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Merge pull request #4113 from facebook/fix4110

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formatString_u() can display numbers > 100
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Yann Collet 2024-08-08 17:19:08 -07:00 committed by GitHub
commit 10e2a8042c
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1 changed files with 36 additions and 27 deletions
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63
programs/benchzstd.c
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@ -139,52 +139,61 @@ static const size_t maxMemory = (sizeof(size_t) == 4)
return r; \
}
/* replacement for snprintf(), which is not supported by C89
* sprintf() would be the supported one, but it's labelled unsafe,
* so some modern static analyzer will flag it as such, making it unusable.
* formatString_u() replaces snprintf() for the specific case where there are only %u arguments */
static size_t uintSize(unsigned value)
{
size_t size = 1;
while (value >= 10) {
size++;
value /= 10;
}
return size;
}
/* Note: presume @buffer is large enough */
static void writeUint_varLen(char* buffer, size_t capacity, unsigned value)
{
int endPos = (int)uintSize(value) - 1;
assert(uintSize(value) >= 1);
assert(uintSize(value) < capacity); (void)capacity;
while (endPos >= 0) {
char c = '0' + (char)(value % 10);
buffer[endPos--] = c;
value /= 10;
}
}
/* replacement for snprintf(), which is not supported by C89.
* sprintf() would be the supported one, but it's labelled unsafe:
* modern static analyzer will flag sprintf() as dangerous, making it unusable.
* formatString_u() replaces snprintf() for the specific case where there is only one %u argument */
static int formatString_u(char* buffer, size_t buffer_size, const char* formatString, unsigned int value)
{
size_t const valueSize = uintSize(value);
size_t written = 0;
int i;
assert(value <= 100);
for (i = 0; formatString[i] != '\0' && written < buffer_size - 1; ++i) {
for (i = 0; formatString[i] != '\0' && written < buffer_size - 1; i++) {
if (formatString[i] != '%') {
buffer[written++] = formatString[i];
continue;
}
if (formatString[++i] == 'u') {
/* Handle single digit */
if (value < 10) {
buffer[written++] = '0' + (char)value;
} else if (value < 100) {
/* Handle two digits */
if (written >= buffer_size - 2) {
return -1; /* buffer overflow */
}
buffer[written++] = '0' + (char)(value / 10);
buffer[written++] = '0' + (char)(value % 10);
} else { /* 100 */
if (written >= buffer_size - 3) {
return -1; /* buffer overflow */
}
buffer[written++] = '1';
buffer[written++] = '0';
buffer[written++] = '0';
}
i++;
if (formatString[i] == 'u') {
if (written + valueSize >= buffer_size) abort(); /* buffer not large enough */
writeUint_varLen(buffer + written, buffer_size - written, value);
written += valueSize;
} else if (formatString[i] == '%') { /* Check for escaped percent sign */
buffer[written++] = '%';
} else {
return -1; /* unsupported format */
abort(); /* unsupported format */
}
}
if (written < buffer_size) {
buffer[written] = '\0';
} else {
buffer[0] = '\0'; /* Handle truncation */
abort(); /* buffer not large enough */
}
return (int)written;