From b006db3fe4da1beb38909232ceaf1c370415c61a Mon Sep 17 00:00:00 2001 From: Leo Tenenbaum Date: Fri, 4 Dec 2020 12:51:35 -0500 Subject: fix arrow keys with tabs --- buffer.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++-------------- main.c | 6 ++++ 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; } -- cgit v1.2.3