oldms: string reading utility (#503)

Author: andiwand

src/odr/internal/oldms/word/io.cpp

@@ -1,7 +1,9 @@
 #include <odr/internal/oldms/word/io.hpp>
 
+#include "odr/internal/util/string_util.hpp"
+
 #include <odr/internal/util/byte_stream_util.hpp>
-#include <odr/internal/util/stream_util.hpp>
+#include <odr/internal/util/string_util.hpp>
 
 namespace odr::internal::oldms {
 
@@ -190,4 +192,97 @@ void oldms::skip_Prc(std::istream &in) {
   in.ignore(cbGrpprl);
 }
 
+std::string oldms::read_string_compressed(std::istream &in,
+                                          const std::size_t size) {
+  static constexpr auto eof = std::istream::traits_type::eof();
+
+  std::string result;
+  result.reserve(size);
+
+  for (std::size_t i = 0; i < size; ++i) {
+    const auto ci = in.get();
+    if (ci == eof) {
+      throw std::runtime_error("Unexpected end of input");
+    }
+    if (ci < 0 || ci > 0xFF) {
+      throw std::runtime_error("Unexpected input: " + std::to_string(ci));
+    }
+    const char c = static_cast<char>(ci);
+    if (const std::optional<char16_t> uncompressed = uncompress_char(c);
+        uncompressed.has_value()) {
+      util::string::append_c32(*uncompressed, result);
+    } else {
+      result.push_back(c);
+    }
+  }
+
+  return result;
+}
+
+std::u16string oldms::read_string_uncompressed(std::istream &in,
+                                               const std::size_t size) {
+  std::u16string result;
+  result.resize(size);
+
+  in.read(reinterpret_cast<char *>(result.data()),
+          static_cast<std::streamsize>(size * sizeof(char16_t)));
+
+  return result;
+}
+
+std::optional<char16_t> oldms::uncompress_char(const char c) {
+  switch (c) {
+  case '\x82':
+    return 0x201A;
+  case '\x83':
+    return 0x0192;
+  case '\x84':
+    return 0x201E;
+  case '\x85':
+    return 0x2026;
+  case '\x86':
+    return 0x2020;
+  case '\x87':
+    return 0x2021;
+  case '\x88':
+    return 0x02C6;
+  case '\x89':
+    return 0x2030;
+  case '\x8A':
+    return 0x0160;
+  case '\x8B':
+    return 0x2039;
+  case '\x8C':
+    return 0x0152;
+  case '\x91':
+    return 0x2018;
+  case '\x92':
+    return 0x2019;
+  case '\x93':
+    return 0x201C;
+  case '\x94':
+    return 0x201D;
+  case '\x95':
+    return 0x2022;
+  case '\x96':
+    return 0x2013;
+  case '\x97':
+    return 0x2014;
+  case '\x98':
+    return 0x02DC;
+  case '\x99':
+    return 0x2122;
+  case '\x9A':
+    return 0x0161;
+  case '\x9B':
+    return 0x203A;
+  case '\x9C':
+    return 0x0153;
+  case '\x9F':
+    return 0x0178;
+  default:
+    return std::nullopt;
+  }
+}
+
 } // namespace odr::internal

src/odr/internal/oldms/word/io.hpp

@@ -6,6 +6,7 @@
 #include <functional>
 #include <iosfwd>
 #include <memory>
+#include <optional>
 
 namespace odr::internal::oldms {
 
@@ -30,4 +31,9 @@ void read_Clx(std::istream &in, const HandlePrc &handle_Prc,
               const HandlePcdt &handle_Pcdt);
 void skip_Prc(std::istream &in);
 
+std::string read_string_compressed(std::istream &in, std::size_t size);
+std::u16string read_string_uncompressed(std::istream &in, std::size_t size);
+
+std::optional<char16_t> uncompress_char(char c);
+
 } // namespace odr::internal::oldms

src/odr/internal/util/string_util.cpp

@@ -3,7 +3,6 @@
 #include <algorithm>
 #include <cstdint>
 #include <iomanip>
-#include <locale>
 #include <sstream>
 
 #include <utf8cpp/utf8/cpp17.h>
@@ -85,4 +84,8 @@ std::string string::c16str_to_string(const char16_t *c16str,
   return u16string_to_string(std::u16string(c16str, length / 2));
 }
 
+void string::append_c32(const char32_t c, std::string &string) {
+  utf8::append(c, string);
+}
+
 } // namespace odr::internal::util

src/odr/internal/util/string_util.hpp

@@ -26,5 +26,6 @@ std::string to_string(double d, int precision);
 std::string u16string_to_string(const std::u16string &string);
 std::u16string string_to_u16string(const std::string &string);
 std::string c16str_to_string(const char16_t *c16str, std::size_t length);
+void append_c32(char32_t c, std::string &string);
 
 } // namespace odr::internal::util::string

test/src/internal/oldms/oldms_test.cpp

@@ -78,8 +78,8 @@ TEST(OldMs, test) {
 
         const auto document_stream = files.open("/WordDocument").stream();
         document_stream->seekg(first_text_offset);
-        const std::string first_text =
-            internal::util::stream::read(*document_stream, first_text_length);
+        const std::string first_text = internal::oldms::read_string_compressed(
+            *document_stream, first_text_length);
         std::cout << "first_text " << first_text << std::endl;
       });
 }