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tokenizer.c
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tokenizer.c
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#include "tokenizer.h"
#include "internal_allocators.h"
#include "symbol.h"
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#define IDENTIFIER_TABLE_SIZE (101)
#define IDENTIFIER_MAX_SIZE (256)
struct token eof_token = { {0}, {0}, &eof_token, TOKEN_EOF };
static struct identifier * identifiers[IDENTIFIER_TABLE_SIZE];
static unsigned int get_string_hash(const char * name)
{
unsigned int hash = 0;
while(*name) {
hash = hash * 31 + (unsigned int) *name;
++name;
}
return hash;
}
static struct identifier * identifier_search(unsigned int hash, const char * name)
{
unsigned int index = hash % IDENTIFIER_TABLE_SIZE;
struct identifier * it;
for(it = identifiers[index]; it; it = it->next) {
if (strcmp(name, it->name) == 0) {
return it;
}
}
return NULL;
}
static struct identifier * identifier_insert(unsigned int hash, const char * name, unsigned int len)
{
unsigned int index = hash % IDENTIFIER_TABLE_SIZE;
struct identifier * identifier = alloc_identifier();
identifier->name = (char *) alloc_bytes(len + 1);
strncpy(identifier->name, name, len);
identifier->name[len] = '\0';
identifier->symbols = NULL;
identifier->next = identifiers[index];
identifiers[index] = identifier;
return identifier;
}
static void read_character(struct stream * stream, struct token * token, int ch)
{
if (ch == EOF) {
fprintf(stderr, "error: not terminated character constant!\n");
exit(EXIT_FAILURE);
}
else if(ch == '\'') {
fprintf(stderr, "error: empty character constant!\n");
exit(EXIT_FAILURE);
}
else if(ch == '\n') {
fprintf(stderr, "error: new line character in cannot allow in character constant!\n");
exit(EXIT_FAILURE);
}
else if(ch == '\\') { /* handle escape sequence */
int next_ch = stream_getchar(stream);
if (next_ch == '\'') {
ch = '\'';
}
else if(next_ch == '\\') {
ch = '\\';
}
else {
fprintf(stderr, "error: unknown escape sequence in character constant: \\%c\n", next_ch);
exit(EXIT_FAILURE);
}
}
token->type = TOKEN_CHARACTER;
token->value.code = ch;
ch = stream_getchar(stream);
if (ch != '\'') {
fprintf(stderr, "error: not terminated character constant!\n");
exit(EXIT_FAILURE);
}
}
static void read_identifier(struct stream * stream, struct token * token, int ch)
{
static char buffer[IDENTIFIER_MAX_SIZE];
int i = 0;
unsigned int hash = 0;
while(ch != EOF && (isalpha(ch) || isdigit(ch) || ch == '_') && i < IDENTIFIER_MAX_SIZE - 1) {
buffer[i++] = ch;
hash = ch + 31 * hash;
ch = stream_getchar(stream);
}
buffer[i] = '\0';
if (ch != EOF)
stream_ungetchar(stream, ch);
if(i >= IDENTIFIER_MAX_SIZE - 1) {
fprintf(stderr, "warning: identifier too long!\n");
while(isalpha(ch) || isdigit(ch) || ch == '_')
ch = stream_getchar(stream);
stream_ungetchar(stream, ch);
}
struct identifier * identifier = identifier_search(hash, buffer);
if (! identifier)
identifier = identifier_insert(hash, buffer, i);
token->value.identifier = identifier;
}
static void read_token(struct stream * stream, struct token * token, int ch)
{
if (isalpha(ch) || ch == '_') {
token->type = TOKEN_IDENTIFIER;
read_identifier(stream, token, ch);
struct symbol * symbol = lookup_symbol(token->value.identifier, SYMBOL_KEYWORD);
if(symbol) {
token->type = TOKEN_KEYWORD;
token->value.code = symbol->value.code;
}
return;
}
switch(ch) {
case ',':
token->type = TOKEN_PUNCTUATOR;
token->value.code = PUNCTUATOR_COMMA;
return;
case ';':
token->type = TOKEN_PUNCTUATOR;
token->value.code = PUNCTUATOR_SEMICOLON;
return;
case '#':
{
int next_ch = stream_getchar(stream);
if(isalpha(next_ch) || next_ch == '_') {
token->type = TOKEN_DIRECTIVE;
read_identifier(stream, token, next_ch);
return;
}
stream_ungetchar(stream, next_ch);
}
goto invalid;
case '@':
{
int next_ch = stream_getchar(stream);
if(isalpha(next_ch) || next_ch == '_') {
token->type = TOKEN_SPECIAL_CHARACTER;
read_identifier(stream, token, next_ch);
return;
}
stream_ungetchar(stream, next_ch);
}
goto invalid;
case '-':
{
int next_ch = stream_getchar(stream);
if (next_ch == '>') {
token->type = TOKEN_PUNCTUATOR;
token->value.code = PUNCTUATOR_HYPHEN_LESS;
return;
}
stream_ungetchar(stream, next_ch);
}
break;
case '\'':
read_character(stream, token, stream_getchar(stream));
return;
}
invalid:
token->type = TOKEN_INVALID;
token->value.code = ch;
}
struct identifier * identifier_create(const char * name)
{
unsigned int hash = get_string_hash(name);
unsigned int len = strlen(name);
return identifier_insert(hash, name, len);
}
struct token * tokenize(struct stream * stream)
{
struct token * token_list, * token, ** last_token;
token_list = &eof_token;
last_token = &token_list;
int ch = stream_getchar(stream);
struct source_location location;
while(ch != EOF) {
if(! isspace(ch)) {
location = stream->location;
if(ch == '/') { /* try to skip comment */
int next_ch = stream_getchar(stream);
if(next_ch == '/') {
do
ch = stream_getchar(stream);
while(ch != '\n' && ch != EOF);
goto next_char;
}
stream_ungetchar(stream, next_ch);
}
token = alloc_token();
token->location = location;
read_token(stream, token, ch);
token->next = &eof_token;
*last_token = token;
last_token = &token->next;
}
next_char:
ch = stream_getchar(stream);
}
return token_list;
}