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#ifndef _STRING_C_ /* -*- linux-c -*- */
#define _STRING_C_
#ifndef STP_NUM_STRINGS
#define STP_NUM_STRINGS 0
#endif
#include <linux/config.h>
/** @file string.c
* @brief Implements String type.
*/
/** @addtogroup string String Functions
*
* One of the biggest restrictions the library has is that it cannot allocate things like strings off the stack.
* It is also not a good idea to dynamically allocate space for strings with kmalloc(). That leaves us with
* statically allocated space for strings. This is what is implemented in the String module. Strings use
* preallocated per-cpu buffers and are safe to use (unlike C strings).
* @{
*/
/** Maximum string size allowed in Strings */
#ifndef STP_STRING_SIZE
#define STP_STRING_SIZE 2048
#endif
struct string {
int len;
char buf[STP_STRING_SIZE];
};
static struct string _stp_string[STP_NUM_STRINGS][NR_CPUS];
typedef struct string *String;
/* set up a special stdout string */
static struct string __stp_stdout;
String _stp_stdout = &__stp_stdout;
void _stp_vsprintf (String str, const char *fmt, va_list args);
/** Initialize a String for our use.
* This grabs one of the global Strings for our temporary use.
*
* @param num Number of the preallocated String to use.
* #STP_NUM_STRINGS are statically allocated for our use. The
* translator (or author) should be sure to grab a free one.
* @returns An empty String.
*/
String _stp_string_init (int num)
{
String str;
if (num >= STP_NUM_STRINGS || num < 0) {
_stp_log ("_stp_string_init internal error: requested string exceeded allocated number or was negative");
return NULL;
}
str = &_stp_string[num][smp_processor_id()];
str->len = 0;
str->buf[0] = 0;
return str;
}
/** Sprintf into a String.
* Like printf, except output goes into a String.
* Safe because overflowing the buffer is not allowed.
* Size is limited by length of String, #STP_STRING_SIZE.
*
* @param str String
* @param fmt A printf-style format string followed by a
* variable number of args.
*/
void _stp_sprintf (String str, const char *fmt, ...)
{
int num;
va_list args;
if (str == _stp_stdout) {
int cpu = smp_processor_id();
char *buf = &_stp_pbuf[cpu][STP_PRINT_BUF_START] + _stp_pbuf_len[cpu];
int size = STP_PRINT_BUF_LEN -_stp_pbuf_len[cpu] + 1;
va_start(args, fmt);
num = vsnprintf(buf, size, fmt, args);
va_end(args);
if (unlikely(num >= size)) {
/* overflowed the buffer */
if (_stp_pbuf_len[cpu] == 0) {
_stp_pbuf_len[cpu] = STP_PRINT_BUF_LEN;
_stp_print_flush();
} else {
_stp_print_flush();
va_start(args, fmt);
_stp_vsprintf(_stp_stdout, fmt, args);
va_end(args);
}
} else {
_stp_pbuf_len[cpu] += num;
}
} else {
va_start(args, fmt);
num = vscnprintf(str->buf + str->len, STP_STRING_SIZE - str->len, fmt, args);
va_end(args);
if (likely(num > 0))
str->len += num;
}
}
/** Vsprintf into a String
* Use this if your function already has a va_list.
* You probably want _stp_sprintf().
*/
void _stp_vsprintf (String str, const char *fmt, va_list args)
{
int num;
if (str == _stp_stdout) {
int cpu = smp_processor_id();
char *buf = &_stp_pbuf[cpu][STP_PRINT_BUF_START] + _stp_pbuf_len[cpu];
int size = STP_PRINT_BUF_LEN -_stp_pbuf_len[cpu] + 1;
num = vsnprintf(buf, size, fmt, args);
if (num < size)
_stp_pbuf_len[cpu] += num;
else {
_stp_pbuf_len[cpu] = STP_PRINT_BUF_LEN;
_stp_print_flush();
}
} else {
num = vscnprintf(str->buf + str->len, STP_STRING_SIZE - str->len, fmt, args);
if (num > 0)
str->len += num;
}
}
/** ConCATenate (append) a C string to a String.
* Like strcat().
* @param str1 String
* @param str2 C string (char *)
* @sa _stp_string_cat
*/
void _stp_string_cat_cstr (String str1, const char *str2)
{
int num = strlen (str2);
if (str1 == _stp_stdout) {
char *buf;
int cpu = smp_processor_id();
int size = STP_PRINT_BUF_LEN -_stp_pbuf_len[cpu];
if (num >= size) {
_stp_print_flush();
if (num > STP_PRINT_BUF_LEN)
num = STP_PRINT_BUF_LEN;
}
buf = &_stp_pbuf[cpu][STP_PRINT_BUF_START] + _stp_pbuf_len[cpu];
strncpy (buf, str2, num + 1);
_stp_pbuf_len[cpu] += num;
} else {
int size = STP_STRING_SIZE - str1->len - 1;
if (num > size)
num = size;
strncpy (str1->buf + str1->len, str2, num);
str1->len += num;
str1->buf[str1->len] = 0;
}
}
/** ConCATenate (append) a String to a String.
* Like strcat().
* @param str1 String
* @param str2 String
* @sa _stp_string_cat
*/
void _stp_string_cat_string (String str1, String str2)
{
if (str2->len)
_stp_string_cat_cstr (str1, str2->buf);
}
void _stp_string_cat_char (String str1, const char c)
{
if (str1 == _stp_stdout) {
char *buf;
int cpu = smp_processor_id();
int size = STP_PRINT_BUF_LEN -_stp_pbuf_len[cpu];
if (1 >= size)
_stp_print_flush();
buf = &_stp_pbuf[cpu][STP_PRINT_BUF_START] + _stp_pbuf_len[cpu];
buf[0] = c;
buf[1] = 0;
_stp_pbuf_len[cpu] ++;
} else {
int size = STP_STRING_SIZE - str1->len - 1;
if (size > 0) {
char *buf = str1->buf + str1->len;
buf[0] = c;
buf[1] = 0;
str1->len ++;
}
}
}
/** Get a pointer to String's buffer
* For rare cases when a C string is needed and you have a String.
* One example is when you want to print a String with _stp_printf().
* @param str String
* @returns A C string (char *)
* @note Readonly. Don't write to this pointer or it will mess up
* the internal String state and probably mess up your output or crash something.
*/
char * _stp_string_ptr (String str)
{
return str->buf;
}
/** ConCATenate (append) a String or C string to a String.
* This macro selects the proper function to call.
* @param str1 A String
* @param str2 A String or C string (char *)
* @sa _stp_string_cat_cstr _stp_string_cat_string
*/
#define _stp_string_cat(str1, str2) \
({ \
if (__builtin_types_compatible_p (typeof (str2), char[])) { \
char *x = (char *)str2; \
_stp_string_cat_cstr(str1,x); \
} else { \
String x = (String)str2; \
_stp_string_cat_string(str1,x); \
} \
})
/** @} */
#endif /* _STRING_C_ */
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