Fixes and testing, all should work now

src/cgram.c

@@ -4,7 +4,7 @@
 
 #include "cgram.h"
 
-const struct cgram_pattern CGRAM_CZ[] = {
+const struct LcdBuf_CGRAM_Symbol CGRAM_CZ[] = {
         {
                 .symbol = "ě",
                 .fallback = 'e',

src/cgram.h

@@ -9,7 +9,7 @@
 #include <stdint.h>
 
 /** Pattern for CGRAM */
-struct cgram_pattern {
+struct LcdBuf_CGRAM_Symbol {
   /** The symbol displayed */
   struct Utf8Char symbol;
 
@@ -20,6 +20,6 @@ struct cgram_pattern {
   uint8_t data[8];
 };
 
-extern const struct cgram_pattern CGRAM_CZ[];
+extern const struct LcdBuf_CGRAM_Symbol CGRAM_CZ[];
 
 #endif //HD44780UTF_CGRAM_H

src/cgrom.c

@@ -2,7 +2,7 @@
 #include "utf8.h"
 #include "cgrom.h"
 
-const struct cgrom_entry CGROM_A00[] = {
+const struct LcdBuf_CGROM_Entry CGROM_A00[] = {
         {.address = 32, .symbol = " "},
         {.address = 33, .symbol = "!"},
         {.address = 34, .symbol = "\""},

src/cgrom.h

@@ -9,7 +9,7 @@
 #include "utf8.h"
 
 /** CGROM look-up table entry */
-struct cgrom_entry {
+struct LcdBuf_CGROM_Entry {
   /** Address in the CGROM */
   uint8_t address;
 
@@ -19,6 +19,6 @@ struct cgrom_entry {
 
 
 /** The standard japanese lookup table, terminated by an empty entry */
-extern const struct cgrom_entry CGROM_A00[];
+extern const struct LcdBuf_CGROM_Entry CGROM_A00[];
 
 #endif //HD44780UTF_CGROM_H

src/lcdbuf.c

@@ -1,14 +1,15 @@
 /**
- * TODO file description
+ * HD44780 utf8-capable display buffer
  */
 
 #include <string.h>
 #include <assert.h>
+//#include <stdio.h>
 #include "lcdbuf.h"
 
 
 /** Initialize the struct */
-void LcdBuffer_Init(struct LcdBuffer *self, const struct cgrom_entry *cgrom, const struct cgram_pattern *custom_symbols)
+void LcdBuffer_Init(struct LcdBuffer *self, const struct LcdBuf_CGROM_Entry *cgrom, const struct LcdBuf_CGRAM_Symbol *custom_symbols)
 {
     assert(self);
     assert(cgrom);
@@ -25,15 +26,17 @@ void LcdBuffer_Clear(struct LcdBuffer *self)
     assert(self);
 
     memset(self->cgram, 0, sizeof(self->cgram));
-    memset(self->screen, 32, sizeof(self->screen));
+    memset(self->screen, ' ', sizeof(self->screen));
     memset(self->dirty_extents, 0, sizeof(self->dirty_extents));
-    self->full_repaint_required = false;
+
+    // everything must be written, who knows what was left on the display before!
+    self->full_repaint_required = true;
 }
 
 /** Write what needs to be written to the HW, clear all dirty marks */
 void LcdBuffer_Flush(struct LcdBuffer *self)
 {
-    for (int i = 0; i < 8; i++) {
+    for (int i = 0; i < LCDBUF_CGRAM_CAPACITY; i++) {
         if (self->cgram[i].refcount > 0 && self->cgram[i].dirty) {
             LcdBuffer_IO_WriteCGRAM(i, self->custom_symbols[self->cgram[i].symbol_index].data);
             self->cgram[i].dirty = false;
@@ -41,13 +44,29 @@ void LcdBuffer_Flush(struct LcdBuffer *self)
     }
 
     if (self->full_repaint_required) {
+        self->full_repaint_required = false;
+        // Check if we have anything on the display - if not, just clear screen
+        bool any_nonspace = false;
+        for (int r = 0; !any_nonspace && r < LINE_NUM; r++) {
+            for (int c = 0; !any_nonspace && c < LINE_LEN; c++) {
+                if (self->screen[r][c] != ' ') {
+                    any_nonspace = true;
+                }
+            }
+        }
+
+        if (!any_nonspace) {
+            LcdBuffer_IO_Clear();
+            return;
+        }
+
         for (int r = 0; r < LINE_NUM; r++) {
             LcdBuffer_IO_WriteAt(r, 0, self->screen[r], LINE_LEN);
         }
         memset(self->dirty_extents, 0, sizeof(self->dirty_extents));
     } else {
-        for (int e = 0; e < BUFLEN_DIRTY_LIST; e++) {
+        for (int e = 0; e < LCDBUF_DIRTY_LIST_LEN; e++) {
-            struct DirtyExtent *ext = &self->dirty_extents[e];
+            struct LcdBuf_DirtyExtent *ext = &self->dirty_extents[e];
             if (!ext->count) {
                 continue;
             }
@@ -60,7 +79,7 @@ void LcdBuffer_Flush(struct LcdBuffer *self)
 /** Fully write everything to the display */
 void LcdBuffer_FlushAll(struct LcdBuffer *self)
 {
-    for (int i = 0; i < 8; i++) {
+    for (int i = 0; i < LCDBUF_CGRAM_CAPACITY; i++) {
         if (self->cgram[i].refcount > 0) {
             LcdBuffer_IO_WriteCGRAM(i, self->custom_symbols[self->cgram[i].symbol_index].data);
         }
@@ -75,11 +94,27 @@ void LcdBuffer_FlushAll(struct LcdBuffer *self)
     self->full_repaint_required = false;
 }
 
-static void mark_dirty(struct LcdBuffer *self, uint8_t row, uint8_t col)
+//static void show_dirty_slots(const struct LcdBuffer *self) {
+//    printf("\n\n");
+//    for (int i = 0; i < LCDBUF_DIRTY_LIST_LEN; i++) {
+//        if (self->dirty_extents[i].count == 0) {
+//            continue;
+//        }
+//        printf("dirty_extent(%d): col %d, row %d, len %d\n", i, self->dirty_extents[i].row, self->dirty_extents[i].col, self->dirty_extents[i].count);
+//    }
+//    printf("\n");
+//}
+
+static void mark_dirty(struct LcdBuffer *self, lcdbuf_pos_t row, lcdbuf_pos_t col)
 {
+    // partial updates are not needed if everything will be written anyway
+    if (self->full_repaint_required) {
+        return;
+    }
+
     int first_empty_extent_slot = -1;
-    for (int i = 0; i < BUFLEN_DIRTY_LIST; i++) {
+    for (int i = 0; i < LCDBUF_DIRTY_LIST_LEN; i++) {
-        struct DirtyExtent *ext = &self->dirty_extents[i];
+        struct LcdBuf_DirtyExtent *ext = &self->dirty_extents[i];
         if (ext->count == 0) {
             // unused
             if (first_empty_extent_slot == -1) {
@@ -94,60 +129,63 @@ static void mark_dirty(struct LcdBuffer *self, uint8_t row, uint8_t col)
 
         // this is a filled extent
 
-        if (ext->col < col && ext->col + ext->count > col) {
+        if ((ext->col <= col) && (ext->col + ext->count > col)) {
             // already in this extent
+//            show_dirty_slots(self);
             return;
         }
 
-        if (col < ext->col && (ext->col - col) <= 5) {
+        if ((col < ext->col) && ((ext->col - col) <= LCDBUF_DIRTY_EXTEND)) {
-            ext->count += (ext->col - col);
+            ext->count += ext->col - col;
             ext->col = col;
+//            show_dirty_slots(self);
             return;
         }
 
-        if (col >= ext->col + ext->count && (col - ext->col + ext->count) <= 5) {
+        if ((col >= ext->col + ext->count) && ((col - (ext->col + ext->count)) <= LCDBUF_DIRTY_EXTEND)) {
-            ext->count += (col - ext->col + ext->count);
+            ext->count += col - (ext->col + ext->count) + 1;
+//            show_dirty_slots(self);
             return;
         }
     }
 
     if (first_empty_extent_slot == -1) {
+//        printf("Give up on dirty extents\n");
         self->full_repaint_required = true;
     } else {
+//        printf("New dirty extent: #%d\n", first_empty_extent_slot);
         self->dirty_extents[first_empty_extent_slot].col = col;
         self->dirty_extents[first_empty_extent_slot].row = row;
         self->dirty_extents[first_empty_extent_slot].count = 1;
     }
+
+//    show_dirty_slots(self);
 }
 
 /** Set one utf8 character at a position */
-void LcdBuffer_Set(struct LcdBuffer *self, uint8_t row, uint8_t col, struct Utf8Char ch)
+void LcdBuffer_Set(struct LcdBuffer *self, lcdbuf_pos_t row, lcdbuf_pos_t col, struct Utf8Char ch)
 {
+//    printf("set %d:%d\n", row, col);
     assert(self);
     assert(row < LINE_NUM);
     assert(col < LINE_LEN);
 
-    uint8_t oldchar = self->screen[row][col];
+    const uint8_t oldchar = self->screen[row][col];
 
-    if (oldchar >= 8 && oldchar == ch.uint) {
+    if (oldchar >= LCDBUF_CGRAM_CAPACITY && oldchar == ch.uint) {
         // No change
         return;
     }
 
-    // Fast path for standard ASCII
+    // Fast path for standard ASCII - assuming this extent of the table is always the same!
     if (ch.uint >= 32 && ch.uint < 126 && ch.uint != '\\') { // A00 has YEN in place of BACKSLASH
         // normal ASCII
-        if (oldchar < 8) {
-            // release refcount on the CGRAM cell
-            self->cgram[oldchar].refcount -= 1;
-        }
-
         self->screen[row][col] = ch.uint;
         goto done_dirty;
     }
 
     // Find if it's in CGROM
-    const struct cgrom_entry *rom = self->cgrom;
+    const struct LcdBuf_CGROM_Entry *rom = self->cgrom;
     for (;;) {
         if (rom->symbol.uint == 0) {
             // End of the lookup table
@@ -156,11 +194,6 @@ void LcdBuffer_Set(struct LcdBuffer *self, uint8_t row, uint8_t col, struct Utf8
 
         if (rom->symbol.uint == ch.uint) {
             // found it!
-            if (oldchar < 8) {
-                // release refcount on the CGRAM cell
-                self->cgram[oldchar].refcount -= 1;
-            }
-
             self->screen[row][col] = rom->address;
             goto done_dirty;
         }
@@ -170,37 +203,27 @@ void LcdBuffer_Set(struct LcdBuffer *self, uint8_t row, uint8_t col, struct Utf8
 
     // Check if the same custom char is already used - if so, increment refcount and reuse it
     int first_empty_custom_slot = -1;
-    for (int i = 0; i < 8; i++) {
+    for (uint8_t slot = 0; slot < LCDBUF_CGRAM_CAPACITY; slot++) {
-        if (self->cgram[i].refcount > 0) {
+        if (self->cgram[slot].refcount > 0) {
-            if (self->cgram[i].uint == ch.uint) {
+            if (self->cgram[slot].uint == ch.uint) {
-                if (oldchar == i) {
+                if (oldchar == slot) {
                     // No change, was already the same custom
                     return;
                 }
 
-                if (oldchar < 8) {
+                self->cgram[slot].refcount++;
-                    // release refcount on the CGRAM cell
+                self->screen[row][col] = slot;
-                    self->cgram[oldchar].refcount -= 1;
-                }
-
-                self->cgram[i].refcount += 1;
-                self->screen[row][col] = i;
                 goto done_dirty;
             }
         } else if (first_empty_custom_slot == -1) {
-            first_empty_custom_slot = i;
+            first_empty_custom_slot = slot;
         }
     }
 
     // New custom pattern is needed
 
-    if (oldchar < 8) {
+    uint16_t index = 0;
-        // release refcount on the CGRAM cell
+    const struct LcdBuf_CGRAM_Symbol *pattern = self->custom_symbols;
-        self->cgram[oldchar].refcount -= 1;
-    }
-
-    uint32_t index = 0;
-    const struct cgram_pattern *pattern = self->custom_symbols;
     for (;;) {
         if (pattern->symbol.uint == 0) {
             // End of the lookup table
@@ -212,8 +235,14 @@ void LcdBuffer_Set(struct LcdBuffer *self, uint8_t row, uint8_t col, struct Utf8
 
             if (first_empty_custom_slot == -1) {
                 // Whoops, out of slots. Show a fallback glyph
-                if (oldchar != pattern->fallback) {
+                if (pattern->fallback != 0) {
-                    self->screen[row][col] = pattern->fallback;
+                    if (oldchar != pattern->fallback) {
+                        self->screen[row][col] = pattern->fallback;
+                        goto done_dirty;
+                    }
+                } else {
+                    // TODO kick out some other CGRAM entry that has fallback?
+                    self->screen[row][col] = LCDBUF_SUBSTITUTION_CHAR;
                     goto done_dirty;
                 }
                 return;
@@ -234,14 +263,20 @@ void LcdBuffer_Set(struct LcdBuffer *self, uint8_t row, uint8_t col, struct Utf8
     }
 
     // Fallback, no way to show this glyph
-    self->screen[row][col] = '?';
+    self->screen[row][col] = LCDBUF_SUBSTITUTION_CHAR;
 
     done_dirty:
+
+    if (oldchar < LCDBUF_CGRAM_CAPACITY) {
+        // release refcount on the CGRAM cell
+        assert(self->cgram[oldchar].refcount > 0);
+        self->cgram[oldchar].refcount--;
+    }
     mark_dirty(self, row, col);
 }
 
 /** Write a UTF8 string at a position */
-void LcdBuffer_Write(struct LcdBuffer *self, uint8_t row, uint8_t col, char *utf_string)
+void LcdBuffer_Write(struct LcdBuffer *self, lcdbuf_pos_t row, lcdbuf_pos_t col, char *utf_string)
 {
     struct Utf8Iterator iter;
     Utf8Iterator_Init(&iter, utf_string);

src/lcdbuf.h

@@ -1,5 +1,5 @@
 /**
- * TODO file description
+ * HD44780 utf8-capable display buffer
  */
 
 #ifndef HD44780UTF_LCDBUF_H
@@ -10,28 +10,48 @@
 #include "cgram.h"
 #include "cgrom.h"
 
+// --- settings ---
+
 #define LINE_NUM 4
 #define LINE_LEN 20
 
-#define BUFLEN_DIRTY_LIST 8
+/// number of remembered dirty regions before giving up and just writing full display
+#define LCDBUF_DIRTY_LIST_LEN 8
+
+/// if a cell is marked dirty closer than this to an existing extent,
+/// the extent can grows in the direction rather than creating a new one
+#define LCDBUF_DIRTY_EXTEND 5
+
+/// Char shown if the requested symbol is missing in lookup tables
+#define LCDBUF_SUBSTITUTION_CHAR 0xDB // this is the katakana box (ro ロ?) in the codepage A00
+
+/// this must contain the full width or height
+typedef uint8_t lcdbuf_pos_t;
 
+/// this must contain the total number of cells in the display
+typedef uint8_t lcdbuf_count_t;
 _Static_assert(LINE_NUM * LINE_LEN < 256, "LINE_NUM * LINE_LEN must fit in u8");
 
+// ----------------
+
+/// Number of custom CGRAM slots (always 8)
+#define LCDBUF_CGRAM_CAPACITY 8
+
 /** Indicates a range of screen cells that were changed and must be written to HW */
-struct DirtyExtent {
+struct LcdBuf_DirtyExtent {
-  uint8_t row;
+  lcdbuf_pos_t row;
-  uint8_t col;
+  lcdbuf_pos_t col;
-  uint8_t count;
+  lcdbuf_count_t count;
 };
 
 /** Struct for one CGRAM slot */
-struct CgramState {
+struct LcdBuf_CgramState {
   /** UTF8 uint shown in this slot */
   uint32_t uint;
   /** Array index in the custom symbols table, use for look-up when writing the font data to HW */
-  uint32_t symbol_index;
+  uint16_t symbol_index;
   /** Number of occurrences of this symbol in the screen array */
-  uint8_t refcount;
+  lcdbuf_count_t refcount;
   /** This CGRAM slot needs to be written to HW */
   bool dirty;
 };
@@ -40,21 +60,21 @@ struct LcdBuffer {
   /** The raw screen buffer. Custom symbols are 0x00-0x07 */
   uint8_t screen[LINE_NUM][LINE_LEN];
   /** CGRAM state array */
-  struct CgramState cgram[8];
+  struct LcdBuf_CgramState cgram[LCDBUF_CGRAM_CAPACITY];
   /** Hardware CGROM lookup table, used to map UTF8 to existing ROM symbols */
-  const struct cgrom_entry *cgrom;
+  const struct LcdBuf_CGROM_Entry *cgrom;
   /** Defined custom display pattern of utf8 symbols */
-  const struct cgram_pattern *custom_symbols;
+  const struct LcdBuf_CGRAM_Symbol *custom_symbols;
 
   /** Array of dirty extents - ranges in the display that need to be flushed to HW */
-  struct DirtyExtent dirty_extents[BUFLEN_DIRTY_LIST];
+  struct LcdBuf_DirtyExtent dirty_extents[LCDBUF_DIRTY_LIST_LEN];
   /** If the dirty extents array was not sufficient to hold all changes, this flag is set,
    * indicating the dirty_extents array should be disregarded. */
   bool full_repaint_required;
 };
 
 /** Initialize the struct */
-void LcdBuffer_Init(struct LcdBuffer *self, const struct cgrom_entry *cgrom, const struct cgram_pattern *custom_symbols);
+void LcdBuffer_Init(struct LcdBuffer *self, const struct LcdBuf_CGROM_Entry *cgrom, const struct LcdBuf_CGRAM_Symbol *custom_symbols);
 
 /** Clear the screen */
 void LcdBuffer_Clear(struct LcdBuffer *self);
@@ -66,15 +86,18 @@ void LcdBuffer_Flush(struct LcdBuffer *self);
 void LcdBuffer_FlushAll(struct LcdBuffer *self);
 
 /** Set one utf8 character at a position */
-void LcdBuffer_Set(struct LcdBuffer *self, uint8_t row, uint8_t col, struct Utf8Char ch);
+void LcdBuffer_Set(struct LcdBuffer *self, lcdbuf_pos_t row, lcdbuf_pos_t col, struct Utf8Char ch);
 
 /** Write a UTF8 string at a position */
-void LcdBuffer_Write(struct LcdBuffer *self, uint8_t row, uint8_t col, char *utf_string);
+void LcdBuffer_Write(struct LcdBuffer *self, lcdbuf_pos_t row, lcdbuf_pos_t col, char *utf_string);
 
 /* Callbacks - need to be implemented by the application! */
 
+/** Clear the entire screen (CGRAM can be left unchanged, but they will be written anew if needed) */
+void LcdBuffer_IO_Clear();
+
 /** Write character data at position */
-void LcdBuffer_IO_WriteAt(uint8_t row, uint8_t col, const uint8_t *buf, uint8_t len);
+void LcdBuffer_IO_WriteAt(lcdbuf_pos_t row, lcdbuf_pos_t col, const uint8_t *buf, lcdbuf_count_t len);
 
 /** Write CGRAM data. Data is always 8 bytes long. */
 void LcdBuffer_IO_WriteCGRAM(uint8_t position, const uint8_t* data);

src/main.c

@@ -7,22 +7,75 @@ int main()
     struct LcdBuffer buf;
     LcdBuffer_Init(&buf, CGROM_A00, CGRAM_CZ);
 
-    LcdBuffer_Write(&buf, 0, 0, "Ahoj");
+    LcdBuffer_Write(&buf, 2, 10, "Ahoj");
+    LcdBuffer_Write(&buf, 2, 9, "x");
+    LcdBuffer_Write(&buf, 2, 6, "mm");
+    LcdBuffer_Write(&buf, 0, 0, "ěščžýíéů");
+    LcdBuffer_Write(&buf, 0, 0, "MEOWžýíéůěščřžýíéů");
 
     LcdBuffer_Flush(&buf);
 
+    LcdBuffer_Write(&buf, 0, 5, "ĚŠČŘŽÝ");
+
+    LcdBuffer_Flush(&buf);
+
+    LcdBuffer_Clear(&buf);
+    LcdBuffer_Flush(&buf);
+
     return 0;
 }
 
 /** Write character data at position */
-void LcdBuffer_IO_WriteAt(uint8_t row, uint8_t col, const uint8_t *buf, uint8_t len)
+void LcdBuffer_IO_Clear()
 {
-    printf("W@%d,%d: \"%.*s\" (len %d)\n", row, col, len, buf, len);
+    printf("ClearScreen\n");
 }
 
+/** Write character data at position */
+void LcdBuffer_IO_WriteAt(lcdbuf_pos_t row, lcdbuf_pos_t col, const uint8_t *buf, lcdbuf_count_t len)
+{
+    printf("W@%d,%d: (len %d) \"", row, col, len); // "\n
+    for(int i=0; i<len; i++) {
+        char c = buf[i];
+        if (c >= 32 && c < 127) {
+            printf("%c", c);
+        } else {
+            printf("\\%d", c);
+        }
+    }
+    printf("\"\n");
+}
+
+#define BYTE_TO_BINARY_PATTERN "%c%c%c%c%c%c%c%c"
+#define BYTE_TO_BINARY(byte)  \
+  ((byte) & 0x80 ? '#' : '.'), \
+  ((byte) & 0x40 ? '#' : '.'), \
+  ((byte) & 0x20 ? '#' : '.'), \
+  ((byte) & 0x10 ? '#' : '.'), \
+  ((byte) & 0x08 ? '#' : '.'), \
+  ((byte) & 0x04 ? '#' : '.'), \
+  ((byte) & 0x02 ? '#' : '.'), \
+  ((byte) & 0x01 ? '#' : '.')
+
 /** Write CGRAM data. Data is always 8 bytes long. */
-void LcdBuffer_IO_WriteCGRAM(uint8_t position, const uint8_t *data)
+void LcdBuffer_IO_WriteCGRAM(lcdbuf_pos_t position, const uint8_t *data)
 {
-    printf("G@%d: %02x %02x %02x %02x %02x %02x %02x %02x\n",
+    printf("G@%d:\n "
-           position, data[0], data[1], data[2], data[3], data[4], data[5], data[6], data[7]);
+        BYTE_TO_BINARY_PATTERN"\n "
+        BYTE_TO_BINARY_PATTERN"\n "
+        BYTE_TO_BINARY_PATTERN"\n "
+        BYTE_TO_BINARY_PATTERN"\n "
+        BYTE_TO_BINARY_PATTERN"\n "
+        BYTE_TO_BINARY_PATTERN"\n "
+        BYTE_TO_BINARY_PATTERN"\n "
+        BYTE_TO_BINARY_PATTERN"\n\n",
+           position,
+           BYTE_TO_BINARY(data[0]),
+           BYTE_TO_BINARY(data[1]),
+           BYTE_TO_BINARY(data[2]),
+           BYTE_TO_BINARY(data[3]),
+           BYTE_TO_BINARY(data[4]),
+           BYTE_TO_BINARY(data[5]),
+           BYTE_TO_BINARY(data[6]),
+           BYTE_TO_BINARY(data[7]));
 }