ZmFont: Rework/modernize API

src/CMakeLists.txt

@@ -82,6 +82,7 @@ target_link_libraries(zm
     libbcrypt::bcrypt
     jwt-cpp::jwt-cpp
     RtspServer::RtspServer
+    martinmoene::span-lite
   PRIVATE
     zm-core-interface)
 

src/zm_font.cpp

@@ -1,77 +1,119 @@
+/*
+ * This file is part of the ZoneMinder Project. See AUTHORS file for Copyright information
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
 #include "zm_font.h"
 
 #include <cstring>
-#include <sys/stat.h>
+#include <fstream>
 
-int ZmFont::ReadFontFile(const std::string &loc) {
+constexpr uint8 FontVariant::kMaxNumCodePoints;
-  FILE *f = fopen(loc.c_str(), "rb");
+constexpr uint8 FontVariant::kMaxCharHeight;
-  if ( !f ) return -1;  // FILE NOT FOUND
+constexpr uint8 FontVariant::kMaxCharWidth;
 
-  font = new ZMFONT;
+FontVariant::FontVariant() : char_height_(0), char_width_(0), codepoint_count_(0) {}
 
-  size_t header_size = 8 + (sizeof(ZMFONT_BH) * NUM_FONT_SIZES);
+FontVariant::FontVariant(uint16 char_height, uint16 char_width, std::vector<uint64> bitmap)
-
+    : char_height_(char_height), char_width_(char_width), bitmap_(std::move(bitmap)) {
-  // MAGIC + pad + BitmapHeaders
+  if (char_height_ > kMaxCharHeight) {
-  size_t readsize = fread(&font[0], 1, header_size, f);
+    throw std::invalid_argument("char_height > kMaxCharHeight");
-  if ( readsize < header_size ) {
-    delete font;
-    font = nullptr;
-    fclose(f);
-    return -2; // EOF reached, invalid file
   }
 
-  if ( memcmp(font->MAGIC, "ZMFNT", 5) != 0 ) { // Check whether magic is correct
+  if (char_width_ > kMaxCharWidth) {
-    delete font;
+    throw std::invalid_argument("char_width > kMaxCharWidth");
-    font = nullptr;
-    fclose(f);
-    return -3;
   }
 
-  struct stat st;
+  if (bitmap_.size() % char_height_ != 0) {
-  stat(loc.c_str(), &st);
+    throw std::invalid_argument("bitmap has wrong length");
+  }
 
-  for ( int i = 0; i < NUM_FONT_SIZES; i++ ) {
+  codepoint_count_ = bitmap_.size() / char_height;
-    /* Character Width cannot be greater than 64 as a row is represented as a uint64_t, 
+}
-       height cannot be greater than 200(arbitary number which i have chosen, shouldn't need more than this) and 
+
-       idx should not be more than filesize
+nonstd::span<const uint64> FontVariant::GetCodepoint(uint8 idx) const {
-    */
+  static constexpr std::array<uint64, kMaxCharHeight> empty_bitmap = {};
-    if ( font->header[i].charWidth > 64 || font->header[i].charWidth == 0 || 
+
-        font->header[i].charHeight > 200 || font->header[i].charHeight == 0 || 
+  if (idx >= GetCodepointsCount()) {
-        (font->header[i].idx > st.st_size) ) {
+    return {empty_bitmap.begin(), GetCharHeight()};
-      delete font;
+  }
-      font = nullptr;
+
-      fclose(f);
+  return {bitmap_.begin() + (idx * GetCharHeight()), GetCharHeight()};
-      return -4;
+}
+
+std::ifstream &operator>>(std::ifstream &stream, FontBitmapHeader &bm_header) {
+  stream.read(reinterpret_cast<char *>(&bm_header), sizeof(bm_header));
+
+  return stream;
+}
+
+std::ifstream &operator>>(std::ifstream &stream, FontFileHeader &header) {
+  stream.read(header.magic, sizeof(header.magic));
+  stream.seekg(sizeof(header.pad), std::ifstream::cur);
+
+  for (FontBitmapHeader &bm_header : header.bitmap_header)
+    stream >> bm_header;
+
+  return stream;
+}
+
+FontLoadError ZmFont::LoadFontFile(const std::string &loc) {
+  std::ifstream font_file(loc, std::ifstream::binary);
+  font_file.exceptions(std::ifstream::badbit);
+
+  if (!font_file.is_open()) {
+    return FontLoadError::kFileNotFound;
+  }
+
+  FontFileHeader file_header = {};
+  font_file >> file_header;
+
+  if (font_file.fail()) {
+    return FontLoadError::kInvalidFile;
+  }
+
+  if (memcmp(file_header.magic, "ZMFNT", 5) != 0) {
+    return FontLoadError::kInvalidFile;
+  }
+
+  for (int i = 0; i < kNumFontSizes; i++) {
+    FontBitmapHeader bitmap_header = file_header.bitmap_header[i];
+
+    if (bitmap_header.char_width > FontVariant::kMaxCharWidth
+        || bitmap_header.char_height > FontVariant::kMaxCharHeight
+        || bitmap_header.number_of_code_points > FontVariant::kMaxNumCodePoints) {
+      return FontLoadError::kInvalidFile;
     }
-  }  // end foreach font size
 
-  datasize = st.st_size - header_size;
+    std::vector<uint64> bitmap;
+    bitmap.resize(bitmap_header.number_of_code_points * bitmap_header.char_height);
 
-  font->data = new uint64_t[datasize/sizeof(uint64_t)];
+    std::size_t bitmap_bytes = bitmap.size() * sizeof(uint64);
-  readsize = fread(&font->data[0], 1, datasize, f);
+    font_file.read(reinterpret_cast<char *>(bitmap.data()), static_cast<std::streamsize>(bitmap_bytes));
-  if ( readsize < datasize ) { // Shouldn't happen
-    delete[] font->data;
-    font->data = nullptr;
-    delete font;
-    font = nullptr;
-    return -2;
-  }
-  fclose(f);
-  return 0;
-}
 
-ZmFont::~ZmFont() {
+    variants_[i] =
-  if ( font && font->data ) {
+        {bitmap_header.char_height, bitmap_header.char_width, std::move(bitmap)};
-    delete[] font->data;
-    font->data = nullptr;
   }
 
-  if ( font ) {
+  if (font_file.fail()) {
-    delete font;
+    return FontLoadError::kInvalidFile;
-    font = nullptr;
   }
+
+  return FontLoadError::kOk;
 }
 
-uint64_t *ZmFont::GetBitmapData() {
+const FontVariant &ZmFont::GetFontVariant(uint8 idx) const {
-  return &font->data[font->header[size].idx];
+  return variants_.at(idx);
 }

src/zm_font.h

@@ -1,40 +1,89 @@
+/*
+ * This file is part of the ZoneMinder Project. See AUTHORS file for Copyright information
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
 #ifndef ZM_FONT_H
 #define ZM_FONT_H
 
 #include "zm_define.h"
+#include <array>
+#include <cassert>
+#include "span.hpp"
 #include <string>
+#include <vector>
 
-#define NUM_FONT_SIZES 4
+constexpr uint8 kNumFontSizes = 4;
 
-struct ZMFONT_BH{
+enum class FontLoadError {
-    uint16_t charHeight;  // Height of every character
+  kOk,
-    uint16_t charWidth;  // Width of every character
+  kFileNotFound,
-    uint32_t numberofCodePoints;  // number of codepoints max 255 for now
+  kInvalidFile
-    uint32_t idx;  // idx in data where data for the bitmap starts
-    uint32_t pad;  // padding to round of the size
 };
 
-struct ZMFONT {
+#pragma pack(push, 1)
-  char MAGIC[6];  // ZMFNT\0
+struct FontBitmapHeader {
-  char pad[2];
+  uint16 char_height; // height of every character
-  ZMFONT_BH header[NUM_FONT_SIZES];
+  uint16 char_width; // width of every character
-  uint64_t *data;
+  uint32 number_of_code_points; // number of codepoints; max. 255 for now
+  uint32 idx; // offset in data where data for the bitmap starts; not used
+  uint32 pad; // padding
+};
+#pragma pack(pop)
+
+#pragma pack(push, 1)
+struct FontFileHeader {
+  char magic[6]; // "ZMFNT\0"
+  uint8 pad[2];
+  std::array<FontBitmapHeader, kNumFontSizes> bitmap_header;
+};
+#pragma pack(pop)
+
+class FontVariant {
+ public:
+  static constexpr uint8 kMaxNumCodePoints = 255;
+  // height cannot be greater than 200 (arbitrary number; shouldn't need more than this)
+  static constexpr uint8 kMaxCharHeight = 200;
+  // character width can't be greater than 64 as a row is represented as an uint64
+  static constexpr uint8 kMaxCharWidth = 64;
+
+  FontVariant();
+  FontVariant(uint16 char_height, uint16 char_width, std::vector<uint64> bitmap);
+
+  uint16 GetCharHeight() const { return char_height_; }
+  uint16 GetCharWidth() const { return char_width_; }
+  uint8 GetCodepointsCount() const { return codepoint_count_; }
+
+  // Returns the bitmap of the codepoint `idx`. If `idx` is greater than `GetCodepointsCount`
+  // a all-zero bitmap with `GetCharHeight` elements is returned.
+  nonstd::span<const uint64> GetCodepoint(uint8 idx) const;
+
+ private:
+  uint16 char_height_;
+  uint16 char_width_;
+  uint8 codepoint_count_;
+  std::vector<uint64> bitmap_;
 };
 
 class ZmFont {
  public:
-    ~ZmFont();
+  FontLoadError LoadFontFile(const std::string &loc);
-    int ReadFontFile(const std::string &loc);
+  const FontVariant &GetFontVariant(uint8 idx) const;
-    ZMFONT *GetFont() { return font; }
-    void SetFontSize(int _size) { size = _size; }
-    uint64_t *GetBitmapData();
-    uint16_t GetCharWidth() { return font->header[size].charWidth; }
-    uint16_t GetCharHeight() { return font->header[size].charHeight; }
 
  private:
-    int size = 0;
+  std::array<FontVariant, kNumFontSizes> variants_;
-    size_t datasize = 0;
-    ZMFONT *font = nullptr;
 };
 
 #endif

src/zm_image.cpp

@@ -564,10 +564,10 @@ void Image::Initialise() {
   g_u_table = g_u_table_global;
   b_u_table = b_u_table_global;
 
-  int res = font.ReadFontFile(config.font_file_location);
+  FontLoadError res = font.LoadFontFile(config.font_file_location);
-  if ( res == -1 ) {
+  if ( res == FontLoadError::kFileNotFound ) {
     Panic("Invalid font location: %s", config.font_file_location);
-  } else if ( res == -2 || res == -3 || res == -4 ) {
+  } else if ( res == FontLoadError::kInvalidFile ) {
     Panic("Invalid font file."); 
   }
   initialised = true;
@@ -1943,9 +1943,9 @@ const Coord Image::centreCoord( const char *text, int size=1 ) const {
     line_no++;
   }
 
-  font.SetFontSize(size-1);
+  FontVariant const &font_variant = font.GetFontVariant(size - 1);
-  uint16_t char_width = font.GetCharWidth();
+  uint16_t char_width = font_variant.GetCharWidth();
-  uint16_t char_height = font.GetCharHeight();
+  uint16_t char_height = font_variant.GetCharHeight();
   int x = (width - (max_line_len * char_width )) / 2;
   int y = (height - (line_no * char_height) ) / 2;
   return Coord(x, y);
@@ -2023,10 +2023,9 @@ void Image::Annotate(
   const Rgb bg_rgb_col = rgb_convert(bg_colour, subpixelorder);
   const bool bg_trans = (bg_colour == kRGBTransparent);
 
-  font.SetFontSize(size-1);
+  FontVariant const &font_variant = font.GetFontVariant(size - 1);
-  const uint16_t char_width = font.GetCharWidth();
+  const uint16_t char_width = font_variant.GetCharWidth();
-  const uint16_t char_height = font.GetCharHeight();
+  const uint16_t char_height = font_variant.GetCharHeight();
-  const uint64_t *font_bitmap = font.GetBitmapData();
   Debug(4, "Font size %d, char_width %d char_height %d", size, char_width, char_height);
 
   while ( (index < text_len) && (line_len = strcspn(line, "\n")) ) {
@@ -2064,7 +2063,7 @@ void Image::Annotate(
       for ( unsigned int y = lo_line_y, r = 0; y < hi_line_y && r < char_height; y++, r++, ptr += width ) {
         unsigned char *temp_ptr = ptr;
         for ( unsigned int x = lo_line_x, c = 0; x < hi_line_x && c < line_len; c++ ) {
-          uint64_t f = font_bitmap[(line[c] * char_height) + r];
+          uint64_t f = font_variant.GetCodepoint(line[c])[r];
           if ( !bg_trans ) memset(temp_ptr, bg_bw_col, char_width);
           while ( f != 0 ) {
             uint64_t t = f & -f;
@@ -2081,7 +2080,7 @@ void Image::Annotate(
       for ( unsigned int y = lo_line_y, r = 0; y < hi_line_y && r < char_height; y++, r++, ptr += wc ) {
         unsigned char *temp_ptr = ptr;
         for ( unsigned int x = lo_line_x, c = 0; x < hi_line_x && c < line_len; c++ ) {
-          uint64_t f = font_bitmap[(line[c] * char_height) + r];
+          uint64_t f = font_variant.GetCodepoint(line[c])[r];
           if ( !bg_trans ) {
             for ( int i = 0; i < char_width; i++ ) {  // We need to set individual r,g,b components
               unsigned char *colour_ptr = temp_ptr + (i*3);
@@ -2109,7 +2108,7 @@ void Image::Annotate(
       for ( unsigned int y = lo_line_y, r = 0; y < hi_line_y && r < char_height; y++, r++, ptr += wc ) {
         Rgb* temp_ptr = (Rgb*)ptr;
         for ( unsigned int x = lo_line_x, c = 0; x < hi_line_x && c < line_len; c++ ) {
-          uint64_t f = font_bitmap[(line[c] * char_height) + r];
+          uint64_t f = font_variant.GetCodepoint(line[c])[r];
           if ( !bg_trans ) {
             for ( int i = 0; i < char_width; i++ )
               *(temp_ptr + i) = bg_rgb_col;