diff options
| -rw-r--r-- | buffer.c | 105 | ||||
| -rw-r--r-- | main.c | 6 | ||||
| -rw-r--r-- | unicode.h | 7 |
3 files changed, 109 insertions, 9 deletions
@@ -18,13 +18,13 @@ #define TEXT_BLOCK_DEFAULT_SIZE (3*(TEXT_BLOCK_MAX_SIZE / 4)) typedef struct { u16 len; - char *contents; + u8 *contents; } TextBlock; // a position in the buffer typedef struct { u32 block; - u32 idx; + u32 index; } BufferPos; typedef struct { @@ -42,7 +42,7 @@ typedef struct { static TextBlock *buffer_add_block(TextBuffer *buffer, u32 where) { // make sure we can actually allocate enough memory for the contents of the block // before doing anything - char *block_contents = calloc(1, TEXT_BLOCK_MAX_SIZE); + u8 *block_contents = calloc(1, TEXT_BLOCK_MAX_SIZE); if (!block_contents) { return NULL; } @@ -167,7 +167,7 @@ static void buffer_text_dimensions(TextBuffer *buffer, u64 *lines, u64 *cols) { u64 col = 0; for (u32 i = 0; i < buffer->nblocks; ++i) { TextBlock *block = &buffer->blocks[i]; - for (char *p = block->contents, *end = p + block->len; p != end; ++p) { + for (u8 *p = block->contents, *end = p + block->len; p != end; ++p) { buffer_update_line_col(buffer, &line, &col, *p); if (col > maxcol) maxcol = col; @@ -219,7 +219,20 @@ void buffer_scroll(TextBuffer *buffer, double dx, double dy) { // returns the line and column of the given buffer position. // line/col can be NULL. void buffer_pos_to_line_col(TextBuffer *buffer, BufferPos pos, u64 *line, u64 *col) { - // @TODO + TextBlock *pos_block = buffer->blocks + pos.block; + assert(pos.index < pos_block->len); + u8 *pos_byte = pos_block->contents + pos.index; + u64 l = 1, c = 0; + for (TextBlock *block = buffer->blocks; block <= pos_block; ++block) { + for (u8 *p = block->contents, *end = p + block->len; p != end; ++p) { + if (p == pos_byte) { + if (line) *line = l; + if (col) *col = c; + return; + } + buffer_update_line_col(buffer, &l, &c, *p); + } + } } // returns the position of the character at the given position in the buffer. @@ -227,8 +240,22 @@ void buffer_pos_to_line_col(TextBuffer *buffer, BufferPos pos, u64 *line, u64 *c void buffer_pos_to_pixels(TextBuffer *buffer, BufferPos pos, float *x, float *y) { u64 line, col; buffer_pos_to_line_col(buffer, pos, &line, &col); - if (x) *x = ((double)col - buffer->scroll_x) * font_char_width(buffer->font); - if (y) *y = ((double)line - buffer->scroll_y) * font_char_height(buffer->font); + if (x) *x = (float)((double)col - buffer->scroll_x) * text_font_char_width(buffer->font) + buffer->x1; + if (y) *y = (float)((double)(line-1) - buffer->scroll_y) * text_font_char_height(buffer->font) + buffer->y1; +} + + +// clip the rectangle so it's all inside the buffer. returns true if there's any rectangle left. +static bool buffer_clip_rect(TextBuffer *buffer, float *x1, float *y1, float *x2, float *y2) { + if (*x1 > buffer->x2 || *y1 > buffer->y2 || *x2 < buffer->x1 || *y2 < buffer->y1) { + *x1 = *y1 = *x2 = *y2 = 0; + return false; + } + if (*x1 < buffer->x1) *x1 = buffer->x1; + if (*y1 < buffer->y1) *y1 = buffer->y1; + if (*x2 > buffer->x2) *x2 = buffer->x2; + if (*y2 > buffer->y2) *y2 = buffer->y2; + return true; } // Render the text buffer in the given rectangle @@ -269,10 +296,14 @@ void buffer_render(TextBuffer *buffer, float x1, float y1, float x2, float y2) { for (u32 block_idx = 0; block_idx < nblocks; ++block_idx) { TextBlock *block = &blocks[block_idx]; - char *p = block->contents, *end = p + block->len; + { + float v = 0.7f + 0.3f * (float)(block_idx % 2); + glColor3f(v, v, 1); + } + u8 *p = block->contents, *end = p + block->len; while (p != end) { char32_t c; - size_t n = mbrtoc32(&c, p, (size_t)(end - p), &mbstate); + size_t n = mbrtoc32(&c, (char *)p, (size_t)(end - p), &mbstate); if (n == 0) { // null character c = UNICODE_BOX_CHARACTER; @@ -311,4 +342,60 @@ void buffer_render(TextBuffer *buffer, float x1, float y1, float x2, float y2) { } } text_chars_end(font); + + { // render cursor + float cur_x1, cur_y1; + buffer_pos_to_pixels(buffer, buffer->cursor_pos, &cur_x1, &cur_y1); + cur_y1 += 0.25f * char_height; + float cur_x2 = cur_x1 + 1.0f, cur_y2 = cur_y1 + char_height; + if (buffer_clip_rect(buffer, &cur_x1, &cur_y1, &cur_x2, &cur_y2)) { + glColor3f(0,1,1); + glBegin(GL_QUADS); + glVertex2f(cur_x1,cur_y1); + glVertex2f(cur_x2,cur_y1); + glVertex2f(cur_x2,cur_y2); + glVertex2f(cur_x1,cur_y2); + glEnd(); + } + } +} + +static u8 buffer_byte_at_pos(TextBuffer *buffer, BufferPos p) { + return buffer->blocks[p.block].contents[p.index]; +} + +// returns true if p could move left (i.e. if it's not the very first position in the file) +static bool buffer_pos_move_left(TextBuffer *buffer, BufferPos *p) { + do { + if (p->index == 0) { + if (p->block == 0) + return false; + --p->block; + } else { + --p->index; + } + } while (!unicode_is_start_of_code_point(buffer_byte_at_pos(buffer, *p))); + return true; +} + +static bool buffer_pos_move_right(TextBuffer *buffer, BufferPos *p) { + do { + TextBlock *block = buffer->blocks + p->block; + if (p->index >= block->len-1) { + if (p->block >= buffer->nblocks-1) + return false; + ++p->block; + } else { + ++p->index; + } + } while (!unicode_is_start_of_code_point(buffer_byte_at_pos(buffer, *p))); + return true; +} + +bool buffer_cursor_move_left(TextBuffer *buffer) { + return buffer_pos_move_left(buffer, &buffer->cursor_pos); +} + +bool buffer_cursor_move_right(TextBuffer *buffer) { + return buffer_pos_move_right(buffer, &buffer->cursor_pos); } @@ -104,6 +104,12 @@ int main(void) { case SDLK_PAGEDOWN: buffer_scroll(&text_buffer, 0, +buffer_display_rows(&text_buffer)); break; + case SDLK_RIGHT: + buffer_cursor_move_right(&text_buffer); + break; + case SDLK_LEFT: + buffer_cursor_move_left(&text_buffer); + break; } } break; } @@ -2,4 +2,11 @@ #define UNICODE_H_ #define UNICODE_BOX_CHARACTER 0x2610 #define UNICODE_CODE_POINTS 0x110000 // number of Unicode code points + +static bool unicode_is_start_of_code_point(u8 byte) { + // see https://en.wikipedia.org/wiki/UTF-8#Encoding + // continuation bytes are of the form 10xxxxxx + return (byte & 0xC0) != 0x80; +} + #endif |