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/*
* Copyright 1996 Thierry Bousch
* Licensed under the Gnu Public License, Version 2
*
* $Id: simple-lexers.c,v 1.5 1996/09/15 16:03:56 bousch Exp $
*
* Two lexers, to read from a file or a region of memory.
*/
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include "saml-parse.h"
#include "saml-util.h"
char *saml_token = NULL;
int (*saml_lexer)(void) = NULL;
static int toklen, tok_maxlen = 0;
static int saml_common_lexer (int (*getc)(void), void (*ungetc)(int));
/*
* State and operations for the "file" lexer
*/
static FILE *flx_fd;
static int getc_fd (void)
{
return getc(flx_fd);
}
static void ungetc_fd (int c)
{
ungetc(c, flx_fd);
}
static int saml_lexer_fd (void)
{
return saml_common_lexer(getc_fd, ungetc_fd);
}
void saml_init_lexer_fd (FILE *fd)
{
flx_fd = fd;
saml_lexer = saml_lexer_fd;
tok_maxlen = saml_token ? 1+strlen(saml_token) : 0;
}
/*
* State and operations for the "memory" lexer
*/
static unsigned char *mlx_start, *mlx_end, *mlx_curr;
static int getc_mem (void)
{
if (mlx_curr < mlx_end)
return (int)(*mlx_curr++);
return EOF;
}
static void ungetc_mem (int c)
{
if (c != EOF && mlx_curr > mlx_start)
--mlx_curr;
}
static int saml_lexer_mem (void)
{
return saml_common_lexer(getc_mem, ungetc_mem);
}
void saml_init_lexer_mem (const void *start, size_t length)
{
mlx_start = mlx_curr = (unsigned char *) start;
mlx_end = mlx_start + length;
saml_lexer = saml_lexer_mem;
tok_maxlen = saml_token ? 1+strlen(saml_token) : 0;
}
/*
* The lexical analyser itself
*/
static void append_to_token (int c)
{
if (toklen >= tok_maxlen) {
tok_maxlen += (toklen + 16);
saml_token = realloc(saml_token, tok_maxlen);
if (!saml_token) panic_out_of_memory();
}
saml_token[toklen++] = c;
}
static int saml_common_lexer (int (*getc)(void), void (*ungetc)(int))
{
int c, bracket;
top:
c = (*getc)();
switch(c) {
case EOF:
/* End of file, return zero */
return STOK_EOF;
case '\0': case '\r':
case '\n': case '\f':
case '\t': case '\v':
case ' ':
/* Ignore whitespace */
goto top;
case '.':
/* Another symbol for multiplication */
return '*';
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
/* Number */
for (toklen = 0; isdigit(c); c = (*getc)())
append_to_token(c);
/* Push back the first non-digit */
(*ungetc)(c);
append_to_token(0);
return STOK_INTEGER;
case '[':
/* FORM literal */
toklen = 0;
bracket = 1;
append_to_token(c);
while (bracket) {
c = (*getc)();
if (c == EOF) break;
if (c == '[') ++bracket;
if (c == ']') --bracket;
append_to_token(c);
}
append_to_token(0);
return STOK_LITERAL;
case 'a': case 'b': case 'c': case 'd': case 'e':
case 'f': case 'g': case 'h': case 'i': case 'j':
case 'k': case 'l': case 'm': case 'n': case 'o':
case 'p': case 'q': case 'r': case 's': case 't':
case 'u': case 'v': case 'w': case 'x': case 'y':
case 'z': case '_':
case 'A': case 'B': case 'C': case 'D': case 'E':
case 'F': case 'G': case 'H': case 'I': case 'J':
case 'K': case 'L': case 'M': case 'N': case 'O':
case 'P': case 'Q': case 'R': case 'S': case 'T':
case 'U': case 'V': case 'W': case 'X': case 'Y':
case 'Z':
/* Literal */
toklen = 0;
next_char:
append_to_token(c);
c = (*getc)();
if (isascii(c) && (c == '_' || isalnum(c)))
goto next_char;
while (c == '[') {
bracket = 1;
append_to_token(c);
while (bracket) {
c = (*getc)();
if (c == EOF) break;
if (c == '[') ++bracket;
if (c == ']') --bracket;
append_to_token(c);
}
/* Found the matching bracket or EOF */
c = (*getc)();
}
/* Push back the character */
(*ungetc)(c);
append_to_token(0);
return STOK_LITERAL;
default:
/* Any other character */
return c;
}
}
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