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Diffstat (limited to 'src/stdlib/atoll.c')
-rw-r--r-- | src/stdlib/atoll.c | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/src/stdlib/atoll.c b/src/stdlib/atoll.c new file mode 100644 index 0000000..ad26449 --- /dev/null +++ b/src/stdlib/atoll.c @@ -0,0 +1,56 @@ +/** + * slibc — Yet another C library + * Copyright © 2015 Mattias Andrée (maandree@member.fsf.org) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include <stdlib.h> +#include <ctype.h> + + + +/** + * Convert a string to an integer, + * without checking for errors. + * + * The string may being with an arbitrary number + * of whitespace characters. Convertion will end + * when a character is encountered that is not a + * decimal digit, and is not an absolutely leading + * '-' or '+'. + * + * @param string The string to convert. + * @return The integer encoded by the string. + */ +long long int atoll(const char* string) +{ + long long int rc = 0; + int neg = 0; + + while (isspace(*string)) + string++; + + switch (*string) + { + case '-': neg = 1; + case '+': string++; + default: break; + } + + while (isdigit(*string)) + rc = rc * 10 - (*string++ & 15); + + return neg ? rc : -rc; +} + |