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sixel: abuse wmemset() when initializing a freshly allocated image buffer

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wmemset() is heavily optimized, and in some cases, *much* faster than
manually initializing the new image pixels.

Furthermore, assume calloc() is better at initializing memory to zero,
and use that when initializing new pixels in a transparent image.
This commit is contained in:
Daniel Eklöf 2024-03-25 16:33:15 +01:00
parent dcd4ab4ab8
commit a99434929c
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GPG key ID: 5BBD4992C116573F
1 changed files with 77 additions and 37 deletions
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114
sixel.c
View file

@ -1385,21 +1385,29 @@ sixel_unhook(struct terminal *term)
render_refresh(term);
}
static void
resize_horizontally(struct terminal *term, int new_width)
static void ALWAYS_INLINE inline
memset_u32(uint32_t *data, uint32_t value, size_t count)
{
if (unlikely(new_width > term->sixel.max_width)) {
static_assert(sizeof(wchar_t) == 4, "wchar_t is not 4 bytes");
wmemset((wchar_t *)data, (wchar_t)value, count);
}
static void
resize_horizontally(struct terminal *term, int new_width_mutable)
{
if (unlikely(new_width_mutable > term->sixel.max_width)) {
LOG_WARN("maximum image dimensions exceeded, truncating");
new_width = term->sixel.max_width;
new_width_mutable = term->sixel.max_width;
}
if (unlikely(term->sixel.image.width == new_width))
if (unlikely(term->sixel.image.width == new_width_mutable))
return;
const int sixel_row_height = 6 * term->sixel.pan;
uint32_t *old_data = term->sixel.image.data;
const int old_width = term->sixel.image.width;
const int new_width = new_width_mutable;
int height;
if (unlikely(term->sixel.image.height == 0)) {
@ -1424,13 +1432,13 @@ resize_horizontally(struct terminal *term, int new_width)
uint32_t bg = term->sixel.default_bg;
/* Copy old rows, and initialize new columns to background color */
for (int r = 0; r < height; r++) {
memcpy(&new_data[r * new_width],
&old_data[r * old_width],
old_width * sizeof(uint32_t));
for (int c = old_width; c < new_width; c++)
new_data[r * new_width + c] = bg;
const uint32_t *end = &new_data[alloc_height * new_width];
for (uint32_t *n = new_data, *o = old_data;
n < end;
n += new_width, o += old_width)
{
memcpy(n, o, old_width * sizeof(uint32_t));
memset_u32(&n[old_width], bg, new_width - old_width);
}
free(old_data);
@ -1443,7 +1451,7 @@ resize_horizontally(struct terminal *term, int new_width)
}
static bool
resize_vertically(struct terminal *term, int new_height)
resize_vertically(struct terminal *term, const int new_height)
{
LOG_DBG("resizing image vertically: (%d)x%d -> (%d)x%d",
term->sixel.image.width, term->sixel.image.height,
@ -1477,13 +1485,11 @@ resize_vertically(struct terminal *term, int new_height)
return false;
}
uint32_t bg = term->sixel.default_bg;
const uint32_t bg = term->sixel.default_bg;
/* Initialize new rows to background color */
for (int r = old_height; r < new_height; r++) {
for (int c = 0; c < width; c++)
new_data[r * width + c] = bg;
}
memset_u32(&new_data[old_height * width],
bg,
(alloc_height - old_height) * width);
term->sixel.image.height = new_height;
term->sixel.image.alloc_height = alloc_height;
@ -1498,43 +1504,69 @@ resize_vertically(struct terminal *term, int new_height)
}
static bool
resize(struct terminal *term, int new_width, int new_height)
resize(struct terminal *term, int new_width_mutable, int new_height_mutable)
{
LOG_DBG("resizing image: %dx%d -> %dx%d",
term->sixel.image.width, term->sixel.image.height,
new_width, new_height);
if (unlikely(new_width > term->sixel.max_width)) {
if (unlikely(new_width_mutable > term->sixel.max_width)) {
LOG_WARN("maximum image width exceeded, truncating");
new_width = term->sixel.max_width;
new_width_mutable = term->sixel.max_width;
}
if (unlikely(new_height > term->sixel.max_height)) {
if (unlikely(new_height_mutable > term->sixel.max_height)) {
LOG_WARN("maximum image height exceeded, truncating");
new_height = term->sixel.max_height;
new_height_mutable = term->sixel.max_height;
}
uint32_t *old_data = term->sixel.image.data;
const int old_width = term->sixel.image.width;
const int old_height = term->sixel.image.height;
const int new_width = new_width_mutable;
const int new_height = new_height_mutable;
if (unlikely(old_width == new_width && old_height == new_height))
return true;
const int sixel_row_height = 6 * term->sixel.pan;
int alloc_new_width = new_width;
int alloc_new_height = (new_height + sixel_row_height - 1) / sixel_row_height * sixel_row_height;
const int alloc_new_height =
(new_height + sixel_row_height - 1) / sixel_row_height * sixel_row_height;
xassert(alloc_new_height >= new_height);
xassert(alloc_new_height - new_height < sixel_row_height);
uint32_t *new_data = NULL;
uint32_t bg = term->sixel.default_bg;
const uint32_t bg = term->sixel.default_bg;
/*
* If the image is resized horizontally, or if it's opaque, we
* need to explicitly initialize the "new" pixels.
*
* When the image is *not* resized horizontally, we simply do a
* realloc(). In this case, there's no need to manually copy the
* old pixels. We do however need to initialize the new pixels
* since realloc() returns uninitialized memory.
*
* When the image *is* resized horizontally, we need to allocate
* new memory (when the width changes, the stride changes, and
* thus we cannot simply realloc())
*
* If the default background is transparent, the new pixels need
* to be initialized to 0x0. We do this by using calloc().
*
* If the default background is opaque, then we need to manually
* initialize the new pixels.
*/
const bool initialize_bg =
!term->sixel.transparent_bg || new_width == old_width;
if (new_width == old_width) {
/* Width (and thus stride) is the same, so we can simply
* re-alloc the existing buffer */
new_data = realloc(old_data, alloc_new_width * alloc_new_height * sizeof(uint32_t));
new_data = realloc(old_data, new_width * alloc_new_height * sizeof(uint32_t));
if (new_data == NULL) {
LOG_ERRNO("failed to reallocate sixel image buffer");
return false;
@ -1545,22 +1577,30 @@ resize(struct terminal *term, int new_width, int new_height)
} else {
/* Width (and thus stride) change - need to allocate a new buffer */
xassert(new_width > old_width);
new_data = xmalloc(alloc_new_width * alloc_new_height * sizeof(uint32_t));
const size_t pixels = new_width * alloc_new_height;
new_data = !initialize_bg
? xcalloc(pixels, sizeof(uint32_t))
: xmalloc(pixels * sizeof(uint32_t));
/* Copy old rows, and initialize new columns to background color */
for (int r = 0; r < min(old_height, new_height); r++) {
memcpy(&new_data[r * new_width], &old_data[r * old_width], old_width * sizeof(uint32_t));
const int row_copy_count = min(old_height, alloc_new_height);
const uint32_t *end = &new_data[row_copy_count * new_width];
for (int c = old_width; c < new_width; c++)
new_data[r * new_width + c] = bg;
for (uint32_t *n = new_data, *o = old_data;
n < end;
n += new_width, o += old_width)
{
memcpy(n, o, old_width * sizeof(uint32_t));
memset_u32(&n[old_width], bg, new_width - old_width);
}
free(old_data);
}
/* Initialize new rows to background color */
for (int r = old_height; r < new_height; r++) {
for (int c = 0; c < new_width; c++)
new_data[r * new_width + c] = bg;
if (initialize_bg) {
memset_u32(&new_data[old_height * new_width],
bg,
(alloc_new_height - old_height) * new_width);
}
xassert(new_data != NULL);