exceeded");
}
return pb_encode_string(stream, bytes->bytes, bytes->size);
}
bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src)
{
/* strnlen() is not always available, so just use a loop */
size_t size = 0;
size_t max_size = field->data_size;
const char *p = (const char*)src;
if (PB_ATYPE(field->type) == PB_ATYPE_POINTER)
max_size = (size_t)-1;
if (src == NULL)
{
size = 0; /* Threat null pointer as an empty string */
}
else
{
while (size < max_size && *p != '\0')
{
size++;
p++;
}
}
return pb_encode_string(stream, (const uint8_t*)src, size);
}
bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src)
{
if (field->ptr == NULL)
PB_RETURN_ERROR(stream, "invalid field descriptor");
return pb_encode_submessage(stream, (const pb_field_t*)field->ptr, src);
}
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