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cgen: fix a sporadic segfault when giving -width in a string interpolation

pull/4799/head
Delyan Angelov 2020-05-09 15:21:40 +03:00
parent 5f435fa1cc
commit 809676a856
2 changed files with 23 additions and 3 deletions
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6
vlib/v/gen/str.v
View File

@ -9,6 +9,10 @@ fn (mut g Gen) write_str_fn_definitions() {
void _STR_PRINT_ARG(const char *fmt, char** refbufp, int *nbytes, int *memsize, int guess, ...) {
va_list args;
va_start(args, guess);
// NB: (*memsize - *nbytes) === how much free space is left at the end of the current buffer refbufp
// *memsize === total length of the buffer refbufp
// *nbytes === already occupied bytes of buffer refbufp
// guess === how many bytes were taken during the current vsnprintf run
for(;;) {
if (guess < *memsize - *nbytes) {
guess = vsnprintf(*refbufp + *nbytes, *memsize - *nbytes, fmt, args);
@ -62,7 +66,7 @@ string _STR(const char *fmt, int nfmts, ...) {
fwidth -= (s.len - utf8_str_visible_length(s));
else
fwidth += (s.len - utf8_str_visible_length(s));
_STR_PRINT_ARG(fmt, &buf, &nbytes, &memsize, k+fwidth-4, fwidth, s.len, s.str);
_STR_PRINT_ARG(fmt, &buf, &nbytes, &memsize, k+s.len-4, fwidth, s.len, s.str);
} else { // %.*s
_STR_PRINT_ARG(fmt, &buf, &nbytes, &memsize, k+s.len-4, s.len, s.str);
}

18
vlib/v/tests/string_interpolation_test.v
View File

@ -111,7 +111,11 @@ fn test_utf8_string_interpolation() {
st := 'Sträßle'
m := '10€'
assert '$a $st $m' == 'à-côté Sträßle 10€'
assert '>${a:10}< >${st:-8}< >${m:5}<-' == '> à-côté< >Sträßle < > 10€<-'
zz := '>${a:10}< >${st:-8}< >${m:5}<-'
zz_expected := '> à-côté< >Sträßle < > 10€<-'
eprintln(' zz: $zz')
eprintln('zz_expected: $zz_expected')
assert zz == zz_expected
// e := '\u20AC' // Eurosign doesn' work with MSVC and tcc
e := '€'
assert '100.00 $e' == '100.00 €'
@ -135,3 +139,15 @@ fn test_string_interpolation_str_evaluation() {
mut x := S{17, 13.455893}
assert '$x' == '[17, 13.456]'
}
fn test_string_interpolation_with_negative_format_width_should_compile_and_run_without_segfaulting() {
// discovered during debugging VLS
i := 3
input := '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}'
eprintln('---------------------------------------------------------------------------------------------')
eprintln('+60 ${i:10} | input.len: ${input.len:10} | ${input.bytes().hex():60} | $input')
eprintln('-60 ${i:10} | input.len: ${input.len:10} | ${input.bytes().hex():-60} | $input')
eprintln('---------------------------------------------------------------------------------------------')
assert true
}