OpenMP, CPIv1 writer and proper size for converter

Also moved *_varint into commons, writers are now separate functions,
maybe I could move them into commons sometime and add readers in case I
would use them at some point.

Makefile

@@ -18,4 +18,7 @@ dependencies/stb/%.o: dependencies/stb/%.h
 wsvpn: wsvpn.o dependencies/mongoose/mongoose.o
 	$(CC) $(LDFLAGS) $^ $(LOADLIBES) $(LDLIBS) -o "$@"
 
+clean:
+	$(RM) -v img2cpi cpi2png wsvpn wsvpn.o cc-common.o dependencies/stb/*.o
+
 .PHONY: all

cc-common.c

@@ -1,5 +1,36 @@
 #include "cc-common.h"
 
+int read_varint(FILE *fp, unsigned int *out) {
+  int position = 0;
+
+  while (true) {
+    unsigned char curr = fgetc(fp);
+    *out |= (curr & 0x7F) << position;
+
+    if ((curr & 0x80) == 0) break;
+
+    position += 7;
+
+    if (position >= 32) return -position / 7;
+  }
+
+  return (position + 7) / 7;
+}
+
+int write_varint(FILE *fp, unsigned int in) {
+  unsigned mask = 0xFFFFFF80;
+  int written = 0;
+  while (true) {
+    if ((in & mask) == 0) {
+      fputc(in & 0xff, fp);
+      return written + 1;
+    }
+    fputc((in & 0x7F) | 0x80, fp);
+    written++;
+    in >>= 7;
+  }
+}
+
 const struct palette cc_default_palette = PALETTE(
   { { 0xf0, 0xf0, 0xf0, 0xff } },
   { { 0xf2, 0xb2, 0x33, 0xff } },

cc-common.h

@@ -2,6 +2,8 @@
 #define _CC_COMMON_H_
 
 #include <stdint.h>
+#include <stdio.h>
+#include <stdbool.h>
 
 typedef uint8_t GlyphBitmap[11];
 
@@ -22,4 +24,8 @@ struct palette {
 const extern GlyphBitmap cc_font_atlas[256];
 const extern struct palette cc_default_palette, cc_default_gray_palette;
 
+
+int read_varint(FILE *fp, unsigned int *out);
+int write_varint(FILE *fp, unsigned int in);
+
 #endif

cpi2png.c

@@ -10,8 +10,6 @@
 
 #include "cc-common.h"
 
-bool read_varint(FILE *fp, unsigned int *out);
-
 int main(int argc, char **argv) {
   if (argc < 3) {
     fprintf(stderr, "Usage: %s [input.cpi] [output.png]\n", argv[0]);
@@ -43,8 +41,8 @@ int main(int argc, char **argv) {
     height = fgetc(fp_in);
     (void)fgetc(fp_in); // XXX: ignore scale
   } else if (version == 1) {
-    assert(read_varint(fp_in, &width) && "Failed to read width varint");
+    assert(read_varint(fp_in, &width) > 0 && "Failed to read width varint");
-    assert(read_varint(fp_in, &height) && "Failed to read height varint");
+    assert(read_varint(fp_in, &height) > 0 && "Failed to read height varint");
   } else {
     assert(false && "Failed to read size: unsupported version");
   }
@@ -55,7 +53,7 @@ int main(int argc, char **argv) {
   // XXX: may change in future when we introduce variable-size palettes
   // though, it may never change, if I'm being honest. Why would I choose
   // worse image quality with less colors when I can use all of them?
-  union color *colors = calloc(16, sizeof(union color));
+  union color colors[16] = { 0 };
 
   // NOTE: our `union color` type is 4 bytes long, while palette stored in the
   // file itself uses 3 bytes per color, so we can't just `fread` them at once,
@@ -67,10 +65,13 @@ int main(int argc, char **argv) {
     colors[i].rgba.a = 0xff;
   }
 
+  unsigned char *buffer = calloc(width * height, 2);
+  fread(buffer, 2, width * height, fp_in);
+
   for (int y = 0; y < height; y++) {
     for (int x = 0; x < width; x++) {
-      unsigned char sym = fgetc(fp_in);
+      unsigned char sym = buffer[(x + y * width) * 2];
-      unsigned char color = fgetc(fp_in);
+      unsigned char color = buffer[(x + y * width) * 2 + 1];
       union color background = colors[color & 0xF];
       union color foreground = colors[color >> 4];
       for (int oy = 0; oy < 9; oy++) {
@@ -84,25 +85,7 @@ int main(int argc, char **argv) {
 
   stbi_write_png(argv[2], width * 6, height * 9, 4, canvas, 0);
 
-  free(colors);
   free(canvas);
   fclose(fp_in);
   return EXIT_SUCCESS;
 }
-
-bool read_varint(FILE *fp, unsigned int *out) {
-  int position = 0;
-
-  while (true) {
-    unsigned char curr = fgetc(fp);
-    *out |= (curr & 0x7F) << position;
-
-    if ((curr & 0x80) == 0) break;
-
-    position += 7;
-
-    if (position >= 32) return false;
-  }
-
-  return true;
-}

img2cpi.c

@@ -13,6 +13,9 @@
 #include <strings.h>
 #include <stdbool.h>
 #include "cc-common.h"
+#ifdef USE_OPENMP
+#include <omp.h>
+#endif
 
 #define MAX_COLOR_DIFFERENCE 768
 #define K_MEANS_ITERATIONS 4
@@ -91,17 +94,23 @@ struct k_means_state {
 
 bool parse_cmdline(int argc, char **argv);
 void show_help(const char *progname, bool show_all, FILE *fp);
+
 struct image *image_load(const char *fp);
 struct image *image_new(int w, int h);
 struct image *image_resize(struct image *original, int new_w, int new_h);
 struct image_pal *image_quantize(struct image *original, const struct palette *palette);
+void image_unload(struct image *img);
+
 float get_color_difference(union color a, union color b);
 float get_color_brightness(union color clr);
-void image_unload(struct image *img);
+
 void get_size_keep_aspect(int w, int h, int dw, int dh, int *ow, int *oh);
 
 void convert_2x3(const struct image_pal *img, struct cc_char *characters);
-void convert_8x11(const struct image_pal *img, struct cc_char *characters);
+void convert_6x9(const struct image_pal *img, struct cc_char *characters);
+
+int save_cpi_0(FILE *fp, const struct palette *pal, const struct cc_char *chars, int w, int h);
+int save_cpi_1(FILE *fp, const struct palette *pal, const struct cc_char *chars, int w, int h);
 
 // Only one global custom palette is maintained
 struct palette *custom_palette_resize(uint8_t size);
@@ -172,7 +181,7 @@ int main(int argc, char **argv) {
   if (args.fast_mode) {
     canvas = image_new(args.width * 2, args.height * 3);
   } else {
-    canvas = image_new(args.width * 8, args.height * 11);
+    canvas = image_new(args.width * 6, args.height * 9);
   }
 
   if (!canvas) {
@@ -225,23 +234,14 @@ int main(int argc, char **argv) {
   if (args.fast_mode) {
     convert_2x3(quantized_image, characters);
   } else {
-    convert_8x11(quantized_image, characters);
+    convert_6x9(quantized_image, characters);
   }
 
-  // TODO: implement something other than CPIv0
   FILE *fp = fopen(args.output_path, "wb");
-  fwrite("CCPI", 1, 4, fp);
+  if (args.width < 256) {
-  fputc(args.width, fp);
+    save_cpi_0(fp, palette, characters, args.width, args.height);
-  fputc(args.height, fp);
+  } else {
-  fputc(0x00, fp);
+    save_cpi_1(fp, palette, characters, args.width, args.height);
-  for (int i = 0; i < 16; i++) {
-    fputc(palette->colors[i].rgba.r, fp);
-    fputc(palette->colors[i].rgba.g, fp);
-    fputc(palette->colors[i].rgba.b, fp);
-  }
-  for (int i = 0; i < args.width * args.height; i++) {
-    fputc(characters[i].character, fp);
-    fputc(characters[i].bg | (characters[i].fg << 4), fp);
   }
   fclose(fp);
 
@@ -250,6 +250,47 @@ int main(int argc, char **argv) {
   return EXIT_SUCCESS;
 }
 
+int _write_palette_full(FILE *fp, const struct palette *pal) {
+  int written = 0;
+  assert(pal->count == 16 && "Invalid palette size");
+  for (int i = 0; i < 16; i++) {
+    written += fputc(pal->colors[i].rgba.r, fp);
+    written += fputc(pal->colors[i].rgba.g, fp);
+    written += fputc(pal->colors[i].rgba.b, fp);
+  }
+  return written;
+}
+
+int _write_pixeldata_v0(FILE *fp, const struct cc_char *chars, int w, int h) {
+  int written = 0;
+  for (int i = 0; i < w * h; i++) {
+    written += fputc(chars[i].character, fp);
+    written += fputc(chars[i].bg | (chars[i].fg << 4), fp);
+  }
+  return written;
+}
+
+int save_cpi_0(FILE *fp, const struct palette *pal, const struct cc_char *chars, int w, int h) {
+  int written = 0;
+  written += fwrite("CCPI", 1, 4, fp);
+  written += fputc(w, fp);
+  written += fputc(h, fp);
+  written += fputc(0x00, fp);
+  written += _write_palette_full(fp, pal);
+  written += _write_pixeldata_v0(fp, chars, w, h);
+  return written;
+}
+
+int save_cpi_1(FILE *fp, const struct palette *pal, const struct cc_char *chars, int w, int h) {
+  int written = 0;
+  written += fwrite("CPI\x01", 1, 4, fp);
+  written += write_varint(fp, w);
+  written += write_varint(fp, h);
+  written += _write_palette_full(fp, pal);
+  written += _write_pixeldata_v0(fp, chars, w, h);
+  return written;
+}
+
 bool parse_cmdline(int argc, char **argv) {
   static struct option options[] = {
     { "help",         no_argument,        0, 'h' },
@@ -593,8 +634,8 @@ void convert_2x3(const struct image_pal *img, struct cc_char *characters) {
   }
 }
 
-void convert_8x11(const struct image_pal *img, struct cc_char *characters) {
+void convert_6x9(const struct image_pal *img, struct cc_char *characters) {
-  int w = img->w / 8, h = img->h / 11;
+  int w = img->w / 6, h = img->h / 9;
   float palette_self_diffs[0x100][0x10] = {{(float) 0xffffff}};
   for (int input_color = 0x0; input_color < 0x100 && input_color < img->palette->count; input_color++) {
     for (int output_color = 0x0; output_color < 0x10 && output_color < img->palette->count; output_color++) {
@@ -603,12 +644,15 @@ void convert_8x11(const struct image_pal *img, struct cc_char *characters) {
   }
 
   for (int y = 0; y < h; y++) {
+#ifdef USE_OPENMP
+#pragma omp parallel for
+#endif
     for (int x = 0; x < w; x++) {
-      float chunk_palette_diffs[8][11][0x10] = {{{(float) 0xffffff}}};
+      float chunk_palette_diffs[6][9][0x10] = {{{(float) 0xffffff}}};
-      for (int ox = 0; ox < 8; ox++) {
+      for (int ox = 0; ox < 6; ox++) {
-        for (int oy = 0; oy < 11; oy++) {
+        for (int oy = 0; oy < 9; oy++) {
           uint8_t pixel_unresolved = img->pixels[
-            ox + (x + (y * 11 + oy) * w) * 8
+            ox + (x + (y * 9 + oy) * w) * 6
           ];
           for (int color = 0x0; color < 0x10 && color < img->palette->count; color++) {
             chunk_palette_diffs[ox][oy][color] = palette_self_diffs[pixel_unresolved][color];
@@ -624,9 +668,9 @@ void convert_8x11(const struct image_pal *img, struct cc_char *characters) {
         }
         for (int color = 0x00; color <= 0xff; color++) {
           float difference = 0;
-          for (int oy = 0; oy < 11; oy++) {
+          for (int oy = 0; oy < 9; oy++) {
             unsigned char sym_line = cc_font_atlas[sym][oy];
-            for (int ox = 0; ox < 8; ox++) {
+            for (int ox = 0; ox < 6; ox++) {
               bool lit = sym_line & (0x80 >> ox);
               difference += chunk_palette_diffs[ox][oy][lit ? color >> 4 : color & 0xF];
             }