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/*
** Test a function that formats and writes characters into a string buffer.
** This program does not test formatting. It tests some behaviors that are
** specific to the buffer. It tests that certain conditions are handled
** properly.
**
** 2015-07-17, Greg King
*/
#include <conio.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
static const char format[] = "1234567890\nabcdefghijklmnopqrstuvwxyz\n%u\n%s\n\n";
#define FORMAT_SIZE (sizeof format - 2u - 2u - 1u)
#define arg1 12345u
#define ARG1_SIZE (5u)
static const char arg2[] = "!@#$%^&*()-+";
#define ARG2_SIZE (sizeof arg2 - 1u)
#define STRING_SIZE (FORMAT_SIZE + ARG1_SIZE + ARG2_SIZE)
static char buf[256];
static int size;
static void fillbuf(void)
{
memset(buf, 0xFF, sizeof buf - 1u);
buf[sizeof buf - 1u] = '\0';
}
unsigned char main(void)
{
static unsigned char failures = 0;
/* Show what sprintf() should create. */
if ((size = printf(format, arg1, arg2)) != STRING_SIZE) {
++failures;
printf("printf() gave the wrong size: %d.\n", size);
}
/* Test the normal behavior of sprintf(). */
fillbuf();
size = sprintf(buf, format, arg1, arg2);
fputs(buf, stdout);
if (size != STRING_SIZE) {
++failures;
printf("sprintf() gave the wrong size: %d.\n", size);
}
/* Test the normal behavior of snprintf(). */
fillbuf();
size = snprintf(buf, sizeof buf, format, arg1, arg2);
fputs(buf, stdout);
if (size != STRING_SIZE) {
++failures;
printf("snprintf(sizeof buf) gave the wrong size:\n %d.\n", size);
}
/* Does snprintf() return the full-formatted size even when the buffer
** is short? Does it write beyond the end of that buffer?
*/
fillbuf();
size = snprintf(buf, STRING_SIZE - 5u, format, arg1, arg2);
if (size != STRING_SIZE) {
++failures;
printf("snprintf(STRING_SIZE-5) gave the wrong size:\n %d.\n", size);
}
if (buf[STRING_SIZE - 5u - 1u] != '\0' || buf[STRING_SIZE - 5u] != 0xFF) {
++failures;
printf("snprintf(STRING_SIZE-5) wrote beyond\n the end of the buffer.\n");
}
/* Does snprintf() detect a buffer size that is too big? */
fillbuf();
errno = 0;
size = snprintf(buf, 0x8000, format, arg1, arg2);
if (size >= 0) {
++failures;
printf("snprintf(0x8000) didn't give an error:\n %d; errno=%d.\n", size, errno);
} else {
printf("snprintf(0x8000) did give an error:\n errno=%d.\n", errno);
}
if (buf[0] != 0xFF) {
++failures;
printf("snprintf(0x8000) wrote into the buffer.\n");
}
/* snprintf() must measure the length of the formatted output even when the
** buffer size is zero. But, it must not touch the buffer.
*/
fillbuf();
size = snprintf(buf, 0, format, arg1, arg2);
if (size != STRING_SIZE) {
++failures;
printf("snprintf(0) gave the wrong size:\n %d.\n", size);
}
if (buf[0] != 0xFF) {
++failures;
printf("snprintf(0) wrote into the buffer.\n");
}
/* Does sprintf() detect a zero buffer-pointer? */
errno = 0;
size = sprintf(NULL, format, arg1, arg2);
if (size >= 0) {
++failures;
printf("sprintf(NULL) didn't give an error:\n %d; errno=%d.\n", size, errno);
} else {
printf("sprintf(NULL) did give an error:\n errno=%d.\n", errno);
}
/* snprintf() must measure the length of the formatted output even when the
** buffer size is zero. A zero pointer is not an error, in that case.
*/
size = snprintf(NULL, 0, format, arg1, arg2);
if (size != STRING_SIZE) {
++failures;
printf("snprintf(NULL,0) gave the wrong size:\n %d.\n", size);
}
if (failures != 0) {
printf("There were %u", failures);
} else {
printf("There were no");
}
printf(" failures.\nTap a key. ");
cgetc();
return failures;
}
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