mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-05-29 00:32:29 +00:00
Fix printf-family long double prec/rounding issues (#1283)
Currently, in cosmopolitan, there is no handling of the current rounding mode for long double conversions, such that round-to-nearest gets always used, regardless of the current rounding mode. %Le also improperly calls gdtoa with a too small precision (which led to relatively similar bugs). This patch fixes these issues, in particular by modifying the FPI object passed to gdtoa such that it is modifiable (so that __fmt can adjust its rounding field to correspond to FLT_ROUNDS (note that this is not needed for dtoa, which checks FLT_ROUNDS directly)) and ors STRTOG_Neg into the kind field in both of the __fmt_dfpbits and __fmt_ldfpbits functions, as the gdtoa function also depends on it to be able to accurately round any negative arguments. The change to kind also requires a few other changes to make sure kind's upper bits (which include STRTOG_Neg) are masked off when attempting to only examine the lower bits' value. Furthermore, this patch also makes exactly one change in gdtoa, which appears to be needed to fix rounding issues with FE_TOWARDZERO (this seems like a gdtoa bug). The patch also adds a few tests for these issues, along with also taking the opportunity to clean up some of the previous tests to do the asserts in the right order (i.e. with the first argument as the expected result, and the second one being used as the value that it is compared against).
This commit is contained in:
Gabriel Ravier
GitHub
parent
f882887178
commit
4754f200ee
3 changed files with 110 additions and 60 deletions
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@ -16,6 +16,7 @@
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/runtime/fenv.h"
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#include "libc/stdio/stdio.h"
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#include "libc/str/str.h"
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#include "libc/testlib/testlib.h"
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@ -24,64 +25,64 @@ TEST(snprintf, testVeryLargePrecision) {
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char buf[512] = {};
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int i = snprintf(buf, sizeof(buf), "%.9999u", 10);
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ASSERT_EQ(i, 9999);
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ASSERT_EQ(strlen(buf), 511);
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ASSERT_EQ(9999, i);
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ASSERT_EQ(511, strlen(buf));
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}
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TEST(snprintf, testPlusFlagOnChar) {
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char buf[10] = {};
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int i = snprintf(buf, sizeof(buf), "%+c", '=');
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ASSERT_EQ(i, 1);
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ASSERT_STREQ(buf, "=");
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ASSERT_EQ(1, i);
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ASSERT_STREQ("=", buf);
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}
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TEST(snprintf, testInf) {
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char buf[10] = {};
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int i = snprintf(buf, sizeof(buf), "%f", 1.0 / 0.0);
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ASSERT_EQ(i, 3);
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ASSERT_STREQ(buf, "inf");
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ASSERT_EQ(3, i);
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ASSERT_STREQ("inf", buf);
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memset(buf, '\0', 4);
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i = snprintf(buf, sizeof(buf), "%Lf", 1.0L / 0.0L);
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ASSERT_EQ(i, 3);
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ASSERT_STREQ(buf, "inf");
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ASSERT_EQ(3, i);
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ASSERT_STREQ("inf", buf);
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memset(buf, '\0', 4);
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i = snprintf(buf, sizeof(buf), "%e", 1.0 / 0.0);
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ASSERT_EQ(i, 3);
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ASSERT_STREQ(buf, "inf");
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ASSERT_EQ(3, i);
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ASSERT_STREQ("inf", buf);
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memset(buf, '\0', 4);
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i = snprintf(buf, sizeof(buf), "%Le", 1.0L / 0.0L);
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ASSERT_EQ(i, 3);
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ASSERT_STREQ(buf, "inf");
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ASSERT_EQ(3, i);
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ASSERT_STREQ("inf", buf);
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memset(buf, '\0', 4);
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i = snprintf(buf, sizeof(buf), "%g", 1.0 / 0.0);
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ASSERT_EQ(i, 3);
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ASSERT_STREQ(buf, "inf");
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ASSERT_EQ(3, i);
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ASSERT_STREQ("inf", buf);
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memset(buf, '\0', 4);
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i = snprintf(buf, sizeof(buf), "%Lg", 1.0L / 0.0L);
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ASSERT_EQ(i, 3);
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ASSERT_STREQ(buf, "inf");
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ASSERT_EQ(3, i);
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ASSERT_STREQ("inf", buf);
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for (i = 4; i < 10; ++i)
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ASSERT_EQ(buf[i], '\0');
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ASSERT_EQ('\0', buf[i]);
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}
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TEST(snprintf, testUppercaseCConversionSpecifier) {
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char buf[10] = {};
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int i = snprintf(buf, sizeof(buf), "%C", L'a');
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ASSERT_EQ(i, 1);
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ASSERT_STREQ(buf, "a");
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ASSERT_EQ(1, i);
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ASSERT_STREQ("a", buf);
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i = snprintf(buf, sizeof(buf), "%C", L'☺');
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ASSERT_EQ(i, 3);
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ASSERT_STREQ(buf, "☺");
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ASSERT_EQ(3, i);
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ASSERT_STREQ("☺", buf);
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}
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// Make sure we don't va_arg the wrong argument size on wide character
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@ -92,22 +93,22 @@ TEST(snprintf,
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int i = snprintf(buf, sizeof(buf), "%d%d%d%d%d%d%d%d%lc%d", 0, 0, 0, 0, 0, 0,
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0, 0, L'x', 1);
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ASSERT_EQ(i, 10);
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ASSERT_STREQ(buf, "00000000x1");
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ASSERT_EQ(10, i);
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ASSERT_STREQ("00000000x1", buf);
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memset(buf, 0, sizeof(buf));
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i = snprintf(buf, sizeof(buf), "%d%d%d%d%d%d%d%d%C%d", 0, 0, 0, 0, 0, 0, 0, 0,
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L'x', 1);
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ASSERT_EQ(i, 10);
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ASSERT_STREQ(buf, "00000000x1");
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ASSERT_EQ(10, i);
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ASSERT_STREQ("00000000x1", buf);
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}
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static void check_n_buffer_contents(char buf[350]) {
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for (int i = 0; i < 284; ++i)
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ASSERT_EQ(buf[i], ' ');
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ASSERT_STREQ(&buf[284], "428463");
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ASSERT_EQ(' ', buf[i]);
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ASSERT_STREQ("428463", &buf[284]);
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for (int i = 290; i < 350; ++i)
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ASSERT_EQ(buf[i], '\0');
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ASSERT_EQ('\0', buf[i]);
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}
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TEST(snprintf, testNConversionSpecifier) {
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@ -115,24 +116,24 @@ TEST(snprintf, testNConversionSpecifier) {
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int n_res_int = -1;
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int i = snprintf(buf, sizeof(buf), "%286d%d%n%d", 42, 84, &n_res_int, 63);
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ASSERT_EQ(i, 290);
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ASSERT_EQ(290, i);
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check_n_buffer_contents(buf);
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ASSERT_EQ(n_res_int, 288);
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ASSERT_EQ(288, n_res_int);
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memset(&buf, '\0', sizeof(buf));
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long n_res_long = -1;
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i = snprintf(buf, sizeof(buf), "%286ld%ld%ln%ld", 42L, 84L, &n_res_long, 63L);
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ASSERT_EQ(i, 290);
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ASSERT_EQ(290, i);
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check_n_buffer_contents(buf);
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ASSERT_EQ(n_res_long, 288);
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ASSERT_EQ(288, n_res_long);
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memset(&buf, '\0', sizeof(buf));
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long long n_res_long_long = -1;
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i = snprintf(buf, sizeof(buf), "%286lld%lld%lln%lld", 42LL, 84LL,
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&n_res_long_long, 63LL);
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ASSERT_EQ(i, 290);
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ASSERT_EQ(290, i);
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check_n_buffer_contents(buf);
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ASSERT_EQ(n_res_long_long, 288);
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ASSERT_EQ(288, n_res_long_long);
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ASSERT_EQ(sizeof(short), 2);
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ASSERT_EQ(sizeof(int), 4);
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@ -140,48 +141,78 @@ TEST(snprintf, testNConversionSpecifier) {
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short n_res_short = -1;
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i = snprintf(buf, sizeof(buf), "%286hd%hd%hn%hd", (42 | 0xFFFF0000),
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(84 | 0xFFFF0000), &n_res_short, (63 | 0xFFFF0000));
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ASSERT_EQ(i, 290);
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ASSERT_EQ(290, i);
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check_n_buffer_contents(buf);
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ASSERT_EQ(n_res_short, 288);
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ASSERT_EQ(288, n_res_short);
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ASSERT_EQ(sizeof(unsigned char), 1);
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memset(&buf, '\0', sizeof(buf));
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signed char n_res_char = -1;
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i = snprintf(buf, sizeof(buf), "%286hhd%hhd%hhn%hhd", (42 | 0xFFFFFF00),
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(84 | 0xFFFFFF00), &n_res_char, (63 | 0xFFFFFF00));
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ASSERT_EQ(i, 290);
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ASSERT_EQ(290, i);
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check_n_buffer_contents(buf);
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ASSERT_EQ(n_res_char, (signed char)288);
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ASSERT_EQ((signed char)288, n_res_char);
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memset(&buf, '\0', sizeof(buf));
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ssize_t n_res_size_t = -1;
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i = snprintf(buf, sizeof(buf), "%286zd%zd%zn%zd", (ssize_t)42, (ssize_t)84,
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&n_res_size_t, (ssize_t)63);
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ASSERT_EQ(i, 290);
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ASSERT_EQ(290, i);
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check_n_buffer_contents(buf);
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ASSERT_EQ(n_res_size_t, 288);
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ASSERT_EQ(288, n_res_size_t);
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memset(&buf, '\0', sizeof(buf));
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intmax_t n_res_intmax_t = -1;
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i = snprintf(buf, sizeof(buf), "%286jd%jd%jn%jd", (intmax_t)42, (intmax_t)84,
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&n_res_intmax_t, (intmax_t)63);
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ASSERT_EQ(i, 290);
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ASSERT_EQ(290, i);
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check_n_buffer_contents(buf);
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ASSERT_EQ(n_res_intmax_t, 288);
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ASSERT_EQ(288, n_res_intmax_t);
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memset(&buf, '\0', sizeof(buf));
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int128_t n_res_int128_t = -1;
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i = snprintf(buf, sizeof(buf), "%286jjd%jjd%jjn%jjd", (int128_t)42,
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(int128_t)84, &n_res_int128_t, (int128_t)63);
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ASSERT_EQ(i, 290);
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ASSERT_EQ(290, i);
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check_n_buffer_contents(buf);
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ASSERT_EQ(n_res_int128_t, 288);
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ASSERT_EQ(288, n_res_int128_t);
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memset(&buf, '\0', sizeof(buf));
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ptrdiff_t n_res_ptrdiff_t = -1;
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i = snprintf(buf, sizeof(buf), "%286td%td%tn%td", (ptrdiff_t)42,
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(ptrdiff_t)84, &n_res_ptrdiff_t, (ptrdiff_t)63);
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ASSERT_EQ(i, 290);
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ASSERT_EQ(290, i);
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check_n_buffer_contents(buf);
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ASSERT_EQ(n_res_ptrdiff_t, 288);
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ASSERT_EQ(288, n_res_ptrdiff_t);
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}
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TEST(snprintf, testLongDoubleEConversionSpecifier) {
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char buf[20] = {};
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int i = snprintf(buf, sizeof(buf), "%Le", 1234567.8L);
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ASSERT_EQ(12, i);
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ASSERT_STREQ("1.234568e+06", buf);
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}
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TEST(snprintf, testLongDoubleRounding) {
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int previous_rounding = fegetround();
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ASSERT_EQ(0, fesetround(FE_DOWNWARD));
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char buf[20];
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int i = snprintf(buf, sizeof(buf), "%.3Lf", 4.4375L);
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ASSERT_EQ(5, i);
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ASSERT_STREQ("4.437", buf);
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i = snprintf(buf, sizeof(buf), "%.3Lf", -4.4375L);
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ASSERT_EQ(6, i);
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ASSERT_STREQ("-4.438", buf);
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ASSERT_EQ(0, fesetround(FE_TOWARDZERO));
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i = snprintf(buf, sizeof(buf), "%.3Lf", -4.4375L);
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ASSERT_EQ(6, i);
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ASSERT_STREQ("-4.437", buf);
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ASSERT_EQ(0, fesetround(previous_rounding));
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}
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