add protobufs

lib/nanopb/pb_encode.c

@@ -0,0 +1,958 @@
+/* pb_encode.c -- encode a protobuf using minimal resources
+ *
+ * 2011 Petteri Aimonen <jpa@kapsi.fi>
+ */
+
+#include "pb.h"
+#include "pb_encode.h"
+#include "pb_common.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 *
+ **************************************/
+static bool checkreturn buf_write(pb_ostream_t *stream, const pb_byte_t *buf, size_t count);
+static bool checkreturn encode_array(pb_ostream_t *stream, pb_field_iter_t *field);
+static bool checkreturn pb_check_proto3_default_value(const pb_field_iter_t *field);
+static bool checkreturn encode_basic_field(pb_ostream_t *stream, const pb_field_iter_t *field);
+static bool checkreturn encode_callback_field(pb_ostream_t *stream, const pb_field_iter_t *field);
+static bool checkreturn encode_field(pb_ostream_t *stream, pb_field_iter_t *field);
+static bool checkreturn encode_extension_field(pb_ostream_t *stream, const pb_field_iter_t *field);
+static bool checkreturn default_extension_encoder(pb_ostream_t *stream, const pb_extension_t *extension);
+static bool checkreturn pb_encode_varint_32(pb_ostream_t *stream, uint32_t low, uint32_t high);
+static bool checkreturn pb_enc_bool(pb_ostream_t *stream, const pb_field_iter_t *field);
+static bool checkreturn pb_enc_varint(pb_ostream_t *stream, const pb_field_iter_t *field);
+static bool checkreturn pb_enc_fixed(pb_ostream_t *stream, const pb_field_iter_t *field);
+static bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_iter_t *field);
+static bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_iter_t *field);
+static bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_iter_t *field);
+static bool checkreturn pb_enc_fixed_length_bytes(pb_ostream_t *stream, const pb_field_iter_t *field);
+
+#ifdef PB_WITHOUT_64BIT
+#define pb_int64_t int32_t
+#define pb_uint64_t uint32_t
+#else
+#define pb_int64_t int64_t
+#define pb_uint64_t uint64_t
+#endif
+
+/*******************************
+ * pb_ostream_t implementation *
+ *******************************/
+
+static bool checkreturn buf_write(pb_ostream_t *stream, const pb_byte_t *buf, size_t count)
+{
+    size_t i;
+    pb_byte_t *dest = (pb_byte_t*)stream->state;
+    stream->state = dest + count;
+    
+    for (i = 0; i < count; i++)
+        dest[i] = buf[i];
+    
+    return true;
+}
+
+pb_ostream_t pb_ostream_from_buffer(pb_byte_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 pb_byte_t *buf, size_t count)
+{
+    if (count > 0 && 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 *
+ *************************/
+
+/* Read a bool value without causing undefined behavior even if the value
+ * is invalid. See issue #434 and
+ * https://stackoverflow.com/questions/27661768/weird-results-for-conditional
+ */
+static bool safe_read_bool(const void *pSize)
+{
+    const char *p = (const char *)pSize;
+    size_t i;
+    for (i = 0; i < sizeof(bool); i++)
+    {
+        if (p[i] != 0)
+            return true;
+    }
+    return false;
+}
+
+/* Encode a static array. Handles the size calculations and possible packing. */
+static bool checkreturn encode_array(pb_ostream_t *stream, pb_field_iter_t *field)
+{
+    pb_size_t i;
+    pb_size_t count;
+#ifndef PB_ENCODE_ARRAYS_UNPACKED
+    size_t size;
+#endif
+
+    count = *(pb_size_t*)field->pSize;
+
+    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");
+    
+#ifndef PB_ENCODE_ARRAYS_UNPACKED
+    /* 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 * (size_t)count;
+        }
+        else if (PB_LTYPE(field->type) == PB_LTYPE_FIXED64)
+        {
+            size = 8 * (size_t)count;
+        }
+        else
+        { 
+            pb_ostream_t sizestream = PB_OSTREAM_SIZING;
+            void *pData_orig = field->pData;
+            for (i = 0; i < count; i++)
+            {
+                if (!pb_enc_varint(&sizestream, field))
+                    PB_RETURN_ERROR(stream, PB_GET_ERROR(&sizestream));
+                field->pData = (char*)field->pData + field->data_size;
+            }
+            field->pData = pData_orig;
+            size = sizestream.bytes_written;
+        }
+        
+        if (!pb_encode_varint(stream, (pb_uint64_t)size))
+            return false;
+        
+        if (stream->callback == NULL)
+            return pb_write(stream, NULL, size); /* Just sizing.. */
+        
+        /* Write the data */
+        for (i = 0; i < count; i++)
+        {
+            if (PB_LTYPE(field->type) == PB_LTYPE_FIXED32 || PB_LTYPE(field->type) == PB_LTYPE_FIXED64)
+            {
+                if (!pb_enc_fixed(stream, field))
+                    return false;
+            }
+            else
+            {
+                if (!pb_enc_varint(stream, field))
+                    return false;
+            }
+
+            field->pData = (char*)field->pData + field->data_size;
+        }
+    }
+    else /* Unpacked fields */
+#endif
+    {
+        for (i = 0; i < count; i++)
+        {
+            /* 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))
+            {
+                bool status;
+                void *pData_orig = field->pData;
+                field->pData = *(void* const*)field->pData;
+
+                if (!field->pData)
+                {
+                    /* Null pointer in array is treated as empty string / bytes */
+                    status = pb_encode_tag_for_field(stream, field) &&
+                             pb_encode_varint(stream, 0);
+                }
+                else
+                {
+                    status = encode_basic_field(stream, field);
+                }
+
+                field->pData = pData_orig;
+
+                if (!status)
+                    return false;
+            }
+            else
+            {
+                if (!encode_basic_field(stream, field))
+                    return false;
+            }
+            field->pData = (char*)field->pData + field->data_size;
+        }
+    }
+    
+    return true;
+}
+
+/* In proto3, all fields are optional and are only encoded if their value is "non-zero".
+ * This function implements the check for the zero value. */
+static bool checkreturn pb_check_proto3_default_value(const pb_field_iter_t *field)
+{
+    pb_type_t type = field->type;
+
+    if (PB_ATYPE(type) == PB_ATYPE_STATIC)
+    {
+        if (PB_HTYPE(type) == PB_HTYPE_REQUIRED)
+        {
+            /* Required proto2 fields inside proto3 submessage, pretty rare case */
+            return false;
+        }
+        else if (PB_HTYPE(type) == PB_HTYPE_REPEATED)
+        {
+            /* Repeated fields inside proto3 submessage: present if count != 0 */
+            return *(const pb_size_t*)field->pSize == 0;
+        }
+        else if (PB_HTYPE(type) == PB_HTYPE_ONEOF)
+        {
+            /* Oneof fields */
+            return *(const pb_size_t*)field->pSize == 0;
+        }
+        else if (PB_HTYPE(type) == PB_HTYPE_OPTIONAL && field->pSize != NULL)
+        {
+            /* Proto2 optional fields inside proto3 message, or proto3
+             * submessage fields. */
+            return safe_read_bool(field->pSize) == false;
+        }
+
+        /* Rest is proto3 singular fields */
+        if (PB_LTYPE(type) == PB_LTYPE_BYTES)
+        {
+            const pb_bytes_array_t *bytes = (const pb_bytes_array_t*)field->pData;
+            return bytes->size == 0;
+        }
+        else if (PB_LTYPE(type) == PB_LTYPE_STRING)
+        {
+            return *(const char*)field->pData == '\0';
+        }
+        else if (PB_LTYPE(type) == PB_LTYPE_FIXED_LENGTH_BYTES)
+        {
+            /* Fixed length bytes is only empty if its length is fixed
+             * as 0. Which would be pretty strange, but we can check
+             * it anyway. */
+            return field->data_size == 0;
+        }
+        else if (PB_LTYPE_IS_SUBMSG(type))
+        {
+            /* Check all fields in the submessage to find if any of them
+             * are non-zero. The comparison cannot be done byte-per-byte
+             * because the C struct may contain padding bytes that must
+             * be skipped. Note that usually proto3 submessages have
+             * a separate has_field that is checked earlier in this if.
+             */
+            pb_field_iter_t iter;
+            if (pb_field_iter_begin(&iter, field->submsg_desc, field->pData))
+            {
+                do
+                {
+                    if (!pb_check_proto3_default_value(&iter))
+                    {
+                        return false;
+                    }
+                } while (pb_field_iter_next(&iter));
+            }
+            return true;
+        }
+    }
+    
+    {
+        /* Catch-all branch that does byte-per-byte comparison for zero value.
+         *
+         * This is for all pointer fields, and for static PB_LTYPE_VARINT,
+         * UVARINT, SVARINT, FIXED32, FIXED64, EXTENSION fields, and also
+         * callback fields. These all have integer or pointer value which
+         * can be compared with 0.
+         */
+        pb_size_t i;
+        const char *p = (const char*)field->pData;
+        for (i = 0; i < field->data_size; i++)
+        {
+            if (p[i] != 0)
+            {
+                return false;
+            }
+        }
+
+        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_iter_t *field)
+{
+    if (!field->pData)
+    {
+        /* Missing pointer field */
+        return true;
+    }
+
+    if (!pb_encode_tag_for_field(stream, field))
+        return false;
+
+    switch (PB_LTYPE(field->type))
+    {
+        case PB_LTYPE_BOOL:
+            return pb_enc_bool(stream, field);
+
+        case PB_LTYPE_VARINT:
+        case PB_LTYPE_UVARINT:
+        case PB_LTYPE_SVARINT:
+            return pb_enc_varint(stream, field);
+
+        case PB_LTYPE_FIXED32:
+        case PB_LTYPE_FIXED64:
+            return pb_enc_fixed(stream, field);
+
+        case PB_LTYPE_BYTES:
+            return pb_enc_bytes(stream, field);
+
+        case PB_LTYPE_STRING:
+            return pb_enc_string(stream, field);
+
+        case PB_LTYPE_SUBMESSAGE:
+        case PB_LTYPE_SUBMSG_W_CB:
+            return pb_enc_submessage(stream, field);
+
+        case PB_LTYPE_FIXED_LENGTH_BYTES:
+            return pb_enc_fixed_length_bytes(stream, field);
+
+        default:
+            PB_RETURN_ERROR(stream, "invalid field type");
+    }
+}
+
+/* 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_iter_t *field)
+{
+    if (field->descriptor->field_callback != NULL)
+    {
+        if (!field->descriptor->field_callback(NULL, stream, field))
+            PB_RETURN_ERROR(stream, "callback error");
+    }
+    return true;
+}
+
+/* Encode a single field of any callback, pointer or static type. */
+static bool checkreturn encode_field(pb_ostream_t *stream, pb_field_iter_t *field)
+{
+    /* Check field presence */
+    if (PB_HTYPE(field->type) == PB_HTYPE_ONEOF)
+    {
+        if (*(const pb_size_t*)field->pSize != field->tag)
+        {
+            /* Different type oneof field */
+            return true;
+        }
+    }
+    else if (PB_HTYPE(field->type) == PB_HTYPE_OPTIONAL)
+    {
+        if (field->pSize)
+        {
+            if (safe_read_bool(field->pSize) == false)
+            {
+                /* Missing optional field */
+                return true;
+            }
+        }
+        else if (PB_ATYPE(field->type) == PB_ATYPE_STATIC)
+        {
+            /* Proto3 singular field */
+            if (pb_check_proto3_default_value(field))
+                return true;
+        }
+    }
+
+    if (!field->pData)
+    {
+        if (PB_HTYPE(field->type) == PB_HTYPE_REQUIRED)
+            PB_RETURN_ERROR(stream, "missing required field");
+
+        /* Pointer field set to NULL */
+        return true;
+    }
+
+    /* Then encode field contents */
+    if (PB_ATYPE(field->type) == PB_ATYPE_CALLBACK)
+    {
+        return encode_callback_field(stream, field);
+    }
+    else if (PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
+    {
+        return encode_array(stream, field);
+    }
+    else
+    {
+        return encode_basic_field(stream, field);
+    }
+}
+
+/* Default handler for extension fields. Expects to have a pb_msgdesc_t
+ * pointer in the extension->type->arg field, pointing to a message with
+ * only one field in it.  */
+static bool checkreturn default_extension_encoder(pb_ostream_t *stream, const pb_extension_t *extension)
+{
+    pb_field_iter_t iter;
+
+    if (!pb_field_iter_begin_extension_const(&iter, extension))
+        PB_RETURN_ERROR(stream, "invalid extension");
+
+    return encode_field(stream, &iter);
+}
+
+
+/* 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_iter_t *field)
+{
+    const pb_extension_t *extension = *(const pb_extension_t* const *)field->pData;
+
+    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_msgdesc_t *fields, const void *src_struct)
+{
+    pb_field_iter_t iter;
+    if (!pb_field_iter_begin_const(&iter, fields, src_struct))
+        return true; /* Empty message type */
+    
+    do {
+        if (PB_LTYPE(iter.type) == PB_LTYPE_EXTENSION)
+        {
+            /* Special case for the extension field placeholder */
+            if (!encode_extension_field(stream, &iter))
+                return false;
+        }
+        else
+        {
+            /* Regular field */
+            if (!encode_field(stream, &iter))
+                return false;
+        }
+    } while (pb_field_iter_next(&iter));
+    
+    return true;
+}
+
+bool checkreturn pb_encode_ex(pb_ostream_t *stream, const pb_msgdesc_t *fields, const void *src_struct, unsigned int flags)
+{
+  if ((flags & PB_ENCODE_DELIMITED) != 0)
+  {
+    return pb_encode_submessage(stream, fields, src_struct);
+  }
+  else if ((flags & PB_ENCODE_NULLTERMINATED) != 0)
+  {
+    const pb_byte_t zero = 0;
+
+    if (!pb_encode(stream, fields, src_struct))
+        return false;
+
+    return pb_write(stream, &zero, 1);
+  }
+  else
+  {
+    return pb_encode(stream, fields, src_struct);
+  }
+}
+
+bool pb_get_encoded_size(size_t *size, const pb_msgdesc_t *fields, const void *src_struct)
+{
+    pb_ostream_t stream = PB_OSTREAM_SIZING;
+    
+    if (!pb_encode(&stream, fields, src_struct))
+        return false;
+    
+    *size = stream.bytes_written;
+    return true;
+}
+
+/********************
+ * Helper functions *
+ ********************/
+
+/* This function avoids 64-bit shifts as they are quite slow on many platforms. */
+static bool checkreturn pb_encode_varint_32(pb_ostream_t *stream, uint32_t low, uint32_t high)
+{
+    size_t i = 0;
+    pb_byte_t buffer[10];
+    pb_byte_t byte = (pb_byte_t)(low & 0x7F);
+    low >>= 7;
+
+    while (i < 4 && (low != 0 || high != 0))
+    {
+        byte |= 0x80;
+        buffer[i++] = byte;
+        byte = (pb_byte_t)(low & 0x7F);
+        low >>= 7;
+    }
+
+    if (high)
+    {
+        byte = (pb_byte_t)(byte | ((high & 0x07) << 4));
+        high >>= 3;
+
+        while (high)
+        {
+            byte |= 0x80;
+            buffer[i++] = byte;
+            byte = (pb_byte_t)(high & 0x7F);
+            high >>= 7;
+        }
+    }
+
+    buffer[i++] = byte;
+
+    return pb_write(stream, buffer, i);
+}
+
+bool checkreturn pb_encode_varint(pb_ostream_t *stream, pb_uint64_t value)
+{
+    if (value <= 0x7F)
+    {
+        /* Fast path: single byte */
+        pb_byte_t byte = (pb_byte_t)value;
+        return pb_write(stream, &byte, 1);
+    }
+    else
+    {
+#ifdef PB_WITHOUT_64BIT
+        return pb_encode_varint_32(stream, value, 0);
+#else
+        return pb_encode_varint_32(stream, (uint32_t)value, (uint32_t)(value >> 32));
+#endif
+    }
+}
+
+bool checkreturn pb_encode_svarint(pb_ostream_t *stream, pb_int64_t value)
+{
+    pb_uint64_t zigzagged;
+    if (value < 0)
+        zigzagged = ~((pb_uint64_t)value << 1);
+    else
+        zigzagged = (pb_uint64_t)value << 1;
+    
+    return pb_encode_varint(stream, zigzagged);
+}
+
+bool checkreturn pb_encode_fixed32(pb_ostream_t *stream, const void *value)
+{
+    uint32_t val = *(const uint32_t*)value;
+    pb_byte_t bytes[4];
+    bytes[0] = (pb_byte_t)(val & 0xFF);
+    bytes[1] = (pb_byte_t)((val >> 8) & 0xFF);
+    bytes[2] = (pb_byte_t)((val >> 16) & 0xFF);
+    bytes[3] = (pb_byte_t)((val >> 24) & 0xFF);
+    return pb_write(stream, bytes, 4);
+}
+
+#ifndef PB_WITHOUT_64BIT
+bool checkreturn pb_encode_fixed64(pb_ostream_t *stream, const void *value)
+{
+    uint64_t val = *(const uint64_t*)value;
+    pb_byte_t bytes[8];
+    bytes[0] = (pb_byte_t)(val & 0xFF);
+    bytes[1] = (pb_byte_t)((val >> 8) & 0xFF);
+    bytes[2] = (pb_byte_t)((val >> 16) & 0xFF);
+    bytes[3] = (pb_byte_t)((val >> 24) & 0xFF);
+    bytes[4] = (pb_byte_t)((val >> 32) & 0xFF);
+    bytes[5] = (pb_byte_t)((val >> 40) & 0xFF);
+    bytes[6] = (pb_byte_t)((val >> 48) & 0xFF);
+    bytes[7] = (pb_byte_t)((val >> 56) & 0xFF);
+    return pb_write(stream, bytes, 8);
+}
+#endif
+
+bool checkreturn pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, uint32_t field_number)
+{
+    pb_uint64_t tag = ((pb_uint64_t)field_number << 3) | wiretype;
+    return pb_encode_varint(stream, tag);
+}
+
+bool pb_encode_tag_for_field ( pb_ostream_t* stream, const pb_field_iter_t* field )
+{
+    pb_wire_type_t wiretype;
+    switch (PB_LTYPE(field->type))
+    {
+        case PB_LTYPE_BOOL:
+        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:
+        case PB_LTYPE_SUBMSG_W_CB:
+        case PB_LTYPE_FIXED_LENGTH_BYTES:
+            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 pb_byte_t *buffer, size_t size)
+{
+    if (!pb_encode_varint(stream, (pb_uint64_t)size))
+        return false;
+    
+    return pb_write(stream, buffer, size);
+}
+
+bool checkreturn pb_encode_submessage(pb_ostream_t *stream, const pb_msgdesc_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, (pb_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 */
+
+static bool checkreturn pb_enc_bool(pb_ostream_t *stream, const pb_field_iter_t *field)
+{
+    uint32_t value = safe_read_bool(field->pData) ? 1 : 0;
+    PB_UNUSED(field);
+    return pb_encode_varint(stream, value);
+}
+
+static bool checkreturn pb_enc_varint(pb_ostream_t *stream, const pb_field_iter_t *field)
+{
+    if (PB_LTYPE(field->type) == PB_LTYPE_UVARINT)
+    {
+        /* Perform unsigned integer extension */
+        pb_uint64_t value = 0;
+
+        if (field->data_size == sizeof(uint_least8_t))
+            value = *(const uint_least8_t*)field->pData;
+        else if (field->data_size == sizeof(uint_least16_t))
+            value = *(const uint_least16_t*)field->pData;
+        else if (field->data_size == sizeof(uint32_t))
+            value = *(const uint32_t*)field->pData;
+        else if (field->data_size == sizeof(pb_uint64_t))
+            value = *(const pb_uint64_t*)field->pData;
+        else
+            PB_RETURN_ERROR(stream, "invalid data_size");
+
+        return pb_encode_varint(stream, value);
+    }
+    else
+    {
+        /* Perform signed integer extension */
+        pb_int64_t value = 0;
+
+        if (field->data_size == sizeof(int_least8_t))
+            value = *(const int_least8_t*)field->pData;
+        else if (field->data_size == sizeof(int_least16_t))
+            value = *(const int_least16_t*)field->pData;
+        else if (field->data_size == sizeof(int32_t))
+            value = *(const int32_t*)field->pData;
+        else if (field->data_size == sizeof(pb_int64_t))
+            value = *(const pb_int64_t*)field->pData;
+        else
+            PB_RETURN_ERROR(stream, "invalid data_size");
+
+        if (PB_LTYPE(field->type) == PB_LTYPE_SVARINT)
+            return pb_encode_svarint(stream, value);
+#ifdef PB_WITHOUT_64BIT
+        else if (value < 0)
+            return pb_encode_varint_32(stream, (uint32_t)value, (uint32_t)-1);
+#endif
+        else
+            return pb_encode_varint(stream, (pb_uint64_t)value);
+
+    }
+}
+
+static bool checkreturn pb_enc_fixed(pb_ostream_t *stream, const pb_field_iter_t *field)
+{
+#ifdef PB_CONVERT_DOUBLE_FLOAT
+    if (field->data_size == sizeof(float) && PB_LTYPE(field->type) == PB_LTYPE_FIXED64)
+    {
+        return pb_encode_float_as_double(stream, *(float*)field->pData);
+    }
+#endif
+
+    if (field->data_size == sizeof(uint32_t))
+    {
+        return pb_encode_fixed32(stream, field->pData);
+    }
+#ifndef PB_WITHOUT_64BIT
+    else if (field->data_size == sizeof(uint64_t))
+    {
+        return pb_encode_fixed64(stream, field->pData);
+    }
+#endif
+    else
+    {
+        PB_RETURN_ERROR(stream, "invalid data_size");
+    }
+}
+
+static bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_iter_t *field)
+{
+    const pb_bytes_array_t *bytes = NULL;
+
+    bytes = (const pb_bytes_array_t*)field->pData;
+    
+    if (bytes == NULL)
+    {
+        /* Treat 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, (size_t)bytes->size);
+}
+
+static bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_iter_t *field)
+{
+    size_t size = 0;
+    size_t max_size = (size_t)field->data_size;
+    const char *str = (const char*)field->pData;
+    
+    if (PB_ATYPE(field->type) == PB_ATYPE_POINTER)
+    {
+        max_size = (size_t)-1;
+    }
+    else
+    {
+        /* pb_dec_string() assumes string fields end with a null
+         * terminator when the type isn't PB_ATYPE_POINTER, so we
+         * shouldn't allow more than max-1 bytes to be written to
+         * allow space for the null terminator.
+         */
+        if (max_size == 0)
+            PB_RETURN_ERROR(stream, "zero-length string");
+
+        max_size -= 1;
+    }
+
+
+    if (str == NULL)
+    {
+        size = 0; /* Treat null pointer as an empty string */
+    }
+    else
+    {
+        const char *p = str;
+
+        /* strnlen() is not always available, so just use a loop */
+        while (size < max_size && *p != '\0')
+        {
+            size++;
+            p++;
+        }
+
+        if (*p != '\0')
+        {
+            PB_RETURN_ERROR(stream, "unterminated string");
+        }
+    }
+
+#ifdef PB_VALIDATE_UTF8
+    if (!pb_validate_utf8(str))
+        PB_RETURN_ERROR(stream, "invalid utf8");
+#endif
+
+    return pb_encode_string(stream, (const pb_byte_t*)str, size);
+}
+
+static bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_iter_t *field)
+{
+    if (field->submsg_desc == NULL)
+        PB_RETURN_ERROR(stream, "invalid field descriptor");
+
+    if (PB_LTYPE(field->type) == PB_LTYPE_SUBMSG_W_CB && field->pSize != NULL)
+    {
+        /* Message callback is stored right before pSize. */
+        pb_callback_t *callback = (pb_callback_t*)field->pSize - 1;
+        if (callback->funcs.encode)
+        {
+            if (!callback->funcs.encode(stream, field, &callback->arg))
+                return false;
+        }
+    }
+    
+    return pb_encode_submessage(stream, field->submsg_desc, field->pData);
+}
+
+static bool checkreturn pb_enc_fixed_length_bytes(pb_ostream_t *stream, const pb_field_iter_t *field)
+{
+    return pb_encode_string(stream, (const pb_byte_t*)field->pData, (size_t)field->data_size);
+}
+
+#ifdef PB_CONVERT_DOUBLE_FLOAT
+bool pb_encode_float_as_double(pb_ostream_t *stream, float value)
+{
+    union { float f; uint32_t i; } in;
+    uint_least8_t sign;
+    int exponent;
+    uint64_t mantissa;
+
+    in.f = value;
+
+    /* Decompose input value */
+    sign = (uint_least8_t)((in.i >> 31) & 1);
+    exponent = (int)((in.i >> 23) & 0xFF) - 127;
+    mantissa = in.i & 0x7FFFFF;
+
+    if (exponent == 128)
+    {
+        /* Special value (NaN etc.) */
+        exponent = 1024;
+    }
+    else if (exponent == -127)
+    {
+        if (!mantissa)
+        {
+            /* Zero */
+            exponent = -1023;
+        }
+        else
+        {
+            /* Denormalized */
+            mantissa <<= 1;
+            while (!(mantissa & 0x800000))
+            {
+                mantissa <<= 1;
+                exponent--;
+            }
+            mantissa &= 0x7FFFFF;
+        }
+    }
+
+    /* Combine fields */
+    mantissa <<= 29;
+    mantissa |= (uint64_t)(exponent + 1023) << 52;
+    mantissa |= (uint64_t)sign << 63;
+
+    return pb_encode_fixed64(stream, &mantissa);
+}
+#endif