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genode/repos/base/include/util/string.h
Norman Feske 19c13877ca Replace use of 'typedef' by 'using' 
Issue #5227
2024-07-02 12:00:11 +02:00

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/*
* \brief String utilities
* \author Norman Feske
* \author Sebastian Sumpf
* \date 2006-05-10
*/
/*
* Copyright (C) 2006-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__UTIL__STRING_H_
#define _INCLUDE__UTIL__STRING_H_
#include <base/stdint.h>
#include <base/output.h>
#include <util/misc_math.h>
#include <util/noncopyable.h>
#include <cpu/string.h>
namespace Genode {
class Number_of_bytes;
class Byte_range_ptr;
class Const_byte_range_ptr;
class Cstring;
template <Genode::size_t> class String;
}
/**
* Wrapper of 'size_t' for selecting the 'ascii_to' function to parse byte values
*/
class Genode::Number_of_bytes
{
size_t _n;
public:
/**
* Default constructor
*/
Number_of_bytes() : _n(0) { }
/**
* Constructor, to be used implicitly via assignment operator
*/
Number_of_bytes(size_t n) : _n(n) { }
/**
* Convert number of bytes to 'size_t' value
*/
operator size_t() const { return _n; }
void print(Output &output) const
{
using Genode::print;
enum { KB = 1024UL, MB = KB*1024UL, GB = MB*1024UL };
if (_n == 0) print(output, 0);
else if (_n % GB == 0) print(output, _n/GB, "G");
else if (_n % MB == 0) print(output, _n/MB, "M");
else if (_n % KB == 0) print(output, _n/KB, "K");
else print(output, _n);
}
};
/**
* Data structure for describing a mutable byte buffer
*
* The type is intended to be used as 'Byte_range_ptr const &' argument.
*/
struct Genode::Byte_range_ptr : Noncopyable
{
struct {
char * const start;
size_t const num_bytes;
};
Byte_range_ptr(char *start, size_t num_bytes)
: start(start), num_bytes(num_bytes) { }
};
/**
* Data structure for describing a constant byte buffer
*/
struct Genode::Const_byte_range_ptr : Noncopyable
{
struct {
char const * const start;
size_t const num_bytes;
};
bool contains(char const *ptr) const
{
return (ptr >= start) && (ptr <= start + num_bytes - 1);
}
bool contains(void const *ptr) const
{
return contains((char const *)ptr);
}
Const_byte_range_ptr(char const *start, size_t num_bytes)
: start(start), num_bytes(num_bytes) { }
};
/***********************
** Utility functions **
***********************/
namespace Genode {
/**
* Return length of null-terminated string in bytes
*/
__attribute((optimize("no-tree-loop-distribute-patterns")))
inline size_t strlen(const char *s)
{
size_t res = 0;
for (; s && *s; s++, res++);
return res;
}
/**
* Compare two strings
*
* \param len maximum number of characters to compare,
* default is unlimited
*
* \return 0 if both strings are equal, or
* a positive number if s1 is higher than s2, or
* a negative number if s1 is lower than s2
*/
inline int strcmp(const char *s1, const char *s2, size_t len = ~0UL)
{
for (; *s1 && *s1 == *s2 && len; s1++, s2++, len--) ;
return len ? *s1 - *s2 : 0;
}
/**
* Copy memory buffer to a potentially overlapping destination buffer
*
* \param dst destination memory block
* \param src source memory block
* \param size number of bytes to move
*
* \return pointer to destination memory block
*/
inline void *memmove(void *dst, const void *src, size_t size)
{
char *d = (char *)dst, *s = (char *)src;
size_t i;
if (s > d)
for (i = 0; i < size; i++, *d++ = *s++);
else
for (s += size - 1, d += size - 1, i = size; i-- > 0; *d-- = *s--);
return dst;
}
/**
* Copy memory buffer to a non-overlapping destination buffer
*
* \param dst destination memory block
* \param src source memory block
* \param size number of bytes to copy
*
* \return pointer to destination memory block
*/
inline void *memcpy(void *dst, const void *src, size_t size)
{
char *d = (char *)dst, *s = (char *)src;
size_t i;
/* check for overlap */
if ((d + size > s) && (s + size > d))
return memmove(dst, src, size);
/* try cpu specific version first */
if ((i = size - memcpy_cpu(dst, src, size)) == size)
return dst;
d += i; s += i; size -= i;
/* copy eight byte chunks */
for (i = size >> 3; i > 0; i--, *d++ = *s++,
*d++ = *s++,
*d++ = *s++,
*d++ = *s++,
*d++ = *s++,
*d++ = *s++,
*d++ = *s++,
*d++ = *s++);
/* copy left over */
for (i = 0; i < (size & 0x7); i++, *d++ = *s++);
return dst;
}
/**
* Copy string
*
* \param dst destination buffer
* \param src buffer holding the null-terminated source string
* \param size maximum number of characters to copy
*
* In contrast to the POSIX 'strncpy' function, 'copy_cstring' always
* produces a null-terminated string in the 'dst' buffer if the 'size'
* argument is greater than 0.
*/
inline void copy_cstring(char *dst, const char *src, size_t size)
{
/* sanity check for corner case of a zero-size destination buffer */
if (size == 0) return;
/*
* Copy characters from 'src' to 'dst' respecting the 'size' limit.
* In each iteration, the 'size' variable holds the maximum remaining
* size. We have to leave at least one character free to add the null
* termination afterwards.
*/
while ((size-- > 1UL) && *src)
*dst++ = *src++;
/* append null termination to the destination buffer */
*dst = 0;
}
/**
* Compare memory blocks
*
* \return 0 if both memory blocks are equal, or
* a negative number if 'p0' is less than 'p1', or
* a positive number if 'p0' is greater than 'p1'
*/
inline int memcmp(const void *p0, const void *p1, size_t size)
{
const unsigned char *c0 = (const unsigned char *)p0;
const unsigned char *c1 = (const unsigned char *)p1;
size_t i;
for (i = 0; i < size; i++)
if (c0[i] != c1[i]) return c0[i] - c1[i];
return 0;
}
/**
* Fill destination buffer with given value
*
* \param dst destination buffer
* \param i byte value
* \param size buffer size in bytes
*
* The compiler attribute is needed to prevent the
* generation of a 'memset()' call in the 'while' loop
* with gcc 10.
*/
__attribute((optimize("no-tree-loop-distribute-patterns")))
inline void *memset(void *dst, uint8_t i, size_t size)
{
using word_t = unsigned long;
enum {
LEN = sizeof(word_t),
MASK = LEN-1
};
size_t d_align = (size_t)dst & MASK;
uint8_t* d = (uint8_t*)dst;
/* write until word aligned */
for (; d_align && d_align < LEN && size;
d_align++, size--, d++)
*d = i;
word_t word = i;
word |= word << 8;
word |= word << 16;
if (LEN == 8)
word |= (word << 16) << 16;
/* write 8-word chunks (likely matches cache line size) */
for (; size >= 8*LEN; size -= 8*LEN, d += 8*LEN) {
((word_t *)d)[0] = word;
((word_t *)d)[1] = word;
((word_t *)d)[2] = word;
((word_t *)d)[3] = word;
((word_t *)d)[4] = word;
((word_t *)d)[5] = word;
((word_t *)d)[6] = word;
((word_t *)d)[7] = word;
}
/* write remaining words */
for (; size >= LEN; size -= LEN, d += LEN)
((word_t *)d)[0] = word;
/* write remaining bytes */
for (; size; size--, d++)
*d = i;
return dst;
}
/**
* Convert ASCII character to digit
*
* \param hex consider hexadecimals
* \return digit or -1 on error
*/
inline int digit(char c, bool hex = false)
{
if (c >= '0' && c <= '9') return c - '0';
if (hex && c >= 'a' && c <= 'f') return c - 'a' + 10;
if (hex && c >= 'A' && c <= 'F') return c - 'A' + 10;
return -1;
}
/**
* Return true if character is a letter
*/
inline bool is_letter(char c)
{
return (((c >= 'a') && (c <= 'z')) || ((c >= 'A') && (c <= 'Z')));
}
/**
* Return true if character is a digit
*/
inline bool is_digit(char c, bool hex = false)
{
return (digit(c, hex) >= 0);
}
/**
* Return true if character is whitespace
*/
inline bool is_whitespace(char c)
{
return (c == '\t' || c == ' ' || c == '\n');
}
/**
* Read unsigned long value from string
*
* \param s source string
* \param result destination variable
* \param base integer base
* \return number of consumed characters
*
* If the base argument is 0, the integer base is detected based on the
* characters in front of the number. If the number is prefixed with "0x",
* a base of 16 is used, otherwise a base of 10.
*/
template <typename T>
inline size_t ascii_to_unsigned(const char *s, T &result, uint8_t base)
{
size_t i = 0;
if (!*s) return i;
/* autodetect hexadecimal base, default is a base of 10 */
if (base == 0) {
/* read '0x' prefix */
if (*s == '0' && (s[1] == 'x' || s[1] == 'X')) {
s += 2; i += 2;
base = 16;
} else
base = 10;
}
/* read number */
T value = 0;
while (true) {
/* read digit, stop when hitting a non-digit character */
int const d = digit(*s, base == 16);
if (d < 0)
break;
/* append digit to integer value */
uint8_t const valid_digit = (uint8_t)d;
value = (T)(value*base + valid_digit);
s++, i++;
}
result = value;
return i;
}
/**
* Read boolean value from string
*
* \return number of consumed characters
*/
inline size_t ascii_to(char const *s, bool &result)
{
if (!strcmp(s, "yes", 3)) { result = true; return 3; }
if (!strcmp(s, "true", 4)) { result = true; return 4; }
if (!strcmp(s, "on", 2)) { result = true; return 2; }
if (!strcmp(s, "no", 2)) { result = false; return 2; }
if (!strcmp(s, "false", 5)) { result = false; return 5; }
if (!strcmp(s, "off", 3)) { result = false; return 3; }
return 0;
}
/**
* Read unsigned char value from string
*
* \return number of consumed characters
*/
inline size_t ascii_to(const char *s, unsigned char &result)
{
return ascii_to_unsigned(s, result, 0);
}
/**
* Read unsigned short value from string
*
* \return number of consumed characters
*/
inline size_t ascii_to(const char *s, unsigned short &result)
{
return ascii_to_unsigned(s, result, 0);
}
/**
* Read unsigned long value from string
*
* \return number of consumed characters
*/
inline size_t ascii_to(const char *s, unsigned long &result)
{
return ascii_to_unsigned(s, result, 0);
}
/**
* Read unsigned long long value from string
*
* \return number of consumed characters
*/
inline size_t ascii_to(const char *s, unsigned long long &result)
{
return ascii_to_unsigned(s, result, 0ULL);
}
/**
* Read unsigned int value from string
*
* \return number of consumed characters
*/
inline size_t ascii_to(const char *s, unsigned int &result)
{
return ascii_to_unsigned(s, result, 0);
}
/**
* Read signed value from string
*
* \return number of consumed characters
*/
template <typename T>
inline size_t ascii_to_signed(const char *s, T &result)
{
size_t i = 0;
/* read sign */
int sign = (*s == '-') ? -1 : 1;
if (*s == '-' || *s == '+') { s++; i++; }
T value = 0;
size_t const j = ascii_to_unsigned(s, value, 0);
if (!j)
return i;
result = sign*value;
return i + j;
}
/**
* Read signed long value from string
*
* \return number of consumed characters
*/
inline size_t ascii_to(const char *s, long &result)
{
return ascii_to_signed<long>(s, result);
}
/**
* Read signed integer value from string
*
* \return number of consumed characters
*/
inline size_t ascii_to(const char *s, int &result)
{
return ascii_to_signed<int>(s, result);
}
/**
* Read 'Number_of_bytes' value from string and handle the size suffixes
*
* This function scales the resulting size value according to the suffixes
* for G (2^30), M (2^20), and K (2^10) if present.
*
* \return number of consumed characters
*/
inline size_t ascii_to(const char *s, Number_of_bytes &result)
{
unsigned long res = 0;
/* convert numeric part of string */
size_t i = ascii_to_unsigned(s, res, 0);
/* handle suffixes */
if (i > 0)
switch (s[i]) {
case 'G': res *= 1024*1024*1024; i++; break;
case 'M': res *= 1024*1024; i++; break;
case 'K': res *= 1024; i++; break;
default: break;
}
result = res;
return i;
}
/**
* Read double float value from string
*
* \return number of consumed characters
*/
inline size_t ascii_to(const char *s, double &result)
{
double v = 0.0; /* decimal part */
double d = 0.1; /* power of fractional digit */
bool neg = false; /* sign */
int i = 0; /* character counter */
if (s[i] == '-') {
neg = true;
i++;
}
/* parse decimal part of number */
for (; s[i] && is_digit(s[i]); i++)
v = 10*v + digit(s[i], false);
/* if no fractional part exists, return current value */
if (s[i] != '.') {
result = neg ? -v : v;
return i;
}
/* skip comma */
i++;
/* parse fractional part of number */
for (; s[i] && is_digit(s[i]); i++, d *= 0.1)
v += d*digit(s[i], false);
result = neg ? -v : v;
return i;
}
/**
* Unpack quoted string
*
* \param src source string including the quotation marks ("...")
* \param dst destination buffer
*
* \return number of characters or ~0UL on error
*/
inline size_t unpack_string(const char *src, char *dst, size_t const dst_len)
{
/* check if quoted string */
if ((*src != '"') || (dst_len < 1))
return ~0UL;
src++;
auto end_of_quote = [] (const char *s) {
return s[0] != '\\' && s[1] == '\"'; };
size_t i = 0;
for (; *src && !end_of_quote(src - 1) && (i < dst_len - 1); i++) {
/* transform '\"' to '"' */
if (src[0] == '\\' && src[1] == '\"') {
*dst++ = '"';
src += 2;
} else
*dst++ = *src++;
}
/* write terminating null */
*dst = 0;
return i;
}
}
/**
* Helper for the formatted output of a length-constrained character buffer
*/
class Genode::Cstring
{
private:
char const * const _str;
size_t const _len;
static size_t _init_len(char const *str, size_t max_len)
{
/*
* In contrast to 'strlen' we stop searching for a terminating
* null once we reach 'max_len'.
*/
size_t res = 0;
for (; res < max_len && str && *str; str++, res++);
return res;
}
public:
/**
* Constructor
*
* \param str null-terminated character buffer
*/
Cstring(char const *str) : _str(str), _len(strlen(str)) { }
/**
* Constructor
*
* \param str character buffer, not neccessarily null-terminated
* \param max_len maximum number of characters to consume
*
* The 'Cstring' contains all characters up to a terminating null in
* the 'str' buffer but not more that 'max_len' characters.
*/
Cstring(char const *str, size_t max_len)
:
_str(str), _len(_init_len(str, max_len))
{ }
void print(Output &out) const { out.out_string(_str, _len); }
size_t length() const { return _len; }
};
/**
* Buffer that contains a null-terminated string
*
* \param CAPACITY buffer size including the terminating zero,
* must be higher than zero
*/
template <Genode::size_t CAPACITY>
class Genode::String
{
private:
char _buf[CAPACITY];
/**
* Number of chars contained in '_buf' including the terminating null
*/
size_t _len { 0 };
/**
* Output facility that targets a character buffer
*/
class Local_output : public Output
{
private:
/*
* Noncopyable
*/
Local_output(Local_output const &);
Local_output &operator = (Local_output const &);
public:
char * const _buf;
size_t _num_chars = 0;
/**
* Return true if '_buf' can fit at least one additional 'char'.
*/
bool _capacity_left() const { return CAPACITY - _num_chars - 1; }
void _append(char c) { _buf[_num_chars++] = c; }
Local_output(char *buf) : _buf(buf) { }
size_t num_chars() const { return _num_chars; }
void out_char(char c) override { if (_capacity_left()) _append(c); }
void out_string(char const *str, size_t n) override
{
while (n-- > 0 && _capacity_left() && *str)
_append(*str++);
}
};
public:
constexpr static size_t size() { return CAPACITY; }
String() { }
/**
* Constructor
*
* The constructor accepts a non-zero number of arguments, which
* are concatenated in the resulting 'String' object. In order to
* generate the textual representation of the arguments, the
* argument types must support the 'Output' interface, e.g., by
* providing 'print' method.
*
* If the textual representation of the supplied arguments exceeds
* 'CAPACITY', the resulting string gets truncated. The caller may
* check for this condition by evaluating the 'length' of the
* constructed 'String'. If 'length' equals 'CAPACITY', the string
* may fit perfectly into the buffer or may have been truncated.
* In general, it would be safe to assume the latter.
*/
template <typename T>
String(T const &head, auto &&... tail)
{
/* initialize string content */
Local_output output(_buf);
Genode::print(output, head, tail...);
/* add terminating null */
_buf[output.num_chars()] = 0;
_len = output.num_chars() + 1;
}
/**
* Constructor
*
* Overload for the common case of constructing a 'String' from a
* string literal.
*/
String(char const *cstr) : _len(min(Genode::strlen(cstr) + 1, CAPACITY))
{
copy_cstring(_buf, cstr, _len);
}
/**
* Copy constructor
*/
template <unsigned N>
String(String<N> const &other) : _len(min(other.length(), CAPACITY))
{
copy_cstring(_buf, other.string(), _len);
}
/**
* Return length of string, including the terminating null character
*/
size_t length() const { return _len; }
static constexpr size_t capacity() { return CAPACITY; }
bool valid() const {
return (_len <= CAPACITY) && (_len != 0) && (_buf[_len - 1] == '\0'); }
char const *string() const { return valid() ? _buf : ""; }
bool operator == (char const *other) const
{
return strcmp(string(), other) == 0;
}
bool operator != (char const *other) const
{
return strcmp(string(), other) != 0;
}
template <size_t OTHER_CAPACITY>
bool operator == (String<OTHER_CAPACITY> const &other) const
{
return strcmp(string(), other.string()) == 0;
}
template <size_t OTHER_CAPACITY>
bool operator != (String<OTHER_CAPACITY> const &other) const
{
return strcmp(string(), other.string()) != 0;
}
template <size_t N>
bool operator > (String<N> const &other) const
{
return strcmp(string(), other.string()) > 0;
}
void print(Output &out) const { Genode::print(out, string()); }
};
#endif /* _INCLUDE__UTIL__STRING_H_ */
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