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Preserve SGR parameter order when mixing colon colors and resets #321

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146 changes: 77 additions & 69 deletions libwcwidth/src/sgr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -108,78 +108,11 @@ set_color(int *dst, int *dst_len, const int *src, int src_len)
}
}

void
wcwidth_sgr_update(wcwidth_sgr_state_t *state, const char *sgr_params, size_t sgr_params_len)
static void
apply_integer_params(wcwidth_sgr_state_t *state, const int *params, int nparams)
{
int stack_params[WCWIDTH_SGR_MAX_PARAMS];
int *params = stack_params;
size_t params_cap = WCWIDTH_SGR_MAX_PARAMS;
int nparams = 0;
const char *p = sgr_params;
const char *end = sgr_params + sgr_params_len;
int i;

/* Empty params is equivalent to "0" (reset): \x1b[m. */
if (sgr_params_len == 0) {
*state = WCWIDTH_SGR_STATE_DEFAULT;
return;
}

/* Phase 1: parse all semicolon-separated segments.
* Colon-separated tuples (ITU T.416 extended colors) are applied
* immediately. Plain integers are collected for phase 2. */
while (p < end) {
const char *seg_end = p;

while (seg_end < end && *seg_end != ';') {
seg_end++;
}
{
size_t seg_len = (size_t) (seg_end - p);

if (seg_len == 0) {
if (!sgr_params_reserve(&params, stack_params, &params_cap, nparams)) {
break;
}
params[nparams++] = 0;
}
else {
int has_colon = 0;
size_t j;

for (j = 0; j < seg_len; j++) {
if (p[j] == ':') {
has_colon = 1;
break;
}
}

if (has_colon) {
int tuple[WCWIDTH_SGR_COLOR_MAX];
int n = parse_colon_tuple(p, seg_len, tuple, WCWIDTH_SGR_COLOR_MAX);
if (n >= 2 && tuple[0] == 38) {
set_color(state->fg, &state->fg_len, tuple, n);
}
else if (n >= 2 && tuple[0] == 48) {
set_color(state->bg, &state->bg_len, tuple, n);
}
}
else {
if (!sgr_params_reserve(&params, stack_params, &params_cap, nparams)) {
break;
}
params[nparams++] = parse_int(p, seg_len);
}
}
}

p = seg_end;
if (p < end && *p == ';') {
p++;
}
}

/* Phase 2: apply integer parameters in order. */
for (i = 0; i < nparams; i++) {
int val = params[i];

Expand Down Expand Up @@ -305,6 +238,81 @@ wcwidth_sgr_update(wcwidth_sgr_state_t *state, const char *sgr_params, size_t sg
}
}
}
}

void
wcwidth_sgr_update(wcwidth_sgr_state_t *state, const char *sgr_params, size_t sgr_params_len)
{
int stack_params[WCWIDTH_SGR_MAX_PARAMS];
int *params = stack_params;
size_t params_cap = WCWIDTH_SGR_MAX_PARAMS;
int nparams = 0;
const char *p = sgr_params;
const char *end = sgr_params + sgr_params_len;

/* Empty params is equivalent to "0" (reset): \x1b[m. */
if (sgr_params_len == 0) {
*state = WCWIDTH_SGR_STATE_DEFAULT;
return;
}

/* Collect runs of integer parameters, applying each run before the next
* colon-separated color so resets and colors retain their original order. */
while (p < end) {
const char *seg_end = p;

while (seg_end < end && *seg_end != ';') {
seg_end++;
}
{
size_t seg_len = (size_t) (seg_end - p);

if (seg_len == 0) {
if (!sgr_params_reserve(&params, stack_params, &params_cap, nparams)) {
break;
}
params[nparams++] = 0;
}
else {
int has_colon = 0;
size_t j;

for (j = 0; j < seg_len; j++) {
if (p[j] == ':') {
has_colon = 1;
break;
}
}

if (has_colon) {
int tuple[WCWIDTH_SGR_COLOR_MAX];
int n = parse_colon_tuple(p, seg_len, tuple, WCWIDTH_SGR_COLOR_MAX);

apply_integer_params(state, params, nparams);
nparams = 0;
if (n >= 2 && tuple[0] == 38) {
set_color(state->fg, &state->fg_len, tuple, n);
}
else if (n >= 2 && tuple[0] == 48) {
set_color(state->bg, &state->bg_len, tuple, n);
}
}
else {
if (!sgr_params_reserve(&params, stack_params, &params_cap, nparams)) {
break;
}
params[nparams++] = parse_int(p, seg_len);
}
}
}

p = seg_end;
if (p < end && *p == ';') {
p++;
}
}

apply_integer_params(state, params, nparams);

if (params != stack_params) {
free(params);
Expand Down
28 changes: 28 additions & 0 deletions libwcwidth/tests/test_sgr.c
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Original file line number Diff line number Diff line change
Expand Up @@ -211,6 +211,33 @@ TEST(attribute_and_color_codes)
}
}

TEST(mixed_color_parameter_order)
{
static const char *const inputs[] = {
"0;38:2::255:0:0", "0;48:2::0:0:255", "31;38:5:196", "39;38:5:196",
"38;5;196;38:5:46", "38:5:196;38;5;46", "38:5:196;0",
};
static const char *const expected[] = {
"\x1b[38:2:0:255:0:0m",
"\x1b[48:2:0:0:0:255m",
"\x1b[38;5;196m",
"\x1b[38;5;196m",
"\x1b[38;5;46m",
"\x1b[38;5;46m",
"",
};
size_t i;

for (i = 0; i < sizeof(inputs) / sizeof(inputs[0]); i++) {
wcwidth_sgr_state_t s = WCWIDTH_SGR_STATE_DEFAULT;
char buf[64];

wcwidth_sgr_update(&s, inputs[i], strlen(inputs[i]));
wcwidth_sgr_to_escape(&s, buf, sizeof(buf));
ASSERT_STREQ(expected[i], buf);
}
}

int
main(void)
{
Expand All @@ -221,5 +248,6 @@ main(void)
RUN_TEST(to_escape_colon_form);
RUN_TEST(propagate_basic);
RUN_TEST(attribute_and_color_codes);
RUN_TEST(mixed_color_parameter_order);
return test_summary();
}
22 changes: 22 additions & 0 deletions tests/test_sgr_state.py
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
import pytest

# local
import wcwidth
from wcwidth import clip, wrap
from wcwidth.sgr_state import (_SGR_STATE_DEFAULT,
_SGRState,
Expand Down Expand Up @@ -171,6 +172,27 @@ def test_propagate_sgr_colon_format_color_is_restored():
(38, 2, 0, 255, 0, 0))


@pytest.mark.parametrize('params,expected', [
('0;38:2::255:0:0', '\x1b[38:2:0:255:0:0m'),
('0;48:2::0:0:255', '\x1b[48:2:0:0:0:255m'),
('31;38:5:196', '\x1b[38;5;196m'),
('39;38:5:196', '\x1b[38;5;196m'),
('38;5;196;38:5:46', '\x1b[38;5;46m'),
('38:5:196;38;5;46', '\x1b[38;5;46m'),
('38:5:196;0', ''),
])
@pytest.mark.parametrize('operation', ['propagate_sgr', 'clip'])
def test_mixed_sgr_parameters_keep_order(params, expected, operation):
"""Apply resets and colors in order when semicolon and colon forms mix."""
opening = f'\x1b[{params}m'
reset = '\x1b[0m' if expected else ''
if operation == 'propagate_sgr':
result = wcwidth.propagate_sgr([opening + 'red', 'text'])[1]
else:
result = clip(opening + 'red text', 4, 8)
assert result == expected + 'text' + reset


def test_sgr_state_color_override():
"""Newer color replaces older regardless of format."""
state = _sgr_state_update(_SGR_STATE_DEFAULT, '\x1b[38;5;208m')
Expand Down