mirror of https://git.sr.ht/~kikoodx/sle
26 lines
654 B
C
26 lines
654 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 <string.h>
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#include <stdio.h>
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/* Attempt to convert a string to positive integer. Return -1 on error. */
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int strtoint(char *string) {
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char character;
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int i;
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const size_t string_len = strlen(string);
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int sum = 0;
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int multiplier = 1;
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for (i = string_len - 1; i >= 0; i -= 1) {
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character = string[i];
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if (character < '0' || character > '9') {
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fprintf(stderr, "ERROR: flag expected a positive number argument, got \"%s\"\n", string);
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return -1;
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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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return sum;
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}
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