lib/libc/string.c

   1 /* lib/libc/string.c
   2  *
   3  * Copyright (C) 2007 David Cohen <dacohen@gmail.com>
   4  * Copyright (C) 2007 Felipe Balbi <me@felipebalbi.com>
   5  *
   6  * This file is part of Tinyx Nanokernel Project.
   7  *
   8  * Tinyx is free software: you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation, either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * Tinyx is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with Tinyx.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include <libc/string.h>
  23
  24 /**
  25  * memset - Fill a memory region with data
  26  * @mem: Pointer to the start of the area.
  27  * @data: The byte to fill the area with
  28  * @count: The size of the area.
  29  */
  30 void *memset(void *mem, int data, size_t count)
  31 {
  32         char *tmp = mem;
  33
  34         while (count--)
  35                 *tmp++ = data;
  36         return mem;
  37 }
  38
  39 /**
  40  * memcpy - Copy memory areas
  41  * @dest: Destination of copy task
  42  * @src: Where the data to copy from is
  43  * @count: The size of the area.
  44  */
  45 void *memcpy(void *dest, const void *src, size_t count)
  46 {
  47         char *tmp = dest;
  48         const char *s = src;
  49
  50         while (count--)
  51                 *tmp++ = *s++;
  52         return dest;
  53 }
  54
  55 /**
  56  * strcat - Apend one string to another
  57  * @str1: The destination string
  58  * @str2: The source string
  59  */
  60 char *strcat(char *str1, const char *str2)
  61 {
  62         char *tmp = str1;
  63
  64         while (*str1)
  65                 str1++;
  66         while ((*str1++ = *str2++) != '\0')
  67                 ;
  68         return tmp;
  69 }
  70
  71 /**
  72  * strchr - Find the first ocurrence of a character in a string
  73  * @str: The string to search into
  74  * @ch: The character to find
  75  */
  76 char *strchr(const char *str, int ch)
  77 {
  78         for (; *str != (char)ch; ++str)
  79                 if (*str == '\0')
  80                         return NULL;
  81         return (char *)str;
  82 }
  83
  84 /**
  85  * strcoll - Compare two strings
  86  * @str1: First string
  87  * @str2: Second string
  88  */
  89 int strcoll(const char *str1, const char *str2)
  90 {
  91         while ((*str1) == (*str2)) {
  92                 if (!*str1++)
  93                         return 0;
  94                 str2++;
  95         }
  96         while ((*str1++) && (*str2++));
  97
  98         return (*str1) ? 1 : -1;
  99 }
 100
 101 /**
 102  * strcmp - Lex comparation of two strings
 103  * @str1: First string
 104  * @str2: Second string
 105  */
 106 int strcmp(const char *str1, const char *str2)
 107 {
 108         signed char ret;
 109
 110         while (1) {
 111                 if ((ret = *str1 - *str2++) != 0 || !*str1++)
 112                         break;
 113         }
 114         return ret;
 115 }
 116
 117 /**
 118  * strcpy - Copy the contents of str2 into str1
 119  * @str1: The destination string
 120  * @str2: The source string
 121  */
 122 char *strcpy(char *str1, const char *str2)
 123 {
 124         char *tmp = str1;
 125
 126         while ((*str1++ = *str2++) != '\0');
 127
 128         return tmp;
 129 }
 130
 131 /**
 132  * strlen - Find the length of a string
 133  * @str: The string to be sized
 134  */
 135 size_t strlen(const char *str)
 136 {
 137         const char *tmp;
 138
 139         for (tmp = str; *tmp != '\0'; ++tmp);
 140
 141         return tmp - str;
 142 }
 143
 144 /**
 145  * strncat - Append count characters of str2 into str1
 146  * @str1: The destination string
 147  * @str2: The source string
 148  * @count: The number of characters to append
 149  */
 150 char *strncat(char *str1, const char *str2, size_t count)
 151 {
 152         char *tmp = str1;
 153
 154         if (count) {
 155                 while (*str1)
 156                         str1++;
 157                 while ((*str1++ = *str2++) != 0) {
 158                         if (--count == 0) {
 159                                 *str1 = '\0';
 160                                 break;
 161                         }
 162                 }
 163         }
 164         return tmp;
 165 }
 166
 167 /**
 168  * strncmp - Comparison of count characters
 169  * @str1: The destination string
 170  * @str2: The source string
 171  * @count: The number of characters
 172  */
 173 int strncmp(const char *str1, const char *str2, size_t count)
 174 {
 175         signed char ret = 0;
 176
 177         while (count) {
 178                 if ((ret = *str1 - *str2++) != 0 || !*str1++)
 179                         break;
 180                 count--;
 181         }
 182         return ret;
 183 }
 184
 185 /**
 186  * strncpy - Copy count characters from str2 into str1
 187  * @str1: The destination string
 188  * @str2: The source string
 189  * @count: The number of characters
 190  */
 191 char *strncpy(char *str1, const char *str2, size_t count)
 192 {
 193         char *tmp = str1;
 194
 195         while (count) {
 196                 if ((*tmp = *str2) != 0)
 197                         str2++;
 198                 tmp++;
 199                 count--;
 200         }
 201
 202         return str1;
 203 }
 204