diff options
Diffstat (limited to 'scan.c')
| -rw-r--r-- | scan.c | 369 |
1 files changed, 369 insertions, 0 deletions
@@ -0,0 +1,369 @@ +#include <ctype.h> +#include <stdarg.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include "util.h" +#include "scan.h" +#include "token.h" + +struct buffer { + char *str; + size_t len, cap; +}; + +struct scanner { + int chr; + struct token next; + struct location loc; + struct buffer buf; + bool usebuf; +}; + +static void +bufadd(struct buffer *b, char c) +{ + if (b->len >= b->cap) { + b->cap = b->cap ? b->cap * 2 : 1<<8; + b->str = xreallocarray(b->str, b->cap, 1); + } + b->str[b->len++] = c; +} + +static char * +bufget(struct buffer *b) +{ + char *s; + + bufadd(b, '\0'); + s = xmalloc(b->len); + memcpy(s, b->str, b->len); + b->len = 0; + + return s; +} + +static void +nextchar(struct scanner *s) +{ + if (s->usebuf) + bufadd(&s->buf, s->chr); + s->chr = getchar(); + if (s->chr == '\n') + ++s->loc.line, s->loc.col = 1; + else + ++s->loc.col; +} + +static int +op2(struct scanner *s, int t1, int t2) +{ + nextchar(s); + if (s->chr != '=') + return t1; + nextchar(s); + return t2; +} + +static int +op3(struct scanner *s, int t1, int t2, int t3) +{ + int c; + + c = s->chr; + nextchar(s); + if (s->chr == '=') { + nextchar(s); + return t2; + } + if (s->chr != c) + return t1; + nextchar(s); + return t3; +} + +static int +op4(struct scanner *s, int t1, int t2, int t3, int t4) +{ + int c; + + c = s->chr; + nextchar(s); + if (s->chr == '=') { + nextchar(s); + return t2; + } + if (s->chr != c) + return t1; + nextchar(s); + if (s->chr != '=') + return t3; + nextchar(s); + return t4; +} + +static int +ident(struct scanner *s) +{ + s->usebuf = true; + do nextchar(s); + while (isalnum(s->chr) || s->chr == '_'); + + return TIDENT; +} + +static int +isodigit(int c) +{ + return (unsigned)c - '0' < 8; +} + +static enum tokenkind +number(struct scanner *s) +{ + bool allowsign = false; + + s->usebuf = true; + for (;;) { + nextchar(s); + switch (s->chr) { + case 'e': + case 'E': + case 'p': + case 'P': + allowsign = true; + break; + case '+': + case '-': + if (!allowsign) + goto done; + break; + case '_': + case '.': + allowsign = false; + break; + default: + if (!isalnum(s->chr)) + goto done; + allowsign = false; + } + } +done: + return TNUMBER; +} + +static void +escape(struct scanner *s) +{ + nextchar(s); + if (s->chr == 'x') { + nextchar(s); + if (!isxdigit(s->chr)) + error(&s->loc, "invalid hexadecimal escape sequence"); + do nextchar(s); + while (isxdigit(s->chr)); + } else if (isodigit(s->chr)) { + nextchar(s); + if (isodigit(s->chr)) { + nextchar(s); + if (isodigit(s->chr)) + nextchar(s); + } + } else if (strchr("'\"?\\abfnrtv", s->chr)) { + nextchar(s); + } else { + error(&s->loc, "invalid escape sequence"); + } +} + +static enum tokenkind +charconst(struct scanner *s) +{ + s->usebuf = true; + nextchar(s); + for (;;) { + switch (s->chr) { + case '\\': + escape(s); + break; + case '\'': + nextchar(s); + return TCHARCONST; + case '\n': + error(&s->loc, "newline in character constant"); + default: + nextchar(s); + break; + } + } +} + +static int +stringlit(struct scanner *s) +{ + s->usebuf = true; + nextchar(s); + for (;;) { + switch (s->chr) { + case '\\': + escape(s); + break; + case '"': + nextchar(s); + return TSTRINGLIT; + case '\n': + error(&s->loc, "newline in string literal"); + default: + nextchar(s); + break; + } + } +} + +static int +scankind(struct scanner *s) +{ + int tok; + struct location loc; + +again: + switch (s->chr) { + case ' ': + case '\t': + case '\f': + case '\v': + nextchar(s); + goto again; + case '!': + return op2(s, TLNOT, TNEQ); + case '"': + return stringlit(s); + case '#': + nextchar(s); + if (s->chr != '#') + return THASH; + nextchar(s); + return THASHHASH; + case '%': + return op2(s, TMOD, TMODASSIGN); + case '&': + return op3(s, TBAND, TBANDASSIGN, TLAND); + // TODO: u8, U, and L string literals + case '\'': + return charconst(s); + case '*': + return op2(s, TMUL, TMULASSIGN); + case '+': + return op3(s, TADD, TADDASSIGN, TINC); + case '-': + tok = op3(s, TSUB, TSUBASSIGN, TDEC); + if (tok != TSUB || s->chr != '>') + return tok; + nextchar(s); + return TARROW; + case '/': + return op2(s, TDIV, TDIVASSIGN); + case '<': + return op4(s, TLESS, TLEQ, TSHL, TSHLASSIGN); + case '=': + return op2(s, TASSIGN, TEQL); + case '>': + return op4(s, TGREATER, TGEQ, TSHR, TSHRASSIGN); + case '^': + return op2(s, TXOR, TXORASSIGN); + case '|': + return op3(s, TBOR, TBORASSIGN, TLOR); + case '\n': + nextchar(s); + return TNEWLINE; + case '[': + nextchar(s); + return TLBRACK; + case ']': + nextchar(s); + return TRBRACK; + case '(': + nextchar(s); + return TLPAREN; + case ')': + nextchar(s); + return TRPAREN; + case '{': + nextchar(s); + return TLBRACE; + case '}': + nextchar(s); + return TRBRACE; + case '.': + nextchar(s); + if (s->chr != '.') + return TPERIOD; + loc = s->loc; + nextchar(s); + if (s->chr != '.') { + ungetc(s->chr, stdout); + s->loc = loc; + s->chr = '.'; + return TPERIOD; + } + nextchar(s); + return TELLIPSIS; + case '~': + nextchar(s); + return TBNOT; + case '?': + nextchar(s); + return TQUESTION; + case ':': + nextchar(s); + return TCOLON; + case ';': + nextchar(s); + return TSEMICOLON; + case ',': + nextchar(s); + return TCOMMA; + case EOF: + return TEOF; + default: + if (isdigit(s->chr)) + return number(s); + if (isalpha(s->chr) || s->chr == '_') + return ident(s); + if (isprint(s->chr)) + error(&s->loc, "unexpected character '%c'", s->chr); + error(&s->loc, "unexpected character '\\x%02x'", s->chr); + } +} + +struct scanner * +mkscanner(const char *file) +{ + struct scanner *s; + + s = xmalloc(sizeof(*s)); + s->buf.str = NULL; + s->buf.len = 0; + s->buf.cap = 0; + s->usebuf = false; + s->loc.file = file; + s->loc.line = 1; + s->loc.col = 0; + nextchar(s); + + return s; +} + +void +scan(struct scanner *s, struct token *t) +{ + t->loc = s->loc; + t->kind = scankind(s); + if (s->usebuf) { + t->lit = bufget(&s->buf); + s->usebuf = false; + } else { + t->lit = NULL; + } +} |