diff options
-rw-r--r-- | include/mbgl/util/char_array_buffer.hpp | 55 | ||||
-rw-r--r-- | platform/default/jpeg_reader.cpp | 7 | ||||
-rw-r--r-- | platform/default/png_reader.cpp | 5 |
3 files changed, 62 insertions, 5 deletions
diff --git a/include/mbgl/util/char_array_buffer.hpp b/include/mbgl/util/char_array_buffer.hpp new file mode 100644 index 0000000000..177f005477 --- /dev/null +++ b/include/mbgl/util/char_array_buffer.hpp @@ -0,0 +1,55 @@ +#pragma once + +#include <streambuf> + +namespace mbgl { +namespace util { + +// ref https://artofcode.wordpress.com/2010/12/12/deriving-from-stdstreambuf/ + +class CharArrayBuffer : public std::streambuf +{ +public: + CharArrayBuffer(char const* data, std::size_t size) + : begin_(data), end_(data + size), current_(data) {} + +private: + int_type underflow() final { + if (current_ == end_) { + return traits_type::eof(); + } + return traits_type::to_int_type(*current_); + } + + int_type uflow() final { + if (current_ == end_) { + return traits_type::eof(); + } + return traits_type::to_int_type(*current_++); + } + + int_type pbackfail(int_type ch) final { + if (current_ == begin_ || (ch != traits_type::eof() && ch != current_[-1])) { + return traits_type::eof(); + } + return traits_type::to_int_type(*--current_); + } + + std::streamsize showmanyc() final { + return end_ - current_; + } + + pos_type seekoff(off_type off, std::ios_base::seekdir dir, std::ios_base::openmode) final { + if (dir == std::ios_base::beg) current_ = std::min(begin_ + off, end_); + else if (dir == std::ios_base::cur) current_ = std::min(current_ + off, end_); + else current_ = std::max(end_ - off, begin_); // dir == std::ios_base::end + return pos_type(off_type(current_ - begin_)); + } + + char const * const begin_; + char const * const end_; + char const * current_; +}; + +} // namespace util +} // namespace mbgl diff --git a/platform/default/jpeg_reader.cpp b/platform/default/jpeg_reader.cpp index bb99aab55c..9bcf3c6bc1 100644 --- a/platform/default/jpeg_reader.cpp +++ b/platform/default/jpeg_reader.cpp @@ -1,4 +1,5 @@ #include <mbgl/util/image.hpp> +#include <mbgl/util/char_array_buffer.hpp> #include <istream> #include <sstream> @@ -21,7 +22,7 @@ struct jpeg_stream_wrapper { static void init_source(j_decompress_ptr cinfo) { jpeg_stream_wrapper* wrap = reinterpret_cast<jpeg_stream_wrapper*>(cinfo->src); - wrap->stream->seekg(0); + wrap->stream->seekg(0, std::ios_base::beg); } static boolean fill_input_buffer(j_decompress_ptr cinfo) { @@ -89,8 +90,8 @@ struct jpeg_info_guard { }; PremultipliedImage decodeJPEG(const uint8_t* data, size_t size) { - std::istringstream source(std::string(reinterpret_cast<const char*>(data), size)); - std::istream stream(source.rdbuf()); + util::CharArrayBuffer dataBuffer { reinterpret_cast<const char*>(data), size }; + std::istream stream(&dataBuffer); jpeg_decompress_struct cinfo; jpeg_info_guard iguard(&cinfo); diff --git a/platform/default/png_reader.cpp b/platform/default/png_reader.cpp index e3f6fdef49..0461ec61a6 100644 --- a/platform/default/png_reader.cpp +++ b/platform/default/png_reader.cpp @@ -1,5 +1,6 @@ #include <mbgl/util/image.hpp> #include <mbgl/util/premultiply.hpp> +#include <mbgl/util/char_array_buffer.hpp> #include <mbgl/platform/log.hpp> #include <istream> @@ -44,8 +45,8 @@ struct png_struct_guard { }; PremultipliedImage decodePNG(const uint8_t* data, size_t size) { - std::istringstream source(std::string(reinterpret_cast<const char*>(data), size)); - std::istream stream(source.rdbuf()); + util::CharArrayBuffer dataBuffer { reinterpret_cast<const char*>(data), size }; + std::istream stream(&dataBuffer); png_byte header[8] = { 0 }; stream.read(reinterpret_cast<char*>(header), 8); |