/src/google/protobuf-c/protobuf-c.c

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/* --- protobuf-c.c: public protobuf c runtime implementation --- */

/*
 * Copyright (c) 2008-2011, Dave Benson.
 * 
 * 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.
 *
 * Neither the name
 * of "protobuf-c" nor the names of its contributors
 * may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * 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.
 */


/* TODO items:

     * 64-BIT OPTIMIZATION: certain implementations use 32-bit math even on 64-bit platforms
        (uint64_size, uint64_pack, parse_uint64)

     * get_packed_size and pack seem to use type-prefixed names,
       whereas parse uses type-suffixed names.  pick one and stick with it.
       Decision:  go with type-suffixed, since the type (or its instance)
       is typically the object of the verb.
       NOTE: perhaps the "parse" methods should be reanemd to "unpack"
       at the same time. (this only affects internal (static) functions)

     * use TRUE and FALSE instead of 1 and 0 as appropriate

     * use size_t consistently
 */

#if HAVE_PROTOBUF_C_CONFIG_H
#include "protobuf-c-config.h"
#endif
#include <stdio.h>                      /* for occasional printf()s */
#include <stdlib.h>                     /* for abort(), malloc() etc */
#include <string.h>                     /* for strlen(), memcpy(), memmove() */
#if 0                                   /* we no longer use alloca. */
#if HAVE_ALLOCA_H
#include <alloca.h>
#elif HAVE_MALLOC_H
#include <malloc.h>
#endif
#endif


#ifndef PRINT_UNPACK_ERRORS
#define PRINT_UNPACK_ERRORS              1
#endif

#include "protobuf-c.h"

unsigned protobuf_c_major = PROTOBUF_C_MAJOR;
unsigned protobuf_c_minor = PROTOBUF_C_MINOR;

#define MAX_UINT64_ENCODED_SIZE 10

/* This should be roughly the biggest message you think you'll encounter.
   However, the only point of the hashing is to detect uninitialized required members.
   I doubt many messages have 128 REQUIRED fields, so hopefully this'll be fine.

   TODO: A better solution is to separately in the descriptor index the required fields,
   and use the allcoator if the required field count is too big.  */
#define MAX_MEMBERS_FOR_HASH_SIZE       128

/* convenience macros */
#define TMPALLOC(allocator, size) ((allocator)->tmp_alloc ((allocator)->allocator_data, (size)))
#define FREE(allocator, ptr)   \
   do { if ((ptr) != NULL) ((allocator)->free ((allocator)->allocator_data, (ptr))); } while(0)
#define UNALIGNED_ALLOC(allocator, size) ALLOC (allocator, size) /* placeholder */
#define STRUCT_MEMBER_P(struct_p, struct_offset)   \
    ((void *) ((uint8_t*) (struct_p) + (struct_offset)))
#define STRUCT_MEMBER(member_type, struct_p, struct_offset)   \
    (*(member_type*) STRUCT_MEMBER_P ((struct_p), (struct_offset)))
#define STRUCT_MEMBER_PTR(member_type, struct_p, struct_offset)   \
    ((member_type*) STRUCT_MEMBER_P ((struct_p), (struct_offset)))
#define TRUE 1
#define FALSE 0

static void
alloc_failed_warning (unsigned size, const char *filename, unsigned line)
{
  fprintf (stderr,
           "WARNING: out-of-memory allocating a block of size %u (%s:%u)\n",
           size, filename, line);
}

/* Try to allocate memory, running some special code if it fails. */
#define DO_ALLOC(dst, allocator, size, fail_code)                           \
{ size_t da__allocation_size = (size);                                      \
  if (da__allocation_size == 0)                                             \
    dst = NULL;                                                             \
  else if ((dst=((allocator)->alloc ((allocator)->allocator_data,           \
                                     da__allocation_size))) == NULL)        \
    {                                                                       \
      alloc_failed_warning (da__allocation_size, __FILE__, __LINE__);       \
      fail_code;                                                            \
    }                                                                       \
}
#define DO_UNALIGNED_ALLOC  DO_ALLOC            /* placeholder */



#define ASSERT_IS_ENUM_DESCRIPTOR(desc) \
  assert((desc)->magic == PROTOBUF_C_ENUM_DESCRIPTOR_MAGIC)
#define ASSERT_IS_MESSAGE_DESCRIPTOR(desc) \
  assert((desc)->magic == PROTOBUF_C_MESSAGE_DESCRIPTOR_MAGIC)
#define ASSERT_IS_MESSAGE(message) \
  ASSERT_IS_MESSAGE_DESCRIPTOR((message)->descriptor)
#define ASSERT_IS_SERVICE_DESCRIPTOR(desc) \
  assert((desc)->magic == PROTOBUF_C_SERVICE_DESCRIPTOR_MAGIC)

/* --- allocator --- */

static void protobuf_c_out_of_memory_default (void)
{
  fprintf (stderr, "Out Of Memory!!!\n");
  abort ();
}
void (*protobuf_c_out_of_memory) (void) = protobuf_c_out_of_memory_default;

static void *system_alloc(void *allocator_data, size_t size)
{
  void *rv;
  (void) allocator_data;
  if (size == 0)
    return NULL;
  rv = malloc (size);
  if (rv == NULL)
    protobuf_c_out_of_memory ();
  return rv;
}

static void system_free (void *allocator_data, void *data)
{
  (void) allocator_data;
  if (data)
    free (data);
}

/* Some users may configure the default allocator;
   providing your own allocator to unpack() is prefered.
   this allocator is still used for packing nested messages. */
ProtobufCAllocator protobuf_c_default_allocator =
{
  system_alloc,
  system_free,
  NULL,         /* tmp_alloc */
  8192,         /* max_alloca */
  NULL          /* allocator_data */
};

/* Users should NOT modify this structure,
   but it's difficult to prevent.

   please modify protobuf_c_default_allocator instead. */
ProtobufCAllocator protobuf_c_system_allocator =
{
  system_alloc,
  system_free,
  NULL,         /* tmp_alloc */
  8192,         /* max_alloca */
  NULL          /* allocator_data */
};


/* === buffer-simple === */
void
protobuf_c_buffer_simple_append (ProtobufCBuffer *buffer,
                                 size_t           len,
                                 const uint8_t   *data)
{
  ProtobufCBufferSimple *simp = (ProtobufCBufferSimple *) buffer;
  size_t new_len = simp->len + len;
  if (new_len > simp->alloced)
    {
      size_t new_alloced = simp->alloced * 2;
      uint8_t *new_data;
      while (new_alloced < new_len)
        new_alloced += new_alloced;
      DO_ALLOC (new_data, &protobuf_c_default_allocator, new_alloced, return);
      memcpy (new_data, simp->data, simp->len);
      if (simp->must_free_data)
        FREE (&protobuf_c_default_allocator, simp->data);
      else
        simp->must_free_data = 1;
      simp->data = new_data;
      simp->alloced = new_alloced;
    }
  memcpy (simp->data + simp->len, data, len);
  simp->len = new_len;
}

/* === get_packed_size() === */

/* Return the number of bytes required to store the
   tag for the field (which includes 3 bits for
   the wire-type, and a single bit that denotes the end-of-tag. */
static inline size_t
get_tag_size (unsigned number)
{
  if (number < (1<<4))
    return 1;
  else if (number < (1<<11))
    return 2;
  else if (number < (1<<18))
    return 3;
  else if (number < (1<<25))
    return 4;
  else
    return 5;
}

/* Return the number of bytes required to store
   a variable-length unsigned integer that fits in 32-bit uint
   in base-128 encoding. */
static inline size_t
uint32_size (uint32_t v)
{
  if (v < (1<<7))
    return 1;
  else if (v < (1<<14))
    return 2;
  else if (v < (1<<21))
    return 3;
  else if (v < (1<<28))
    return 4;
  else
    return 5;
}
/* Return the number of bytes required to store
   a variable-length signed integer that fits in 32-bit int
   in base-128 encoding. */
static inline size_t
int32_size (int32_t v)
{
  if (v < 0)
    return 10;
  else if (v < (1<<7))
    return 1;
  else if (v < (1<<14))
    return 2;
  else if (v < (1<<21))
    return 3;
  else if (v < (1<<28))
    return 4;
  else
    return 5;
}
/* return the zigzag-encoded 32-bit unsigned int from a 32-bit signed int */
static inline uint32_t
zigzag32 (int32_t v)
{
  if (v < 0)
    return ((uint32_t)(-v)) * 2 - 1;
  else
    return v * 2;
}
/* Return the number of bytes required to store
   a variable-length signed integer that fits in 32-bit int,
   converted to unsigned via the zig-zag algorithm,
   then packed using base-128 encoding. */
static inline size_t
sint32_size (int32_t v)
{
  return uint32_size(zigzag32(v));
}

/* Return the number of bytes required to store
   a variable-length unsigned integer that fits in 64-bit uint
   in base-128 encoding. */
static inline size_t
uint64_size (uint64_t v)
{
  uint32_t upper_v = (uint32_t )(v>>32);
  if (upper_v == 0)
    return uint32_size ((uint32_t)v);
  else if (upper_v < (1<<3))
    return 5;
  else if (upper_v < (1<<10))
    return 6;
  else if (upper_v < (1<<17))
    return 7;
  else if (upper_v < (1<<24))
    return 8;
  else if (upper_v < (1U<<31))
    return 9;
  else
    return 10;
}

/* return the zigzag-encoded 64-bit unsigned int from a 64-bit signed int */
static inline uint64_t
zigzag64 (int64_t v)
{
  if (v < 0)
    return ((uint64_t)(-v)) * 2 - 1;
  else
    return v * 2;
}

/* Return the number of bytes required to store
   a variable-length signed integer that fits in 64-bit int,
   converted to unsigned via the zig-zag algorithm,
   then packed using base-128 encoding. */
static inline size_t
sint64_size (int64_t v)
{
  return uint64_size(zigzag64(v));
}

/* Get serialized size of a single field in the message,
   including the space needed by the identifying tag. */
static size_t
required_field_get_packed_size (const ProtobufCFieldDescriptor *field,
                                const void *member)
{
  size_t rv = get_tag_size (field->id);
  switch (field->type)
    {
    case PROTOBUF_C_TYPE_SINT32:
      return rv + sint32_size (*(const int32_t *) member);
    case PROTOBUF_C_TYPE_INT32:
      return rv + int32_size (*(const uint32_t *) member);
    case PROTOBUF_C_TYPE_UINT32:
      return rv + uint32_size (*(const uint32_t *) member);
    case PROTOBUF_C_TYPE_SINT64:
      return rv + sint64_size (*(const int64_t *) member);
    case PROTOBUF_C_TYPE_INT64:
    case PROTOBUF_C_TYPE_UINT64:
      return rv + uint64_size (*(const uint64_t *) member);
    case PROTOBUF_C_TYPE_SFIXED32:
    case PROTOBUF_C_TYPE_FIXED32:
      return rv + 4;
    case PROTOBUF_C_TYPE_SFIXED64:
    case PROTOBUF_C_TYPE_FIXED64:
      return rv + 8;
    case PROTOBUF_C_TYPE_BOOL:
      return rv + 1;
    case PROTOBUF_C_TYPE_FLOAT:
      return rv + 4;
    case PROTOBUF_C_TYPE_DOUBLE:
      return rv + 8;
    case PROTOBUF_C_TYPE_ENUM:
      // TODO: is this correct for negative-valued enums?
      return rv + uint32_size (*(const uint32_t *) member);
    case PROTOBUF_C_TYPE_STRING:
      {
        const char *str = *(char * const *) member;
        size_t len = str ? strlen (str) : 0;
        return rv + uint32_size (len) + len;
      }
    case PROTOBUF_C_TYPE_BYTES:
      {
        size_t len = ((const ProtobufCBinaryData*) member)->len;
        return rv + uint32_size (len) + len;
      }
    //case PROTOBUF_C_TYPE_GROUP:
    case PROTOBUF_C_TYPE_MESSAGE:
      {
        const ProtobufCMessage *msg = * (ProtobufCMessage * const *) member;
        size_t subrv = msg ? protobuf_c_message_get_packed_size (msg) : 0;
        return rv + uint32_size (subrv) + subrv;
      }
    }
  PROTOBUF_C_ASSERT_NOT_REACHED ();
  return 0;
}

/* Get serialized size of a single optional field in the message,
   including the space needed by the identifying tag.
   Returns 0 if the optional field isn't set. */
static size_t
optional_field_get_packed_size (const ProtobufCFieldDescriptor *field,
                                const protobuf_c_boolean *has,
                                const void *member)
{
  if (field->type == PROTOBUF_C_TYPE_MESSAGE
   || field->type == PROTOBUF_C_TYPE_STRING)
    {
      const void *ptr = * (const void * const *) member;
      if (ptr == NULL
       || ptr == field->default_value)
        return 0;
    }
  else
    {
      if (!*has)
        return 0;
    }
  return required_field_get_packed_size (field, member);
}

/* Get serialized size of a repeated field in the message,
   which may consist of any number of values (including 0).
   Includes the space needed by the identifying tags (as needed). */
static size_t
repeated_field_get_packed_size (const ProtobufCFieldDescriptor *field,
                                size_t count,
                                const void *member)
{
  size_t header_size;
  size_t rv = 0;
  unsigned i;
  void *array = * (void * const *) member;
  if (count == 0)
    return 0;
  header_size = get_tag_size (field->id);
  if (!field->packed)
    header_size *= count;
  switch (field->type)
    {
    case PROTOBUF_C_TYPE_SINT32:
      for (i = 0; i < count; i++)
        rv += sint32_size (((int32_t*)array)[i]);
      break;
    case PROTOBUF_C_TYPE_INT32:
      for (i = 0; i < count; i++)
        rv += int32_size (((uint32_t*)array)[i]);
      break;
    case PROTOBUF_C_TYPE_UINT32:
    case PROTOBUF_C_TYPE_ENUM:
      for (i = 0; i < count; i++)
        rv += uint32_size (((uint32_t*)array)[i]);
      break;
    case PROTOBUF_C_TYPE_SINT64:
      for (i = 0; i < count; i++)
        rv += sint64_size (((int64_t*)array)[i]);
      break;
    case PROTOBUF_C_TYPE_INT64:
    case PROTOBUF_C_TYPE_UINT64:
      for (i = 0; i < count; i++)
        rv += uint64_size (((uint64_t*)array)[i]);
      break;
    case PROTOBUF_C_TYPE_SFIXED32:
    case PROTOBUF_C_TYPE_FIXED32:
    case PROTOBUF_C_TYPE_FLOAT:
      rv += 4 * count;
      break;
    case PROTOBUF_C_TYPE_SFIXED64:
    case PROTOBUF_C_TYPE_FIXED64:
    case PROTOBUF_C_TYPE_DOUBLE:
      rv += 8 * count;
      break;
    case PROTOBUF_C_TYPE_BOOL:
      rv += count;
      break;
    case PROTOBUF_C_TYPE_STRING:
      for (i = 0; i < count; i++)
        {
          size_t len = strlen (((char**) array)[i]);
          rv += uint32_size (len) + len;
        }
      break;
      
    case PROTOBUF_C_TYPE_BYTES:
      for (i = 0; i < count; i++)
        {
          size_t len = ((ProtobufCBinaryData*) array)[i].len;
          rv += uint32_size (len) + len;
        }
      break;
    case PROTOBUF_C_TYPE_MESSAGE:
      for (i = 0; i < count; i++)
        {
          size_t len = protobuf_c_message_get_packed_size (((ProtobufCMessage **) array)[i]);
          rv += uint32_size (len) + len;
        }
      break;
    //case PROTOBUF_C_TYPE_GROUP:          // NOT SUPPORTED
    }
  if (field->packed)
    header_size += uint32_size (rv);
  return header_size + rv;
}

/* Get the packed size of a unknown field (meaning one that
   is passed through mostly uninterpreted... this is done
   for forward compatibilty with the addition of new fields). */
static inline size_t
unknown_field_get_packed_size (const ProtobufCMessageUnknownField *field)
{
  return get_tag_size (field->tag) + field->len;
}

/* Get the number of bytes that the message will occupy once serialized. */
size_t
protobuf_c_message_get_packed_size(const ProtobufCMessage *message)
{
  unsigned i;
  size_t rv = 0;
  ASSERT_IS_MESSAGE (message);
  for (i = 0; i < message->descriptor->n_fields; i++)
    {
      const ProtobufCFieldDescriptor *field = message->descriptor->fields + i;
      const void *member = ((const char *) message) + field->offset;
      const void *qmember = ((const char *) message) + field->quantifier_offset;

      if (field->label == PROTOBUF_C_LABEL_REQUIRED)
        rv += required_field_get_packed_size (field, member);
      else if (field->label == PROTOBUF_C_LABEL_OPTIONAL)
        rv += optional_field_get_packed_size (field, qmember, member);
      else 
        rv += repeated_field_get_packed_size (field, * (const size_t *) qmember, member);
    }
  for (i = 0; i < message->n_unknown_fields; i++)
    rv += unknown_field_get_packed_size (&message->unknown_fields[i]);
  return rv;
}
/* === pack() === */
/* Pack an unsigned 32-bit integer in base-128 encoding, and return the number of bytes needed:
   this will be 5 or less. */
static inline size_t
uint32_pack (uint32_t value, uint8_t *out)
{
  unsigned rv = 0;
  if (value >= 0x80)
    {
      out[rv++] = value | 0x80;
      value >>= 7;
      if (value >= 0x80)
        {
          out[rv++] = value | 0x80;
          value >>= 7;
          if (value >= 0x80)
            {
              out[rv++] = value | 0x80;
              value >>= 7;
              if (value >= 0x80)
                {
                  out[rv++] = value | 0x80;
                  value >>= 7;
                }
            }
        }
    }
  /* assert: value<128 */
  out[rv++] = value;
  return rv;
}

/* Pack a 32-bit signed integer, returning the number of bytes needed.
   Negative numbers are packed as twos-complement 64-bit integers. */
static inline size_t
int32_pack (int32_t value, uint8_t *out)
{
  if (value < 0)
    {
      out[0] = value | 0x80;
      out[1] = (value>>7) | 0x80;
      out[2] = (value>>14) | 0x80;
      out[3] = (value>>21) | 0x80;
      out[4] = (value>>28) | 0x80;
      out[5] = out[6] = out[7] = out[8] = 0xff;
      out[9] = 0x01;
      return 10;
    }
  else
    return uint32_pack (value, out);
}

/* Pack a 32-bit integer in zigzag encoding. */
static inline size_t
sint32_pack (int32_t value, uint8_t *out)
{
  return uint32_pack (zigzag32 (value), out);
}

/* Pack a 64-bit unsigned integer that fits in a 64-bit uint,
   using base-128 encoding. */
static size_t
uint64_pack (uint64_t value, uint8_t *out)
{
  uint32_t hi = (uint32_t )(value>>32);
  uint32_t lo = (uint32_t )value;
  unsigned rv;
  if (hi == 0)
    return uint32_pack ((uint32_t)lo, out);
  out[0] = (lo) | 0x80;
  out[1] = (lo>>7) | 0x80;
  out[2] = (lo>>14) | 0x80;
  out[3] = (lo>>21) | 0x80;
  if (hi < 8)
    {
      out[4] = (hi<<4) | (lo>>28);
      return 5;
    }
  else
    {
      out[4] = ((hi&7)<<4) | (lo>>28) | 0x80;
      hi >>= 3;
    }
  rv = 5;
  while (hi >= 128)
    {
      out[rv++] = hi | 0x80;
      hi >>= 7;
    }
  out[rv++] = hi;
  return rv;
}

/* Pack a 64-bit signed integer in zigzan encoding,
   return the size of the packed output.
   (Max returned value is 10) */
static inline size_t
sint64_pack (int64_t value, uint8_t *out)
{
  return uint64_pack (zigzag64 (value), out);
}

/* Pack a 32-bit value, little-endian.
   Used for fixed32, sfixed32, float) */
static inline size_t
fixed32_pack (uint32_t value, void *out)
{
#if IS_LITTLE_ENDIAN
  memcpy (out, &value, 4);
#else
  uint8_t *buf = out;
  buf[0] = value;
  buf[1] = value>>8;
  buf[2] = value>>16;
  buf[3] = value>>24;
#endif
  return 4;
}

/* Pack a 64-bit fixed-length value.
   (Used for fixed64, sfixed64, double) */
/* XXX: the big-endian impl is really only good for 32-bit machines,
   a 64-bit version would be appreciated, plus a way
   to decide to use 64-bit math where convenient. */
static inline size_t
fixed64_pack (uint64_t value, void *out)
{
#if IS_LITTLE_ENDIAN
  memcpy (out, &value, 8);
#else
  fixed32_pack (value, out);
  fixed32_pack (value>>32, ((char*)out)+4);
#endif
  return 8;
}


/* Pack a boolean as 0 or 1, even though the protobuf_c_boolean
   can really assume any integer value. */
/* XXX: perhaps on some platforms "*out = !!value" would be
   a better impl, b/c that is idiotmatic c++ in some stl impls. */
static inline size_t
boolean_pack (protobuf_c_boolean value, uint8_t *out)
{
  *out = value ? 1 : 0;
  return 1;
}

/* Pack a length-prefixed string.
   The input string is NUL-terminated.

   The NULL pointer is treated as an empty string.
   This isn't really necessary, but it allows people
   to leave required strings blank.
   (See Issue 13 in the bug tracker for a 
   little more explanation).
 */
static inline size_t
string_pack (const char * str, uint8_t *out)
{
  if (str == NULL)
    {
      out[0] = 0;
      return 1;
    }
  else
    {
      size_t len = strlen (str);
      size_t rv = uint32_pack (len, out);
      memcpy (out + rv, str, len);
      return rv + len;
    }
}

static inline size_t
binary_data_pack (const ProtobufCBinaryData *bd, uint8_t *out)
{
  size_t len = bd->len;
  size_t rv = uint32_pack (len, out);
  memcpy (out + rv, bd->data, len);
  return rv + len;
}

static inline size_t
prefixed_message_pack (const ProtobufCMessage *message, uint8_t *out)
{
  if (message == NULL)
    {
      out[0] = 0;
      return 1;
    }
  else
    {
      size_t rv = protobuf_c_message_pack (message, out + 1);
      uint32_t rv_packed_size = uint32_size (rv);
      if (rv_packed_size != 1)
        memmove (out + rv_packed_size, out + 1, rv);
      return uint32_pack (rv, out) + rv;
    }
}

/* wire-type will be added in required_field_pack() */
/* XXX: just call uint64_pack on 64-bit platforms. */
static size_t
tag_pack (uint32_t id, uint8_t *out)
{
  if (id < (1<<(32-3)))
    return uint32_pack (id<<3, out);
  else
    return uint64_pack (((uint64_t)id) << 3, out);
}

static size_t
required_field_pack (const ProtobufCFieldDescriptor *field,
                     const void *member,
                     uint8_t *out)
{
  size_t rv = tag_pack (field->id, out);
  switch (field->type)
    {
    case PROTOBUF_C_TYPE_SINT32:
      out[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      return rv + sint32_pack (*(const int32_t *) member, out + rv);
    case PROTOBUF_C_TYPE_INT32:
      out[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      return rv + int32_pack (*(const uint32_t *) member, out + rv);
    case PROTOBUF_C_TYPE_UINT32:
    case PROTOBUF_C_TYPE_ENUM:
      out[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      return rv + uint32_pack (*(const uint32_t *) member, out + rv);
    case PROTOBUF_C_TYPE_SINT64:
      out[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      return rv + sint64_pack (*(const int64_t *) member, out + rv);
    case PROTOBUF_C_TYPE_INT64:
    case PROTOBUF_C_TYPE_UINT64:
      out[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      return rv + uint64_pack (*(const uint64_t *) member, out + rv);
    case PROTOBUF_C_TYPE_SFIXED32:
    case PROTOBUF_C_TYPE_FIXED32:
    case PROTOBUF_C_TYPE_FLOAT:
      out[0] |= PROTOBUF_C_WIRE_TYPE_32BIT;
      return rv + fixed32_pack (*(const uint32_t *) member, out + rv);
    case PROTOBUF_C_TYPE_SFIXED64:
    case PROTOBUF_C_TYPE_FIXED64:
    case PROTOBUF_C_TYPE_DOUBLE:
      out[0] |= PROTOBUF_C_WIRE_TYPE_64BIT;
      return rv + fixed64_pack (*(const uint64_t *) member, out + rv);
    case PROTOBUF_C_TYPE_BOOL:
      out[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      return rv + boolean_pack (*(const protobuf_c_boolean *) member, out + rv);
    case PROTOBUF_C_TYPE_STRING:
      {
        out[0] |= PROTOBUF_C_WIRE_TYPE_LENGTH_PREFIXED;
        return rv + string_pack (*(char * const *) member, out + rv);
      }
      
    case PROTOBUF_C_TYPE_BYTES:
      {
        const ProtobufCBinaryData * bd = ((const ProtobufCBinaryData*) member);
        out[0] |= PROTOBUF_C_WIRE_TYPE_LENGTH_PREFIXED;
        return rv + binary_data_pack (bd, out + rv);
      }
    //case PROTOBUF_C_TYPE_GROUP:          // NOT SUPPORTED
    case PROTOBUF_C_TYPE_MESSAGE:
      {
        out[0] |= PROTOBUF_C_WIRE_TYPE_LENGTH_PREFIXED;
        return rv + prefixed_message_pack (*(ProtobufCMessage * const *) member,
                                           out + rv);
      }
    }
  PROTOBUF_C_ASSERT_NOT_REACHED ();
  return 0;
}
static size_t
optional_field_pack (const ProtobufCFieldDescriptor *field,
                     const protobuf_c_boolean *has,
                     const void *member,
                     uint8_t *out)
{
  if (field->type == PROTOBUF_C_TYPE_MESSAGE
   || field->type == PROTOBUF_C_TYPE_STRING)
    {
      const void *ptr = * (const void * const *) member;
      if (ptr == NULL
       || ptr == field->default_value)
        return 0;
    }
  else
    {
      if (!*has)
        return 0;
    }
  return required_field_pack (field, member, out);
}

/* TODO: implement as a table lookup */
static inline size_t
sizeof_elt_in_repeated_array (ProtobufCType type)
{
  switch (type)
    {
    case PROTOBUF_C_TYPE_SINT32:
    case PROTOBUF_C_TYPE_INT32:
    case PROTOBUF_C_TYPE_UINT32:
    case PROTOBUF_C_TYPE_SFIXED32:
    case PROTOBUF_C_TYPE_FIXED32:
    case PROTOBUF_C_TYPE_FLOAT:
    case PROTOBUF_C_TYPE_ENUM:
      return 4;
    case PROTOBUF_C_TYPE_SINT64:
    case PROTOBUF_C_TYPE_INT64:
    case PROTOBUF_C_TYPE_UINT64:
    case PROTOBUF_C_TYPE_SFIXED64:
    case PROTOBUF_C_TYPE_FIXED64:
    case PROTOBUF_C_TYPE_DOUBLE:
      return 8;
    case PROTOBUF_C_TYPE_BOOL:
      return sizeof (protobuf_c_boolean);
    case PROTOBUF_C_TYPE_STRING:
    case PROTOBUF_C_TYPE_MESSAGE:
      return sizeof (void *);
    case PROTOBUF_C_TYPE_BYTES:
      return sizeof (ProtobufCBinaryData);
    }
  PROTOBUF_C_ASSERT_NOT_REACHED ();
  return 0;
}

static void
copy_to_little_endian_32 (void *out, const void *in, unsigned N)
{
#if IS_LITTLE_ENDIAN
  memcpy (out, in, N * 4);
#else
  unsigned i;
  const uint32_t *ini = in;
  for (i = 0; i < N; i++)
    fixed32_pack (ini[i], (uint32_t*)out + i);
#endif
}
static void
copy_to_little_endian_64 (void *out, const void *in, unsigned N)
{
#if IS_LITTLE_ENDIAN
  memcpy (out, in, N * 8);
#else
  unsigned i;
  const uint64_t *ini = in;
  for (i = 0; i < N; i++)
    fixed64_pack (ini[i], (uint64_t*)out + i);
#endif
}

static unsigned
get_type_min_size (ProtobufCType type)
{
  if (type == PROTOBUF_C_TYPE_SFIXED32
   || type == PROTOBUF_C_TYPE_FIXED32
   || type == PROTOBUF_C_TYPE_FLOAT)
    return 4;
  if (type == PROTOBUF_C_TYPE_SFIXED64
   || type == PROTOBUF_C_TYPE_FIXED64
   || type == PROTOBUF_C_TYPE_DOUBLE)
    return 8;
  return 1;
}

static size_t
repeated_field_pack (const ProtobufCFieldDescriptor *field,
                     size_t count,
                     const void *member,
                     uint8_t *out)
{
  char *array = * (char * const *) member;
  unsigned i;
  if (field->packed)
    {
      unsigned header_len;
      unsigned len_start;
      unsigned min_length;
      unsigned payload_len;
      unsigned length_size_min;
      unsigned actual_length_size;
      uint8_t *payload_at;
      if (count == 0)
        return 0;
      header_len = tag_pack (field->id, out);
      out[0] |= PROTOBUF_C_WIRE_TYPE_LENGTH_PREFIXED;
      len_start = header_len;
      min_length = get_type_min_size (field->type) * count;
      length_size_min = uint32_size (min_length);
      header_len += length_size_min;
      payload_at = out + header_len;
      switch (field->type)
        {
        case PROTOBUF_C_TYPE_SFIXED32:
        case PROTOBUF_C_TYPE_FIXED32:
        case PROTOBUF_C_TYPE_FLOAT:
          copy_to_little_endian_32 (payload_at, array, count);
          payload_at += count * 4;
          break;

        case PROTOBUF_C_TYPE_SFIXED64:
        case PROTOBUF_C_TYPE_FIXED64:
        case PROTOBUF_C_TYPE_DOUBLE:
          copy_to_little_endian_64 (payload_at, array, count);
          payload_at += count * 8;
          break;

        case PROTOBUF_C_TYPE_INT32:
          {
            const int32_t *arr = (const int32_t *) array;
            for (i = 0; i < count; i++)
              payload_at += int32_pack (arr[i], payload_at);
          }
          break;

        case PROTOBUF_C_TYPE_SINT32:
          {
            const int32_t *arr = (const int32_t *) array;
            for (i = 0; i < count; i++)
              payload_at += sint32_pack (arr[i], payload_at);
          }
          break;

        case PROTOBUF_C_TYPE_SINT64:
          {
            const int64_t *arr = (const int64_t *) array;
            for (i = 0; i < count; i++)
              payload_at += sint64_pack (arr[i], payload_at);
          }
          break;
        case PROTOBUF_C_TYPE_ENUM:
        case PROTOBUF_C_TYPE_UINT32:
          {
            const uint32_t *arr = (const uint32_t *) array;
            for (i = 0; i < count; i++)
              payload_at += uint32_pack (arr[i], payload_at);
          }
          break;
        case PROTOBUF_C_TYPE_INT64:
        case PROTOBUF_C_TYPE_UINT64:
          {
            const uint64_t *arr = (const uint64_t *) array;
            for (i = 0; i < count; i++)
              payload_at += uint64_pack (arr[i], payload_at);
          }
          break;
        case PROTOBUF_C_TYPE_BOOL:
          {
            const protobuf_c_boolean *arr = (const protobuf_c_boolean *) array;
            for (i = 0; i < count; i++)
              payload_at += boolean_pack (arr[i], payload_at);
          }
          break;
          
        default:
          assert (0);
        }
      payload_len = payload_at - (out + header_len);
      actual_length_size = uint32_size (payload_len);
      if (length_size_min != actual_length_size)
        {
          assert (actual_length_size == length_size_min + 1);
          memmove (out + header_len + 1, out + header_len, payload_len);
          header_len++;
        }
      uint32_pack (payload_len, out + len_start);
      return header_len + payload_len;
    }
  else
    {
      /* CONSIDER: optimize this case a bit (by putting the loop inside the switch) */
      size_t rv = 0;
      unsigned siz = sizeof_elt_in_repeated_array (field->type);
      for (i = 0; i < count; i++)
        {
          rv += required_field_pack (field, array, out + rv);
          array += siz;
        }
      return rv;
    }
}
static size_t
unknown_field_pack (const ProtobufCMessageUnknownField *field,
                    uint8_t *out)
{
  size_t rv = tag_pack (field->tag, out);
  out[0] |= field->wire_type;
  memcpy (out + rv, field->data, field->len);
  return rv + field->len;
}

size_t
protobuf_c_message_pack           (const ProtobufCMessage *message,
                                   uint8_t                *out)
{
  unsigned i;
  size_t rv = 0;
  ASSERT_IS_MESSAGE (message);
  for (i = 0; i < message->descriptor->n_fields; i++)
    {
      const ProtobufCFieldDescriptor *field = message->descriptor->fields + i;
      const void *member = ((const char *) message) + field->offset;

      /* it doesn't hurt to compute qmember (a pointer to the quantifier
         field of the structure), but the pointer is only valid if
         the field is one of:
           - a repeated field
           - an optional field that isn't a pointer type
             (meaning: not a message or a string) */
      const void *qmember = ((const char *) message) + field->quantifier_offset;

      if (field->label == PROTOBUF_C_LABEL_REQUIRED)
        rv += required_field_pack (field, member, out + rv);
      else if (field->label == PROTOBUF_C_LABEL_OPTIONAL)
        /* note that qmember is bogus for strings and messages,
           but it isn't used */
        rv += optional_field_pack (field, qmember, member, out + rv);
      else
        rv += repeated_field_pack (field, * (const size_t *) qmember, member, out + rv);
    }
  for (i = 0; i < message->n_unknown_fields; i++)
    rv += unknown_field_pack (&message->unknown_fields[i], out + rv);
  return rv;
}

/* === pack_to_buffer() === */
static size_t
required_field_pack_to_buffer (const ProtobufCFieldDescriptor *field,
                               const void *member,
                               ProtobufCBuffer *buffer)
{
  size_t rv;
  uint8_t scratch[MAX_UINT64_ENCODED_SIZE * 2];
  rv = tag_pack (field->id, scratch);
  switch (field->type)
    {
    case PROTOBUF_C_TYPE_SINT32:
      scratch[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      rv += sint32_pack (*(const int32_t *) member, scratch + rv);
      buffer->append (buffer, rv, scratch);
      break;
    case PROTOBUF_C_TYPE_INT32:
      scratch[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      rv += int32_pack (*(const uint32_t *) member, scratch + rv);
      buffer->append (buffer, rv, scratch);
      break;
    case PROTOBUF_C_TYPE_UINT32:
    case PROTOBUF_C_TYPE_ENUM:
      scratch[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      rv += uint32_pack (*(const uint32_t *) member, scratch + rv);
      buffer->append (buffer, rv, scratch);
      break;
    case PROTOBUF_C_TYPE_SINT64:
      scratch[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      rv += sint64_pack (*(const int64_t *) member, scratch + rv);
      buffer->append (buffer, rv, scratch);
      break;
    case PROTOBUF_C_TYPE_INT64:
    case PROTOBUF_C_TYPE_UINT64:
      scratch[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      rv += uint64_pack (*(const uint64_t *) member, scratch + rv);
      buffer->append (buffer, rv, scratch);
      break;
    case PROTOBUF_C_TYPE_SFIXED32:
    case PROTOBUF_C_TYPE_FIXED32:
    case PROTOBUF_C_TYPE_FLOAT:
      scratch[0] |= PROTOBUF_C_WIRE_TYPE_32BIT;
      rv += fixed32_pack (*(const uint32_t *) member, scratch + rv);
      buffer->append (buffer, rv, scratch);
      break;
    case PROTOBUF_C_TYPE_SFIXED64:
    case PROTOBUF_C_TYPE_FIXED64:
    case PROTOBUF_C_TYPE_DOUBLE:
      scratch[0] |= PROTOBUF_C_WIRE_TYPE_64BIT;
      rv += fixed64_pack (*(const uint64_t *) member, scratch + rv);
      buffer->append (buffer, rv, scratch);
      break;
    case PROTOBUF_C_TYPE_BOOL:
      scratch[0] |= PROTOBUF_C_WIRE_TYPE_VARINT;
      rv += boolean_pack (*(const protobuf_c_boolean *) member, scratch + rv);
      buffer->append (buffer, rv, scratch);
      break;
    case PROTOBUF_C_TYPE_STRING:
      {
        const char *str = *(char * const *) member;
        size_t sublen = str ? strlen (str) : 0;
        scratch[0] |= PROTOBUF_C_WIRE_TYPE_LENGTH_PREFIXED;
        rv += uint32_pack (sublen, scratch + rv);
        buffer->append (buffer, rv, scratch);
        buffer->append (buffer, sublen, (const uint8_t *) str);
        rv += sublen;
        break;
      }
      
    case PROTOBUF_C_TYPE_BYTES:
      {
        const ProtobufCBinaryData * bd = ((const ProtobufCBinaryData*) member);
        size_t sublen = bd->len;
        scratch[0] |= PROTOBUF_C_WIRE_TYPE_LENGTH_PREFIXED;
        rv += uint32_pack (sublen, scratch + rv);
        buffer->append (buffer, rv, scratch);
        buffer->append (buffer, sublen, bd->data);
        rv += sublen;
        break;
      }
    //PROTOBUF_C_TYPE_GROUP,          // NOT SUPPORTED
    case PROTOBUF_C_TYPE_MESSAGE:
      {
        uint8_t simple_buffer_scratch[256];
        size_t sublen;
        ProtobufCBufferSimple simple_buffer
          = PROTOBUF_C_BUFFER_SIMPLE_INIT (simple_buffer_scratch);
        const ProtobufCMessage *msg = *(ProtobufCMessage * const *) member;
        scratch[0] |= PROTOBUF_C_WIRE_TYPE_LENGTH_PREFIXED;
        if (msg == NULL)
          sublen = 0;
        else
          sublen = protobuf_c_message_pack_to_buffer (msg, &simple_buffer.base);
        rv += uint32_pack (sublen, scratch + rv);
        buffer->append (buffer, rv, scratch);
        buffer->append (buffer, sublen, simple_buffer.data);
        rv += sublen;
        PROTOBUF_C_BUFFER_SIMPLE_CLEAR (&simple_buffer);
        break;
      }
    default:
      PROTOBUF_C_ASSERT_NOT_REACHED ();
    }
  return rv;
}
static size_t
optional_field_pack_to_buffer (const ProtobufCFieldDescriptor *field,
                               const protobuf_c_boolean *has,
                               const void *member,
                               ProtobufCBuffer *buffer)
{
  if (field->type == PROTOBUF_C_TYPE_MESSAGE
   || field->type == PROTOBUF_C_TYPE_STRING)
    {
      const void *ptr = * (const void * const *) member;
      if (ptr == NULL
       || ptr == field->default_value)
        return 0;
    }
  else
    {
      if (!*has)
        return 0;
    }
  return required_field_pack_to_buffer (field, member, buffer);
}

static size_t
get_packed_payload_length (const ProtobufCFieldDescriptor *field,
                           unsigned count,
                           const void *array)
{
  unsigned rv = 0;
  unsigned i;
  switch (field->type)
    {
    case PROTOBUF_C_TYPE_SFIXED32:
    case PROTOBUF_C_TYPE_FIXED32:
    case PROTOBUF_C_TYPE_FLOAT:
      return count * 4;

    case PROTOBUF_C_TYPE_SFIXED64:
    case PROTOBUF_C_TYPE_FIXED64:
    case PROTOBUF_C_TYPE_DOUBLE:
      return count * 8;

    case PROTOBUF_C_TYPE_INT32:
      {
        const int32_t *arr = (const int32_t *) array;
        for (i = 0; i < count; i++)
          rv += int32_size (arr[i]);
      }
      break;

    case PROTOBUF_C_TYPE_SINT32:
      {
        const int32_t *arr = (const int32_t *) array;
        for (i = 0; i < count; i++)
          rv += sint32_size (arr[i]);
      }
      break;
    case PROTOBUF_C_TYPE_ENUM:
    case PROTOBUF_C_TYPE_UINT32:
      {
        const uint32_t *arr = (const uint32_t *) array;
        for (i = 0; i < count; i++)
          rv += uint32_size (arr[i]);
      }
      break;

    case PROTOBUF_C_TYPE_SINT64:
      {
        const int64_t *arr = (const int64_t *) array;
        for (i = 0; i < count; i++)
          rv += sint64_size (arr[i]);
      }
      break;
    case PROTOBUF_C_TYPE_INT64:
    case PROTOBUF_C_TYPE_UINT64:
      {
        const uint64_t *arr = (const uint64_t *) array;
        for (i = 0; i < count; i++)
          rv += uint64_size (arr[i]);
      }
      break;
    case PROTOBUF_C_TYPE_BOOL:
      return count;
    default:
      assert (0);
    }
  return rv;
}
static size_t
pack_buffer_packed_payload (const ProtobufCFieldDescriptor *field,
                            unsigned count,
                            const void *array,
                            ProtobufCBuffer *buffer)
{
  uint8_t scratch[16];
  size_t rv = 0;
  unsigned i;
  switch (field->type)
    {
      case PROTOBUF_C_TYPE_SFIXED32:
      case PROTOBUF_C_TYPE_FIXED32:
      case PROTOBUF_C_TYPE_FLOAT:
#if IS_LITTLE_ENDIAN
        rv = count * 4;
        goto no_packing_needed;
#else
        for (i = 0; i < count; i++)
          {
            unsigned len = fixed32_pack (((uint32_t*)array)[i], scratch);
            buffer->append (buffer, len, scratch);
            rv += len;
          }
#endif
        break;
      case PROTOBUF_C_TYPE_SFIXED64:
      case PROTOBUF_C_TYPE_FIXED64:
      case PROTOBUF_C_TYPE_DOUBLE:
#if IS_LITTLE_ENDIAN
        rv = count * 8;
        goto no_packing_needed;
#else
        for (i = 0; i < count; i++)
          {
            unsigned len = fixed64_pack (((uint64_t*)array)[i], scratch);
            buffer->append (buffer, len, scratch);
            rv += len;
          }
        break;
#endif
      case PROTOBUF_C_TYPE_INT32:
        for (i = 0; i < count; i++)
          {
            unsigned len = int32_pack (((int32_t*)array)[i], scratch);
            buffer->append (buffer, len, scratch);
            rv += len;
          }
        break;

      case PROTOBUF_C_TYPE_SINT32:
        for (i = 0; i < count; i++)
          {
            unsigned len = sint32_pack (((int32_t*)array)[i], scratch);
            buffer->append (buffer, len, scratch);
            rv += len;
          }
        break;
      case PROTOBUF_C_TYPE_ENUM:
      case PROTOBUF_C_TYPE_UINT32:
        for (i = 0; i < count; i++)
          {
            unsigned len = uint32_pack (((uint32_t*)array)[i], scratch);
            buffer->append (buffer, len, scratch);
            rv += len;
          }
        break;

      case PROTOBUF_C_TYPE_SINT64:
        for (i = 0; i < count; i++)
          {
            unsigned len = sint64_pack (((int64_t*)array)[i], scratch);
            buffer->append (buffer, len, scratch);
            rv += len;
          }
        break;
      case PROTOBUF_C_TYPE_INT64:
      case PROTOBUF_C_TYPE_UINT64:
        for (i = 0; i < count; i++)
          {
            unsigned len = uint64_pack (((uint64_t*)array)[i], scratch);
            buffer->append (buffer, len, scratch);
            rv += len;
          }
        break;
      case PROTOBUF_C_TYPE_BOOL:
        for (i = 0; i < count; i++)
          {
            unsigned len = boolean_pack (((protobuf_c_boolean*)array)[i], scratch);
            buffer->append (buffer, len, scratch);
            rv += len;
          }
        return count;
      default:
        assert(0);
    }
  return rv;

no_packing_needed:
  buffer->append (buffer, rv, array);
  return rv;
}

static size_t
repeated_field_pack_to_buffer (const ProtobufCFieldDescriptor *field,
                               unsigned count,
                               const void *member,
                               ProtobufCBuffer *buffer)
{
  char *array = * (char * const *) member;
  if (count == 0)
    return 0;
  if (field->packed)
    {
      uint8_t scratch[MAX_UINT64_ENCODED_SIZE * 2];
      size_t rv = tag_pack (field->id, scratch);
      size_t payload_len = get_packed_payload_length (field, count, array);
      size_t tmp;
      scratch[0] |= PROTOBUF_C_WIRE_TYPE_LENGTH_PREFIXED;
      rv += uint32_pack (payload_len, scratch + rv);
      buffer->append (buffer, rv, scratch);
      tmp = pack_buffer_packed_payload (field, count, array, buffer);
      assert (tmp == payload_len);
      return rv + payload_len;
    }
  else
    {
      size_t siz;
      unsigned i;
      /* CONSIDER: optimize this case a bit (by putting the loop inside the switch) */
      unsigned rv = 0;
      siz = sizeof_elt_in_repeated_array (field->type);
      for (i = 0; i < count; i++)
        {
          rv += required_field_pack_to_buffer (field, array, buffer);
          array += siz;
        }
      return rv;
    }
}

static size_t
unknown_field_pack_to_buffer (const ProtobufCMessageUnknownField *field,
                              ProtobufCBuffer *buffer)
{
  uint8_t header[MAX_UINT64_ENCODED_SIZE];
  size_t rv = tag_pack (field->tag, header);
  header[0] |= field->wire_type;
  buffer->append (buffer, rv, header);
  buffer->append (buffer, field->len, field->data);
  return rv + field->len;
}

size_t
protobuf_c_message_pack_to_buffer (const ProtobufCMessage *message,
                                   ProtobufCBuffer  *buffer)
{
  unsigned i;
  size_t rv = 0;
  ASSERT_IS_MESSAGE (message);
  for (i = 0; i < message->descriptor->n_fields; i++)
    {
      const ProtobufCFieldDescriptor *field = message->descriptor->fields + i;
      const void *member = ((const char *) message) + field->offset;
      const void *qmember = ((const char *) message) + field->quantifier_offset;

      if (field->label == PROTOBUF_C_LABEL_REQUIRED)
        rv += required_field_pack_to_buffer (field, member, buffer);
      else if (field->label == PROTOBUF_C_LABEL_OPTIONAL)
        rv += optional_field_pack_to_buffer (field, qmember, member, buffer);
      else
        rv += repeated_field_pack_to_buffer (field, * (const size_t *) qmember, member, buffer);
    }
  for (i = 0; i < message->n_unknown_fields; i++)
    rv += unknown_field_pack_to_buffer (&message->unknown_fields[i], buffer);

  return rv;
}

/* === unpacking === */
#if PRINT_UNPACK_ERRORS
# define UNPACK_ERROR(args)  do { printf args;printf("\n"); }while(0)
#else
# define UNPACK_ERROR(args)  do { } while (0)
#endif

static inline int
int_range_lookup (unsigned n_ranges,
                  const ProtobufCIntRange *ranges,
                  int value)
{
  unsigned start, n;
  if (n_ranges == 0)
    return -1;
  start = 0;
  n = n_ranges;
  while (n > 1)
    {
      unsigned mid = start + n / 2;
      if (value < ranges[mid].start_value)
        {
          n = mid - start;
        }
      else if (value >= ranges[mid].start_value + (int)(ranges[mid+1].orig_index-ranges[mid].orig_index))
        {
          unsigned new_start = mid + 1;
          n = start + n - new_start;
          start = new_start;
        }
      else
        return (value - ranges[mid].start_value) + ranges[mid].orig_index;
    }
  if (n > 0)
    {
      unsigned start_orig_index = ranges[start].orig_index;
      unsigned range_size = ranges[start+1].orig_index - start_orig_index;

      if (ranges[start].start_value <= value
       && value < (int)(ranges[start].start_value + range_size))
        return (value - ranges[start].start_value) + start_orig_index;
    }
  return -1;
}

static size_t
parse_tag_and_wiretype (size_t len,
                        const uint8_t *data,
                        uint32_t *tag_out,
                        ProtobufCWireType *wiretype_out)
{
  unsigned max_rv = len > 5 ? 5 : len;
  uint32_t tag = (data[0]&0x7f) >> 3;
  unsigned shift = 4;
  unsigned rv;
  *wiretype_out = data[0] & 7;
  if ((data[0] & 0x80) == 0)
    {
      *tag_out = tag;
      return 1;
    }
  for (rv = 1; rv < max_rv; rv++)
    if (data[rv] & 0x80)
      {
        tag |= (data[rv] & 0x7f) << shift;
        shift += 7;
      }
    else
      {
        tag |= data[rv] << shift;
        *tag_out = tag;
        return rv + 1;
      }
  return 0;                   /* error: bad header */
}

/* sizeof(ScannedMember) must be <= (1<<BOUND_SIZEOF_SCANNED_MEMBER_LOG2) */
#define BOUND_SIZEOF_SCANNED_MEMBER_LOG2  5
typedef struct _ScannedMember ScannedMember;
struct _ScannedMember
{
  uint32_t tag;
  uint8_t wire_type;
  uint8_t length_prefix_len;
  const ProtobufCFieldDescriptor *field;
  size_t len;
  const uint8_t *data;
};

static inline uint32_t
scan_length_prefixed_data (size_t len, const uint8_t *data, size_t *prefix_len_out)
{
  unsigned hdr_max = len < 5 ? len : 5;
  unsigned hdr_len;
  uint32_t val = 0;
  unsigned i;
  unsigned shift = 0;
  for (i = 0; i < hdr_max; i++)
    {
      val |= (data[i] & 0x7f) << shift;
      shift += 7;
      if ((data[i] & 0x80) == 0)
        break;
    }
  if (i == hdr_max)
    {
      UNPACK_ERROR (("error parsing length for length-prefixed data"));
      return 0;
    }
  hdr_len = i + 1;
  *prefix_len_out = hdr_len;
  if (hdr_len + val > len)
    {
      UNPACK_ERROR (("data too short after length-prefix of %u",
                     val));
      return 0;
    }
  return hdr_len + val;
}

static size_t 
max_b128_numbers (size_t len, const uint8_t *data)
{
  size_t rv = 0;
  while (len--)
    if ((*data++ & 0x80) == 0)
      ++rv;
  return rv;
}


/* Given a raw slab of packed-repeated values,
   determine the number of elements.
   This function detects certain kinds of errors
   but not others; the remaining error checking is done by
   parse_packed_repeated_member() */
static protobuf_c_boolean
count_packed_elements (ProtobufCType type,
                       size_t len,
                       const uint8_t *data,
                       size_t *count_out)
{
  switch (type)
    {
    case PROTOBUF_C_TYPE_SFIXED32:
    case PROTOBUF_C_TYPE_FIXED32:
    case PROTOBUF_C_TYPE_FLOAT:
      if (len % 4 != 0)
        {
          UNPACK_ERROR (("length must be a multiple of 4 for fixed-length 32-bit types"));
          return FALSE;
        }
      *count_out = len / 4;
      return TRUE;

    case PROTOBUF_C_TYPE_SFIXED64:
    case PROTOBUF_C_TYPE_FIXED64:
    case PROTOBUF_C_TYPE_DOUBLE:
      if (len % 8 != 0)
        {
          UNPACK_ERROR (("length must be a multiple of 8 for fixed-length 64-bit types"));
          return FALSE;
        }
      *count_out = len / 8;
      return TRUE;

    case PROTOBUF_C_TYPE_INT32:
    case PROTOBUF_C_TYPE_SINT32:
    case PROTOBUF_C_TYPE_ENUM:
    case PROTOBUF_C_TYPE_UINT32:
    case PROTOBUF_C_TYPE_INT64:
    case PROTOBUF_C_TYPE_SINT64:
    case PROTOBUF_C_TYPE_UINT64:
      *count_out = max_b128_numbers (len, data);
      return TRUE;
    case PROTOBUF_C_TYPE_BOOL:
      *count_out = len;
      return TRUE;

    case PROTOBUF_C_TYPE_STRING:
    case PROTOBUF_C_TYPE_BYTES:
    case PROTOBUF_C_TYPE_MESSAGE:
    default:
      UNPACK_ERROR (("bad protobuf-c type %u for packed-repeated", type));
      return FALSE;
    }
}

static inline uint32_t
parse_uint32 (unsigned len, const uint8_t *data)
{
  unsigned rv = data[0] & 0x7f;
  if (len > 1)
    {
      rv |= ((data[1] & 0x7f) << 7);
      if (len > 2)
        {
          rv |= ((data[2] & 0x7f) << 14);
          if (len > 3)
            {
              rv |= ((data[3] & 0x7f) << 21);
              if (len > 4)
                rv |= (data[4] << 28);
            }
        }
    }
  return rv;
}
static inline uint32_t
parse_int32 (unsigned len, const uint8_t *data)
{
  return parse_uint32 (len, data);
}
static inline int32_t
unzigzag32 (uint32_t v)
{
  if (v&1)
    return -(v>>1) - 1;
  else
    return v>>1;
}
static inline uint32_t
parse_fixed_uint32 (const uint8_t *data)
{
#if IS_LITTLE_ENDIAN
  uint32_t t;
  memcpy (&t, data, 4);
  return t;
#else
  return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
#endif
}
static uint64_t
parse_uint64 (unsigned len, const uint8_t *data)
{
  unsigned shift, i;
  uint64_t rv;
  if (len < 5)
    return parse_uint32 (len, data);
  rv = ((data[0] & 0x7f))
              | ((data[1] & 0x7f)<<7)
              | ((data[2] & 0x7f)<<14)
              | ((data[3] & 0x7f)<<21);
  shift = 28;
  for (i = 4; i < len; i++)
    {
      rv |= (((uint64_t)(data[i]&0x7f)) << shift);
      shift += 7;
    }
  return rv;
}
static inline int64_t
unzigzag64 (uint64_t v)
{
  if (v&1)
    return -(v>>1) - 1;
  else
    return v>>1;
}
static inline uint64_t
par…