bson.c

// bson.c
/**
 *  Copyright 2009-2011 10gen, Inc.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

#include <php.h>
#include <zend_exceptions.h>

#ifdef WIN32
#  include <memory.h>
#  ifndef int64_t
     typedef __int64 int64_t;
#  endif
#endif

#include "php_mongo.h"
#include "bson.h"
#include "mongo_types.h"

extern zend_class_entry *mongo_ce_BinData,
  *mongo_ce_Code,
  *mongo_ce_Date,
  *mongo_ce_Id,
  *mongo_ce_Regex,
  *mongo_ce_Timestamp,
  *mongo_ce_MinKey,
  *mongo_ce_MaxKey,
  *mongo_ce_Exception,
  *mongo_ce_CursorException,
  *mongo_ce_Int32,
  *mongo_ce_Int64;

ZEND_EXTERN_MODULE_GLOBALS(mongo);

static int get_limit(mongo_cursor *cursor);
static int prep_obj_for_db(buffer *buf, HashTable *array TSRMLS_DC);
#if ZEND_MODULE_API_NO >= 20090115
static int apply_func_args_wrapper(void **data TSRMLS_DC, int num_args, va_list args, zend_hash_key *key);
#else
static int apply_func_args_wrapper(void **data, int num_args, va_list args, zend_hash_key *key);
#endif /* ZEND_MODULE_API_NO >= 20090115 */
static int is_utf8(const char *s, int len);
static int insert_helper(buffer *buf, zval *doc, int max TSRMLS_DC);


static int prep_obj_for_db(buffer *buf, HashTable *array TSRMLS_DC) {
  zval temp, **data, *newid;

  // if _id field doesn't exist, add it
  if (zend_hash_find(array, "_id", 4, (void**)&data) == FAILURE) {
    // create new MongoId
    MAKE_STD_ZVAL(newid);
    object_init_ex(newid, mongo_ce_Id);
    MONGO_METHOD(MongoId, __construct, &temp, newid);

    // add to obj
    zend_hash_add(array, "_id", 4, &newid, sizeof(zval*), NULL);

    // set to data
    data = &newid;
  }

  php_mongo_serialize_element("_id", data, buf, 0 TSRMLS_CC);
  if (EG(exception)) {
    return FAILURE;
  }

  return SUCCESS;
}


// serialize a zval
int zval_to_bson(buffer *buf, HashTable *hash, int prep TSRMLS_DC) {
  uint start;
  int num = 0;

  // check buf size
  if(BUF_REMAINING <= 5) {
    resize_buf(buf, 5);
  }

  // keep a record of the starting position
  // as an offset, in case the memory is resized
  start = buf->pos-buf->start;

  // skip first 4 bytes to leave room for size
  buf->pos += INT_32;

  if (zend_hash_num_elements(hash) > 0) {
    if (prep) {
      prep_obj_for_db(buf, hash TSRMLS_CC);
      num++;
    }

#if ZEND_MODULE_API_NO >= 20090115
    zend_hash_apply_with_arguments(hash TSRMLS_CC, (apply_func_args_t)apply_func_args_wrapper, 3, buf, prep, &num);
#else
    zend_hash_apply_with_arguments(hash, (apply_func_args_t)apply_func_args_wrapper, 4, buf, prep, &num TSRMLS_CC);
#endif /* ZEND_MODULE_API_NO >= 20090115 */
  }

  php_mongo_serialize_null(buf);
  php_mongo_serialize_size(buf->start + start, buf TSRMLS_CC);
  return EG(exception) ? FAILURE : num;
}

#if ZEND_MODULE_API_NO >= 20090115
static int apply_func_args_wrapper(void **data TSRMLS_DC, int num_args, va_list args, zend_hash_key *key)
#else
static int apply_func_args_wrapper(void **data, int num_args, va_list args, zend_hash_key *key)
#endif /* ZEND_MODULE_API_NO >= 20090115 */
{
  buffer *buf = va_arg(args, buffer*);
  int prep = va_arg(args, int);
  int *num = va_arg(args, int*);

#if ZEND_MODULE_API_NO < 20090115
  void ***tsrm_ls = va_arg(args, void***);
#endif /* ZEND_MODULE_API_NO < 20090115 */

  if (key->nKeyLength) {
    return php_mongo_serialize_element(key->arKey, (zval**)data, buf, prep TSRMLS_CC);
  }
  else {
    long current = key->h;
    int pos = 29, negative = 0;
    char name[30];

    // if the key is a number in ascending order, we're still
    // dealing with an array, not an object, so increase the count
    if (key->h == (unsigned int)*num) {
      (*num)++;
    }

    name[pos--] = '\0';

    // take care of negative indexes
    if (current < 0) {
      current *= -1;
      negative = 1;
    }

    do {
      int digit = current % 10;
      digit += (int)'0';
      name[pos--] = (char)digit;

      current = current / 10;
    } while (current > 0);

    if (negative) {
      name[pos--] = '-';
    }

    return php_mongo_serialize_element(name+pos+1, (zval**)data, buf, prep TSRMLS_CC);
  }
}

int php_mongo_serialize_element(char *name, zval **data, buffer *buf, int prep TSRMLS_DC) {
  int name_len = strlen(name);

  if (prep && strcmp(name, "_id") == 0) {
    return ZEND_HASH_APPLY_KEEP;
  }

  switch (Z_TYPE_PP(data)) {
  case IS_NULL:
    PHP_MONGO_SERIALIZE_KEY(BSON_NULL);
    break;
  case IS_LONG:
    if (MonGlo(native_long)) {
#if SIZEOF_LONG == 4
      PHP_MONGO_SERIALIZE_KEY(BSON_INT);
      php_mongo_serialize_int(buf, Z_LVAL_PP(data));
#else
# if SIZEOF_LONG == 8
      PHP_MONGO_SERIALIZE_KEY(BSON_LONG);
      php_mongo_serialize_long(buf, Z_LVAL_PP(data));
# else
#  error The PHP number size is neither 4 or 8 bytes; no clue what to do with that!
# endif
#endif
    } else {
      PHP_MONGO_SERIALIZE_KEY(BSON_INT);
      php_mongo_serialize_int(buf, Z_LVAL_PP(data));
    }
    break;
  case IS_DOUBLE:
    PHP_MONGO_SERIALIZE_KEY(BSON_DOUBLE);
    php_mongo_serialize_double(buf, Z_DVAL_PP(data));
    break;
  case IS_BOOL:
    PHP_MONGO_SERIALIZE_KEY(BSON_BOOL);
    php_mongo_serialize_bool(buf, Z_BVAL_PP(data));
    break;
  case IS_STRING: {
    PHP_MONGO_SERIALIZE_KEY(BSON_STRING);

    // if this is not a valid string, stop
    if (MonGlo(utf8) && !is_utf8(Z_STRVAL_PP(data), Z_STRLEN_PP(data))) {
      zend_throw_exception_ex(mongo_ce_Exception, 12 TSRMLS_CC, "non-utf8 string: %s", Z_STRVAL_PP(data));
      return ZEND_HASH_APPLY_STOP;
    }

    php_mongo_serialize_int(buf, Z_STRLEN_PP(data)+1);
    php_mongo_serialize_string(buf, Z_STRVAL_PP(data), Z_STRLEN_PP(data));
    break;
  }
  case IS_ARRAY: {
    int num;

    // if we realloc, we need an offset, not an abs pos (phew)
    int type_offset = buf->pos-buf->start;

    //serialize
    PHP_MONGO_SERIALIZE_KEY(BSON_ARRAY);
    num = zval_to_bson(buf, Z_ARRVAL_PP(data), NO_PREP TSRMLS_CC);
    if (EG(exception)) {
      return ZEND_HASH_APPLY_STOP;
    }

    // now go back and set the type bit
    //php_mongo_set_type(buf, BSON_ARRAY);
    if (num == zend_hash_num_elements(Z_ARRVAL_PP(data))) {
      buf->start[type_offset] = BSON_ARRAY;
    }
    else {
      buf->start[type_offset] = BSON_OBJECT;
    }

    break;
  }
  case IS_OBJECT: {
    zend_class_entry *clazz = Z_OBJCE_PP( data );
    /* check for defined classes */
    // MongoId
    if(clazz == mongo_ce_Id) {
      mongo_id *id;

      PHP_MONGO_SERIALIZE_KEY(BSON_OID);
      id = (mongo_id*)zend_object_store_get_object(*data TSRMLS_CC);
      if (!id->id) {
	return ZEND_HASH_APPLY_KEEP;
      }

      php_mongo_serialize_bytes(buf, id->id, OID_SIZE);
    }
    // MongoDate
    else if (clazz == mongo_ce_Date) {
      PHP_MONGO_SERIALIZE_KEY(BSON_DATE);
      php_mongo_serialize_date(buf, *data TSRMLS_CC);
    }
    // MongoRegex
    else if (clazz == mongo_ce_Regex) {
      PHP_MONGO_SERIALIZE_KEY(BSON_REGEX);
      php_mongo_serialize_regex(buf, *data TSRMLS_CC);
    }
    // MongoCode
    else if (clazz == mongo_ce_Code) {
      PHP_MONGO_SERIALIZE_KEY(BSON_CODE);
      php_mongo_serialize_code(buf, *data TSRMLS_CC);
      if (EG(exception)) {
        return ZEND_HASH_APPLY_STOP;
      }
    }
    // MongoBin
    else if (clazz == mongo_ce_BinData) {
      PHP_MONGO_SERIALIZE_KEY(BSON_BINARY);
      php_mongo_serialize_bin_data(buf, *data TSRMLS_CC);
    }
    // MongoTimestamp
    else if (clazz == mongo_ce_Timestamp) {
      PHP_MONGO_SERIALIZE_KEY(BSON_TIMESTAMP);
      php_mongo_serialize_ts(buf, *data TSRMLS_CC);
    }
    else if (clazz == mongo_ce_MinKey) {
      PHP_MONGO_SERIALIZE_KEY(BSON_MINKEY);
    }
    else if (clazz == mongo_ce_MaxKey) {
      PHP_MONGO_SERIALIZE_KEY(BSON_MAXKEY);
    }
    // Integer types
    else if (clazz == mongo_ce_Int32) {
      PHP_MONGO_SERIALIZE_KEY(BSON_INT);
      php_mongo_serialize_int32(buf, *data TSRMLS_CC);
    }
    else if (clazz == mongo_ce_Int64) {
      PHP_MONGO_SERIALIZE_KEY(BSON_LONG);
      php_mongo_serialize_int64(buf, *data TSRMLS_CC);
    }
    // serialize a normal obj
    else {
      HashTable *hash = Z_OBJPROP_PP(data);

      // go through the k/v pairs and serialize them
      PHP_MONGO_SERIALIZE_KEY(BSON_OBJECT);

      zval_to_bson(buf, hash, NO_PREP TSRMLS_CC);
      if (EG(exception)) {
        return ZEND_HASH_APPLY_STOP;
      }
    }
    break;
  }
  }

  return ZEND_HASH_APPLY_KEEP;
}

int resize_buf(buffer *buf, int size) {
  int total = buf->end - buf->start;
  int used = buf->pos - buf->start;

  total = total < GROW_SLOWLY ? total*2 : total+INITIAL_BUF_SIZE;
  while (total-used < size) {
    total += size;
  }

  buf->start = (char*)erealloc(buf->start, total);
  buf->pos = buf->start + used;
  buf->end = buf->start + total;
  return total;
}

/*
 * create a bson date
 *
 * type: 9
 * 8 bytes of ms since the epoch
 */
void php_mongo_serialize_date(buffer *buf, zval *date TSRMLS_DC) {
  int64_t ms;
  zval *sec = zend_read_property(mongo_ce_Date, date, "sec", 3, 0 TSRMLS_CC);
  zval *usec = zend_read_property(mongo_ce_Date, date, "usec", 4, 0 TSRMLS_CC);

  ms = ((int64_t)Z_LVAL_P(sec) * 1000) + ((int64_t)Z_LVAL_P(usec) / 1000);
  php_mongo_serialize_long(buf, ms);
}

#if defined(_MSC_VER)
# define strtoll(s, f, b) _atoi64(s)
#elif !defined(HAVE_STRTOLL)
# if defined(HAVE_ATOLL)
#  define strtoll(s, f, b) atoll(s)
# else
#  define strtoll(s, f, b) strtol(s, f, b)
# endif
#endif


/*
 * create a bson int from an Int32 object
 */
void php_mongo_serialize_int32(buffer *buf, zval *data TSRMLS_DC) {
  int value;
  zval *zvalue = zend_read_property(mongo_ce_Int32, data, "value", 5, 0 TSRMLS_CC);
  value = strtol(Z_STRVAL_P(zvalue), NULL, 10);

  php_mongo_serialize_int(buf, value);
}

/*
 * create a bson long from an Int64 object
 */
void php_mongo_serialize_int64(buffer *buf, zval *data TSRMLS_DC) {
  int64_t value;
  zval *zvalue = zend_read_property(mongo_ce_Int64, data, "value", 5, 0 TSRMLS_CC);
  value = strtoll(Z_STRVAL_P(zvalue), NULL, 10);

  php_mongo_serialize_long(buf, value);
}

/*
 * create a bson regex
 *
 * type: 11
 * cstring cstring
 */
void php_mongo_serialize_regex(buffer *buf, zval *regex TSRMLS_DC) {
  zval *z;

  z = zend_read_property(mongo_ce_Regex, regex, "regex", 5, 0 TSRMLS_CC);
  php_mongo_serialize_string(buf, Z_STRVAL_P(z), Z_STRLEN_P(z));
  z = zend_read_property(mongo_ce_Regex, regex, "flags", 5, 0 TSRMLS_CC);
  php_mongo_serialize_string(buf, Z_STRVAL_P(z), Z_STRLEN_P(z));
}

/*
 * create a bson code with scope
 *
 * type: 15
 * 4 bytes total size
 * 4 bytes cstring size + NULL
 * cstring
 * bson object scope
 */
void php_mongo_serialize_code(buffer *buf, zval *code TSRMLS_DC) {
  uint start;
  zval *zid;

  // save spot for size
  start = buf->pos-buf->start;
  buf->pos += INT_32;
  zid = zend_read_property(mongo_ce_Code, code, "code", 4, NOISY TSRMLS_CC);
  // string size
  php_mongo_serialize_int(buf, Z_STRLEN_P(zid)+1);
  // string
  php_mongo_serialize_string(buf, Z_STRVAL_P(zid), Z_STRLEN_P(zid));
  // scope
  zid = zend_read_property(mongo_ce_Code, code, "scope", 5, NOISY TSRMLS_CC);
  zval_to_bson(buf, HASH_P(zid), NO_PREP TSRMLS_CC);
  if (EG(exception)) {
    return;
  }

  // get total size
  php_mongo_serialize_size(buf->start+start, buf TSRMLS_CC);
}

/*
 * create bson binary data
 *
 * type: 5
 * 4 bytes: length of bindata
 * 1 byte: bindata type
 * bindata
 */
void php_mongo_serialize_bin_data(buffer *buf, zval *bin TSRMLS_DC) {
  zval *zbin, *ztype;

  zbin = zend_read_property(mongo_ce_BinData, bin, "bin", 3, 0 TSRMLS_CC);
  ztype = zend_read_property(mongo_ce_BinData, bin, "type", 4, 0 TSRMLS_CC);

  /*
   * type 2 has the redundant structure:
   *
   * |------|--|-------==========|
   *  length 02 length   bindata
   *
   *   - 4 bytes: length of bindata (+4 for length below)
   *   - 1 byte type (0x02)
   *   - N bytes: 4 bytes of length of the following bindata + bindata
   *
   */

  if (Z_LVAL_P(ztype) == 2) {
    // length
    php_mongo_serialize_int(buf, Z_STRLEN_P(zbin)+4);
    // 02
    php_mongo_serialize_byte(buf, 2);
    // length
    php_mongo_serialize_int(buf, Z_STRLEN_P(zbin));
  }
  /* other types have
   *
   * |------|--|==========|
   *  length     bindata
   *        type
   */
  else {
    // length
    php_mongo_serialize_int(buf, Z_STRLEN_P(zbin));
    // type
    php_mongo_serialize_byte(buf, (unsigned char)Z_LVAL_P(ztype));
  }

  // bindata
  php_mongo_serialize_bytes(buf, Z_STRVAL_P(zbin), Z_STRLEN_P(zbin));
}

/*
 * create bson timestamp
 *
 * type: 17
 * 4 bytes seconds since epoch
 * 4 bytes increment
 */
void php_mongo_serialize_ts(buffer *buf, zval *time TSRMLS_DC) {
  zval *ts, *inc;

  ts = zend_read_property(mongo_ce_Timestamp, time, "sec", strlen("sec"), NOISY TSRMLS_CC);
  inc = zend_read_property(mongo_ce_Timestamp, time, "inc", strlen("inc"), NOISY TSRMLS_CC);

  php_mongo_serialize_int(buf, Z_LVAL_P(inc));
  php_mongo_serialize_int(buf, Z_LVAL_P(ts));
}

void php_mongo_serialize_byte(buffer *buf, char b) {
  if(BUF_REMAINING <= 1) {
    resize_buf(buf, 1);
  }
  *(buf->pos) = b;
  buf->pos += 1;
}

void php_mongo_serialize_bytes(buffer *buf, char *str, int str_len) {
  if(BUF_REMAINING <= str_len) {
    resize_buf(buf, str_len);
  }
  memcpy(buf->pos, str, str_len);
  buf->pos += str_len;
}

void php_mongo_serialize_string(buffer *buf, char *str, int str_len) {
  if(BUF_REMAINING <= str_len+1) {
    resize_buf(buf, str_len+1);
  }

  memcpy(buf->pos, str, str_len);
  // add \0 at the end of the string
  buf->pos[str_len] = 0;
  buf->pos += str_len + 1;
}

void php_mongo_serialize_int(buffer *buf, int num) {
  int i = MONGO_32(num);

  if(BUF_REMAINING <= INT_32) {
    resize_buf(buf, INT_32);
  }

  memcpy(buf->pos, &i, INT_32);
  buf->pos += INT_32;
}

void php_mongo_serialize_long(buffer *buf, int64_t num) {
  int64_t i = MONGO_64(num);

  if(BUF_REMAINING <= INT_64) {
    resize_buf(buf, INT_64);
  }

  memcpy(buf->pos, &i, INT_64);
  buf->pos += INT_64;
}

void php_mongo_serialize_double(buffer *buf, double num) {
  int64_t dest, *dest_p;
  dest_p = &dest;
  memcpy(dest_p, &num, 8);
  dest = MONGO_64(dest);

  if(BUF_REMAINING <= INT_64) {
    resize_buf(buf, INT_64);
  }

  memcpy(buf->pos, dest_p, DOUBLE_64);
  buf->pos += DOUBLE_64;
}

/*
 * prep == true
 *    we are inserting, so keys can't have .s in them
 */
void php_mongo_serialize_key(buffer *buf, char *str, int str_len, int prep TSRMLS_DC) {
  if (str[0] == '\0' && !MonGlo(allow_empty_keys)) {
    zend_throw_exception_ex(mongo_ce_Exception, 1 TSRMLS_CC, "zero-length keys are not allowed, did you use $ with double quotes?");
    return;
  }

  if(BUF_REMAINING <= str_len+1) {
    resize_buf(buf, str_len+1);
  }

  if (prep && (strchr(str, '.') != 0)) {
    zend_throw_exception_ex(mongo_ce_Exception, 2 TSRMLS_CC, "'.' not allowed in key: %s", str);
    return;
  }

  if (MonGlo(cmd_char) && strchr(str, MonGlo(cmd_char)[0]) == str) {
    *(buf->pos) = '$';
    memcpy(buf->pos+1, str+1, str_len-1);
  }
  else {
    memcpy(buf->pos, str, str_len);
  }

  // add \0 at the end of the string
  buf->pos[str_len] = 0;
  buf->pos += str_len + 1;
}

/*
 * replaces collection names starting with MonGlo(cmd_char)
 * with the '$' character.
 *
 * TODO: this doesn't handle main.$oplog-type situations (if
 * MonGlo(cmd_char) is set)
 */
void php_mongo_serialize_ns(buffer *buf, char *str TSRMLS_DC) {
  char *collection = strchr(str, '.')+1;

  if(BUF_REMAINING <= (int)strlen(str)+1) {
    resize_buf(buf, strlen(str)+1);
  }

  if (MonGlo(cmd_char) && strchr(collection, MonGlo(cmd_char)[0]) == collection) {
    memcpy(buf->pos, str, collection-str);
    buf->pos += collection-str;
    *(buf->pos) = '$';
    memcpy(buf->pos+1, collection+1, strlen(collection)-1);
    buf->pos[strlen(collection)] = 0;
    buf->pos += strlen(collection) + 1;
  }
  else {
    memcpy(buf->pos, str, strlen(str));
    buf->pos[strlen(str)] = 0;
    buf->pos += strlen(str) + 1;
  }
}


/* the position is not increased, we are just filling
 * in the first 4 bytes with the size.
 */
int php_mongo_serialize_size(char *start, buffer *buf TSRMLS_DC) {
  int total = MONGO_32((buf->pos - start));
  if (buf->pos - start > 16000000) {
    zend_throw_exception_ex(mongo_ce_Exception, 3 TSRMLS_CC, "insert too large: %d, max: 16000000", buf->pos - start);
    return FAILURE;
  }
  memcpy(start, &total, INT_32);
  return SUCCESS;
}

static int insert_helper(buffer *buf, zval *doc, int max TSRMLS_DC) {
  int start = buf->pos - buf->start;

  int result = zval_to_bson(buf, HASH_P(doc), PREP TSRMLS_CC);

  // throw exception if serialization crapped out
  if (EG(exception) || FAILURE == result) {
    return FAILURE;
  }
  // return if there were 0 elements
  else if (0 == result) {
    zend_throw_exception_ex(mongo_ce_Exception, 4 TSRMLS_CC, "no elements in doc");
    return FAILURE;
  }

  // throw an exception if the doc was too big
  if(buf->pos - (buf->start + start) > max) {
    zend_throw_exception_ex(mongo_ce_Exception, 5 TSRMLS_CC, "size of BSON doc is %d bytes, max is %d",
                            buf->pos - (buf->start + start), max);
    return FAILURE;
  }

  return php_mongo_serialize_size(buf->start + start, buf TSRMLS_CC);
}

int php_mongo_write_insert(buffer *buf, char *ns, zval *doc, int max TSRMLS_DC) {
  mongo_msg_header header;
  int start = buf->pos - buf->start;

  CREATE_HEADER(buf, ns, OP_INSERT);

  if (FAILURE == insert_helper(buf, doc, max TSRMLS_CC)) {
    return FAILURE;
  }

  return php_mongo_serialize_size(buf->start + start, buf TSRMLS_CC);
}

int php_mongo_write_batch_insert(buffer *buf, char *ns, zval *docs, int max TSRMLS_DC) {
  int start = buf->pos - buf->start, count = 0;
  HashPosition pointer;
  zval **doc;
  mongo_msg_header header;

  CREATE_HEADER(buf, ns, OP_INSERT);

  for(zend_hash_internal_pointer_reset_ex(HASH_P(docs), &pointer);
      zend_hash_get_current_data_ex(HASH_P(docs), (void**)&doc, &pointer) == SUCCESS;
      zend_hash_move_forward_ex(HASH_P(docs), &pointer)) {

    if (IS_SCALAR_PP(doc)) {
      continue;
    }

    if (FAILURE == insert_helper(buf, *doc, max TSRMLS_CC) ||
        buf->pos - buf->start >= MonGlo(max_send_size)) {
      return FAILURE;
    }

    count++;
  }

  // if there are no elements, don't bother saving
  if (count == 0) {
    zend_throw_exception_ex(mongo_ce_Exception, 6 TSRMLS_CC, "no documents given");
    return FAILURE;
  }

  // this is a hard limit in the db server (util/messages.cpp)
  if (buf->pos - (buf->start + start) > 16000000) {
    zend_throw_exception_ex(mongo_ce_Exception, 3 TSRMLS_CC, "insert too large: %d, max: 16000000", buf->pos - (buf->start+start));
    return FAILURE;
  }

  return php_mongo_serialize_size(buf->start + start, buf TSRMLS_CC);
}

int php_mongo_write_update(buffer *buf, char *ns, int flags, zval *criteria, zval *newobj TSRMLS_DC) {
  mongo_msg_header header;
  int start = buf->pos - buf->start;

  CREATE_HEADER(buf, ns, OP_UPDATE);

  php_mongo_serialize_int(buf, flags);

  if (zval_to_bson(buf, HASH_P(criteria), NO_PREP TSRMLS_CC) == FAILURE ||
      EG(exception) ||
      zval_to_bson(buf, HASH_P(newobj), NO_PREP TSRMLS_CC) == FAILURE ||
      EG(exception)) {
    return FAILURE;
  }

  return php_mongo_serialize_size(buf->start + start, buf TSRMLS_CC);
}

int php_mongo_write_delete(buffer *buf, char *ns, int flags, zval *criteria TSRMLS_DC) {
  mongo_msg_header header;
  int start = buf->pos - buf->start;

  CREATE_HEADER(buf, ns, OP_DELETE);

  php_mongo_serialize_int(buf, flags);

  if (zval_to_bson(buf, HASH_P(criteria), NO_PREP TSRMLS_CC) == FAILURE ||
      EG(exception)) {
    return FAILURE;
  }

  return php_mongo_serialize_size(buf->start + start, buf TSRMLS_CC);
}

/*
 * Creates a query string in buf.
 *
 * The following fields of cursor are used:
 *  - ns
 *  - opts
 *  - skip
 *  - limit
 *  - query
 *  - fields
 *
 */
int php_mongo_write_query(buffer *buf, mongo_cursor *cursor TSRMLS_DC) {
  mongo_msg_header header;
  int start = buf->pos - buf->start;

  CREATE_HEADER_WITH_OPTS(buf, cursor->ns, OP_QUERY, cursor->opts);
  cursor->send.request_id = header.request_id;

  php_mongo_serialize_int(buf, cursor->skip);
  php_mongo_serialize_int(buf, get_limit(cursor));

  if (zval_to_bson(buf, HASH_P(cursor->query), NO_PREP TSRMLS_CC) == FAILURE ||
      EG(exception)) {
    return FAILURE;
  }
  if (cursor->fields && zend_hash_num_elements(HASH_P(cursor->fields)) > 0) {
    if (zval_to_bson(buf, HASH_P(cursor->fields), NO_PREP TSRMLS_CC) == FAILURE ||
        EG(exception)) {
      return FAILURE;
    }
  }

  return php_mongo_serialize_size(buf->start + start, buf TSRMLS_CC);
}

int php_mongo_write_kill_cursors(buffer *buf, mongo_cursor *cursor TSRMLS_DC) {
  mongo_msg_header header;

  CREATE_MSG_HEADER(MonGlo(request_id)++, 0, OP_KILL_CURSORS);
  APPEND_HEADER(buf, 0);
  cursor->send.request_id = header.request_id;

  // # of cursors
  php_mongo_serialize_int(buf, 1);
  // cursor ids
  php_mongo_serialize_long(buf, cursor->cursor_id);
  return php_mongo_serialize_size(buf->start, buf TSRMLS_CC);
}

/*
 * Creates a GET_MORE request
 *
 * The following fields of cursor are used:
 *  - ns
 *  - recv.request_id
 *  - limit
 *  - cursor_id
 */
int php_mongo_write_get_more(buffer *buf, mongo_cursor *cursor TSRMLS_DC) {
  mongo_msg_header header;
  int start = buf->pos - buf->start;

  CREATE_RESPONSE_HEADER(buf, cursor->ns, cursor->recv.request_id, OP_GET_MORE);
  cursor->send.request_id = header.request_id;

  php_mongo_serialize_int(buf, get_limit(cursor));
  php_mongo_serialize_long(buf, cursor->cursor_id);

  return php_mongo_serialize_size(buf->start + start, buf TSRMLS_CC);
}


static int get_limit(mongo_cursor *cursor) {
  int lim_at;

  if (cursor->limit < 0) {
    return cursor->limit;
  }
  else if (cursor->batch_size < 0) {
    return cursor->batch_size;
  }

  lim_at = cursor->limit > cursor->batch_size ? cursor->limit - cursor->at : cursor->limit;
  if (cursor->batch_size && (!lim_at || cursor->batch_size <= lim_at)) {
    return cursor->batch_size;
  }
  else if (lim_at && (!cursor->batch_size || lim_at < cursor->batch_size)) {
    return lim_at;
  }

  return 0;
}


char* bson_to_zval(char *buf, HashTable *result TSRMLS_DC) {
  /*
   * buf_start is used for debugging
   *
   * if the deserializer runs into bson it can't
   * parse, it will dump the bytes to that point.
   *
   * we lose buf's position as we iterate, so we
   * need buf_start to save it.
   */
  char *buf_start = buf;
  char type;

  if (buf == 0) {
    return 0;
  }

  // for size
  buf += INT_32;

  while ((type = *buf++) != 0) {
    char *name;
    zval *value;

    name = buf;
    // get past field name
    buf += strlen(buf) + 1;

    MAKE_STD_ZVAL(value);
    ZVAL_NULL(value);

    // get value
    switch(type) {
    case BSON_OID: {
      mongo_id *this_id;
      zval *str = 0;

      object_init_ex(value, mongo_ce_Id);

      this_id = (mongo_id*)zend_object_store_get_object(value TSRMLS_CC);
      this_id->id = estrndup(buf, OID_SIZE);

      MAKE_STD_ZVAL(str);
      ZVAL_NULL(str);

      MONGO_METHOD(MongoId, __toString, str, value);
      zend_update_property(mongo_ce_Id, value, "$id", strlen("$id"), str TSRMLS_CC);
      zval_ptr_dtor(&str);

      buf += OID_SIZE;
      break;
    }
    case BSON_DOUBLE: {
      double d = *(double*)buf;
      int64_t i, *i_p;
      i_p = &i;

      memcpy(i_p, &d, DOUBLE_64);
      i = MONGO_64(i);
      memcpy(&d, i_p, DOUBLE_64);

      ZVAL_DOUBLE(value, d);
      buf += DOUBLE_64;
      break;
    }
    case BSON_SYMBOL:
    case BSON_STRING: {
      // len includes \0
      int len = MONGO_32(*((int*)buf));
      if (INVALID_STRING_LEN(len)) {
        zval_ptr_dtor(&value);
        zend_throw_exception_ex(mongo_ce_CursorException, 0 TSRMLS_CC, "invalid string length for key \"%s\": %d", name, len);
        return 0;
      }
      buf += INT_32;

      ZVAL_STRINGL(value, buf, len-1, 1);
      buf += len;
      break;
    }
    case BSON_OBJECT:
    case BSON_ARRAY: {
      array_init(value);
      buf = bson_to_zval(buf, Z_ARRVAL_P(value) TSRMLS_CC);
      if (EG(exception)) {
        zval_ptr_dtor(&value);
        return 0;
      }
      break;
    }
    case BSON_BINARY: {
      char type;

      int len = MONGO_32(*(int*)buf);
      if (INVALID_STRING_LEN(len)) {
        zval_ptr_dtor(&value);
        zend_throw_exception_ex(mongo_ce_CursorException, 1 TSRMLS_CC, "invalid binary length for key \"%s\": %d", name, len);
        return 0;
      }
      buf += INT_32;

      type = *buf++;

      /* If the type is 2, check if the binary data
       * is prefixed by its length.
       *
       * There is an infinitesimally small chance that
       * the first four bytes will happen to be the
       * length of the rest of the string.  In this
       * case, the data will be corrupted.
       */
      if ((int)type == 2) {
        int len2 = MONGO_32(*(int*)buf);

        /* if the lengths match, the data is to spec,
         * so we use len2 as the true length.
         */
        if (len2 == len - 4) {
          len = len2;
          buf += INT_32;
        }
      }

      object_init_ex(value, mongo_ce_BinData);

      zend_update_property_stringl(mongo_ce_BinData, value, "bin", strlen("bin"), buf, len TSRMLS_CC);
      zend_update_property_long(mongo_ce_BinData, value, "type", strlen("type"), type TSRMLS_CC);

      buf += len;
      break;
    }
    case BSON_BOOL: {
      char d = *buf++;
      ZVAL_BOOL(value, d);
      break;
    }
    case BSON_UNDEF:
    case BSON_NULL: {
      ZVAL_NULL(value);
      break;
    }
    case BSON_INT: {
      ZVAL_LONG(value, MONGO_32(*((int*)buf)));
      buf += INT_32;
      break;
    }
    case BSON_LONG: {
      if (MonGlo(long_as_object)) {
        char *buffer;

#ifdef WIN32
        spprintf(&buffer, 0, "%I64d", (int64_t)MONGO_64(*((int64_t*)buf)));
#else
        spprintf(&buffer, 0, "%lld", (long long int)MONGO_64(*((int64_t*)buf)));
#endif
        object_init_ex(value, mongo_ce_Int64);

        zend_update_property_string(mongo_ce_Int64, value, "value", strlen("value"), buffer TSRMLS_CC);

        efree(buffer);
      } else {
        if (MonGlo(native_long)) {
#if SIZEOF_LONG == 4
          zend_throw_exception_ex(mongo_ce_CursorException, 1 TSRMLS_CC, "Can not natively represent the long %llu on this platform", (int64_t)MONGO_64(*((int64_t*)buf)));
          return 0;
#else
# if SIZEOF_LONG == 8
          ZVAL_LONG(value, (long)MONGO_64(*((int64_t*)buf)));
# else
#  error The PHP number size is neither 4 or 8 bytes; no clue what to do with that!
# endif
#endif
        } else {
          ZVAL_DOUBLE(value, (double)MONGO_64(*((int64_t*)buf)));
        }
      }
      buf += INT_64;
      break;
    }
    case BSON_DATE: {
      int64_t d = MONGO_64(*((int64_t*)buf));
      buf += INT_64;

      object_init_ex(value, mongo_ce_Date);

      zend_update_property_long(mongo_ce_Date, value, "sec", strlen("sec"), (long)(d/1000) TSRMLS_CC);
      zend_update_property_long(mongo_ce_Date, value, "usec", strlen("usec"), (long)((d*1000)%1000000) TSRMLS_CC);

      break;
    }
    case BSON_REGEX: {
      char *regex, *flags;
      int regex_len, flags_len;

      regex = buf;
      regex_len = strlen(buf);
      buf += regex_len+1;

      flags = buf;
      flags_len = strlen(buf);
      buf += flags_len+1;

      object_init_ex(value, mongo_ce_Regex);

      zend_update_property_stringl(mongo_ce_Regex, value, "regex", strlen("regex"), regex, regex_len TSRMLS_CC);
      zend_update_property_stringl(mongo_ce_Regex, value, "flags", strlen("flags"), flags, flags_len TSRMLS_CC);

      break;
    }
    case BSON_CODE:
    case BSON_CODE__D: {
      zval *zcope;
      int code_len;
      char *code;

      // CODE has a useless total size field
      if (type == BSON_CODE) {
        buf += INT_32;
      }

      // length of code (includes \0)
      code_len = MONGO_32(*(int*)buf);
      if (INVALID_STRING_LEN(code_len)) {
        zval_ptr_dtor(&value);
        zend_throw_exception_ex(mongo_ce_CursorException, 2 TSRMLS_CC, "invalid code length for key \"%s\": %d", name, code_len);
        return 0;
      }
      buf += INT_32;

      code = buf;
      buf += code_len;

      // initialize scope array
      MAKE_STD_ZVAL(zcope);
      array_init(zcope);

      if (type == BSON_CODE) {
        buf = bson_to_zval(buf, HASH_P(zcope) TSRMLS_CC);
        if (EG(exception)) {
          zval_ptr_dtor(&zcope);
          return 0;
        }
      }

      object_init_ex(value, mongo_ce_Code);
      // exclude \0
      zend_update_property_stringl(mongo_ce_Code, value, "code", strlen("code"), code, code_len-1 TSRMLS_CC);
      zend_update_property(mongo_ce_Code, value, "scope", strlen("scope"), zcope TSRMLS_CC);
      zval_ptr_dtor(&zcope);

      break;
    }
    /* DEPRECATED
     * database reference (12)
     *   - 4 bytes ns length (includes trailing \0)
     *   - ns + \0
     *   - 12 bytes MongoId
     * This converts the deprecated, old-style db ref type
     * into the new type (array('$ref' => ..., $id => ...)).
     */
    case BSON_DBREF: {
      int ns_len;
      char *ns;
      zval *zoid;
      mongo_id *this_id;

      // ns
      ns_len = *(int*)buf;
      if (INVALID_STRING_LEN(ns_len)) {
        zval_ptr_dtor(&value);
        zend_throw_exception_ex(mongo_ce_CursorException, 3 TSRMLS_CC, "invalid dbref length for key \"%s\": %d", name, ns_len);
        return 0;
      }
      buf += INT_32;
      ns = buf;
      buf += ns_len;

      // id
      MAKE_STD_ZVAL(zoid);
      object_init_ex(zoid, mongo_ce_Id);

      this_id = (mongo_id*)zend_object_store_get_object(zoid TSRMLS_CC);
      this_id->id = estrndup(buf, OID_SIZE);

      buf += OID_SIZE;

      // put it all together
      array_init(value);
      add_assoc_stringl(value, "$ref", ns, ns_len-1, 1);
      add_assoc_zval(value, "$id", zoid);
      break;
    }
    /* MongoTimestamp (17)
     * 8 bytes total:
     *  - sec: 4 bytes
     *  - inc: 4 bytes
     */
    case BSON_TIMESTAMP: {
      object_init_ex(value, mongo_ce_Timestamp);
      zend_update_property_long(mongo_ce_Timestamp, value, "inc", strlen("inc"), MONGO_32(*(int*)buf) TSRMLS_CC);
      buf += INT_32;
      zend_update_property_long(mongo_ce_Timestamp, value, "sec", strlen("sec"), MONGO_32(*(int*)buf) TSRMLS_CC);
      buf += INT_32;
      break;
    }
    /* max key (127)
     * max and min keys are used only for sharding, and
     * cannot be resaved to the database at the moment
     */
    case BSON_MINKEY: {
      object_init_ex(value, mongo_ce_MinKey);
      break;
    }
    /* min key (0)
     */
    case BSON_MAXKEY: {
      object_init_ex(value, mongo_ce_MaxKey);
      break;
    }
    default: {
      /* if we run into a type we don't recognize, there's
       * either been some corruption or we've messed up on
       * the parsing.  Either way, it's helpful to know the
       * situation that led us here, so this dumps the
       * buffer up to this point to stdout and returns.
       *
       * We can't dump any more of the buffer, unfortunately,
       * because we don't keep track of the size.  Besides,
       * if it is corrupt, the size might be messed up, too.
       */
      char *msg, *pos, *template;
      int i, width, len;
      unsigned char t = type;

      template = "type 0x00 not supported:";

      // each byte is " xx" (3 chars)
      width = 3;
      len = (buf - buf_start) * width;

      msg = (char*)emalloc(strlen(template)+len+1);
      memcpy(msg, template, strlen(template));
      pos = msg+7;

      sprintf(pos++, "%x", t/16);
      t = t%16;
      sprintf(pos++, "%x", t);
      // remove '\0' added by sprintf
      *(pos) = ' ';

      // jump to end of template
      pos = msg + strlen(template);
      for (i=0; i<buf-buf_start; i++) {
        sprintf(pos, " %02x", (unsigned char)buf_start[i]);
        pos += width;
      }
      // sprintf 0-terminates the string

      zend_throw_exception(mongo_ce_Exception, msg, 17 TSRMLS_CC);
      efree(msg);
      return 0;
    }
    }

    zend_symtable_update(result, name, strlen(name)+1, &value, sizeof(zval*), NULL);
  }

  return buf;
}

static int is_utf8(const char *s, int len) {
  int i;

  for (i=0; i<len; i++) {
    if (i+3 < len &&
        (s[i] & 248) == 240 &&
        (s[i+1] & 192) == 128 &&
        (s[i+2] & 192) == 128 &&
        (s[i+3] & 192) == 128) {
      i += 3;
    }
    else if (i+2 < len &&
             (s[i] & 240) == 224 &&
             (s[i+1] & 192) == 128 &&
             (s[i+2] & 192) == 128) {
      i += 2;
    }
    else if (i+1 < len &&
             (s[i] & 224) == 192 &&
             (s[i+1] & 192) == 128) {
      i += 1;
    }
    else if ((s[i] & 128) != 0) {
      return 0;
    }
  }
  return 1;
}

/*
 * Takes any type of PHP var and turns it into BSON
 */
PHP_FUNCTION(bson_encode) {
  zval *z;
  buffer buf;

  if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z", &z) == FAILURE) {
    return;
  }

  switch (Z_TYPE_P(z)) {
  case IS_NULL: {
    RETURN_STRING("", 1);
    break;
  }
  case IS_LONG: {
    CREATE_BUF_STATIC(9);
#if SIZEOF_LONG == 4
    php_mongo_serialize_int(&buf, Z_LVAL_P(z));
    RETURN_STRINGL(buf.start, 4, 1);
#else
    php_mongo_serialize_long(&buf, Z_LVAL_P(z));
    RETURN_STRINGL(buf.start, 8, 1);
#endif
    break;
  }
  case IS_DOUBLE: {
    CREATE_BUF_STATIC(9);
    php_mongo_serialize_double(&buf, Z_DVAL_P(z));
    RETURN_STRINGL(b, 8, 1);
    break;
  }
  case IS_BOOL: {
    if (Z_BVAL_P(z)) {
      RETURN_STRINGL("\x01", 1, 1);
    }
    else {
      RETURN_STRINGL("\x00", 1, 1);
    }
    break;
  }
  case IS_STRING: {
    RETURN_STRINGL(Z_STRVAL_P(z), Z_STRLEN_P(z), 1);
    break;
  }
  case IS_OBJECT: {
    zend_class_entry *clazz = Z_OBJCE_P(z);
    if (clazz == mongo_ce_Id) {
      mongo_id *id = (mongo_id*)zend_object_store_get_object(z TSRMLS_CC);
      RETURN_STRINGL(id->id, 12, 1);
      break;
    }
    else if (clazz == mongo_ce_Date) {
      CREATE_BUF_STATIC(9);
      php_mongo_serialize_date(&buf, z TSRMLS_CC);
      RETURN_STRINGL(buf.start, 8, 0);
      break;
    }
    else if (clazz == mongo_ce_Regex) {
      CREATE_BUF(buf, 128);

      php_mongo_serialize_regex(&buf, z TSRMLS_CC);
      RETVAL_STRINGL(buf.start, buf.pos-buf.start, 1);
      efree(buf.start);
      break;
    }
    else if (clazz == mongo_ce_Code) {
      CREATE_BUF(buf, INITIAL_BUF_SIZE);

      php_mongo_serialize_code(&buf, z TSRMLS_CC);
      RETVAL_STRINGL(buf.start, buf.pos-buf.start, 1);
      efree(buf.start);
      break;
    }
    else if (clazz == mongo_ce_BinData) {
      CREATE_BUF(buf, INITIAL_BUF_SIZE);

      php_mongo_serialize_bin_data(&buf, z TSRMLS_CC);
      RETVAL_STRINGL(buf.start, buf.pos-buf.start, 1);
      efree(buf.start);
      break;
    }
    else if (clazz == mongo_ce_Timestamp) {
      CREATE_BUF(buf, 9);
      buf.pos[8] = (char)0;

      php_mongo_serialize_bin_data(&buf, z TSRMLS_CC);
      RETURN_STRINGL(buf.start, 8, 0);
      break;
    }
  }
  /* fallthrough for a normal obj */
  case IS_ARRAY: {
    CREATE_BUF(buf, INITIAL_BUF_SIZE);
    zval_to_bson(&buf, HASH_P(z), 0 TSRMLS_CC);

    RETVAL_STRINGL(buf.start, buf.pos-buf.start, 1);
    efree(buf.start);
    break;
  }
  default:
#if ZEND_MODULE_API_NO >= 20060613
    zend_throw_exception(zend_exception_get_default(TSRMLS_C), "couldn't serialize element", 0 TSRMLS_CC);
#else
    zend_throw_exception(zend_exception_get_default(), "couldn't serialize element", 0 TSRMLS_CC);
#endif
    return;
  }
}

/*
 * Takes a serialized BSON object and turns it into a PHP array.
 * This only deserializes entire documents!
 */
PHP_FUNCTION(bson_decode) {
  char *str;
  int str_len;

  if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len) == FAILURE) {
    return;
  }

  array_init(return_value);
  bson_to_zval(str, HASH_P(return_value) TSRMLS_CC);
}

void mongo_buf_init(char *dest) {
  dest[0] = '\0';
}

void mongo_buf_append(char *dest, char *piece) {
  int pos = strlen(dest);
  memcpy(dest+pos, piece, strlen(piece)+1);
}