add hexdump utility

rx/CMakeLists.txt

@@ -4,6 +4,7 @@ find_package(Git)
 
 
 add_library(${PROJECT_NAME} OBJECT
+    src/hexdump.cpp
     src/mem.cpp
     src/Version.cpp
 )

rx/include/rx/hexdump.hpp

@@ -0,0 +1,8 @@
+#pragma once
+
+#include <cstddef>
+#include <span>
+
+namespace rx {
+void hexdump(std::span<std::byte> bytes);
+} // namespace rx

rx/src/hexdump.cpp

@@ -0,0 +1,85 @@
+#include "hexdump.hpp"
+#include <cstdio>
+#include <cstring>
+#include <string>
+
+void rx::hexdump(std::span<std::byte> bytes) {
+  unsigned sizeWidth = 1;
+
+  {
+    std::size_t size = bytes.size() / 0x10;
+
+    while (size > 0) {
+      sizeWidth++;
+      size /= 0x10;
+    }
+  }
+
+  flockfile(stderr);
+  std::fprintf(stderr, "%s ", std::string(sizeWidth, ' ').c_str());
+  for (unsigned i = 0; i < 16; ++i) {
+    std::fprintf(stderr, " %02x", i);
+  }
+  std::fprintf(stderr, "\n%s ", std::string(sizeWidth, ' ').c_str());
+  for (unsigned i = 0; i < 16; ++i) {
+    std::fprintf(stderr, " --");
+  }
+
+  std::byte zeros[16]{};
+
+  bool wasAllZeros = true;
+  bool dotsPrinted = false;
+  for (std::size_t i = 0; i < bytes.size(); ++i) {
+    if (i % 16 == 0) {
+      if (i > 0) {
+        if (wasAllZeros && bytes.size() - i > 16) {
+          if (std::memcmp(bytes.data() + i, zeros, 16) == 0) {
+            if (!dotsPrinted) {
+              dotsPrinted = true;
+              std::printf("\n...");
+            }
+            i += 15;
+            continue;
+          }
+        }
+
+        if (!dotsPrinted) {
+          std::fprintf(stderr, " | ");
+
+          for (std::size_t j = i - 16; j < i; ++j) {
+            auto c = unsigned(bytes[j]);
+            std::fprintf(stderr, "%c",
+                         (std::isprint(c) && c != '\n') ? c : '.');
+          }
+        }
+      }
+      std::fprintf(stderr, "\n");
+      std::fprintf(stderr, "%0*zx ", sizeWidth, i);
+      wasAllZeros = true;
+      dotsPrinted = false;
+    }
+
+    std::fprintf(stderr, " %02x", unsigned(bytes[i]));
+
+    if (bytes[i] != std::byte{0}) {
+      wasAllZeros = false;
+    }
+  }
+
+  if (!bytes.empty()) {
+    for (std::size_t i = 0; i < (16 - (bytes.size() % 16)) % 16; ++i) {
+      std::fprintf(stderr, "   ");
+    }
+    std::fprintf(stderr, " | ");
+
+    for (std::size_t j = bytes.size() -
+                         std::min(bytes.size(),
+                                  (bytes.size() % 16 ? bytes.size() % 16 : 16));
+         j < bytes.size(); ++j) {
+      auto c = unsigned(bytes[j]);
+      std::fprintf(stderr, "%c", (std::isprint(c) && c != '\n') ? c : '.');
+    }
+  }
+  std::fprintf(stderr, "\n");
+  funlockfile(stderr);
+}