/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright (C) 2014 David Herrmann systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see . ***/ /* * Terminal Page/Line/Cell/Char Handling * This file implements page handling of a terminal. It is split into pages, * lines, cells and characters. Each object is independent of the next upper * object. * * The Terminal layer keeps each line of a terminal separate and dynamically * allocated. This allows us to move lines from main-screen to history-buffers * very fast. Same is true for scrolling, top/bottom borders and other buffer * operations. * * While lines are dynamically allocated, cells are not. This would be a waste * of memory and causes heavy fragmentation. Furthermore, cells are moved much * less frequently than lines so the performance-penalty is pretty small. * However, to support combining-characters, we have to initialize and cleanup * cells properly and cannot just release the underlying memory. Therefore, * cells are treated as proper objects despite being allocated in arrays. * * Each cell has a set of attributes and a stored character. This is usually a * single Unicode character stored as 32bit UCS-4 char. However, we need to * support Unicode combining-characters, therefore this gets more complicated. * Characters themselves are represented by a "term_char_t" object. It * should be treated as a normal integer and passed by value. The * sorrounding struct is just to hide the internals. A term-char can contain a * base character together with up to 2 combining-chars in a single integer. * Only if you need more combining-chars (very unlikely!) a term-char is a * pointer to an allocated storage. This requires you to always free term-char * objects once no longer used (even though this is a no-op most of the time). * Furthermore, term-char objects are not ref-counted so you must duplicate them * in case you want to store it somewhere and retain a copy yourself. By * convention, all functions that take a term-char object will not duplicate * it but implicitly take ownership of the passed value. It's up to the caller * to duplicate it beforehand, in case it wants to retain a copy. * * If it turns out, that more than 2 comb-chars become common in specific * languages, we can try to optimize this. One idea is to ref-count allocated * characters and store them in a hash-table (like gnome's libvte3 does). This * way we will never have two allocated chars for the same content. Or we can * simply put two uint64_t into a "term_char_t". This will slow down operations * on systems that don't need that many comb-chars, but avoid the dynamic * allocations on others. * Anyhow, until we have proper benchmarks, we will keep the current code. It * seems to compete very well with other solutions so far. */ #include #include #include #include #include "macro.h" #include "term-internal.h" #include "util.h" /* maximum UCS-4 character */ #define CHAR_UCS4_MAX (0x10ffff) /* mask for valid UCS-4 characters (21bit) */ #define CHAR_UCS4_MASK (0x1fffff) /* UCS-4 replacement character */ #define CHAR_UCS4_REPLACEMENT (0xfffd) /* real storage behind "term_char_t" in case it's not packed */ typedef struct term_character { uint8_t n; uint32_t codepoints[]; } term_character; /* * char_pack() takes 3 UCS-4 values and packs them into a term_char_t object. * Note that UCS-4 chars only take 21 bits, so we still have the LSB as marker. * We set it to 1 so others can distinguish it from pointers. */ static inline term_char_t char_pack(uint32_t v1, uint32_t v2, uint32_t v3) { uint64_t packed, u1, u2, u3; u1 = v1; u2 = v2; u3 = v3; packed = 0x01; packed |= (u1 & (uint64_t)CHAR_UCS4_MASK) << 43; packed |= (u2 & (uint64_t)CHAR_UCS4_MASK) << 22; packed |= (u3 & (uint64_t)CHAR_UCS4_MASK) << 1; return TERM_CHAR_INIT(packed); } #define char_pack1(_v1) char_pack2((_v1), CHAR_UCS4_MAX + 1) #define char_pack2(_v1, _v2) char_pack3((_v1), (_v2), CHAR_UCS4_MAX + 1) #define char_pack3(_v1, _v2, _v3) char_pack((_v1), (_v2), (_v3)) /* * char_unpack() is the inverse of char_pack(). It extracts the 3 stored UCS-4 * characters and returns them. Note that this does not validate the passed * term_char_t. That's the responsibility of the caller. * This returns the number of characters actually packed. This obviously is a * number between 0 and 3 (inclusive). */ static inline uint8_t char_unpack(term_char_t packed, uint32_t *out_v1, uint32_t *out_v2, uint32_t *out_v3) { uint32_t v1, v2, v3; v1 = (packed._value >> 43) & (uint64_t)CHAR_UCS4_MASK; v2 = (packed._value >> 22) & (uint64_t)CHAR_UCS4_MASK; v3 = (packed._value >> 1) & (uint64_t)CHAR_UCS4_MASK; if (out_v1) *out_v1 = v1; if (out_v2) *out_v2 = v2; if (out_v3) *out_v3 = v3; return (v1 > CHAR_UCS4_MAX) ? 0 : ((v2 > CHAR_UCS4_MAX) ? 1 : ((v3 > CHAR_UCS4_MAX) ? 2 : 3)); } /* cast a term_char_t to a term_character* */ static inline term_character *char_to_ptr(term_char_t ch) { return (term_character*)(unsigned long)ch._value; } /* cast a term_character* to a term_char_t */ static inline term_char_t char_from_ptr(term_character *c) { return TERM_CHAR_INIT((unsigned long)c); } /* * char_alloc() allocates a properly aligned term_character object and returns * a pointer to it. NULL is returned on allocation errors. The object will have * enough room for @n following UCS-4 chars. * Note that we allocate (n+1) characters and set the last one to 0 in case * anyone prints this string for debugging. */ static term_character *char_alloc(uint8_t n) { term_character *c; int r; r = posix_memalign((void**)&c, MAX(sizeof(void*), (size_t)2), sizeof(*c) + sizeof(*c->codepoints) * (n + 1)); if (r) return NULL; c->n = n; c->codepoints[n] = 0; return c; } /* * char_free() frees the memory allocated via char_alloc(). It is safe to call * this on any term_char_t, only allocated characters are freed. */ static inline void char_free(term_char_t ch) { if (term_char_is_allocated(ch)) free(char_to_ptr(ch)); } /* * This appends @append_ucs4 to the existing character @base and returns * it as a new character. In case that's not possible, @base is returned. The * caller can use term_char_same() to test whether the returned character was * freshly allocated or not. */ static term_char_t char_build(term_char_t base, uint32_t append_ucs4) { /* soft-limit for combining-chars; hard-limit is currently 255 */ const size_t climit = 64; term_character *c; uint32_t buf[3], *t; uint8_t n; /* ignore invalid UCS-4 */ if (append_ucs4 > CHAR_UCS4_MAX) return base; if (term_char_is_null(base)) { return char_pack1(append_ucs4); } else if (!term_char_is_allocated(base)) { /* unpack and try extending the packed character */ n = char_unpack(base, &buf[0], &buf[1], &buf[2]); switch (n) { case 0: return char_pack1(append_ucs4); case 1: if (climit < 2) return base; return char_pack2(buf[0], append_ucs4); case 2: if (climit < 3) return base; return char_pack3(buf[0], buf[1], append_ucs4); default: /* fallthrough */ break; } /* already fully packed, we need to allocate a new one */ t = buf; } else { /* already an allocated type, we need to allocate a new one */ c = char_to_ptr(base); t = c->codepoints; n = c->n; } /* bail out if soft-limit is reached */ if (n >= climit) return base; /* allocate new char */ c = char_alloc(n + 1); if (!c) return base; memcpy(c->codepoints, t, sizeof(*t) * n); c->codepoints[n] = append_ucs4; return char_from_ptr(c); } /** * term_char_set() - Reset character to a single UCS-4 character * @previous: term-char to reset * @append_ucs4: UCS-4 char to set * * This frees all resources in @previous and re-initializes it to @append_ucs4. * The new char is returned. * * Usually, this is used like this: * obj->ch = term_char_set(obj->ch, ucs4); * * Returns: The previous character reset to @append_ucs4. */ term_char_t term_char_set(term_char_t previous, uint32_t append_ucs4) { char_free(previous); return char_build(TERM_CHAR_NULL, append_ucs4); } /** * term_char_merge() - Merge UCS-4 char at the end of an existing char * @base: existing term-char * @append_ucs4: UCS-4 character to append * * This appends @append_ucs4 to @base and returns the result. @base is * invalidated by this function and must no longer be used. The returned value * replaces the old one. * * Usually, this is used like this: * obj->ch = term_char_merge(obj->ch, ucs4); * * Returns: The new merged character. */ term_char_t term_char_merge(term_char_t base, uint32_t append_ucs4) { term_char_t ch; ch = char_build(base, append_ucs4); if (!term_char_same(ch, base)) term_char_free(base); return ch; } /** * term_char_dup() - Duplicate character * @ch: character to duplicate * * This duplicates a term-character. In case the character is not allocated, * nothing is done. Otherwise, the underlying memory is copied and returned. You * need to call term_char_free() on the returned character to release it again. * On allocation errors, a replacement character is returned. Therefore, the * caller can safely assume that this function always succeeds. * * Returns: The duplicated term-character. */ term_char_t term_char_dup(term_char_t ch) { term_character *c, *newc; if (!term_char_is_allocated(ch)) return ch; c = char_to_ptr(ch); newc = char_alloc(c->n); if (!newc) return char_pack1(CHAR_UCS4_REPLACEMENT); memcpy(newc->codepoints, c->codepoints, sizeof(*c->codepoints) * c->n); return char_from_ptr(newc); } /** * term_char_dup_append() - Duplicate tsm-char with UCS-4 character appended * @base: existing term-char * @append_ucs4: UCS-4 character to append * * This is similar to term_char_merge(), but it returns a separately allocated * character. That is, @base will stay valid after this returns and is not * touched. In case the append-operation fails, @base is duplicated and * returned. That is, the returned char is always independent of @base. * * Returns: Newly allocated character with @append_ucs4 appended to @base. */ term_char_t term_char_dup_append(term_char_t base, uint32_t append_ucs4) { term_char_t ch; ch = char_build(base, append_ucs4); if (term_char_same(ch, base)) ch = term_char_dup(base); return ch; } /** * term_char_resolve() - Retrieve the UCS-4 string for a term-char * @ch: character to resolve * @s: storage for size of string or NULL * @b: storage for string or NULL * * This takes a term-character and returns the UCS-4 string associated with it. * In case @ch is not allocated, the string is stored in @b (in case @b is NULL * static storage is used). Otherwise, a pointer to the allocated storage is * returned. * * The returned string is only valid as long as @ch and @b are valid. The string * is zero-terminated and can safely be printed via long-character printf(). * The length of the string excluding the zero-character is returned in @s. * * This never returns NULL. Even if the size is 0, this points to a buffer of at * least a zero-terminator. * * Returns: The UCS-4 string-representation of @ch, and its size in @s. */ const uint32_t *term_char_resolve(term_char_t ch, size_t *s, term_charbuf_t *b) { static term_charbuf_t static_b; term_character *c; uint32_t *cache; size_t len; if (b) cache = b->buf; else cache = static_b.buf; if (term_char_is_null(ch)) { len = 0; cache[0] = 0; } else if (term_char_is_allocated(ch)) { c = char_to_ptr(ch); len = c->n; cache = c->codepoints; } else { len = char_unpack(ch, &cache[0], &cache[1], &cache[2]); cache[len] = 0; } if (s) *s = len; return cache; } /** * term_char_lookup_width() - Lookup cell-width of a character * @ch: character to return cell-width for * * This is an equivalent of wcwidth() for term_char_t. It can deal directly * with UCS-4 and combining-characters and avoids the mess that is wchar_t and * locale handling. * * Returns: 0 for unprintable characters, >0 for everything else. */ unsigned int term_char_lookup_width(term_char_t ch) { term_charbuf_t b; const uint32_t *str; unsigned int max; size_t i, len; int r; max = 0; str = term_char_resolve(ch, &len, &b); for (i = 0; i < len; ++i) { /* * Oh god, C99 locale handling strikes again: wcwidth() expects * wchar_t, but there is no way for us to know the * internal encoding of wchar_t. Moreover, it is nearly * impossible to convert UCS-4 into wchar_t (except for iconv, * which is way too much overhead). * Therefore, we use our own copy of wcwidth(). Lets just hope * that glibc will one day export it's internal UCS-4 and UTF-8 * helpers for direct use. */ assert_cc(sizeof(wchar_t) >= 4); r = mk_wcwidth((wchar_t)str[i]); if (r > 0 && (unsigned int)r > max) max = r; } return max; } /** * term_cell_init() - Initialize a new cell * @cell: cell to initialize * @ch: character to set on the cell or TERM_CHAR_NULL * @cwidth: character width of @ch * @attr: attributes to set on the cell or NULL * @age: age to set on the cell or TERM_AGE_NULL * * This initializes a new cell. The backing-memory of the cell must be allocated * by the caller beforehand. The caller is responsible to destroy the cell via * term_cell_destroy() before freeing the backing-memory. * * It is safe (and supported!) to use: * zero(*c); * instead of: * term_cell_init(c, TERM_CHAR_NULL, NULL, TERM_AGE_NULL); * * Note that this call takes ownership of @ch. If you want to use it yourself * after this call, you need to duplicate it before calling this. */ static void term_cell_init(term_cell *cell, term_char_t ch, unsigned int cwidth, const term_attr *attr, term_age_t age) { assert(cell); cell->ch = ch; cell->cwidth = cwidth; cell->age = age; if (attr) memcpy(&cell->attr, attr, sizeof(*attr)); else zero(cell->attr); } /** * term_cell_destroy() - Destroy previously initialized cell * @cell: cell to destroy or NULL * * This releases all resources associated with a cell. The backing memory is * kept as-is. It's the responsibility of the caller to manage it. * * You must not call any other cell operations on this cell after this call * returns. You must re-initialize the cell via term_cell_init() before you can * use it again. * * If @cell is NULL, this is a no-op. */ static void term_cell_destroy(term_cell *cell) { if (!cell) return; term_char_free(cell->ch); } /** * term_cell_set() - Change contents of a cell * @cell: cell to modify * @ch: character to set on the cell or cell->ch * @cwidth: character width of @ch or cell->cwidth * @attr: attributes to set on the cell or NULL * @age: age to set on the cell or cell->age * * This changes the contents of a cell. It can be used to change the character, * attributes and age. To keep the current character, pass cell->ch as @ch. To * reset the current attributes, pass NULL. To keep the current age, pass * cell->age. * * This call takes ownership of @ch. You need to duplicate it first, in case you * want to use it for your own purposes after this call. * * The cell must have been initialized properly before calling this. See * term_cell_init(). */ static void term_cell_set(term_cell *cell, term_char_t ch, unsigned int cwidth, const term_attr *attr, term_age_t age) { assert(cell); if (!term_char_same(ch, cell->ch)) { term_char_free(cell->ch); cell->ch = ch; } cell->cwidth = cwidth; cell->age = age; if (attr) memcpy(&cell->attr, attr, sizeof(*attr)); else zero(cell->attr); } /** * term_cell_append() - Append a combining-char to a cell * @cell: cell to modify * @ucs4: UCS-4 character to append to the cell * @age: new age to set on the cell or cell->age * * This appends a combining-character to a cell. No validation of the UCS-4 * character is done, so this can be used to append any character. Additionally, * this can update the age of the cell. * * The cell must have been initialized properly before calling this. See * term_cell_init(). */ static void term_cell_append(term_cell *cell, uint32_t ucs4, term_age_t age) { assert(cell); cell->ch = term_char_merge(cell->ch, ucs4); cell->age = age; } /** * term_cell_init_n() - Initialize an array of cells * @cells: pointer to an array of cells to initialize * @n: number of cells * @attr: attributes to set on all cells or NULL * @age: age to set on all cells * * This is the same as term_cell_init() but initializes an array of cells. * Furthermore, this always sets the character to TERM_CHAR_NULL. * If you want to set a specific characters on all cells, you need to hard-code * this loop and duplicate the character for each cell. */ static void term_cell_init_n(term_cell *cells, unsigned int n, const term_attr *attr, term_age_t age) { for ( ; n > 0; --n, ++cells) term_cell_init(cells, TERM_CHAR_NULL, 0, attr, age); } /** * term_cell_destroy_n() - Destroy an array of cells * @cells: pointer to an array of cells to destroy * @n: number of cells * * This is the same as term_cell_destroy() but destroys an array of cells. */ static void term_cell_destroy_n(term_cell *cells, unsigned int n) { for ( ; n > 0; --n, ++cells) term_cell_destroy(cells); } /** * term_cell_clear_n() - Clear contents of an array of cells * @cells: pointer to an array of cells to modify * @n: number of cells * @attr: attributes to set on all cells or NULL * @age: age to set on all cells * * This is the same as term_cell_set() but operates on an array of cells. Note * that all characters are always set to TERM_CHAR_NULL, unlike term_cell_set() * which takes the character as argument. * If you want to set a specific characters on all cells, you need to hard-code * this loop and duplicate the character for each cell. */ static void term_cell_clear_n(term_cell *cells, unsigned int n, const term_attr *attr, term_age_t age) { for ( ; n > 0; --n, ++cells) term_cell_set(cells, TERM_CHAR_NULL, 0, attr, age); } /** * term_line_new() - Allocate a new line * @out: place to store pointer to new line * * This allocates and initialized a new line. The line is unlinked and * independent of any page. It can be used for any purpose. The initial * cell-count is set to 0. * * The line has to be freed via term_line_free() once it's no longer needed. * * Returns: 0 on success, negative error code on failure. */ int term_line_new(term_line **out) { _term_line_free_ term_line *line = NULL; assert_return(out, -EINVAL); line = new0(term_line, 1); if (!line) return -ENOMEM; *out = line; line = NULL; return 0; } /** * term_line_free() - Free a line * @line: line to free or NULL * * This frees a line that was previously allocated via term_line_free(). All its * cells are released, too. * * If @line is NULL, this is a no-op. */ term_line *term_line_free(term_line *line) { if (!line) return NULL; term_cell_destroy_n(line->cells, line->n_cells); free(line->cells); free(line); return NULL; } /** * term_line_reserve() - Pre-allocate cells for a line * @line: line to pre-allocate cells for * @width: numbers of cells the line shall have pre-allocated * @attr: attribute for all allocated cells or NULL * @age: current age for all modifications * @protect_width: width to protect from erasure * * This pre-allocates cells for this line. Please note that @width is the number * of cells the line is guaranteed to have allocated after this call returns. * It's not the number of cells that are added, neither is it the new width of * the line. * * This function never frees memory. That is, reducing the line-width will * always succeed, same is true for increasing the width to a previously set * width. * * @attr and @age are used to initialize new cells. Additionally, any * existing cell outside of the protected area specified by @protect_width are * cleared and reset with @attr and @age. * * Returns: 0 on success, negative error code on failure. */ int term_line_reserve(term_line *line, unsigned int width, const term_attr *attr, term_age_t age, unsigned int protect_width) { unsigned int min_width; term_cell *t; assert_return(line, -EINVAL); /* reset existing cells if required */ min_width = MIN(line->n_cells, width); if (min_width > protect_width) term_cell_clear_n(line->cells + protect_width, min_width - protect_width, attr, age); /* allocate new cells if required */ if (width > line->n_cells) { t = realloc_multiply(line->cells, sizeof(*t), width); if (!t) return -ENOMEM; if (!attr && !age) memzero(t + line->n_cells, sizeof(*t) * (width - line->n_cells)); else term_cell_init_n(t + line->n_cells, width - line->n_cells, attr, age); line->cells = t; line->n_cells = width; } line->fill = MIN(line->fill, protect_width); return 0; } /** * term_line_set_width() - Change width of a line * @line: line to modify * @width: new width * * This changes the actual width of a line. It is the caller's responsibility * to use term_line_reserve() to make sure enough space is allocated. If @width * is greater than the allocated size, it is cropped. * * This does not modify any cells. Use term_line_reserve() or term_line_erase() * to clear any newly added cells. * * NOTE: The fill state is cropped at line->width. Therefore, if you increase * the line-width afterwards, but there is a multi-cell character at the * end of the line that got cropped, then the fill-state will _not_ be * adjusted. * This means, the fill-state always includes the cells up to the start * of the right-most character, but it might or might not cover it until * its end. This should be totally fine, though. You should never access * multi-cell tails directly, anyway. */ void term_line_set_width(term_line *line, unsigned int width) { assert(line); if (width > line->n_cells) width = line->n_cells; line->width = width; line->fill = MIN(line->fill, width); } /** * line_insert() - Insert characters and move existing cells to the right * @from: position to insert cells at * @num: number of cells to insert * @head_char: character that is set on the first cell * @head_cwidth: character-length of @head_char * @attr: attribute for all inserted cells or NULL * @age: current age for all modifications * * The INSERT operation (or writes with INSERT_MODE) writes data at a specific * position on a line and shifts the existing cells to the right. Cells that are * moved beyond the right hand border are discarded. * * This helper contains the actual INSERT implementation which is independent of * the data written. It works on cells, not on characters. The first cell is set * to @head_char, all others are reset to TERM_CHAR_NULL. See each caller for a * more detailed description. */ static inline void line_insert(term_line *line, unsigned int from, unsigned int num, term_char_t head_char, unsigned int head_cwidth, const term_attr *attr, term_age_t age) { unsigned int i, rem, move; if (from >= line->width) return; if (from + num < from || from + num > line->width) num = line->width - from; if (!num) return; move = line->width - from - num; rem = MIN(num, move); if (rem > 0) { /* * Make room for @num cells; shift cells to the right if * required. @rem is the number of remaining cells that we will * knock off on the right and overwrite during the right shift. * * For INSERT_MODE, @num/@rem are usually 1 or 2, @move is 50% * of the line on average. Therefore, the actual move is quite * heavy and we can safely invalidate cells manually instead of * the whole line. * However, for INSERT operations, any parameters are * possible. But we cannot place any assumption on its usage * across applications, so we just handle it the same as * INSERT_MODE and do per-cell invalidation. */ /* destroy cells that are knocked off on the right */ term_cell_destroy_n(line->cells + line->width - rem, rem); /* move remaining bulk of cells */ memmove(line->cells + from + num, line->cells + from, sizeof(*line->cells) * move); /* invalidate cells */ for (i = 0; i < move; ++i) line->cells[from + num + i].age = age; /* initialize fresh head-cell */ term_cell_init(line->cells + from, head_char, head_cwidth, attr, age); /* initialize fresh tail-cells */ term_cell_init_n(line->cells + from + 1, num - 1, attr, age); /* adjust fill-state */ DISABLE_WARNING_SHADOW; line->fill = MIN(line->width, MAX(line->fill + num, from + num)); REENABLE_WARNING; } else { /* modify head-cell */ term_cell_set(line->cells + from, head_char, head_cwidth, attr, age); /* reset tail-cells */ term_cell_clear_n(line->cells + from + 1, num - 1, attr, age); /* adjust fill-state */ line->fill = line->width; } } /** * term_line_write() - Write to a single, specific cell * @line: line to write to * @pos_x: x-position of cell in @line to write to * @ch: character to write to the cell * @cwidth: character width of @ch * @attr: attributes to set on the cell or NULL * @age: current age for all modifications * @insert_mode: true if INSERT-MODE is enabled * * This writes to a specific cell in a line. The cell is addressed by its * X-position @pos_x. If that cell does not exist, this is a no-op. * * @ch and @attr are set on this cell. * * If @insert_mode is true, this inserts the character instead of overwriting * existing data (existing data is now moved to the right before writing). * * This function is the low-level handler of normal writes to a terminal. */ void term_line_write(term_line *line, unsigned int pos_x, term_char_t ch, unsigned int cwidth, const term_attr *attr, term_age_t age, bool insert_mode) { unsigned int len; assert(line); if (pos_x >= line->width) return; len = MAX(1U, cwidth); if (pos_x + len < pos_x || pos_x + len > line->width) len = line->width - pos_x; if (!len) return; if (insert_mode) { /* Use line_insert() to insert the character-head and fill * the remains with NULLs. */ line_insert(line, pos_x, len, ch, cwidth, attr, age); } else { /* modify head-cell */ term_cell_set(line->cells + pos_x, ch, cwidth, attr, age); /* reset tail-cells */ term_cell_clear_n(line->cells + pos_x + 1, len - 1, attr, age); /* adjust fill-state */ DISABLE_WARNING_SHADOW; line->fill = MIN(line->width, MAX(line->fill, pos_x + len)); REENABLE_WARNING; } } /** * term_line_insert() - Insert empty cells * @line: line to insert empty cells into * @from: x-position where to insert cells * @num: number of cells to insert * @attr: attributes to set on the cells or NULL * @age: current age for all modifications * * This inserts @num empty cells at position @from in line @line. All existing * cells to the right are shifted to make room for the new cells. Cells that get * pushed beyond the right hand border are discarded. */ void term_line_insert(term_line *line, unsigned int from, unsigned int num, const term_attr *attr, term_age_t age) { /* use line_insert() to insert @num empty cells */ return line_insert(line, from, num, TERM_CHAR_NULL, 0, attr, age); } /** * term_line_delete() - Delete cells from line * @line: line to delete cells from * @from: position to delete cells at * @num: number of cells to delete * @attr: attributes to set on any new cells * @age: current age for all modifications * * Delete cells from a line. All cells to the right of the deleted cells are * shifted to the left to fill the empty space. New cells appearing on the right * hand border are cleared and initialized with @attr. */ void term_line_delete(term_line *line, unsigned int from, unsigned int num, const term_attr *attr, term_age_t age) { unsigned int rem, move, i; assert(line); if (from >= line->width) return; if (from + num < from || from + num > line->width) num = line->width - from; if (!num) return; /* destroy and move as many upfront as possible */ move = line->width - from - num; rem = MIN(num, move); if (rem > 0) { /* destroy to be removed cells */ term_cell_destroy_n(line->cells + from, rem); /* move tail upfront */ memmove(line->cells + from, line->cells + from + num, sizeof(*line->cells) * move); /* invalidate copied cells */ for (i = 0; i < move; ++i) line->cells[from + i].age = age; /* initialize tail that was moved away */ term_cell_init_n(line->cells + line->width - rem, rem, attr, age); /* reset remaining cells in case the move was too small */ if (num > move) term_cell_clear_n(line->cells + from + move, num - move, attr, age); } else { /* reset cells */ term_cell_clear_n(line->cells + from, num, attr, age); } /* adjust fill-state */ if (from + num < line->fill) line->fill -= num; else if (from < line->fill) line->fill = from; } /** * term_line_append_combchar() - Append combining char to existing cell * @line: line to modify * @pos_x: position of cell to append combining char to * @ucs4: combining character to append * @age: current age for all modifications * * Unicode allows trailing combining characters, which belong to the * char in front of them. The caller is responsible of detecting * combining characters and calling term_line_append_combchar() instead of * term_line_write(). This simply appends the char to the correct cell then. * If the cell is not in the visible area, this call is skipped. * * Note that control-sequences are not 100% compatible with combining * characters as they require delayed parsing. However, we must handle * control-sequences immediately. Therefore, there might be trailing * combining chars that should be discarded by the parser. * However, to prevent programming errors, we're also being pedantic * here and discard weirdly placed combining chars. This prevents * situations were invalid content is parsed into the terminal and you * might end up with cells containing only combining chars. * * Long story short: To get combining-characters working with old-fashioned * terminal-emulation, we parse them exclusively for direct cell-writes. Other * combining-characters are usually simply discarded and ignored. */ void term_line_append_combchar(term_line *line, unsigned int pos_x, uint32_t ucs4, term_age_t age) { assert(line); if (pos_x >= line->width) return; /* Unused cell? Skip appending any combining chars then. */ if (term_char_is_null(line->cells[pos_x].ch)) return; term_cell_append(line->cells + pos_x, ucs4, age); } /** * term_line_erase() - Erase parts of a line * @line: line to modify * @from: position to start the erase * @num: number of cells to erase * @attr: attributes to initialize erased cells with * @age: current age for all modifications * @keep_protected: true if protected cells should be kept * * This is the standard erase operation. It clears all cells in the targetted * area and re-initializes them. Cells to the right are not shifted left, you * must use DELETE to achieve that. Cells outside the visible area are skipped. * * If @keep_protected is true, protected cells will not be erased. */ void term_line_erase(term_line *line, unsigned int from, unsigned int num, const term_attr *attr, term_age_t age, bool keep_protected) { term_cell *cell; unsigned int i, last_protected; assert(line); if (from >= line->width) return; if (from + num < from || from + num > line->width) num = line->width - from; if (!num) return; last_protected = 0; for (i = 0; i < num; ++i) { cell = line->cells + from + i; if (keep_protected && cell->attr.protect) { /* only count protected-cells inside the fill-region */ if (from + i < line->fill) last_protected = from + i; continue; } term_cell_set(cell, TERM_CHAR_NULL, 0, attr, age); } /* Adjust fill-state. This is a bit tricks, we can only adjust it in * case the erase-region starts inside the fill-region and ends at the * tail or beyond the fill-region. Otherwise, the current fill-state * stays as it was. * Furthermore, we must account for protected cells. The loop above * ensures that protected-cells are only accounted for if they're * inside the fill-region. */ if (from < line->fill && from + num >= line->fill) line->fill = MAX(from, last_protected); } /** * term_line_reset() - Reset a line * @line: line to reset * @attr: attributes to initialize all cells with * @age: current age for all modifications * * This resets all visible cells of a line and sets their attributes and ages * to @attr and @age. This is equivalent to erasing a whole line via * term_line_erase(). */ void term_line_reset(term_line *line, const term_attr *attr, term_age_t age) { assert(line); return term_line_erase(line, 0, line->width, attr, age, 0); } /** * term_line_link() - Link line in front of a list * @line: line to link * @first: member pointing to first entry * @last: member pointing to last entry * * This links a line into a list of lines. The line is inserted at the front and * must not be linked, yet. See the TERM_LINE_LINK() macro for an easier usage of * this. */ void term_line_link(term_line *line, term_line **first, term_line **last) { assert(line); assert(first); assert(last); assert(!line->lines_prev); assert(!line->lines_next); line->lines_prev = NULL; line->lines_next = *first; if (*first) (*first)->lines_prev = line; else *last = line; *first = line; } /** * term_line_link_tail() - Link line at tail of a list * @line: line to link * @first: member pointing to first entry * @last: member pointing to last entry * * Same as term_line_link() but links the line at the tail. */ void term_line_link_tail(term_line *line, term_line **first, term_line **last) { assert(line); assert(first); assert(last); assert(!line->lines_prev); assert(!line->lines_next); line->lines_next = NULL; line->lines_prev = *last; if (*last) (*last)->lines_next = line; else *first = line; *last = line; } /** * term_line_unlink() - Unlink line from a list * @line: line to unlink * @first: member pointing to first entry * @last: member pointing to last entry * * This unlinks a previously linked line. See TERM_LINE_UNLINK() for an easier to * use macro. */ void term_line_unlink(term_line *line, term_line **first, term_line **last) { assert(line); assert(first); assert(last); if (line->lines_prev) line->lines_prev->lines_next = line->lines_next; else *first = line->lines_next; if (line->lines_next) line->lines_next->lines_prev = line->lines_prev; else *last = line->lines_prev; line->lines_prev = NULL; line->lines_next = NULL; }