protobuf/upb/msg.c

/*
 * Copyright (c) 2009-2021, Google LLC
 * 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 Google LLC 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 Google LLC 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.
 */

#include "upb/msg.h"

#include <math.h>

#include "upb/msg_internal.h"

// Must be last.
#include "upb/port_def.inc"

const float kUpb_FltInfinity = INFINITY;
const double kUpb_Infinity = INFINITY;

static const size_t overhead = sizeof(upb_Message_InternalData);

static const upb_Message_Internal* upb_Message_Getinternal_const(
    const upb_Message* msg) {
  ptrdiff_t size = sizeof(upb_Message_Internal);
  return (upb_Message_Internal*)((char*)msg - size);
}

upb_Message* upb_Message_New(const upb_MiniTable* mini_table,
                             upb_Arena* arena) {
  return _upb_Message_New(mini_table, arena);
}

void _upb_Message_Clear(upb_Message* msg, const upb_MiniTable* l) {
  void* mem = UPB_PTR_AT(msg, -sizeof(upb_Message_Internal), char);
  memset(mem, 0, upb_msg_sizeof(l));
}

static bool realloc_internal(upb_Message* msg, size_t need, upb_Arena* arena) {
  upb_Message_Internal* in = upb_Message_Getinternal(msg);
  if (!in->internal) {
    /* No internal data, allocate from scratch. */
    size_t size = UPB_MAX(128, _upb_Log2CeilingSize(need + overhead));
    upb_Message_InternalData* internal = upb_Arena_Malloc(arena, size);
    if (!internal) return false;
    internal->size = size;
    internal->unknown_end = overhead;
    internal->ext_begin = size;
    in->internal = internal;
  } else if (in->internal->ext_begin - in->internal->unknown_end < need) {
    /* Internal data is too small, reallocate. */
    size_t new_size = _upb_Log2CeilingSize(in->internal->size + need);
    size_t ext_bytes = in->internal->size - in->internal->ext_begin;
    size_t new_ext_begin = new_size - ext_bytes;
    upb_Message_InternalData* internal =
        upb_Arena_Realloc(arena, in->internal, in->internal->size, new_size);
    if (!internal) return false;
    if (ext_bytes) {
      /* Need to move extension data to the end. */
      char* ptr = (char*)internal;
      memmove(ptr + new_ext_begin, ptr + internal->ext_begin, ext_bytes);
    }
    internal->ext_begin = new_ext_begin;
    internal->size = new_size;
    in->internal = internal;
  }
  UPB_ASSERT(in->internal->ext_begin - in->internal->unknown_end >= need);
  return true;
}

bool _upb_Message_AddUnknown(upb_Message* msg, const char* data, size_t len,
                             upb_Arena* arena) {
  if (!realloc_internal(msg, len, arena)) return false;
  upb_Message_Internal* in = upb_Message_Getinternal(msg);
  memcpy(UPB_PTR_AT(in->internal, in->internal->unknown_end, char), data, len);
  in->internal->unknown_end += len;
  return true;
}

void _upb_Message_DiscardUnknown_shallow(upb_Message* msg) {
  upb_Message_Internal* in = upb_Message_Getinternal(msg);
  if (in->internal) {
    in->internal->unknown_end = overhead;
  }
}

const char* upb_Message_GetUnknown(const upb_Message* msg, size_t* len) {
  const upb_Message_Internal* in = upb_Message_Getinternal_const(msg);
  if (in->internal) {
    *len = in->internal->unknown_end - overhead;
    return (char*)(in->internal + 1);
  } else {
    *len = 0;
    return NULL;
  }
}

void upb_Message_DeleteUnknown(upb_Message* msg, const char* data, size_t len) {
  upb_Message_Internal* in = upb_Message_Getinternal(msg);
  const char* internal_unknown_end =
      UPB_PTR_AT(in->internal, in->internal->unknown_end, char);
#ifndef NDEBUG
  size_t full_unknown_size;
  const char* full_unknown = upb_Message_GetUnknown(msg, &full_unknown_size);
  UPB_ASSERT((uintptr_t)data >= (uintptr_t)full_unknown);
  UPB_ASSERT((uintptr_t)data < (uintptr_t)(full_unknown + full_unknown_size));
  UPB_ASSERT((uintptr_t)(data + len) > (uintptr_t)data);
  UPB_ASSERT((uintptr_t)(data + len) <= (uintptr_t)internal_unknown_end);
#endif
  if ((data + len) != internal_unknown_end) {
    memmove((char*)data, data + len, internal_unknown_end - data - len);
  }
  in->internal->unknown_end -= len;
}

const upb_Message_Extension* _upb_Message_Getexts(const upb_Message* msg,
                                                  size_t* count) {
  const upb_Message_Internal* in = upb_Message_Getinternal_const(msg);
  if (in->internal) {
    *count = (in->internal->size - in->internal->ext_begin) /
             sizeof(upb_Message_Extension);
    return UPB_PTR_AT(in->internal, in->internal->ext_begin, void);
  } else {
    *count = 0;
    return NULL;
  }
}

const upb_Message_Extension* _upb_Message_Getext(
    const upb_Message* msg, const upb_MiniTable_Extension* e) {
  size_t n;
  const upb_Message_Extension* ext = _upb_Message_Getexts(msg, &n);

  /* For now we use linear search exclusively to find extensions. If this
   * becomes an issue due to messages with lots of extensions, we can introduce
   * a table of some sort. */
  for (size_t i = 0; i < n; i++) {
    if (ext[i].ext == e) {
      return &ext[i];
    }
  }

  return NULL;
}

void _upb_Message_Clearext(upb_Message* msg,
                           const upb_MiniTable_Extension* ext_l) {
  upb_Message_Internal* in = upb_Message_Getinternal(msg);
  if (!in->internal) return;
  const upb_Message_Extension* base =
      UPB_PTR_AT(in->internal, in->internal->ext_begin, void);
  upb_Message_Extension* ext =
      (upb_Message_Extension*)_upb_Message_Getext(msg, ext_l);
  if (ext) {
    *ext = *base;
    in->internal->ext_begin += sizeof(upb_Message_Extension);
  }
}

upb_Message_Extension* _upb_Message_GetOrCreateExtension(
    upb_Message* msg, const upb_MiniTable_Extension* e, upb_Arena* arena) {
  upb_Message_Extension* ext =
      (upb_Message_Extension*)_upb_Message_Getext(msg, e);
  if (ext) return ext;
  if (!realloc_internal(msg, sizeof(upb_Message_Extension), arena)) return NULL;
  upb_Message_Internal* in = upb_Message_Getinternal(msg);
  in->internal->ext_begin -= sizeof(upb_Message_Extension);
  ext = UPB_PTR_AT(in->internal, in->internal->ext_begin, void);
  memset(ext, 0, sizeof(upb_Message_Extension));
  ext->ext = e;
  return ext;
}

size_t upb_Message_ExtensionCount(const upb_Message* msg) {
  size_t count;
  _upb_Message_Getexts(msg, &count);
  return count;
}