Refactor hex en/decoding

src/CMakeLists.txt

@@ -32,6 +32,7 @@ target_sources(osm2pgsql_lib PRIVATE
     geom-functions.cpp
     geom-pole-of-inaccessibility.cpp
     geom.cpp
+    hex.cpp
     idlist.cpp
     input.cpp
     locator.cpp

src/db-copy-mgr.hpp

@@ -15,7 +15,7 @@
 #include <string>
 
 #include "db-copy.hpp"
-#include "util.hpp"
+#include "hex.hpp"
 
 /**
  * Management class that fills and manages copy buffers.
@@ -237,13 +237,7 @@ class db_copy_mgr_t
      */
     void add_hex_geom(std::string const &wkb)
     {
-        char const *const lookup_hex = "0123456789ABCDEF";
-
-        for (auto c : wkb) {
-            unsigned int const num = static_cast<unsigned char>(c);
-            m_current.buffer += lookup_hex[(num >> 4U) & 0xfU];
-            m_current.buffer += lookup_hex[num & 0xfU];
-        }
+        util::encode_hex(wkb, &m_current.buffer);
         m_current.buffer += '\t';
     }
 

src/gen/canvas.cpp

@@ -9,6 +9,7 @@
 
 #include "canvas.hpp"
 
+#include "hex.hpp"
 #include "raster.hpp"
 #include "tile.hpp"
 
@@ -139,19 +140,3 @@ void canvas_t::merge(canvas_t const &other)
 {
     cv::bitwise_or(m_rast, other.m_rast, m_rast);
 }
-
-std::string to_hex(std::string const &in)
-{
-    std::string result;
-    result.reserve(in.size() * 2);
-
-    char const *const lookup_hex = "0123456789ABCDEF";
-
-    for (const auto c : in) {
-        unsigned int const num = static_cast<unsigned char>(c);
-        result += lookup_hex[(num >> 4U) & 0xfU];
-        result += lookup_hex[num & 0xfU];
-    }
-
-    return result;
-}

src/gen/canvas.hpp

@@ -77,6 +77,4 @@ class canvas_t
     image_type m_rast;
 }; // class canvas_t
 
-std::string to_hex(std::string const &in);
-
 #endif // OSM2PGSQL_CANVAS_HPP

src/gen/gen-rivers.cpp

@@ -10,6 +10,7 @@
 #include "gen-rivers.hpp"
 
 #include "geom-functions.hpp"
+#include "hex.hpp"
 #include "logging.hpp"
 #include "params.hpp"
 #include "pgsql.hpp"
@@ -264,7 +265,7 @@ SELECT "{id_column}", "{width_column}", "{name_column}", "{geom_column}"
             if (!name.empty()) {
                 names.emplace(id, name);
             }
-            auto const geom = ewkb_to_geom(decode_hex(result.get(i, 3)));
+            auto const geom = ewkb_to_geom(util::decode_hex(result.get(i, 3)));
 
             if (geom.is_linestring()) {
                 auto const &ls = geom.get<geom::linestring_t>();

src/gen/gen-tile-builtup.cpp

@@ -11,6 +11,7 @@
 
 #include "canvas.hpp"
 #include "geom-functions.hpp"
+#include "hex.hpp"
 #include "logging.hpp"
 #include "params.hpp"
 #include "pgsql.hpp"
@@ -33,7 +34,7 @@ void save_image_to_table(pg_conn_t *connection, canvas_t const &canvas,
                          std::string const &table, char const *variant,
                          std::string const &table_prefix)
 {
-    auto const wkb = to_hex(canvas.to_wkb(tile, margin));
+    auto const wkb = util::encode_hex(canvas.to_wkb(tile, margin));
 
     connection->exec("INSERT INTO \"{}_{}_{}\" (zoom, x, y, rast)"
                      " VALUES ({}, {}, {}, '{}')",
@@ -61,7 +62,7 @@ void draw_from_db(double margin, canvas_list_t *canvas_list, pg_conn_t *conn,
                                 box.max_x(), box.max_y());
 
         for (int n = 0; n < result.num_tuples(); ++n) {
-            auto const geom = ewkb_to_geom(decode_hex(result.get(n, 0)));
+            auto const geom = ewkb_to_geom(util::decode_hex(result.get(n, 0)));
             cc.canvas.draw(geom, tile);
         }
     }
@@ -251,7 +252,7 @@ void gen_tile_builtup_t::process(tile_t const &tile)
     log_gen("Write geometries to destination table...");
     timer(m_timer_write).start();
     for (auto const &geom : geometries) {
-        auto const wkb = to_hex(geom_to_ewkb(geom));
+        auto const wkb = util::encode_hex(geom_to_ewkb(geom));
         if (m_has_area_column) {
             connection().exec_prepared("insert_geoms", wkb, tile.x(), tile.y(),
                                        geom::area(geom));

src/gen/gen-tile-raster.cpp

@@ -10,6 +10,7 @@
 #include "gen-tile-raster.hpp"
 
 #include "canvas.hpp"
+#include "hex.hpp"
 #include "logging.hpp"
 #include "params.hpp"
 #include "pgsql.hpp"
@@ -49,7 +50,7 @@ void draw_from_db(double margin, unsigned int image_extent,
 
     for (int n = 0; n < result.num_tuples(); ++n) {
         std::string param = result.get_value(n, 1);
-        auto const geom = ewkb_to_geom(decode_hex(result.get(n, 0)));
+        auto const geom = ewkb_to_geom(util::decode_hex(result.get(n, 0)));
 
         auto const [it, success] = canvas_list->try_emplace(
             std::move(param), image_extent, image_buffer);
@@ -63,7 +64,7 @@ void save_image_to_table(pg_conn_t *connection, canvas_t const &canvas,
                          std::string const &param, char const *variant,
                          std::string const &table_prefix)
 {
-    auto const wkb = to_hex(canvas.to_wkb(tile, margin));
+    auto const wkb = util::encode_hex(canvas.to_wkb(tile, margin));
 
     connection->exec("INSERT INTO \"{}_{}\" (type, zoom, x, y, rast)"
                      " VALUES ('{}', {}, {}, {}, '{}')",

src/hex.cpp

@@ -0,0 +1,78 @@
+/**
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This file is part of osm2pgsql (https://osm2pgsql.org/).
+ *
+ * Copyright (C) 2006-2025 by the osm2pgsql developer community.
+ * For a full list of authors see the git log.
+ */
+
+#include "hex.hpp"
+
+#include <array>
+#include <cassert>
+#include <stdexcept>
+
+namespace util {
+
+void encode_hex(std::string const &in, std::string *out)
+{
+    assert(out);
+
+    constexpr char const *const LOOKUP_HEX = "0123456789ABCDEF";
+
+    for (auto const c : in) {
+        unsigned int const num = static_cast<unsigned char>(c);
+        (*out) += LOOKUP_HEX[(num >> 4U) & 0xfU];
+        (*out) += LOOKUP_HEX[num & 0xfU];
+    }
+}
+
+std::string encode_hex(std::string const &in)
+{
+    std::string result;
+    result.reserve(in.size() * 2);
+    encode_hex(in, &result);
+    return result;
+}
+
+namespace {
+
+constexpr std::array<char, 256> const HEX_TABLE = {
+    0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,
+    0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,
+    0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,
+    0, 1, 2, 3,   4, 5, 6, 7,   8, 9, 0, 0,   0, 0, 0, 0,
+
+    0, 10, 11, 12,   13, 14, 15, 0,   0, 0, 0, 0,   0, 0, 0, 0,
+    0,  0,  0,  0,    0,  0,  0, 0,   0, 0, 0, 0,   0, 0, 0, 0,
+    0, 10, 11, 12,   13, 14, 15, 0,   0, 0, 0, 0,   0, 0, 0, 0,
+};
+
+} // anonymous namespace
+
+unsigned char decode_hex_char(char c) noexcept
+{
+    // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-constant-array-index)
+    return HEX_TABLE[static_cast<std::size_t>(static_cast<unsigned char>(c))];
+}
+
+std::string decode_hex(std::string_view hex_string)
+{
+    if (hex_string.size() % 2 != 0) {
+        throw std::runtime_error{"Invalid wkb: Not a valid hex string"};
+    }
+
+    std::string wkb;
+    wkb.reserve(hex_string.size() / 2);
+
+    // NOLINTNEXTLINE(llvm-qualified-auto, readability-qualified-auto)
+    for (auto hex = hex_string.begin(); hex != hex_string.end();) {
+        unsigned int const c = decode_hex_char(*hex++);
+        wkb += static_cast<char>((c << 4U) | decode_hex_char(*hex++));
+    }
+
+    return wkb;
+}
+
+} // namespace util

src/hex.hpp

@@ -0,0 +1,47 @@
+#ifndef OSM2PGSQL_HEX_HPP
+#define OSM2PGSQL_HEX_HPP
+
+/**
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * This file is part of osm2pgsql (https://osm2pgsql.org/).
+ *
+ * Copyright (C) 2006-2025 by the osm2pgsql developer community.
+ * For a full list of authors see the git log.
+ */
+
+#include <string>
+
+namespace util {
+
+/**
+ * Convert content of input string to hex and append to output.
+ *
+ * \param in The input data.
+ * \param out Pointer to output string.
+ */
+void encode_hex(std::string const &in, std::string *out);
+
+/**
+ * Convert content of input string to hex and return it.
+ *
+ * \param in The input data.
+ * \returns Hex encoded string.
+ */
+[[nodiscard]] std::string encode_hex(std::string const &in);
+
+/**
+ * Decode one hex character (0-9A-F or 0-9a-f) and return its value.
+ * Returns 0 for characters that are not hex characters.
+ */
+[[nodiscard]] unsigned char decode_hex_char(char c) noexcept;
+
+/**
+ * Decode a string of hex characters. Throws an exception if the input is not
+ * a valid hex encoding.
+ */
+[[nodiscard]] std::string decode_hex(std::string_view hex);
+
+} // namespace util
+
+#endif // OSM2PGSQL_HEX_HPP

src/locator.cpp

@@ -12,6 +12,7 @@
 #include "geom-boost-adaptor.hpp"
 #include "geom-box.hpp"
 #include "geom-functions.hpp"
+#include "hex.hpp"
 #include "overloaded.hpp"
 #include "pgsql-capabilities.hpp"
 #include "pgsql.hpp"
@@ -60,7 +61,7 @@ void locator_t::add_regions(pg_conn_t const &db_connection,
 
     for (int n = 0; n < result.num_tuples(); ++n) {
         std::string const name = result.get_value(n, 0);
-        auto geometry = ewkb_to_geom(decode_hex(result.get(n, 1)));
+        auto geometry = ewkb_to_geom(util::decode_hex(result.get(n, 1)));
 
         if (geometry.srid() == 4326) {
             add_region(name, geometry);

src/wkb.cpp

@@ -575,42 +575,3 @@ geom::geometry_t ewkb_to_geom(std::string_view wkb)
 
     return geom;
 }
-
-namespace {
-
-constexpr std::array<char, 256> const HEX_TABLE = {
-    0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,
-    0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,
-    0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,   0, 0, 0, 0,
-    0, 1, 2, 3,   4, 5, 6, 7,   8, 9, 0, 0,   0, 0, 0, 0,
-
-    0, 10, 11, 12,   13, 14, 15, 0,   0, 0, 0, 0,   0, 0, 0, 0,
-    0,  0,  0,  0,    0,  0,  0, 0,   0, 0, 0, 0,   0, 0, 0, 0,
-    0, 10, 11, 12,   13, 14, 15, 0,   0, 0, 0, 0,   0, 0, 0, 0,
-};
-
-} // anonymous namespace
-
-unsigned char decode_hex_char(char c) noexcept
-{
-    // NOLINTNEXTLINE(cppcoreguidelines-pro-bounds-constant-array-index)
-    return HEX_TABLE[static_cast<std::size_t>(static_cast<unsigned char>(c))];
-}
-
-std::string decode_hex(std::string_view hex_string)
-{
-    if (hex_string.size() % 2 != 0) {
-        throw std::runtime_error{"Invalid wkb: Not a valid hex string"};
-    }
-
-    std::string wkb;
-    wkb.reserve(hex_string.size() / 2);
-
-    // NOLINTNEXTLINE(llvm-qualified-auto, readability-qualified-auto)
-    for (auto hex = hex_string.begin(); hex != hex_string.end();) {
-        unsigned int const c = decode_hex_char(*hex++);
-        wkb += static_cast<char>((c << 4U) | decode_hex_char(*hex++));
-    }
-
-    return wkb;
-}

src/wkb.hpp

@@ -40,16 +40,4 @@
  */
 [[nodiscard]] geom::geometry_t ewkb_to_geom(std::string_view wkb);
 
-/**
- * Decode one hex character (0-9A-F or 0-9a-f) and return its value.
- * Returns 0 for characters that are not hex characters.
- */
-[[nodiscard]] unsigned char decode_hex_char(char c) noexcept;
-
-/**
- * Decode a string of hex characters. Throws an exception if the input is not
- * a valid hex encoding.
- */
-[[nodiscard]] std::string decode_hex(std::string_view hex);
-
 #endif // OSM2PGSQL_WKB_HPP

tests/CMakeLists.txt

@@ -57,6 +57,7 @@ set_test(test-geom-points LABELS NoDB)
 set_test(test-geom-pole-of-inaccessibility LABELS NoDB)
 set_test(test-geom-polygons LABELS NoDB)
 set_test(test-geom-transform LABELS NoDB)
+set_test(test-hex LABELS NoDB)
 set_test(test-json-writer LABELS NoDB)
 set_test(test-locator LABELS NoDB)
 set_test(test-lua-utils LABELS NoDB)