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/* Copyright (C) 2023 Aryadev Chavali
* You may distribute and modify this code under the terms of the
* GPLv2 license. You should have received a copy of the GPLv2
* license with this file. If not, please write to:
* aryadev@aryadevchavali.com.
* Created: 2023-10-24
* Author: Aryadev Chavali
* Description: Lexer for assembly language
*/
#include <ctype.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include "./lexer.h"
const char *token_type_as_cstr(token_type_t type)
{
switch (type)
{
case TOKEN_LITERAL_NUMBER:
return "LITERAL_NUMBER";
case TOKEN_LITERAL_CHAR:
return "LITERAL_CHAR";
case TOKEN_SYMBOL:
return "SYMBOL";
}
return "";
}
const char *lerr_as_cstr(lerr_t lerr)
{
switch (lerr)
{
case LERR_INVALID_CHAR_LITERAL:
return "INVALID_CHAR_LITERAL";
break;
case LERR_OK:
return "OK";
break;
}
return "";
}
size_t space_left(buffer_t *buffer)
{
if (buffer->available == buffer->used)
return 0;
return buffer->available - 1 - buffer->used;
}
bool is_symbol(char c)
{
return isalpha(c) || c == '-' || c == '_' || c == '.';
}
char uppercase(char c)
{
if (c >= 'a' && c <= 'z')
return (c - 'a') + 'A';
return c;
}
token_t tokenise_symbol(buffer_t *buffer, size_t *column)
{
token_t token = {.type = TOKEN_SYMBOL, .str_size = 0, .column = *column};
for (; token.str_size < space_left(buffer) &&
is_symbol(buffer->data[buffer->used + token.str_size]);
++token.str_size)
buffer->data[buffer->used + token.str_size] =
uppercase(buffer->data[buffer->used + token.str_size]);
token.str = calloc(token.str_size + 1, 1);
memcpy(token.str, buffer->data + buffer->used, token.str_size);
token.str[token.str_size] = '\0';
buffer->used += token.str_size;
*column += token.str_size;
return token;
}
token_t tokenise_number_literal(buffer_t *buffer, size_t *column)
{
token_t token = {
.type = TOKEN_LITERAL_NUMBER, .str_size = 0, .column = *column};
if (buffer->data[buffer->used] == '-')
++token.str_size;
for (; token.str_size < space_left(buffer) &&
isdigit(buffer->data[buffer->used + token.str_size]);
++token.str_size)
continue;
token.str = calloc(token.str_size + 1, 1);
memcpy(token.str, buffer->data + buffer->used, token.str_size);
token.str[token.str_size] = '\0';
buffer->used += token.str_size;
*column += token.str_size;
return token;
}
token_t tokenise_char_literal(buffer_t *buffer, size_t *column)
{
token_t token = {
.type = TOKEN_LITERAL_CHAR, .str_size = 1, .column = *column};
token.str = calloc(1, 1);
token.str[0] = buffer->data[buffer->used + 1];
buffer->used += 3;
*column += 3;
return token;
}
lerr_t tokenise_buffer(buffer_t *buffer, token_stream_t *tokens_ptr)
{
size_t column = 0, line = 1;
token_stream_t tokens = {0};
darr_init(&tokens, sizeof(token_t));
while (space_left(buffer) != 0)
{
bool is_token = true;
token_t t = {0};
char c = buffer->data[buffer->used];
if (isspace(c) || c == '\0')
{
// Clean whitespace
for (; space_left(buffer) > 0 && (isspace(c) || c == '\0');
++buffer->used, c = buffer->data[buffer->used])
{
++column;
if (c == '\n')
{
column = 0;
++line;
}
}
++column;
is_token = false;
}
else if (c == ';')
{
// Stop lexing till next line
for (; space_left(buffer) > 0 && c != '\n';
++buffer->used, c = buffer->data[buffer->used])
continue;
column = 0;
++line;
++buffer->used;
is_token = false;
}
else if (isdigit(c) || (space_left(buffer) > 1 && c == '-' &&
isdigit(buffer->data[buffer->used + 1])))
t = tokenise_number_literal(buffer, &column);
else if (is_symbol(c))
t = tokenise_symbol(buffer, &column);
else if (c == '\'')
{
if (space_left(buffer) < 2)
{
free(tokens.data);
return LERR_INVALID_CHAR_LITERAL;
}
else if (buffer->data[buffer->used + 1] == '\\')
{
char escape = '\0';
if (space_left(buffer) < 3 || buffer->data[buffer->used + 3] != '\'')
{
free(tokens.data);
return LERR_INVALID_CHAR_LITERAL;
}
switch (buffer->data[buffer->used + 2])
{
case 'n':
escape = '\n';
break;
case 't':
escape = '\t';
break;
case 'r':
escape = '\r';
break;
case '\\':
escape = '\\';
break;
default:
column += 2;
free(tokens.data);
return LERR_INVALID_CHAR_LITERAL;
break;
}
t = (token_t){.type = TOKEN_LITERAL_CHAR,
.str = malloc(1),
.str_size = 1,
.column = column};
column += 4;
buffer->used += 4;
t.str[0] = escape;
}
else
t = tokenise_char_literal(buffer, &column);
}
if (is_token)
{
t.line = line;
darr_append_bytes(&tokens, (byte *)&t, sizeof(t));
}
}
size_t n_tokens = tokens.used / sizeof(token_t);
tokens.available = n_tokens;
tokens.used = 0;
*tokens_ptr = tokens;
return LERR_OK;
}
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