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20faa8b84e
This overload covers the common case for initializing a string from a literal without employing the 'Output' mechanism. This way, such strings can by constructed without calling virtual functions, which in turn makes the 'String' usable for the 'init_rtld' phase of the dynamic linker.
692 lines
15 KiB
C++
692 lines
15 KiB
C++
/*
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* \brief String utilities
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* \author Norman Feske
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* \author Sebastian Sumpf
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* \date 2006-05-10
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*/
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/*
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* Copyright (C) 2006-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#ifndef _INCLUDE__UTIL__STRING_H_
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#define _INCLUDE__UTIL__STRING_H_
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#include <base/stdint.h>
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#include <base/output.h>
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#include <util/misc_math.h>
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#include <cpu/string.h>
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namespace Genode {
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class Number_of_bytes;
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class Cstring;
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template <Genode::size_t> class String;
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}
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/**
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* Wrapper of 'size_t' for selecting the 'ascii_to' function to parse byte values
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*/
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class Genode::Number_of_bytes
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{
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size_t _n;
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public:
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/**
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* Default constructor
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*/
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Number_of_bytes() : _n(0) { }
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/**
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* Constructor, to be used implicitly via assignment operator
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*/
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Number_of_bytes(size_t n) : _n(n) { }
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/**
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* Convert number of bytes to 'size_t' value
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*/
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operator size_t() const { return _n; }
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};
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/***********************
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** Utility functions **
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***********************/
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namespace Genode {
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/**
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* Return length of null-terminated string in bytes
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*/
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inline size_t strlen(const char *s)
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{
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size_t res = 0;
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for (; s && *s; s++, res++);
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return res;
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}
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/**
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* Compare two strings
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*
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* \param len maximum number of characters to compare,
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* default is unlimited
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*
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* \return 0 if both strings are equal, or
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* a positive number if s1 is higher than s2, or
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* a negative number if s1 is lower than s2
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*/
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inline int strcmp(const char *s1, const char *s2, size_t len = ~0UL)
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{
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for (; *s1 && *s1 == *s2 && len; s1++, s2++, len--) ;
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return len ? *s1 - *s2 : 0;
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}
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/**
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* Copy memory buffer to a potentially overlapping destination buffer
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*
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* \param dst destination memory block
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* \param src source memory block
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* \param size number of bytes to move
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*
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* \return pointer to destination memory block
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*/
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inline void *memmove(void *dst, const void *src, size_t size)
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{
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char *d = (char *)dst, *s = (char *)src;
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size_t i;
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if (s > d)
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for (i = 0; i < size; i++, *d++ = *s++);
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else
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for (s += size - 1, d += size - 1, i = size; i-- > 0; *d-- = *s--);
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return dst;
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}
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/**
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* Copy memory buffer to a non-overlapping destination buffer
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*
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* \param dst destination memory block
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* \param src source memory block
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* \param size number of bytes to copy
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*
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* \return pointer to destination memory block
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*/
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inline void *memcpy(void *dst, const void *src, size_t size)
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{
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char *d = (char *)dst, *s = (char *)src;
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size_t i;
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/* check for overlap */
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if ((d + size > s) && (s + size > d))
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return memmove(dst, src, size);
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/* try cpu specific version first */
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if ((i = size - memcpy_cpu(dst, src, size)) == size)
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return dst;
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d += i; s += i; size -= i;
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/* copy eight byte chunks */
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for (i = size >> 3; i > 0; i--, *d++ = *s++,
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*d++ = *s++,
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*d++ = *s++,
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*d++ = *s++,
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*d++ = *s++,
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*d++ = *s++,
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*d++ = *s++,
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*d++ = *s++);
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/* copy left over */
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for (i = 0; i < (size & 0x7); i++, *d++ = *s++);
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return dst;
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}
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/**
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* Copy string
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*
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* \param dst destination buffer
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* \param src buffer holding the null-terminated source string
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* \param size maximum number of characters to copy
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* \return pointer to destination string
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*
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* Note that this function is not fully compatible to the C standard, in
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* particular there is no zero-padding if the length of 'src' is smaller
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* than 'size'. Furthermore, in contrast to the libc version, this function
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* always produces a null-terminated string in the 'dst' buffer if the
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* 'size' argument is greater than 0.
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*/
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inline char *strncpy(char *dst, const char *src, size_t size)
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{
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/* sanity check for corner case of a zero-size destination buffer */
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if (size == 0) return dst;
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/* backup original 'dst' for the use as return value */
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char *orig_dst = dst;
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/*
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* Copy characters from 'src' to 'dst' respecting the 'size' limit.
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* In each iteration, the 'size' variable holds the maximum remaining
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* size. We have to leave at least one character free to add the null
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* termination afterwards.
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*/
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while ((size-- > 1UL) && *src)
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*dst++ = *src++;
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/* append null termination to the destination buffer */
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*dst = 0;
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return orig_dst;
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}
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/**
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* Compare memory blocks
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*
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* \return 0 if both memory blocks are equal, or
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* a negative number if 'p0' is less than 'p1', or
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* a positive number if 'p0' is greater than 'p1'
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*/
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inline int memcmp(const void *p0, const void *p1, size_t size)
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{
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const unsigned char *c0 = (const unsigned char *)p0;
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const unsigned char *c1 = (const unsigned char *)p1;
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size_t i;
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for (i = 0; i < size; i++)
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if (c0[i] != c1[i]) return c0[i] - c1[i];
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return 0;
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}
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/**
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* Fill destination buffer with given value
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*
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* \param dst destination buffer
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* \param i byte value
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* \param size buffer size in bytes
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*/
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inline void *memset(void *dst, int i, size_t size)
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{
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while (size--) ((char *)dst)[size] = i;
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return dst;
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}
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/**
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* Convert ASCII character to digit
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*
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* \param hex consider hexadecimals
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* \return digit or -1 on error
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*/
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inline int digit(char c, bool hex = false)
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{
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if (c >= '0' && c <= '9') return c - '0';
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if (hex && c >= 'a' && c <= 'f') return c - 'a' + 10;
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if (hex && c >= 'A' && c <= 'F') return c - 'A' + 10;
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return -1;
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}
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/**
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* Return true if character is a letter
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*/
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inline bool is_letter(char c)
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{
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return (((c >= 'a') && (c <= 'z')) || ((c >= 'A') && (c <= 'Z')));
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}
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/**
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* Return true if character is a digit
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*/
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inline bool is_digit(char c, bool hex = false)
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{
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return (digit(c, hex) >= 0);
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}
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/**
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* Return true if character is whitespace
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*/
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inline bool is_whitespace(char c)
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{
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return (c == '\t' || c == ' ' || c == '\n');
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}
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/**
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* Read unsigned long value from string
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*
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* \param s source string
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* \param result destination variable
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* \param base integer base
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* \return number of consumed characters
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*
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* If the base argument is 0, the integer base is detected based on the
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* characters in front of the number. If the number is prefixed with "0x",
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* a base of 16 is used, otherwise a base of 10.
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*/
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template <typename T>
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inline size_t ascii_to_unsigned(const char *s, T &result, unsigned base)
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{
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T i = 0, value = 0;
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if (!*s) return i;
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/* autodetect hexadecimal base, default is a base of 10 */
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if (base == 0) {
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/* read '0x' prefix */
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if (*s == '0' && (s[1] == 'x' || s[1] == 'X')) {
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s += 2; i += 2;
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base = 16;
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} else
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base = 10;
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}
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/* read number */
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for (int d; ; s++, i++) {
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/* read digit, stop when hitting a non-digit character */
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if ((d = digit(*s, base == 16)) < 0) break;
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/* append digit to integer value */
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value = value*base + d;
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}
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result = value;
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return i;
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}
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/**
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* Read boolean value from string
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*
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* \return number of consumed characters
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*/
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inline size_t ascii_to(char const *s, bool &result)
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{
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if (!strcmp(s, "yes", 3)) { result = true; return 3; }
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if (!strcmp(s, "true", 4)) { result = true; return 4; }
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if (!strcmp(s, "on", 2)) { result = true; return 2; }
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if (!strcmp(s, "no", 2)) { result = false; return 2; }
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if (!strcmp(s, "false", 5)) { result = false; return 5; }
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if (!strcmp(s, "off", 3)) { result = false; return 3; }
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return 0;
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}
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/**
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* Read unsigned long value from string
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*
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* \return number of consumed characters
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*/
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inline size_t ascii_to(const char *s, unsigned long &result)
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{
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return ascii_to_unsigned(s, result, 0);
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}
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/**
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* Read unsigned long long value from string
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*
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* \return number of consumed characters
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*/
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inline size_t ascii_to(const char *s, unsigned long long &result)
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{
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return ascii_to_unsigned(s, result, 0);
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}
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/**
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* Read unsigned int value from string
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*
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* \return number of consumed characters
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*/
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inline size_t ascii_to(const char *s, unsigned int &result)
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{
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return ascii_to_unsigned(s, result, 0);
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}
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/**
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* Read signed long value from string
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*
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* \return number of consumed characters
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*/
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inline size_t ascii_to(const char *s, long &result)
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{
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int i = 0;
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/* read sign */
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int sign = (*s == '-') ? -1 : 1;
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if (*s == '-' || *s == '+') { s++; i++; }
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int j = 0;
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unsigned long value = 0;
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j = ascii_to_unsigned(s, value, 10);
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if (!j) return i;
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result = sign*value;
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return i + j;
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}
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/**
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* Read 'Number_of_bytes' value from string and handle the size suffixes
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*
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* This function scales the resulting size value according to the suffixes
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* for G (2^30), M (2^20), and K (2^10) if present.
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*
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* \return number of consumed characters
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*/
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inline size_t ascii_to(const char *s, Number_of_bytes &result)
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{
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unsigned long res = 0;
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/* convert numeric part of string */
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int i = ascii_to_unsigned(s, res, 0);
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/* handle suffixes */
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if (i > 0)
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switch (s[i]) {
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case 'G': res *= 1024;
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case 'M': res *= 1024;
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case 'K': res *= 1024; i++;
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default: break;
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}
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result = res;
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return i;
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}
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/**
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* Read double float value from string
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*
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* \return number of consumed characters
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*/
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inline size_t ascii_to(const char *s, double &result)
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{
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double v = 0.0; /* decimal part */
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double d = 0.1; /* power of fractional digit */
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bool neg = false; /* sign */
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int i = 0; /* character counter */
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if (s[i] == '-') {
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neg = true;
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i++;
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}
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/* parse decimal part of number */
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for (; s[i] && is_digit(s[i]); i++)
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v = 10*v + digit(s[i], false);
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/* if no fractional part exists, return current value */
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if (s[i] != '.') {
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result = neg ? -v : v;
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return i;
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}
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/* skip comma */
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i++;
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/* parse fractional part of number */
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for (; s[i] && is_digit(s[i]); i++, d *= 0.1)
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v += d*digit(s[i], false);
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result = neg ? -v : v;
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return i;
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}
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/**
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* Check for end of quotation
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*
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* Checks if next character is non-backslashed quotation mark.
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*/
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inline bool end_of_quote(const char *s) {
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return s[0] != '\\' && s[1] == '\"'; }
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/**
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* Unpack quoted string
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*
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* \param src source string including the quotation marks ("...")
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* \param dst destination buffer
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*
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* \return number of characters or negative error code
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*/
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inline int unpack_string(const char *src, char *dst, int dst_len)
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{
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/* check if quoted string */
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if (*src != '"') return -1;
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src++;
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int i = 0;
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for (; *src && !end_of_quote(src - 1) && (i < dst_len - 1); i++) {
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/* transform '\"' to '"' */
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if (src[0] == '\\' && src[1] == '\"') {
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*dst++ = '"';
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src += 2;
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} else
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*dst++ = *src++;
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}
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/* write terminating null */
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*dst = 0;
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return i;
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}
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}
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/**
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* Helper for the formatted output of a length-constrained character buffer
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*/
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class Genode::Cstring
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{
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private:
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char const * const _str;
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size_t const _len;
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static size_t _init_len(char const *str, size_t max_len)
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{
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/*
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* In contrast to 'strlen' we stop searching for a terminating
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* null once we reach 'max_len'.
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*/
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size_t res = 0;
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for (; str && *str && res < max_len; str++, res++);
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return res;
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}
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public:
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/**
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* Constructor
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*
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* \param str null-terminated character buffer
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*/
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Cstring(char const *str) : _str(str), _len(strlen(str)) { }
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/**
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* Constructor
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*
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* \param str character buffer, not neccessarily null-terminated
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* \param max_len maximum number of characters to consume
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*
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* The 'Cstring' contains all characters up to a terminating null in
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* the 'str' buffer but not more that 'max_len' characters.
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*/
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Cstring(char const *str, size_t max_len)
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:
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_str(str), _len(_init_len(str, max_len))
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{ }
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void print(Output &out) const { out.out_string(_str, _len); }
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size_t length() const { return _len; }
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};
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/**
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* Buffer that contains a null-terminated string
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*
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* \param CAPACITY buffer size including the terminating zero,
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* must be higher than zero
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*/
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template <Genode::size_t CAPACITY>
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class Genode::String
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{
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private:
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char _buf[CAPACITY];
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/**
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* Number of chars contained in '_buf' including the terminating null
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*/
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size_t _len;
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/**
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* Output facility that targets a character buffer
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*/
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struct Local_output : Output
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{
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char * const _buf;
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size_t _num_chars = 0;
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/**
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* Return true if '_buf' can fit at least one additional 'char'.
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*/
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bool _capacity_left() const { return CAPACITY - _num_chars - 1; }
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void _append(char c) { _buf[_num_chars++] = c; }
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Local_output(char *buf) : _buf(buf) { }
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size_t num_chars() const { return _num_chars; }
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void out_char(char c) override { if (_capacity_left()) _append(c); }
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void out_string(char const *str, size_t n) override
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{
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while (n-- > 0 && _capacity_left())
|
|
_append(*str++);
|
|
}
|
|
};
|
|
|
|
public:
|
|
|
|
constexpr static size_t size() { return CAPACITY; }
|
|
|
|
String() : _len(0) { }
|
|
|
|
/**
|
|
* 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, typename... TAIL>
|
|
String(T const &arg, TAIL &&... args)
|
|
{
|
|
/* initialize string content */
|
|
Local_output output(_buf);
|
|
Genode::print(output, arg, args...);
|
|
|
|
/* 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))
|
|
{
|
|
Genode::strncpy(_buf, cstr, _len);
|
|
}
|
|
|
|
/**
|
|
* Copy constructor
|
|
*/
|
|
template <unsigned N>
|
|
String(String<N> const &other) : _len(min(other.length(), CAPACITY))
|
|
{
|
|
Genode::strncpy(_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;
|
|
}
|
|
|
|
void print(Output &out) const { Genode::print(out, string()); }
|
|
};
|
|
|
|
#endif /* _INCLUDE__UTIL__STRING_H_ */
|