多索引表（4）multi_index.hpp源代码

1. 在线hpp源代码

https://developers.eos.io/manuals/eosio.cdt/v1.7/group__multiindex

1.1 get_code和get_scope

//Returns the code member property.
name eosio::multi_index< TableName, T, Indices >::get_code() const//Returns the scope member property.
uint64_t eosio::multi_index< TableName, T, Indices >::get_scope() const

1.2 迭代

const_iterator eosio::multi_index< TableName, T, Indices >::cbegin() const
const_iterator eosio::multi_index< TableName, T, Indices >::begin() const
const_iterator eosio::multi_index< TableName, T, Indices >::cend() const
const_iterator eosio::multi_index< TableName, T, Indices >::end() constconst_reverse_iterator eosio::multi_index< TableName, T, Indices >::crbegin() const
const_reverse_iterator eosio::multi_index< TableName, T, Indices >::rbegin() const
const_reverse_iterator eosio::multi_index< TableName, T, Indices >::crend() const
const_reverse_iterator eosio::multi_index< TableName, T, Indices >::rend() constconst_iterator eosio::multi_index< TableName, T, Indices >::lower_bound(uint64_t primary
) constconst_iterator eosio::multi_index< TableName, T, Indices >::upper_bound(uint64_t primary
) const

eg.

void myaction() {// create reference to address_index  - see emplace example below// add dan account to table           - see emplace example below// add additional account - brendanaddresses.emplace(payer, [&](auto& address) {address.account_name = "brendan"_n;address.first_name = "Brendan";address.last_name = "Blumer";address.street = "1 EOS Way";address.city = "Hong Kong";address.state = "HK";address.zip = 93445;});uint32_t zipnumb = 93445;auto zip_index = addresses.get_index<name("zip")>();auto itr = zip_index.lower_bound(zipnumb);eosio::check(itr->account_name == name("brendan"), "Lock arf, Incorrect First Lower Bound Record ");itr++;eosio::check(itr->account_name == name("dan"), "Lock arf, Incorrect Second Lower Bound Record");itr++;eosio::check(itr == zip_index.end(), "Lock arf, Incorrect End of Iterator");}

1.3 available_primary_key

uint64_t eosio::multi_index< TableName, T, Indices >::available_primary_key() const

eg.

void myaction() {address_index addresses(_self, _self.value);  // code, scope// add to table, first argument is account to bill for storageaddresses.emplace(payer, [&](auto& address) {address.key = addresses.available_primary_key();address.first_name = "Daniel";address.last_name = "Larimer";address.street = "1 EOS Way";address.city = "Blacksburg";address.state = "VA";});
}

1.4 get_index

template< IndexName> auto eosio::multi_index< TableName, T, Indices >::get_index()

eg.

#include <eosiolib/eosio.hpp>
using namespace eosio;
using namespace std;
class addressbook: contract {struct address {uint64_t account_name;string first_name;string last_name;string street;string city;string state;uint32_t zip = 0;uint64_t primary_key() const { return account_name; }uint64_t by_zip() const { return zip; }};public:addressbook(name receiver, name code, datastream<const char*> ds):contract(receiver, code, ds) {}typedef eosio::multi_index< name("address"), address, indexed_by< name("zip"), const_mem_fun<address, uint64_t, &address::by_zip> > address_index;void myaction() {// create reference to address_index  - see emplace example below// add dan account to table           - see emplace example belowuint32_t zipnumb = 93446;auto zip_index = addresses.get_index<name("zip")>();auto itr = zip_index.find(zipnumb);eosio::check(itr->account_name == name("dan"), "Lock arf, Incorrect Record ");}
}
EOSIO_DISPATCH( addressbook, (myaction) )// This assumes the code from the get_index() example. Replace myaction() {...}
void myaction() {// create reference to address_index  - see emplace example below// add dan account to table           - see emplace example below// add additional account - brendanaddresses.emplace(payer, [&](auto& address) {address.account_name = "brendan"_n;address.first_name = "Brendan";address.last_name = "Blumer";address.street = "1 EOS Way";address.city = "Hong Kong";address.state = "HK";address.zip = 93445;});uint32_t zipnumb = 93445;auto zip_index = addresses.get_index<name("zip")>();auto itr = zip_index.upper_bound(zipnumb);eosio::check(itr->account_name == name("dan"), "Lock arf, Incorrect First Upper Bound Record ");itr++;eosio::check(itr == zip_index.end(), "Lock arf, Incorrect End of Iterator");}
}
EOSIO_DISPATCH( addressbook, (myaction) )

1.5 iterator_to

const_iterator eosio::multi_index< TableName, T, Indices >::iterator_to(const T & obj
) const

eg.

// This assumes the code from the get_index() example. Replace myaction() {...}
void myaction() {// create reference to address_index  - see emplace example below// add dan account to table           - see emplace example below// add additional account - brendanaddresses.emplace(payer, [&](auto& address) {address.account_name = "brendan"_n;address.first_name = "Brendan";address.last_name = "Blumer";address.street = "1 EOS Way";address.city = "Hong Kong";address.state = "HK";address.zip = 93445;});auto user = addresses.get("dan"_n);auto itr = address.find("dan"_n);eosio::check(iterator_to(user) == itr, "Invalid iterator");}
}
EOSIO_DISPATCH( addressbook, (myaction) )

1.6 get

const T& eosio::multi_index< TableName, T, Indices >::get(uint64_t primary,const char * error_msg = "unable to find key"
) const

eg.

void myaction() {// create reference to address_index  - see emplace example// add dan account to table           - see emplace exampleauto user = addresses.get("dan"_n);eosio::check(user.first_name == "Daniel", "Couldn't get him.");
}

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