split_message.c

#include <ruby.h>
#include <ctype.h>
#define MAX_LENGTH 2000

VALUE rb_mBigBrain = Qnil;

int bigbrain_find_ideal(char *str) {
    int len = strlen(str);
    char* loc;

    if(len <= MAX_LENGTH)
        return len;
    
    for(loc = &str[MAX_LENGTH]; loc > str && !isspace(*loc); loc--);

    if (loc == str)
        return MAX_LENGTH;
    else
        return (loc + 1) - str;
}

VALUE bigbrain_split_message(VALUE self, VALUE str) {
	char* cstr = StringValueCStr(str);
	int len = strlen(cstr);
    int index = 0;
    int ending_index = len;
    int ideal_size;

    VALUE rb_msg_arr = rb_ary_new();
    if(len > MAX_LENGTH) {
        while((len - index) >= MAX_LENGTH) {
            ideal_size = bigbrain_find_ideal(&cstr[index]);
            rb_ary_push(rb_msg_arr, rb_str_new(&cstr[index], (long)ideal_size));
            index += ideal_size;
        }
    }
    
    do {
        ending_index--;
    } while(isspace(cstr[ending_index]));

    rb_ary_push(rb_msg_arr, rb_str_new(&cstr[index], (ending_index + 1) - index));

    return rb_msg_arr;
}

void Init_bigbrain() {
	rb_mBigBrain = rb_define_module("BigBrain");
	rb_define_const(rb_mBigBrain, "MAX_LENGTH", INT2NUM(MAX_LENGTH));
	rb_define_module_function(rb_mBigBrain, "split_message", bigbrain_split_message, 1);
}

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