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Merged
jledet merged 1 commit into from
Jul 12, 2025
Merged

slash: keep track of changed bytes in buffer for refresh #15

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6 changes: 4 additions & 2 deletions include/slash/slash.h
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Original file line number Diff line number Diff line change
Expand Up @@ -272,8 +272,9 @@ struct slash_command {
* @cursor_screen: Current index of cursor in line buffer on screen.
* @length: Current amount of used bytes in line buffer.
* @length_screen: Current amount of used bytes in line buffer on screen.
* @change_start: Index of first byte in line buffer that needs screen refresh.
* @change_end: Index of first byte in line buffer that does not need screen refresh.
* @refresh_full: Force a full screen refresh including prompt.
* @refresh_buffer: Force a screen refresh of buffer.
* @last_char: Last input character.
* @history_size: Size in byte of the history buffer.
* @history_depth: Number of history entries browsed back.
Expand Down Expand Up @@ -314,8 +315,9 @@ struct slash {
size_t cursor_screen;
size_t length;
size_t length_screen;
size_t change_start;
size_t change_end;
bool refresh_full;
bool refresh_buffer;
char last_char;

/* History */
Expand Down
166 changes: 107 additions & 59 deletions src/slash.c
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Original file line number Diff line number Diff line change
Expand Up @@ -198,6 +198,19 @@ static int slash_getchar(struct slash *slash)
return c;
}

static void slash_mark_changed(struct slash *slash, size_t start, size_t end)
{
if (slash->change_start == slash->change_end) {
slash->change_start = start;
slash->change_end = end;
} else {
if (start < slash->change_start)
slash->change_start = start;
if (end > slash->change_end)
slash->change_end = end;
}
}

#ifdef SLASH_HAVE_SELECT
static int slash_wait_select(struct slash *slash, unsigned int ms)
{
Expand Down Expand Up @@ -622,7 +635,9 @@ static void slash_set_completion(struct slash *slash,
complete[len] = '\0';
if (space)
strncat(complete, " ", slash->line_size - 1);
slash->cursor = slash->length = strlen(slash->buffer);
slash->length = strlen(slash->buffer);
slash_mark_changed(slash, slash->cursor, slash->length);
slash->cursor = slash->length;
}

static bool slash_complete_matches(struct slash *slash,
Expand Down Expand Up @@ -875,7 +890,7 @@ static bool slash_history_next(struct slash *slash)
slash->buffer[srclen] = '\0';
slash->history_cursor = src;
slash->cursor = slash->length = srclen;
slash->refresh_buffer = true;
slash_mark_changed(slash, 0, slash->length);

/* Rewind if use to store buffer temporarily */
if (!slash->history_depth && slash->history_cursor != slash->history_tail)
Expand Down Expand Up @@ -905,28 +920,64 @@ static bool slash_history_previous(struct slash *slash)
slash->buffer[srclen] = '\0';
slash->history_cursor = src;
slash->cursor = slash->length = srclen;
slash->refresh_buffer = true;
slash_mark_changed(slash, 0, slash->length);

return true;
}

/* Line editing */
static int slash_cursor_back(struct slash *slash, size_t n)
static int slash_screen_cursor_back(struct slash *slash, size_t n)
{
/* If we need to move more than 3 colums, CUB uses fewer bytes */
if (n > 3) {
slash_printf(slash, ESCAPE("%zuD"), n);
slash->cursor_screen -= n;
} else {
while (n--)
while (n--) {
slash_putchar(slash, '\b');
slash->cursor_screen--;
}
}

return 0;
}

static int slash_screen_cursor_forward(struct slash *slash, size_t n)
{
/* If we need to move more than 3 colums, CUF uses fewer bytes */
if (n > 3) {
slash_printf(slash, ESCAPE("%zuC"), n);
slash->cursor_screen += n;
} else {
while (n--) {
slash_putchar(slash, slash->buffer[slash->cursor_screen]);
slash->cursor_screen++;
}
}

return 0;
}

static int slash_screen_cursor_to_column(struct slash *slash, size_t col)
{
size_t diff;

if (col > slash->cursor_screen) {
diff = col - slash->cursor_screen;
return slash_screen_cursor_forward(slash, diff);
} else if (col < slash->cursor_screen) {
diff = slash->cursor_screen - col;
return slash_screen_cursor_back(slash, diff);
}

return 0;
}

int slash_refresh(struct slash *slash)
{
const char *esc = ESCAPE("K");

/* Full refresh with prompt */
if (slash->refresh_full) {
slash_putchar(slash, '\r');
if (slash_write(slash, esc, strlen(esc)) < 0)
Expand All @@ -935,61 +986,64 @@ int slash_refresh(struct slash *slash)
return -1;
slash->cursor_screen = 0;
slash->length_screen = 0;
slash->change_start = 0;
slash->change_end = slash->length;
slash->refresh_full = false;
}

if (slash->refresh_buffer) {
slash_cursor_back(slash, slash->cursor_screen);
slash->cursor_screen = 0;
slash->refresh_buffer = false;
}

while (slash->cursor_screen < slash->cursor) {
slash_putchar(slash, slash->buffer[slash->cursor_screen]);
slash->cursor_screen++;
}

if (slash->cursor_screen > slash->cursor) {
slash_cursor_back(slash,
slash->cursor_screen - slash->cursor);
slash->cursor_screen = slash->cursor;
}

if (slash->length_screen != slash->length) {
/* Buffer contents have changed */
if (slash->change_start != slash->change_end) {
if (slash_screen_cursor_to_column(slash, slash->change_start) < 0)
return -1;
if (slash_write(slash,
&slash->buffer[slash->cursor],
slash->length - slash->cursor) < 0)
&slash->buffer[slash->change_start],
slash->change_end - slash->change_start) < 0)
return -1;
slash->cursor_screen = slash->length;

if (slash->length_screen > slash->length) {
if (slash_write(slash, esc, strlen(esc)) < 0)
return -1;
}

if (slash->cursor_screen > slash->cursor) {
slash_cursor_back(slash,
slash->cursor_screen - slash->cursor);
slash->cursor_screen = slash->cursor;
}
slash->cursor_screen = slash->change_end;
slash->change_start = slash->change_end = 0;
}

slash->length_screen = slash->length;
/* If screen contents were truncated, erase remainder */
if (slash->length_screen > slash->length) {
if (slash_screen_cursor_to_column(slash, slash->length) < 0)
return -1;
if (slash_write(slash, esc, strlen(esc)) < 0)
return -1;
}
slash->length_screen = slash->length;

/* Restore screen cursor position */
if (slash_screen_cursor_to_column(slash, slash->cursor) < 0)
return -1;

return slash_write_flush(slash);
}

static void slash_insert(struct slash *slash, int c)
{
if (slash->length + 1 > slash->line_size)
if (slash->length >= slash->line_size)
return;

memmove(&slash->buffer[slash->cursor + 1],
&slash->buffer[slash->cursor],
slash->length - slash->cursor);
slash->buffer[slash->cursor] = c;
slash->cursor++;
slash->length++;
slash_mark_changed(slash, slash->cursor, slash->length);
slash->cursor++;
slash->buffer[slash->length] = '\0';
}

static void slash_delete(struct slash *slash)
{
if (slash->cursor >= slash->length)
return;

slash->length--;
memmove(&slash->buffer[slash->cursor],
&slash->buffer[slash->cursor + 1],
slash->length - slash->cursor);
slash_mark_changed(slash, slash->cursor, slash->length);
slash->buffer[slash->length] = '\0';
}

Expand All @@ -998,6 +1052,8 @@ void slash_reset(struct slash *slash)
slash->buffer[0] = '\0';
slash->length = 0;
slash->cursor = 0;
slash->change_start = 0;
slash->change_end = 0;
slash->refresh_full = true;
}

Expand Down Expand Up @@ -1025,17 +1081,6 @@ static void slash_arrow_left(struct slash *slash)
slash->cursor--;
}

static void slash_delete(struct slash *slash)
{
if (slash->cursor < slash->length) {
slash->length--;
memmove(&slash->buffer[slash->cursor],
&slash->buffer[slash->cursor + 1],
slash->length - slash->cursor);
slash->buffer[slash->length] = '\0';
}
}

void slash_clear_screen(struct slash *slash)
{
const char *esc = ESCAPE("H") ESCAPE("2J");
Expand All @@ -1045,14 +1090,16 @@ void slash_clear_screen(struct slash *slash)

static void slash_backspace(struct slash *slash)
{
if (slash->cursor > 0) {
slash->cursor--;
slash->length--;
memmove(&slash->buffer[slash->cursor],
&slash->buffer[slash->cursor + 1],
slash->length - slash->cursor);
slash->buffer[slash->length] = '\0';
}
if (slash->cursor == 0)
return;

slash->cursor--;
slash->length--;
memmove(&slash->buffer[slash->cursor],
&slash->buffer[slash->cursor + 1],
slash->length - slash->cursor);
slash_mark_changed(slash, slash->cursor, slash->length);
slash->buffer[slash->length] = '\0';
}

static void slash_delete_word(struct slash *slash)
Expand All @@ -1068,6 +1115,7 @@ static void slash_delete_word(struct slash *slash)
memmove(&slash->buffer[slash->cursor],
&slash->buffer[old_cursor],
slash->length - slash->cursor);
slash_mark_changed(slash, slash->cursor, slash->length);
slash->buffer[slash->length] = '\0';
}

Expand Down