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60 lines
1.5 KiB
C++
60 lines
1.5 KiB
C++
#include <iostream>
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#include <fstream>
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#include <string>
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#include <zlib.h>
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#include "vector_tile.pb.h"
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#define XMAX 4096
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#define YMAX 4096
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// https://github.com/mapbox/mapnik-vector-tile/blob/master/src/vector_tile_compression.hpp
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static inline int compress(std::string const& input, std::string& output) {
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z_stream deflate_s;
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deflate_s.zalloc = Z_NULL;
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deflate_s.zfree = Z_NULL;
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deflate_s.opaque = Z_NULL;
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deflate_s.avail_in = 0;
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deflate_s.next_in = Z_NULL;
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deflateInit(&deflate_s, Z_DEFAULT_COMPRESSION);
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deflate_s.next_in = (Bytef *)input.data();
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deflate_s.avail_in = input.size();
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size_t length = 0;
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do {
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size_t increase = input.size() / 2 + 1024;
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output.resize(length + increase);
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deflate_s.avail_out = increase;
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deflate_s.next_out = (Bytef *)(output.data() + length);
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int ret = deflate(&deflate_s, Z_FINISH);
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if (ret != Z_STREAM_END && ret != Z_OK && ret != Z_BUF_ERROR) {
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return -1;
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}
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length += (increase - deflate_s.avail_out);
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} while (deflate_s.avail_out == 0);
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deflateEnd(&deflate_s);
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output.resize(length);
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return 0;
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}
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void write_tile(char *name) {
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GOOGLE_PROTOBUF_VERIFY_VERSION;
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mapnik::vector::tile tile;
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mapnik::vector::tile_layer *layer = tile.add_layers();
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layer->set_name("name");
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layer->set_version(1);
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layer->set_extent(XMAX);
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std::string s;
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std::string compressed;
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tile.SerializeToString(&s);
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compress(s, compressed);
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std::cout << compressed;
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}
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