130 lines
3.4 KiB
C
130 lines
3.4 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* str_to_i64.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: maiboyer <maiboyer@student.42.fr> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2024/02/01 21:15:19 by maiboyer #+# #+# */
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/* Updated: 2024/02/01 23:18:52 by maiboyer ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include "me/char/isalpha.h"
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#include "me/convert/str_to_numbers.h"
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#include "me/string/str_len.h"
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#include "me/types.h"
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#define OP_ADD 0b0001
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#define OP_SUB 0b0010
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#define OP_MUL 0b0100
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#define OP_CHK 0b1000
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t_error checked_add_u16(t_u16 lhs, t_u16 rhs, t_u16 *out);
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t_error checked_sub_u16(t_u16 lhs, t_u16 rhs, t_u16 *out);
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t_error checked_mul_u16(t_u16 lhs, t_u16 rhs, t_u16 *out);
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static inline bool can_not_overflow(t_u32 radix, bool is_signed_type,
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t_usize digits_len)
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{
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return (radix <= 16 &&
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digits_len <= sizeof(t_u16) * 2 - (t_usize)is_signed_type);
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}
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static inline t_error to_digit(t_u8 ascii, t_u32 radix, t_u32 *out)
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{
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t_u32 digit;
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if (radix < 2 || radix > 36)
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return (ERROR);
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digit = ascii - '0';
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if (radix > 10 && digit >= 10)
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{
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if (!me_isalpha(ascii))
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return (ERROR);
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digit = ((ascii | 0b100000) - 'a') + 10;
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}
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if (digit >= radix)
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return (ERROR);
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*out = digit;
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return (NO_ERROR);
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}
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static inline t_error do_operation(t_u16 digit, t_u8 op, t_u16 *result)
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{
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t_u16 rhs;
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t_u16 res;
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rhs = *result;
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res = *result;
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if (op & OP_CHK)
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{
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if (op & OP_MUL && checked_mul_u16(rhs, digit, &res))
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return (ERROR);
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else if (op & OP_ADD && checked_add_u16(rhs, digit, &res))
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return (ERROR);
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else if (op & OP_SUB && checked_sub_u16(rhs, digit, &res))
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return (ERROR);
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}
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else
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{
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if (op & OP_MUL)
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res = rhs * digit;
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else if (op & OP_ADD)
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res = rhs + digit;
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else if (op & OP_SUB)
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res = rhs - digit;
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}
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*result = res;
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return (NO_ERROR);
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}
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static inline t_error loop_inner(t_const_str s, t_u32 radix, t_u8 op,
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t_u16 *out)
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{
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t_u32 digit;
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t_u16 result;
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result = 0u;
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while (*s)
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{
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if (do_operation(radix, (op & OP_CHK) | OP_MUL, &result))
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return (ERROR);
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if (to_digit(*s, radix, &digit))
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return (ERROR);
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if (do_operation(digit, op, &result))
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return (ERROR);
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s++;
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}
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if (out)
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*out = result;
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return (NO_ERROR);
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}
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t_error str_to_u16(t_const_str s, t_u32 radix, t_u16 *out)
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{
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t_usize digits_len;
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bool is_positive;
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t_u8 op;
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if (radix < 2 || radix > 36)
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return (ERROR);
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digits_len = str_len(s);
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is_positive = true;
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if (digits_len == 0)
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return (ERROR);
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if ((s[0] == '-' || s[0] == '+') && s[1] == '\0')
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return (ERROR);
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else if (s[0] == '+')
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is_positive = (s++, digits_len--, true);
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else if (s[0] == '-' && false)
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is_positive = (s++, digits_len--, false);
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if (is_positive)
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op = OP_ADD;
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else
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op = OP_SUB;
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if (!can_not_overflow(radix, false, digits_len))
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op |= OP_CHK;
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return (loop_inner(s, radix, op, out));
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}
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