pc-bios/s390-ccw/libc.c

   1 /*
   2  * libc-style definitions and functions
   3  *
   4  * Copyright 2018 IBM Corp.
   5  * Author(s): Collin L. Walling <walling@linux.vnet.ibm.com>
   6  *
   7  * This code is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the
   9  * Free Software Foundation; either version 2 of the License, or (at your
  10  * option) any later version.
  11  */
  12
  13 #include "libc.h"
  14 #include "s390-ccw.h"
  15
  16 /**
  17  * atoui:
  18  * @str: the string to be converted.
  19  *
  20  * Given a string @str, convert it to an integer. Leading spaces are
  21  * ignored. Any other non-numerical value will terminate the conversion
  22  * and return 0. This function only handles numbers between 0 and
  23  * UINT64_MAX inclusive.
  24  *
  25  * Returns: an integer converted from the string @str, or the number 0
  26  * if an error occurred.
  27  */
  28 uint64_t atoui(const char *str)
  29 {
  30     int val = 0;
  31
  32     if (!str || !str[0]) {
  33         return 0;
  34     }
  35
  36     while (*str == ' ') {
  37         str++;
  38     }
  39
  40     while (*str) {
  41         if (!isdigit(*str)) {
  42             break;
  43         }
  44         val = val * 10 + *str - '0';
  45         str++;
  46     }
  47
  48     return val;
  49 }
  50
  51 /**
  52  * uitoa:
  53  * @num: an integer (base 10) to be converted.
  54  * @str: a pointer to a string to store the conversion.
  55  * @len: the length of the passed string.
  56  *
  57  * Given an integer @num, convert it to a string. The string @str must be
  58  * allocated beforehand. The resulting string will be null terminated and
  59  * returned. This function only handles numbers between 0 and UINT64_MAX
  60  * inclusive.
  61  *
  62  * Returns: the string @str of the converted integer @num
  63  */
  64 char *uitoa(uint64_t num, char *str, size_t len)
  65 {
  66     size_t num_idx = 1; /* account for NUL */
  67     uint64_t tmp = num;
  68
  69     IPL_assert(str != NULL, "uitoa: no space allocated to store string");
  70
  71     /* Count indices of num */
  72     while ((tmp /= 10) != 0) {
  73         num_idx++;
  74     }
  75
  76     /* Check if we have enough space for num and NUL */
  77     IPL_assert(len > num_idx, "uitoa: array too small for conversion");
  78
  79     str[num_idx--] = '\0';
  80
  81     /* Convert int to string */
  82     while (num_idx >= 0) {
  83         str[num_idx--] = num % 10 + '0';
  84         num /= 10;
  85     }
  86
  87     return str;
  88 }