mirror of https://git.sr.ht/~kikoodx/sle
35 lines
762 B
C
35 lines
762 B
C
/* SPDX-License-Identifier: GPL-3.0-or-later */
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/* Copyright (C) 2021 KikooDX */
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#include "strtoint.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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/* Attempt to convert a string to integer. */
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int strtoint(char *string)
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{
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const size_t string_len = strlen(string);
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int character;
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int i;
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int sum = 0;
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int multiplier = 1;
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int negative = string[0] == '-';
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for (i = string_len - 1; i >= negative; i -= 1) {
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character = string[i];
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if (character < '0' || character > '9') {
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fprintf(stderr,
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"ERROR: flag expected a number "
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"argument, got \"%s\"\n",
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string);
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exit(EXIT_FAILURE);
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}
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sum += multiplier * (character - '0');
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multiplier *= 10;
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}
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if (negative)
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return sum * -1;
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else
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return sum;
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}
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