Preparations for rdb image API: base64 encoder and decoder without Qt

src/tl/tl/tl.pro

@@ -10,6 +10,7 @@ FORMS =
 
 SOURCES = \
     tlAssert.cc \
+    tlBase64.cc \
     tlClassRegistry.cc \
     tlCopyOnWrite.cc \
     tlDataMapping.cc \
@@ -56,6 +57,7 @@ SOURCES = \
 HEADERS = \
     tlAlgorithm.h \
     tlAssert.h \
+    tlBase64.h \
     tlClassRegistry.h \
     tlCopyOnWrite.h \
     tlDataMapping.h \

src/tl/tl/tlBase64.cc

@@ -0,0 +1,139 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2022 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
+#include "tlBase64.h"
+#include "tlException.h"
+#include "tlInternational.h"
+
+namespace tl
+{
+
+namespace {
+
+class EncoderTable
+{
+public:
+  EncoderTable ()
+  {
+    char charset[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+    for (unsigned int i = 0; i < 256; ++i) {
+      m_char2bin[i] = 0xff;
+    }
+    for (unsigned int i = 0; i < 64; ++i) {
+      m_bin2char[i] = charset[i];
+      m_char2bin[(unsigned int) charset[i]] = i;
+    }
+  }
+
+  inline char c (unsigned char b) const { return m_bin2char[b]; }
+  inline unsigned char b (char c) const { return m_char2bin[(unsigned char) c]; }
+
+private:
+  char m_bin2char[64];
+  unsigned char m_char2bin[256];
+};
+
+}
+
+static EncoderTable s_enc;
+
+std::vector<unsigned char> from_base64 (const char *s)
+{
+  size_t sz = 0;
+  for (const char *t = s; *t; ++t) {
+    ++sz;
+  }
+
+  unsigned int sh = 0;
+
+  std::vector<unsigned char> data;
+  data.reserve ((sz * 6 + 7) / 8);
+
+  for (const char *t = s; *t; ++t) {
+
+    if ((unsigned char) *t <= ' ') {
+
+      //  ignore white space characters
+
+    } else if (*t == '=') {
+
+      //  padding/termination
+      if (data.empty () || data.back () != 0) {
+        throw tl::Exception (tl::to_string (tr ("Error decoding base64 data: padding character does not match zero byte")));
+      }
+      data.pop_back ();
+      break;
+
+    } else {
+
+      unsigned char b = s_enc.b (*t);
+      if (b >= 64) {
+        throw tl::Exception (tl::to_string (tr ("Error decoding base64 data: invalid character '%c'")), *t);
+      }
+
+      sh += 2;
+
+      if (sh == 8) {
+        data.back () |= b;
+        sh = 0;
+      } else if (sh == 2) {
+        data.push_back (b << 2);
+      } else {
+        data.back () |= (b >> (8 - sh));
+        data.push_back (b << sh);
+      }
+
+    }
+
+  }
+
+  return data;
+}
+
+std::string to_base64 (const unsigned char *data, size_t size)
+{
+  std::string s;
+  s.reserve (((size + 2) / 3) * 4);
+
+  size_t bits = size * 8;
+
+  for (size_t b = 0; b < bits; b += 6) {
+    size_t bit = b % 8;
+    size_t byte = b / 8;
+    if (bit <= 2) {
+      s += s_enc.c ((data [byte] >> (2 - bit)) & 0x3f);
+    } else if (b + 8 < bits) {
+      s += s_enc.c (((data [byte] << (bit - 2)) | (data [byte + 1] >> (10 - bit))) & 0x3f);
+    } else {
+      s += s_enc.c ((data [byte] << (bit - 2)) & 0x3f);
+      s += '=';
+      if (bit == 6) {
+        s += '=';
+      }
+    }
+  }
+
+  return s;
+}
+
+}

src/tl/tl/tlBase64.h

@@ -0,0 +1,47 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2022 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
+
+#ifndef HDR_tlBase64
+#define HDR_tlBase64
+
+#include "tlCommon.h"
+
+#include <string>
+#include <vector>
+
+namespace tl
+{
+
+/**
+ *  Converts a base64-encoded string into binary data
+ */
+TL_PUBLIC std::vector<unsigned char> from_base64 (const char *s);
+
+/**
+ *  Converts binary data into a base64-encoded string
+ */
+TL_PUBLIC std::string to_base64 (const unsigned char *data, size_t size);
+
+}
+
+#endif

src/tl/unit_tests/tlBase64Tests.cc

@@ -0,0 +1,98 @@
+
+/*
+
+  KLayout Layout Viewer
+  Copyright (C) 2006-2022 Matthias Koefferlein
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
+
+#include "tlBase64.h"
+#include "tlUnitTest.h"
+
+TEST(1)
+{
+  std::vector<unsigned char> r = tl::from_base64 ("");
+  EXPECT_EQ (r.empty (), true);
+
+  r = tl::from_base64 ("YQ==");
+  EXPECT_EQ (std::string ((const char *) r.begin ().operator-> (), r.size ()), "a");
+
+  r = tl::from_base64 ("YQ==");
+  EXPECT_EQ (std::string ((const char *) r.begin ().operator-> (), r.size ()), "a");
+
+  r = tl::from_base64 ("YWI=");
+  EXPECT_EQ (std::string ((const char *) r.begin ().operator-> (), r.size ()), "ab");
+
+  r = tl::from_base64 ("YWJj");
+  EXPECT_EQ (std::string ((const char *) r.begin ().operator-> (), r.size ()), "abc");
+
+  r = tl::from_base64 ("YWJjZA==");
+  EXPECT_EQ (std::string ((const char *) r.begin ().operator-> (), r.size ()), "abcd");
+
+  r = tl::from_base64 ("YWJjZA=");
+  EXPECT_EQ (std::string ((const char *) r.begin ().operator-> (), r.size ()), "abcd");
+
+  r = tl::from_base64 ("SGVsbG8sIHdvcmxkIQo=");
+  EXPECT_EQ (std::string ((const char *) r.begin ().operator-> (), r.size ()), "Hello, world!\n");
+
+  r = tl::from_base64 ("SGVsbG\n8sIHd  \tvcmxkIQo=");
+  EXPECT_EQ (std::string ((const char *) r.begin ().operator-> (), r.size ()), "Hello, world!\n");
+
+  try {
+    r = tl::from_base64 ("YWJjZ==");
+    EXPECT_EQ (true, false);
+  } catch (tl::Exception &ex) {
+    EXPECT_EQ (ex.msg (), "Error decoding base64 data: padding character does not match zero byte");
+  }
+
+  try {
+    r = tl::from_base64 ("YW#jZA==");
+    EXPECT_EQ (true, false);
+  } catch (tl::Exception &ex) {
+    EXPECT_EQ (ex.msg (), "Error decoding base64 data: invalid character '#'");
+  }
+}
+
+TEST(2)
+{
+  std::string s, r;
+
+  s = "";
+  r = tl::to_base64 ((const unsigned char *) s.c_str (), s.size ());
+  EXPECT_EQ (r, "");
+
+  s = "a";
+  r = tl::to_base64 ((const unsigned char *) s.c_str (), s.size ());
+  EXPECT_EQ (r, "YQ==");
+
+  s = "ab";
+  r = tl::to_base64 ((const unsigned char *) s.c_str (), s.size ());
+  EXPECT_EQ (r, "YWI=");
+
+  s = "abc";
+  r = tl::to_base64 ((const unsigned char *) s.c_str (), s.size ());
+  EXPECT_EQ (r, "YWJj");
+
+  s = "abcd";
+  r = tl::to_base64 ((const unsigned char *) s.c_str (), s.size ());
+  EXPECT_EQ (r, "YWJjZA==");
+
+  s = "Hello, world!\n";
+  r = tl::to_base64 ((const unsigned char *) s.c_str (), s.size ());
+  EXPECT_EQ (r, "SGVsbG8sIHdvcmxkIQo=");
+}

src/tl/unit_tests/unit_tests.pro

@@ -8,6 +8,7 @@ include($$PWD/../../lib_ut.pri)
 
 SOURCES = \
   tlAlgorithmTests.cc \
+  tlBase64Tests.cc \
   tlClassRegistryTests.cc \
   tlCommandLineParserTests.cc \
   tlCopyOnWriteTests.cc \