From bce9758e32d0c3029a26efb486a342ff05f6df72 Mon Sep 17 00:00:00 2001
From: znone <glyc@sina.com.cn>
Date: Sat, 27 Feb 2021 12:57:25 +0000
Subject: [PATCH] PostgreSQL: support array type
---
include/qtl_postgres.hpp | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 102 insertions(+), 7 deletions(-)
diff --git a/include/qtl_postgres.hpp b/include/qtl_postgres.hpp
index 47be380..cbb780a 100644
--- a/include/qtl_postgres.hpp
+++ b/include/qtl_postgres.hpp
@@ -98,8 +98,8 @@
return ntoh(static_cast<uint64_t>(v));
}
- template<typename T>
- inline T& ntoh_inplace(typename std::enable_if<std::is_integral<T>::value && !std::is_const<T>::value, T>::type& v)
+ template<typename T, typename = typename std::enable_if<std::is_integral<T>::value && !std::is_const<T>::value>::type>
+ inline T& ntoh_inplace(T& v)
{
v = ntoh(v);
return v;
@@ -134,8 +134,8 @@
return hton(static_cast<uint64_t>(v));
}
- template<typename T>
- inline T& hton_inplace(typename std::enable_if<std::is_integral<T>::value && !std::is_const<T>::value>::type& v)
+ template<typename T, typename = typename std::enable_if<std::is_integral<T>::value && !std::is_const<T>::value>::type>
+ inline T& hton_inplace(T& v)
{
v = hton(v);
return v;
@@ -684,6 +684,17 @@
int m_fd;
};
+struct array_header
+{
+ int32_t ndim;
+ int32_t flags;
+ int32_t elemtype;
+ struct dimension {
+ int32_t length;
+ int32_t lower_bound;
+ } dims[1];
+};
+
/*
template<typename T>
struct oid_traits
@@ -901,6 +912,76 @@
{
return object_traits<int32_t>::data(v.oid(), data);
}
+};
+
+template<typename T, Oid id>
+struct array_traits : public base_object_traits<std::vector<T>, id>
+{
+ typedef typename base_object_traits<std::vector<T>, id>::value_type value_type;
+ static value_type get(const char* data, size_t n)
+ {
+ array_header header = *reinterpret_cast<const array_header*>(data);
+ detail::ntoh_inplace(header.ndim);
+ detail::ntoh_inplace(header.flags);
+ detail::ntoh_inplace(header.elemtype);
+ detail::ntoh_inplace(header.dims[0].length);
+ detail::ntoh_inplace(header.dims[0].lower_bound);
+ if (header.ndim != 1 || !object_traits<T>::is_match(header.elemtype))
+ throw std::bad_cast();
+
+ std::vector<T> result;
+ data += sizeof(array_header);
+ result.reserve(header.dims[0].length);
+
+ for (int32_t i = 0; i != header.dims[0].length; i++)
+ {
+ int32_t size = detail::ntoh(*reinterpret_cast<const int32_t*>(data));
+ const char* elem_data = data + sizeof(int32_t);
+ result.push_back(object_traits<T>::get(elem_data, size));
+ data = elem_data + size;
+ }
+ return result;
+ }
+ static std::pair<const char*, size_t> data(const std::vector<T>& v, std::vector<char>& data)
+ {
+ assert(v.size() <= INT32_MAX);
+ data.resize(sizeof(array_header));
+ array_header* header = reinterpret_cast<array_header*>(data.data());
+ header->ndim = detail::hton(1);
+ header->flags = detail::hton(0);
+ header->elemtype = detail::hton(object_traits<T>::type);
+ header->dims[0].length = detail::hton(static_cast<int32_t>(v.size()));
+ header->dims[0].lower_bound = detail::hton(1);
+ std::vector<char> temp;
+ for (const T& e : v)
+ {
+ std::pair<const char*, size_t> buffer = object_traits<T>::data(e, temp);
+ int32_t size = detail::hton(static_cast<int32_t>(buffer.second));
+ data.insert(data.end(), reinterpret_cast<char*>(&size), reinterpret_cast<char*>(&size) + sizeof(int32_t));
+ data.insert(data.end(), buffer.first, buffer.first + buffer.second);
+ }
+ return std::make_pair(reinterpret_cast<const char*>(data.data()), data.size());
+ }
+};
+
+template<> class object_traits<std::vector<int16_t>> : public array_traits<int16_t, INT2ARRAYOID>
+{
+};
+
+template<> class object_traits<std::vector<int32_t>> : public array_traits<int32_t, INT4ARRAYOID>
+{
+};
+
+template<> class object_traits<std::vector<float>> : public array_traits<float, FLOAT4ARRAYOID>
+{
+};
+
+template<> class object_traits<std::vector<std::string>> : public array_traits<std::string, TEXTARRAYOID>
+{
+};
+
+template<> class object_traits<std::vector<large_object>> : public array_traits<large_object, OIDARRAYOID>
+{
};
struct binder
@@ -1174,7 +1255,10 @@
template<class Type>
void bind_field(size_t index, Type&& value)
{
- value = m_binders[index].get<typename std::remove_const<Type>::type>();
+ if (m_res.is_null(0, static_cast<int>(index)))
+ value = Type();
+ else
+ value = m_binders[index].get<typename std::remove_const<Type>::type>();
}
void bind_field(size_t index, char* value, size_t length)
@@ -1208,11 +1292,22 @@
void bind_field(size_t index, large_object&& value)
{
- value = m_binders[index].get<large_object>(m_conn);
+ if (m_res.is_null(0, static_cast<int>(index)))
+ value.close();
+ else
+ value = m_binders[index].get<large_object>(m_conn);
}
void bind_field(size_t index, blob_data&& value)
{
- m_binders[index].get(value);
+ if (m_res.is_null(0, static_cast<int>(index)))
+ {
+ value.data = nullptr;
+ value.size = 0;
+ }
+ else
+ {
+ m_binders[index].get(value);
+ }
}
protected:
--
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