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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define NUM_KEYWORDS 32
static char *KEYWORDS[NUM_KEYWORDS] = {
"auto", "break", "case", "char", "const", "continue",
"default", "do", "double", "else", "enum", "extern",
"float", "for", "goto", "if", "int", "long",
"register", "return", "short", "signed", "sizeof", "static",
"struct", "switch", "typedef", "union", "unsigned", "void",
"volatile", "while"};
enum keyword {
kW_AUTO,
KW_BREAK,
KW_CASE,
KW_CHAR,
KW_CONST,
KW_CONTINUE,
KW_DEFAULT,
KW_DO,
KW_DOUBLE,
KW_ELSE,
KW_ENUM,
KW_EXTERN,
KW_FLOAT,
KW_FOR,
KW_GOTO,
KW_IF,
KW_INT,
KW_LONG,
KW_REGISTER,
KW_RETURN,
KW_SHORT,
KW_SIGNED,
KW_SIZEOF,
KW_STATIC,
KW_STRUCT,
KW_SWITCH,
KW_TYPEDEF,
KW_UNION,
KW_UNSIGNED,
KW_VOID,
KW_VOLATILE,
KW_WHILE,
};
enum operator{
OP_ADD,
OP_SUB,
OP_MUL,
OP_DIV,
OP_MOD,
};
enum token_kind {
IDENTIFIER,
KEYWORD,
CONSTANT,
OPERATOR,
END,
};
union token_data {
char *identifier;
enum keyword keyword;
int constant_value;
enum operator operator;
};
struct token {
enum token_kind kind;
union token_data data;
};
struct token *tokenize(char *source) {
char *end = source + strlen(source);
char *p = source;
int num_tokens = 0;
struct token *tokens;
while (*p) {
int remaining = end - p;
//* comments
if (remaining >= 2) {
if (p[0] == '/' && p[1] == '/') {
p += 2;
while (*p) {
if (*p++ == '\n') {
break;
}
}
continue;
} else if (p[0] == '/' && p[1] == '*') {
p += 2;
char last = '\0';
while (*p) {
if (*p == '/' && last == '*') {
p++;
break;
}
last = *p;
p++;
}
continue;
}
}
//* keyword
for (int i = 0; i < NUM_KEYWORDS; i++) {
char *kw = KEYWORDS[i];
if (remaining >= strlen(kw)) {
if (strcmp(kw, p) == 0) {
num_tokens += 1;
tokens = realloc(tokens, sizeof(struct token) * num_tokens);
if (!tokens) {
fprintf(stderr, "realloc failed");
return NULL;
}
struct token *new_token = &tokens[num_tokens - 1];
new_token->kind = KEYWORD;
new_token->data.keyword = i;
p += strlen(kw);
continue;
}
}
}
fprintf(stderr, "unknown token\n");
return NULL;
}
return tokens;
}
int main() {}
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