#include "../include/al/str.h"

// https://sourceware.org/git/?p=newlib-cygwin.git;a=blob;f=newlib/libc/stdlib/strtol.c;h=09d4333ed05f497ec00b7192204644349441e58d;hb=HEAD#l130
s64 al_str_to_long(str *s, u32 base, bool *error)
{
    u64 ret = 0;
    u32 i = 0;
    bool neg = 0;

    while (al_isspace(al_str_at(s, i)) && i < s->length) {
        i++;
    }

    if (al_str_at(s, i) == '-') {
        neg = true;
        i++;
    } else if (al_str_at(s, i) == '+') {
        i++;
    }

    if (al_str_at(s, i) == '0' &&
        ((base == 16 && (al_str_at(s, i + 1) == 'x' || al_str_at(s, i + 1) == 'X')) ||
         (base == 2  && (al_str_at(s, i + 1) == 'b' || al_str_at(s, i + 1) == 'B')))) {
        i += 2;
    }

    u64 cutoff = neg ? ((u64)INT64_MAX + 1) : (u64)INT64_MAX;
    u64 add_limit = cutoff % base;
    cutoff /= base;

    *error = false;

    for (; i < s->length; i++) {
        uchar c = (uchar)al_str_at(s, i);

        if (c >= '0' && c <= '9') c -= '0';
        else if (c >= 'A' && c <= 'Z') c -= 'A' - 10;
        else if (c >= 'a' && c <= 'z') c -= 'a' - 10;
        else {
            // Character not valid for expressing a number.
            *error = true;
            break;
        }

        if (c >= base || ret > cutoff || (ret == cutoff && c > add_limit)) {
            // Either the character is invalid for the requested base or
            // attempting to add it would cause an overflow.
            *error = true;
            break;
        }

        ret = ret * base + c;
    }

    return neg ? -(s64)ret : (s64)ret;
}

bool al_str_get_line(str *buffer, char sep, str *line)
{
    u32 bytes = 0;

    // line must be zero'd before calling get_line() for the first time.
    if (line->data == NULL) {
        *line = *buffer;
    } else {
        // Move to the start of the next line, if it exists.
        line->data += line->length + 1;
        if ((bytes = (u32)(line->data - buffer->data)) >= buffer->length) {
            // No more lines.
            return false;
        }
    }

    if ((bytes = buffer->length - bytes) == 0) {
        // buffer is completely empty.
        return false;
    }

    char *nl = (char *)al_memchr(line->data, sep, bytes);

    // If we couldn't find a separator, move to the end of the buffer.
    line->length = !nl ? bytes : (u32)(nl - line->data);

    return true;
}