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Allow ContainerRWops to work with both const and non-const containers

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Analogus to how StreamRWops work. Also add more tests for
ContainerRWops.
This commit is contained in:
Dmitry Marakasov 2014-12-18 16:48:48 +03:00
parent 53aa26dec5
commit d7987b33da
2 changed files with 42 additions and 66 deletions
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86
SDL2pp/ContainerRWops.hh
View File

@ -24,16 +24,36 @@
#include <SDL2pp/RWops.hh>
#include <type_traits>
#include <stdexcept>
namespace SDL2pp {
template<typename C>
template <class C>
class ContainerRWops : public CustomRWops {
protected:
C& container_;
size_t position_;
private:
template <class CC>
typename std::enable_if<!std::is_const<CC>::value, size_t>::type WriteHelper(const void* ptr, size_t size, size_t maxnum) {
if (position_ + size * maxnum > container_.size())
container_.resize(position_ + size * maxnum);
std::copy(reinterpret_cast<const unsigned char*>(ptr), reinterpret_cast<const unsigned char*>(ptr) + size * maxnum, container_.begin() + position_);
position_ += size * maxnum;
return maxnum;
}
template <class CC>
typename std::enable_if<std::is_const<CC>::value, size_t>::type WriteHelper(const void*, size_t, size_t) {
SDL_SetError("Can't write to read-only container");
return 0;
}
public:
ContainerRWops(C& container) : container_(container), position_(0) {
}
@ -74,69 +94,7 @@ public:
}
virtual size_t Write(const void* ptr, size_t size, size_t maxnum) override {
if (position_ + size * maxnum > container_.size())
container_.resize(position_ + size * maxnum);
std::copy(reinterpret_cast<const unsigned char*>(ptr), reinterpret_cast<const unsigned char*>(ptr) + size * maxnum, container_.begin() + position_);
position_ += size * maxnum;
return maxnum;
}
virtual int Close() override {
return 0;
}
};
template<typename C>
class ConstContainerRWops : public CustomRWops {
protected:
const C& container_;
size_t position_;
public:
ConstContainerRWops(const C& container) : container_(container), position_(0) {
}
ConstContainerRWops(const ConstContainerRWops<C>&) = default;
ConstContainerRWops& operator=(const ConstContainerRWops<C>&) = delete;
ConstContainerRWops(ConstContainerRWops<C>&&) noexcept = default;
ConstContainerRWops& operator=(ConstContainerRWops<C>&&) = delete;
virtual Sint64 Seek(Sint64 offset, int whence) override {
switch (whence) {
case RW_SEEK_SET:
position_ = offset;
break;
case RW_SEEK_CUR:
position_ = position_ + offset;
break;
case RW_SEEK_END:
position_ = container_.size() + offset;
break;
default:
throw std::logic_error("Unexpected whence value for ConstContainerRWops::Seek");
}
return position_;
}
virtual size_t Read(void* ptr, size_t size, size_t maxnum) override {
if (position_ + size > container_.size())
return 0;
int toread = std::min((container_.size() - position_), maxnum * size);
std::copy(container_.begin() + position_, container_.begin() + position_ + toread, reinterpret_cast<unsigned char*>(ptr));
position_ += toread;
return toread / size;
}
virtual size_t Write(const void*, size_t, size_t) override {
SDL_SetError("Can't write to read-only container");
return 0;
return WriteHelper<C>(ptr, size, maxnum);
}
virtual int Close() override {

22
tests/test_rwops.cc
View File

@ -119,7 +119,7 @@ BEGIN_TEST()
{
const std::vector<char> buffer = { 'a', 'b', 'c', 'd' };
RWops rw((ConstContainerRWops<std::vector<char>>(buffer)));
RWops rw((ContainerRWops<const std::vector<char>>(buffer)));
{
// Read via C++
@ -134,12 +134,30 @@ BEGIN_TEST()
}
{
// Write
// Write to const container fails
char buf[4] = {0};
EXPECT_TRUE(rw.Write(buf, 1, 4) == 0);
EXPECT_TRUE(rw.Write(buf, 4, 1) == 0);
}
{
// Write to non-const container
std::vector<char> vec;
RWops rw((ContainerRWops<std::vector<char>>(vec)));
char buf[4] = {'a', 'b', 'c', 'd'};
EXPECT_TRUE(rw.Write(buf, 1, 4) == 4);
EXPECT_TRUE(rw.Write(buf, 4, 1) == 1);
EXPECT_TRUE(rw.Seek(2, SEEK_SET) == 2);
EXPECT_TRUE(rw.Write(buf, 2, 2) == 2);
EXPECT_TRUE(vec.size() == 8);
EXPECT_TRUE(std::string(vec.data(), 8) == "ababcdcd");
}
}
// Test for StreamRWops