#ifndef __LEXER_H__
#define __LEXER_H__

#include "token.h"
#define LEXER_MAX_TOKEN_SIZE 63
#define LEXER_BUFFER_SIZE 4095

typedef int (*lexer_sread_fn)(void *dst_buf, int dst_size,
        int elem_size, int count, void *stream);

struct Lexer {
    int line;
    int index;
    // const char current_file_name[LEXER_BUFFER_SIZE+1];

    unsigned char* cur_ptr; // 当前扫描的字符，但是还没有开始扫描
    unsigned char* end_ptr; // 缓冲区最后一个字符的下一个位置
    char buffer[LEXER_BUFFER_SIZE+1];

    lexer_sread_fn sread;
    void* stream;
};

struct Token {
    enum TokenType type;
    struct TokenConstant constant;
};

void init_lexer(struct Lexer* lexer, const char* file_name, void* stream,
    lexer_sread_fn sread);

// 
void get_token(struct Lexer* lexer, struct Token* token);

// get_token maybe got invalid (with parser as TOKEN_FLUSH)
void get_valid_token(struct Lexer* lexer, struct Token* token);

const char* get_token_name(enum TokenType token);

#endif