use binary instead of linear search (#30)

use binary instead of linear search using algorithm from https://en.wikipedia.org/wiki/Binary_search_algorithm
gitdode · Sep 6, 2023 · 1499b99 · 1499b99
1 parent 5583921
commit 1499b99
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Showing 12 changed files with 36 additions and 40 deletions.
diff --git a/thermidity-avr/bitmaps.c b/thermidity-avr/bitmaps.c
@@ -108,7 +108,7 @@ const __flash uint8_t BAT_100PCT_DATA[] = {
     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
 };
 
-const __flash Bitmap AllBitmaps[] = {
+const __flash Bitmap bitmaps[] = {
     {32, 16, BAT_0PCT_DATA},
     {32, 16, BAT_13PCT_DATA},
     {32, 16, BAT_25PCT_DATA},
@@ -119,7 +119,3 @@ const __flash Bitmap AllBitmaps[] = {
     {32, 16, BAT_88PCT_DATA},
     {32, 16, BAT_100PCT_DATA}
 };
-
-/*const __flash Bitmap* getBitmapAddress (uint8_t index) {
-    return & AllBitmaps[index];
-    }*/
diff --git a/thermidity-avr/bitmaps.h b/thermidity-avr/bitmaps.h
@@ -33,12 +33,9 @@ typedef struct {
 } Bitmap;
 
 /**
- * Returns the flash adress bitmap at the given index.
- * @param index
- * @return Bitmap
+ * Available bitmaps.
  */
-
-extern const __flash Bitmap AllBitmaps[];
+extern const __flash Bitmap bitmaps[];
 
 #endif /* BITMAPS_H */
 
diff --git a/thermidity-avr/dejavu.c b/thermidity-avr/dejavu.c
@@ -7,7 +7,6 @@
  */
 
 #include <stdio.h>
-#include <avr/pgmspace.h>
 #include "font.h"
 #include "dejavu.h"
 #include "utils.h"
@@ -794,4 +793,4 @@ const __flash Glyph glyphs[] = {
     {0x00b0, 16, DEGREE_SIGN}
 };
 
-const __flash Font theDejaVu = { glyphs, ARRAY_LENGTH(glyphs), HEIGHT };
+const __flash Font dejaVuFont = {glyphs, ARRAY_LENGTH(glyphs), HEIGHT};
diff --git a/thermidity-avr/dejavu.h b/thermidity-avr/dejavu.h
@@ -12,12 +12,9 @@
 #include "font.h"
 
 /**
- * Returns an instance of the font derived from DejaVu.
- * @return unifont
+ * DejaVu font.
  */
-const Font getDejaVu(void);
-
-extern const __flash Font theDejaVu;
+extern const __flash Font dejaVuFont;
 
 #endif /* DEJAVU_H */
 
diff --git a/thermidity-avr/display.c b/thermidity-avr/display.c
@@ -48,9 +48,9 @@ static void bufferByte(uint16_t index, uint16_t *address, uint16_t height,
  * @param width
  * @param height
  */
-static void bufferBitmap (uint8_t row, uint16_t col,
-                          const __flash  uint8_t *bitmap,
-                          uint16_t width, uint16_t height) {
+static void bufferBitmap(uint8_t row, uint16_t col,
+                         const __flash  uint8_t *bitmap,
+                         uint16_t width, uint16_t height) {
     uint16_t size = width * height / 8;
     uint16_t origin = DISPLAY_WIDTH * DISPLAY_H_BYTES + row - col * DISPLAY_H_BYTES;
 
@@ -115,16 +115,15 @@ void setFrame(uint8_t byte) {
 }
 
 uint8_t writeBitmap(uint16_t row, uint16_t col, uint16_t index) {
-    const __flash Bitmap *bitmap = & AllBitmaps[index];
+    const __flash Bitmap *bitmap = & bitmaps[index];
     bufferBitmap (row, col, bitmap->bitmap, bitmap->width, bitmap->height);
 
     return bitmap->width;
 }
 
-uint8_t writeGlyph(uint16_t row, uint16_t col, const __flash Font *font, uint16_t code)
-{
-    const __flash Glyph *glyph = getGlyphAddress (font, code);
-    bufferBitmap (row, col, glyph->bitmap, glyph->width, font->height);
+uint8_t writeGlyph(uint16_t row, uint16_t col, const __flash Font *font, uint16_t code) {
+    const __flash Glyph *glyph = getGlyphAddress(font, code);
+    bufferBitmap(row, col, glyph->bitmap, glyph->width, font->height);
 
     return glyph->width;
 }

diff --git a/thermidity-avr/font.c b/thermidity-avr/font.c
@@ -8,14 +8,25 @@
 #include <stdio.h>
 #include "font.h"
 
-const __flash Glyph* getGlyphAddress (const __flash Font *font, uint16_t code) {
-    const __flash Glyph *pglyph = & font->glyphs[0];
-    for (size_t i = 0; i < font->length; i++, pglyph++) {
-        if (pglyph->code == code) {
+const __flash Glyph* getGlyphAddress(const __flash Font *font, uint16_t code) {
+
+    // https://en.wikipedia.org/wiki/Binary_search_algorithm
+    int16_t l = 0;
+    int16_t r = font->length - 1;
+
+    while (l <= r) {
+        uint8_t m = (l + r) / 2;
+        const __flash Glyph *pglyph = &font->glyphs[m];
+        if (pglyph->code < code) {
+            l = m + 1;
+        } else if (pglyph->code > code) {
+            r = m - 1;
+        } else {
+            // found code point, return address of glyph
             return pglyph;
         }
     }
 
     // return question mark if unknown code point
-    return getGlyphAddress (font, 0x003f);
+    return getGlyphAddress(font, 0x003f);
 }
diff --git a/thermidity-avr/font.h b/thermidity-avr/font.h
@@ -41,6 +41,6 @@ typedef struct {
  * @param code
  * @return Glyph
  */
-const __flash Glyph* getGlyphAddress (const __flash Font *font, uint16_t code);
+const __flash Glyph* getGlyphAddress(const __flash Font *font, uint16_t code);
 
 #endif /* FONT_H */
diff --git a/thermidity-avr/meter.c b/thermidity-avr/meter.c
@@ -160,8 +160,8 @@ bool displayValues(bool fast) {
     prevRh = rh;
     prevVBatx10 = vBatx10;
 
-    const __flash Font *unifont = & theUnifont;
-    const __flash Font *dejavu = & theDejaVu;
+    const __flash Font *unifont = &unifontFont;
+    const __flash Font *dejavu = &dejaVuFont;
 
     // clear frame
     setFrame(0x00);

diff --git a/thermidity-avr/nbproject/configurations.xml b/thermidity-avr/nbproject/configurations.xml
@@ -47,6 +47,7 @@
           <cleanCommand>${MAKE} -f Makefile clean</cleanCommand>
           <executablePath>/home/dode/dev/thermidity/thermidity-avr/thermidity.elf</executablePath>
           <cTool>
+            <standard>3</standard>
             <incDir>
               <pElem>.</pElem>
             </incDir>

diff --git a/thermidity-avr/thermidity.c b/thermidity-avr/thermidity.c
@@ -20,7 +20,6 @@
 #include <avr/interrupt.h>
 #include <avr/sleep.h>
 #include <avr/wdt.h>
-#include <avr/pgmspace.h>
 #include <util/delay.h>
 #include <util/atomic.h>
 

diff --git a/thermidity-avr/unifont.c b/thermidity-avr/unifont.c
@@ -970,4 +970,4 @@ static const __flash Glyph glyphs[] = {
     {0x00ff, WIDTH, y_diaeresis}
 };
 
-const __flash Font theUnifont = { glyphs, ARRAY_LENGTH(glyphs), HEIGHT };
+const __flash Font unifontFont = {glyphs, ARRAY_LENGTH(glyphs), HEIGHT};
diff --git a/thermidity-avr/unifont.h b/thermidity-avr/unifont.h
@@ -14,12 +14,9 @@
 #define UNIFONT_DEMO_SIZE 7
 
 /**
- * Returns an instance of the Unifont font.
- * @return unifont
+ * Unifont font.
  */
-const Font getUnifont(void);
-
-extern const __flash Font theUnifont;
+extern const __flash Font unifontFont;
 
 #endif /* UNIFONT_H */