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/* Copyright (c) 2024 Freya Murphy */
#ifndef __LEX_H__
#define __LEX_H__
#include <mlimits.h>
#include <stdio.h>
#include <stdint.h>
/// represents a non null
/// terminated string
struct string {
char *str;
uint32_t len;
uint32_t size;
bool allocated;
};
/* initalize a string */
void string_init(struct string *string);
/* free a string */
void string_free(struct string *string);
/* clone a string, leave the old one */
int string_clone(struct string *dst, const struct string *const src);
/* move a string, delete the old one */
void string_move(struct string *dst, struct string *src);
/* pushes a char onto a string */
int string_push(struct string *string, char c);
/* load a string from the bss (not allocated) */
void string_bss(struct string *string, char *src);
enum token_type {
/// has no associated
/// data
TOK_COMMA,
TOK_EQUAL,
TOK_LPAREN,
TOK_RPAREN,
TOK_EOF,
TOK_NL,
/// uses number
TOK_NUMBER,
/// uses string
TOK_REG,
TOK_IDENT,
TOK_LABEL,
TOK_STRING,
TOK_DIRECTIVE,
};
/// represents a token
/// returned from the lexer
struct token {
/// type
enum token_type type;
/// position
int x, y;
/// pos in bytes
int off;
/// data
union {
int64_t number;
struct string string;
};
};
/* frees a token*/
void token_free(struct token *token);
/// holds the data
/// for the current lexer
struct lexer {
// the currently
// open file
FILE *file;
// the last character peeked
int peek;
// the current position
int x, y;
};
/// holds a previous state of a
/// lexer, which allows rebounding
struct lexer_state {
long offset;
int peek;
int x;
int y;
};
/* initalize a lexer */
int lexer_init(const char *file, struct lexer *lexer);
/* free the lexer */
void lexer_free(struct lexer *lexer);
/* lexes the next token, returns M_ERROR on error,
* and TOK_EOF on EOF */
int lexer_next(struct lexer *lexer, struct token *token);
/* token type to string */
char *token_str(enum token_type);
/* save the state of a lexer */
void lexer_save(struct lexer *lexer, struct lexer_state *state);
/* load a different state into a lexer */
void lexer_load(struct lexer *lexer, const struct lexer_state *state);
#endif /* __LEX_H__ */
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