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-rw-r--r--buffer.c109
-rw-r--r--main.c6
2 files changed, 92 insertions, 23 deletions
diff --git a/buffer.c b/buffer.c
index 3c2dbe1..c0213ea 100644
--- a/buffer.c
+++ b/buffer.c
@@ -6,7 +6,7 @@
// a position in the buffer
typedef struct {
u32 line;
- u32 col;
+ u32 index; // index of character in line (not the same as column, since a tab is buffer->tab_size columns)
} BufferPos;
typedef struct {
@@ -146,23 +146,65 @@ void buffer_free(TextBuffer *buffer) {
buffer->lines = NULL;
}
+static u32 buffer_index_to_column(TextBuffer *buffer, u32 line, u32 index) {
+ char32_t *str = buffer->lines[line].str;
+ u32 col = 0;
+ for (u32 i = 0; i < index; ++i) {
+ switch (str[i]) {
+ case U'\t':
+ do
+ ++col;
+ while (col % buffer->tab_width);
+ break;
+ default:
+ ++col;
+ break;
+ }
+ }
+ return col;
+}
+
+static u32 buffer_column_to_index(TextBuffer *buffer, u32 line, u32 column) {
+ char32_t *str = buffer->lines[line].str;
+ u32 len = buffer->lines[line].len;
+ u32 col = 0;
+ for (u32 i = 0; i < len; ++i) {
+ switch (str[i]) {
+ case U'\t':
+ do {
+ if (col == column)
+ return i;
+ ++col;
+ } while (col % buffer->tab_width);
+ break;
+ default:
+ if (col == column)
+ return i;
+ ++col;
+ break;
+ }
+ }
+ return len;
+}
+
// returns the number of lines of text in the buffer into *lines (if not NULL),
-// and the number of columns of text, i.e. the length of the longest line, into *cols (if not NULL)
-void buffer_text_dimensions(TextBuffer *buffer, u32 *lines, u32 *cols) {
+// and the number of columns of text, i.e. the number of columns in the longest line, into *cols (if not NULL)
+void buffer_text_dimensions(TextBuffer *buffer, u32 *lines, u32 *columns) {
if (lines) {
*lines = buffer->nlines;
}
- if (cols) {
+ if (columns) {
// @OPTIMIZE
u32 nlines = buffer->nlines;
Line *line_arr = buffer->lines;
u32 maxcol = 0;
for (u32 i = 0; i < nlines; ++i) {
Line *line = &line_arr[i];
- if (line->len > maxcol)
- maxcol = line->len;
+ u32 cols = buffer_index_to_column(buffer, i, line->len);
+ if (cols > maxcol)
+ maxcol = cols;
}
- *cols = maxcol;
+ *columns = maxcol;
}
}
@@ -209,7 +251,9 @@ void buffer_scroll(TextBuffer *buffer, double dx, double dy) {
// returns the position of the character at the given position in the buffer.
// x/y can be NULL.
void buffer_pos_to_pixels(TextBuffer *buffer, BufferPos pos, float *x, float *y) {
- u32 line = pos.line, col = pos.col;
+ u32 line = pos.line, index = pos.index;
+ u32 col = buffer_index_to_column(buffer, line, index);
+ // we need to convert the index to a column
if (x) *x = (float)((double)col - buffer->scroll_x) * text_font_char_width(buffer->font) + buffer->x1;
if (y) *y = (float)((double)line - buffer->scroll_y) * text_font_char_height(buffer->font) + buffer->y1;
}
@@ -315,9 +359,9 @@ char32_t buffer_char_at_pos(TextBuffer *buffer, BufferPos p) {
return 0; // invalid (line too large)
Line *line = &buffer->lines[p.line];
- if (p.col < line->len) {
- return line->str[p.col];
- } else if (p.col > line->len) {
+ if (p.index < line->len) {
+ return line->str[p.index];
+ } else if (p.index > line->len) {
// invalid (col too large)
return 0;
} else {
@@ -327,42 +371,45 @@ char32_t buffer_char_at_pos(TextBuffer *buffer, BufferPos p) {
BufferPos buffer_start_pos(TextBuffer *buffer) {
(void)buffer;
- return (BufferPos){.line = 0, .col = 0};
+ return (BufferPos){.line = 0, .index = 0};
}
BufferPos buffer_end_pos(TextBuffer *buffer) {
- return (BufferPos){.line = buffer->nlines - 1, .col = buffer->lines[buffer->nlines-1].len};
+ return (BufferPos){.line = buffer->nlines - 1, .index = buffer->lines[buffer->nlines-1].len};
}
// returns true if p could move left (i.e. if it's not the very first position in the file)
bool buffer_pos_move_left(TextBuffer *buffer, BufferPos *p) {
if (p->line >= buffer->nlines)
- *p = buffer_end_pos(buffer);
- if (p->col == 0) {
+ *p = buffer_end_pos(buffer); // invalid position; move to end of buffer
+ if (p->index == 0) {
+ // first column; move to previous line
if (p->line == 0)
return false;
--p->line;
- p->col = buffer->lines[p->line].len;
+ p->index = buffer->lines[p->line].len;
} else {
- --p->col;
+ --p->index;
}
return true;
}
bool buffer_pos_move_right(TextBuffer *buffer, BufferPos *p) {
if (p->line >= buffer->nlines)
- *p = buffer_end_pos(buffer);
+ *p = buffer_end_pos(buffer); // invalid position; move to end of buffer
Line *line = &buffer->lines[p->line];
- if (p->col >= line->len) {
+ if (p->index >= line->len) {
+ // last column; move to next line
if (p->line >= buffer->nlines - 1) {
+ // last line
*p = buffer_end_pos(buffer);
return false;
} else {
- p->col = 0;
+ p->index = 0;
++p->line;
}
} else {
- ++p->col;
+ ++p->index;
}
return true;
}
@@ -371,18 +418,27 @@ bool buffer_pos_move_up(TextBuffer *buffer, BufferPos *pos) {
(void)buffer;
if (pos->line == 0)
return false;
+ // moving up/down should preserve the column, not the index.
+ // consider:
+ // tab|hello world
+ // tab|tab|more text
+ // the character above the 'm' is the 'o', not the 'e'
+ u32 column = buffer_index_to_column(buffer, pos->line, pos->index);
--pos->line;
+ pos->index = buffer_column_to_index(buffer, pos->line, column);
u32 line_len = buffer->lines[pos->line].len;
- if (pos->col >= line_len) pos->col = line_len;
+ if (pos->index >= line_len) pos->index = line_len;
return true;
}
bool buffer_pos_move_down(TextBuffer *buffer, BufferPos *pos) {
if (pos->line >= buffer->nlines-1)
return false;
+ u32 column = buffer_index_to_column(buffer, pos->line, pos->index);
++pos->line;
+ pos->index = buffer_column_to_index(buffer, pos->line, column);
u32 line_len = buffer->lines[pos->line].len;
- if (pos->col >= line_len) pos->col = line_len;
+ if (pos->index >= line_len) pos->index = line_len;
return true;
}
@@ -394,3 +450,10 @@ bool buffer_cursor_move_right(TextBuffer *buffer) {
return buffer_pos_move_right(buffer, &buffer->cursor_pos);
}
+bool buffer_cursor_move_up(TextBuffer *buffer) {
+ return buffer_pos_move_up(buffer, &buffer->cursor_pos);
+}
+
+bool buffer_cursor_move_down(TextBuffer *buffer) {
+ return buffer_pos_move_down(buffer, &buffer->cursor_pos);
+}
diff --git a/main.c b/main.c
index 9351436..ac5fcc4 100644
--- a/main.c
+++ b/main.c
@@ -110,6 +110,12 @@ int main(void) {
case SDLK_LEFT:
buffer_cursor_move_left(&text_buffer);
break;
+ case SDLK_UP:
+ buffer_cursor_move_up(&text_buffer);
+ break;
+ case SDLK_DOWN:
+ buffer_cursor_move_down(&text_buffer);
+ break;
}
} break;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-26 22:06:48 +0000