04b8418b54
By now, the memcmp implementation of Genode's basic string utilities just returned whether two memory blocks are equal or differ. It gave no hint which block is greater, or lesser than the other one. This isn't the behaviour anticipated by implementations that rely on the C standard memcmp, e.g. GCC's libsupc++, or the nic_bridge's AVL tree implementation.
453 lines
9.7 KiB
C++
453 lines
9.7 KiB
C++
/*
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* \brief String utility functions
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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 <util/misc_math.h>
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#include <cpu/string.h>
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namespace Genode {
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/**
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* Determine length of null-terminated string
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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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* \retval 0 strings are equal
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* \retval >0 s1 is higher than s2
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* \retval <0 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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* Simple memmove
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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 block
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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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* This function is not fully compatible to the C standard, in particular
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* there is no zero-padding if the length of 'src' is smaller than 'size'.
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* Furthermore, in contrast to the libc version, this function always
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* produces a null-terminated string in the 'dst' buffer if the 'size'
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* 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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* \retval 0 memory blocks are equal
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* \retval <0 first memory block is less than second one
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* \retval >0 first memory block is greater than second one
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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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* Memset
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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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* Convert ASCII string to another type
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*
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* \param T destination type of conversion
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* \param s null-terminated source string
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* \param result destination pointer to conversion result
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* \param base base, autodetected if set to 0
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* \return number of consumed characters
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*
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* Please note that 'base' and 's_max_len' are not evaluated by all
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* template specializations.
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*/
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template <typename T>
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inline size_t ascii_to(const char *s, T *result, unsigned base = 0);
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/**
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* Read unsigned long value from string
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*/
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template <>
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inline size_t ascii_to<unsigned long>(const char *s, unsigned long *result,
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unsigned base)
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{
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unsigned long 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 unsigned int value from string
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*/
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template <>
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inline size_t ascii_to<unsigned int>(const char *s, unsigned int *result,
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unsigned base)
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{
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unsigned long result_long = 0;
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size_t ret = ascii_to<unsigned long>(s, &result_long, base);
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*result = result_long;
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return ret;
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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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template <>
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inline size_t ascii_to<long>(const char *s, long *result, unsigned base)
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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(s, &value, base);
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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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* Wrapper of 'size_t' for selecting 'ascii_to' specialization
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*/
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class 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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* 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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template <>
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inline size_t ascii_to(const char *s, Number_of_bytes *result, unsigned)
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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(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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template <>
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inline size_t ascii_to<double>(const char *s, double *result, unsigned)
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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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#endif /* _INCLUDE__UTIL__STRING_H_ */
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