- Rework the way literals are handled, these are now kept as strings until
[cparser] / lexer.c
diff --git a/lexer.c b/lexer.c
index 45327f6..c3f86b3 100644 (file)
--- a/lexer.c
+++ b/lexer.c
@@ -1,7 +1,27 @@
+/*
+ * This file is part of cparser.
+ * Copyright (C) 2007-2009 Matthias Braun <matze@braunis.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
 #include <config.h>
 
 #include "diagnostic.h"
 #include "lexer.h"
+#include "symbol_t.h"
 #include "token_t.h"
 #include "symbol_table_t.h"
 #include "adt/error.h"
@@ -12,6 +32,7 @@
 #include "target_architecture.h"
 #include "parser.h"
 #include "warning.h"
+#include "lang_features.h"
 
 #include <assert.h>
 #include <errno.h>
 #include <stdbool.h>
 #include <ctype.h>
 
+#ifndef _WIN32
+#include <strings.h>
+#endif
+
 //#define DEBUG_CHARS
 #define MAX_PUTBACK 3
+#define BUF_SIZE    1024
 
-#ifdef _WIN32
+#if defined(_WIN32) || defined(__CYGWIN__)
 /* No strtold on windows and no replacement yet */
 #define strtold(s, e) strtod(s, e)
 #endif
 
-#if defined HAS_SIGNED_CHAR
-typedef signed char char_type;
-#elif defined HAS_UNSIGNED_CHAR
-typedef unsigned char char_type;
-#else
-#      error signedness of char not determined
-#endif
-
-static int         c;
-token_t            lexer_token;
-symbol_t          *symbol_L;
-static FILE       *input;
-static char        buf[1024 + MAX_PUTBACK];
-static const char *bufend;
-static const char *bufpos;
-static strset_t    stringset;
+static utf32        c;
+token_t             lexer_token;
+symbol_t           *symbol_L;
+static FILE        *input;
+static utf32        buf[BUF_SIZE + MAX_PUTBACK];
+static const utf32 *bufend;
+static const utf32 *bufpos;
+static strset_t     stringset;
+bool                allow_dollar_in_symbol = true;
 
 /**
- * Print an error prefix at the given coordinates.
+ * Prints a parse error message at the current token.
  *
- * @param input_name   the input file name
- * @param linenr       the line number
+ * @param msg   the error message
  */
-static void error_prefix_at(const char *input_name, unsigned linenr)
+static void parse_error(const char *msg)
 {
-       fprintf(stderr, "%s:%u: Error: ", input_name, linenr);
+       errorf(&lexer_token.source_position, "%s", msg);
 }
 
 /**
- * Print an error prefix at the current token coordinates.
+ * Prints an internal error message at the current token.
+ *
+ * @param msg   the error message
  */
-static void error_prefix(void)
+static NORETURN internal_error(const char *msg)
 {
-       error_prefix_at(lexer_token.source_position.input_name,
-                       lexer_token.source_position.linenr);
+       internal_errorf(&lexer_token.source_position, "%s", msg);
 }
 
-/**
- * Prints a parse error message at the current token.
- *
- * @param msg   the error message
- */
-static void parse_error(const char *msg)
+static size_t read_block(unsigned char *const read_buf, size_t const n)
+{
+       size_t const s = fread(read_buf, 1, n, input);
+       if (s == 0) {
+               if (ferror(input))
+                       parse_error("read from input failed");
+               buf[MAX_PUTBACK] = EOF;
+               bufpos           = buf + MAX_PUTBACK;
+               bufend           = buf + MAX_PUTBACK + 1;
+       }
+       return s;
+}
+
+static void decode_iso_8859_1(void)
+{
+       unsigned char read_buf[BUF_SIZE];
+       size_t const s = read_block(read_buf, sizeof(read_buf));
+       if (s == 0)
+               return;
+
+       unsigned char const *src = read_buf;
+       unsigned char const *end = read_buf + s;
+       utf32               *dst = buf + MAX_PUTBACK;
+       while (src != end)
+               *dst++ = *src++;
+
+       bufpos = buf + MAX_PUTBACK;
+       bufend = dst;
+}
+
+static void decode_iso_8859_15(void)
+{
+       unsigned char read_buf[BUF_SIZE];
+       size_t const s = read_block(read_buf, sizeof(read_buf));
+       if (s == 0)
+               return;
+
+       unsigned char const *src = read_buf;
+       unsigned char const *end = read_buf + s;
+       utf32               *dst = buf + MAX_PUTBACK;
+       while (src != end) {
+               utf32 tc = *src++;
+               switch (tc) {
+                       case 0xA4: tc = 0x20AC; break; // €
+                       case 0xA6: tc = 0x0160; break; // Š
+                       case 0xA8: tc = 0x0161; break; // š
+                       case 0xB4: tc = 0x017D; break; // Ž
+                       case 0xB8: tc = 0x017E; break; // ž
+                       case 0xBC: tc = 0x0152; break; // Œ
+                       case 0xBD: tc = 0x0153; break; // œ
+                       case 0xBE: tc = 0x0178; break; // Ÿ
+               }
+               *dst++ = tc;
+       }
+
+       bufpos = buf + MAX_PUTBACK;
+       bufend = dst;
+}
+
+static void decode_utf8(void)
+{
+       static utf32  part_decoded_min_code;
+       static utf32  part_decoded_char;
+       static size_t part_decoded_rest_len;
+
+       do {
+               unsigned char read_buf[BUF_SIZE];
+               size_t const s = read_block(read_buf, sizeof(read_buf));
+               if (s == 0) {
+                       if (part_decoded_rest_len > 0)
+                               parse_error("incomplete input char at end of input");
+                       return;
+               }
+
+               unsigned char const *src = read_buf;
+               unsigned char const *end = read_buf + s;
+               utf32               *dst = buf + MAX_PUTBACK;
+               utf32                decoded;
+               utf32                min_code;
+
+               if (part_decoded_rest_len != 0) {
+                       min_code              = part_decoded_min_code;
+                       decoded               = part_decoded_char;
+                       size_t const rest_len = part_decoded_rest_len;
+                       part_decoded_rest_len = 0;
+                       switch (rest_len) {
+                               case 4:  goto realign;
+                               case 3:  goto three_more;
+                               case 2:  goto two_more;
+                               default: goto one_more;
+                       }
+               }
+
+               while (src != end) {
+                       if ((*src & 0x80) == 0) {
+                               decoded = *src++;
+                       } else if ((*src & 0xE0) == 0xC0) {
+                               min_code = 0x80;
+                               decoded  = *src++ & 0x1F;
+one_more:
+                               if (src == end) {
+                                       part_decoded_min_code = min_code;
+                                       part_decoded_char     = decoded;
+                                       part_decoded_rest_len = 1;
+                                       break;
+                               }
+                               if ((*src & 0xC0) == 0x80) {
+                                       decoded = (decoded << 6) | (*src++ & 0x3F);
+                               } else {
+                                       goto invalid_char;
+                               }
+                               if (decoded < min_code                      ||
+                                               decoded > 0x10FFFF                      ||
+                                               (0xD800 <= decoded && decoded < 0xE000) || // high/low surrogates
+                                               (0xFDD0 <= decoded && decoded < 0xFDF0) || // noncharacters
+                                               (decoded & 0xFFFE) == 0xFFFE) {            // noncharacters
+                                       parse_error("invalid byte sequence in input");
+                               }
+                       } else if ((*src & 0xF0) == 0xE0) {
+                               min_code = 0x800;
+                               decoded  = *src++ & 0x0F;
+two_more:
+                               if (src == end) {
+                                       part_decoded_min_code = min_code;
+                                       part_decoded_char     = decoded;
+                                       part_decoded_rest_len = 2;
+                                       break;
+                               }
+                               if ((*src & 0xC0) == 0x80) {
+                                       decoded = (decoded << 6) | (*src++ & 0x3F);
+                               } else {
+                                       goto invalid_char;
+                               }
+                               goto one_more;
+                       } else if ((*src & 0xF8) == 0xF0) {
+                               min_code = 0x10000;
+                               decoded  = *src++ & 0x07;
+three_more:
+                               if (src == end) {
+                                       part_decoded_min_code = min_code;
+                                       part_decoded_char     = decoded;
+                                       part_decoded_rest_len = 3;
+                                       break;
+                               }
+                               if ((*src & 0xC0) == 0x80) {
+                                       decoded = (decoded << 6) | (*src++ & 0x3F);
+                               } else {
+                                       goto invalid_char;
+                               }
+                               goto two_more;
+                       } else {
+invalid_char:
+                               parse_error("invalid byte sequence in input");
+realign:
+                               do {
+                                       ++src;
+                                       if (src == end) {
+                                               part_decoded_rest_len = 4;
+                                               break;
+                                       }
+                               } while ((*src & 0xC0) == 0x80 || (*src & 0xF8) == 0xF8);
+                               continue;
+                       }
+                       *dst++ = decoded;
+               }
+
+               bufpos = buf + MAX_PUTBACK;
+               bufend = dst;
+       } while (bufpos == bufend);
+}
+
+static void decode_windows_1252(void)
+{
+       unsigned char read_buf[BUF_SIZE];
+       size_t const s = read_block(read_buf, sizeof(read_buf));
+       if (s == 0)
+               return;
+
+       unsigned char const *src = read_buf;
+       unsigned char const *end = read_buf + s;
+       utf32               *dst = buf + MAX_PUTBACK;
+       while (src != end) {
+               utf32 tc = *src++;
+               switch (tc) {
+                       case 0x80: tc = 0x20AC; break; // €
+                       case 0x82: tc = 0x201A; break; // ‚
+                       case 0x83: tc = 0x0192; break; // ƒ
+                       case 0x84: tc = 0x201E; break; // „
+                       case 0x85: tc = 0x2026; break; // …
+                       case 0x86: tc = 0x2020; break; // †
+                       case 0x87: tc = 0x2021; break; // ‡
+                       case 0x88: tc = 0x02C6; break; // ˆ
+                       case 0x89: tc = 0x2030; break; // ‰
+                       case 0x8A: tc = 0x0160; break; // Š
+                       case 0x8B: tc = 0x2039; break; // ‹
+                       case 0x8C: tc = 0x0152; break; // Œ
+                       case 0x8E: tc = 0x017D; break; // Ž
+                       case 0x91: tc = 0x2018; break; // ‘
+                       case 0x92: tc = 0x2019; break; // ’
+                       case 0x93: tc = 0x201C; break; // “
+                       case 0x94: tc = 0x201D; break; // ”
+                       case 0x95: tc = 0x2022; break; // •
+                       case 0x96: tc = 0x2013; break; // –
+                       case 0x97: tc = 0x2014; break; // —
+                       case 0x98: tc = 0x02DC; break; // ˜
+                       case 0x99: tc = 0x2122; break; // ™
+                       case 0x9A: tc = 0x0161; break; // š
+                       case 0x9B: tc = 0x203A; break; // ›
+                       case 0x9C: tc = 0x0153; break; // œ
+                       case 0x9E: tc = 0x017E; break; // ž
+                       case 0x9F: tc = 0x0178; break; // Ÿ
+               }
+               *dst++ = tc;
+       }
+
+       bufpos = buf + MAX_PUTBACK;
+       bufend = dst;
+}
+
+typedef void (*decoder_t)(void);
+
+static decoder_t decoder = decode_utf8;
+
+typedef struct named_decoder_t {
+       char const *name;
+       decoder_t   decoder;
+} named_decoder_t;
+
+static named_decoder_t const decoders[] = {
+       { "CP819",           decode_iso_8859_1   }, // offical alias
+       { "IBM819",          decode_iso_8859_1   }, // offical alias
+       { "ISO-8859-1",      decode_iso_8859_1   }, // offical alias
+       { "ISO-8859-15",     decode_iso_8859_15  }, // offical name
+       { "ISO8859-1",       decode_iso_8859_1   },
+       { "ISO8859-15",      decode_iso_8859_15  },
+       { "ISO_8859-1",      decode_iso_8859_1   }, // offical alias
+       { "ISO_8859-15",     decode_iso_8859_15  }, // offical alias
+       { "ISO_8859-1:1987", decode_iso_8859_1   }, // offical name
+       { "Latin-9",         decode_iso_8859_15  }, // offical alias
+       { "UTF-8",           decode_utf8         }, // offical name
+       { "csISOLatin1",     decode_iso_8859_1   }, // offical alias
+       { "cp1252",          decode_windows_1252 },
+       { "iso-ir-100",      decode_iso_8859_1   }, // offical alias
+       { "l1",              decode_iso_8859_1   }, // offical alias
+       { "latin1",          decode_iso_8859_1   }, // offical alias
+       { "windows-1252",    decode_windows_1252 }, // official name
+
+       { NULL,              NULL                }
+};
+
+void select_input_encoding(char const* const encoding)
 {
-       error_prefix();
-       fprintf(stderr, "%s\n", msg);
+       for (named_decoder_t const *i = decoders; i->name != NULL; ++i) {
+               if (strcasecmp(encoding, i->name) != 0)
+                       continue;
+               decoder = i->decoder;
+               return;
+       }
+       fprintf(stderr, "error: input encoding \"%s\" not supported\n", encoding);
 }
 
 static inline void next_real_char(void)
 {
        assert(bufpos <= bufend);
        if (bufpos >= bufend) {
-               size_t s = fread(buf + MAX_PUTBACK, 1, sizeof(buf) - MAX_PUTBACK,
-                                input);
-               if(s == 0) {
+               if (input == NULL) {
                        c = EOF;
                        return;
                }
-               bufpos = buf + MAX_PUTBACK;
-               bufend = buf + MAX_PUTBACK + s;
+               decoder();
        }
        c = *bufpos++;
 }
 
-static inline void put_back(int pc)
+/**
+ * Put a character back into the buffer.
+ *
+ * @param pc  the character to put back
+ */
+static inline void put_back(utf32 const pc)
 {
        assert(bufpos > buf);
-       *(--bufpos - buf + buf) = (char) pc;
+       *(--bufpos - buf + buf) = pc;
 
 #ifdef DEBUG_CHARS
-       printf("putback '%c'\n", pc);
+       printf("putback '%lc'\n", pc);
 #endif
 }
 
@@ -106,7 +377,7 @@ static inline void next_char(void);
 #define MATCH_NEWLINE(code)                   \
        case '\r':                                \
                next_char();                          \
-               if(c == '\n') {                       \
+               if (c == '\n') {                      \
                        next_char();                      \
                }                                     \
                lexer_token.source_position.linenr++; \
@@ -116,13 +387,13 @@ static inline void next_char(void);
                lexer_token.source_position.linenr++; \
                code
 
-#define eat(c_type)  do { assert(c == c_type); next_char(); } while(0)
+#define eat(c_type)  do { assert(c == c_type); next_char(); } while (0)
 
 static void maybe_concat_lines(void)
 {
        eat('\\');
 
-       switch(c) {
+       switch (c) {
        MATCH_NEWLINE(return;)
 
        default:
@@ -133,28 +404,32 @@ static void maybe_concat_lines(void)
        c = '\\';
 }
 
+/**
+ * Set c to the next input character, ie.
+ * after expanding trigraphs.
+ */
 static inline void next_char(void)
 {
        next_real_char();
 
        /* filter trigraphs */
-       if(UNLIKELY(c == '\\')) {
+       if (UNLIKELY(c == '\\')) {
                maybe_concat_lines();
                goto end_of_next_char;
        }
 
-       if(LIKELY(c != '?'))
+       if (LIKELY(c != '?'))
                goto end_of_next_char;
 
        next_real_char();
-       if(LIKELY(c != '?')) {
+       if (LIKELY(c != '?')) {
                put_back(c);
                c = '?';
                goto end_of_next_char;
        }
 
        next_real_char();
-       switch(c) {
+       switch (c) {
        case '=': c = '#'; break;
        case '(': c = '['; break;
        case '/': c = '\\'; maybe_concat_lines(); break;
@@ -178,6 +453,7 @@ end_of_next_char:;
 }
 
 #define SYMBOL_CHARS  \
+       case '$': if (!allow_dollar_in_symbol) goto dollar_sign; \
        case 'a':         \
        case 'b':         \
        case 'c':         \
@@ -244,16 +520,17 @@ end_of_next_char:;
        case '8':         \
        case '9':
 
+/**
+ * Read a symbol from the input and build
+ * the lexer_token.
+ */
 static void parse_symbol(void)
 {
-       symbol_t *symbol;
-       char     *string;
-
        obstack_1grow(&symbol_obstack, (char) c);
        next_char();
 
-       while(1) {
-               switch(c) {
+       while (true) {
+               switch (c) {
                DIGITS
                SYMBOL_CHARS
                        obstack_1grow(&symbol_obstack, (char) c);
@@ -261,6 +538,7 @@ static void parse_symbol(void)
                        break;
 
                default:
+dollar_sign:
                        goto end_symbol;
                }
        }
@@ -268,392 +546,308 @@ static void parse_symbol(void)
 end_symbol:
        obstack_1grow(&symbol_obstack, '\0');
 
-       string = obstack_finish(&symbol_obstack);
-       symbol = symbol_table_insert(string);
+       char     *string = obstack_finish(&symbol_obstack);
+       symbol_t *symbol = symbol_table_insert(string);
 
-       lexer_token.type     = symbol->ID;
-       lexer_token.v.symbol = symbol;
+       lexer_token.type   = symbol->ID;
+       lexer_token.symbol = symbol;
 
-       if(symbol->string != string) {
+       if (symbol->string != string) {
                obstack_free(&symbol_obstack, string);
        }
 }
 
-static void parse_integer_suffix(bool is_oct_hex)
+/**
+ * parse suffixes like 'LU' or 'f' after numbers
+ */
+static void parse_number_suffix(void)
 {
-       bool is_unsigned  = false;
-       bool min_long     = false;
-       bool min_longlong = false;
-
-       if(c == 'U' || c == 'u') {
-               is_unsigned = true;
-               next_char();
-               if(c == 'L' || c == 'l') {
-                       min_long = true;
-                       next_char();
-                       if(c == 'L' || c == 'l') {
-                               min_longlong = true;
-                               next_char();
-                       }
-               }
-       } else if(c == 'l' || c == 'L') {
-               min_long = true;
-               next_char();
-               if(c == 'l' || c == 'L') {
-                       min_longlong = true;
-                       next_char();
-                       if(c == 'u' || c == 'U') {
-                               is_unsigned = true;
-                               next_char();
-                       }
-               } else if(c == 'u' || c == 'U') {
-                       is_unsigned = true;
+       assert(obstack_object_size(&symbol_obstack) == 0);
+       while (true) {
+               switch (c) {
+               SYMBOL_CHARS
+                       obstack_1grow(&symbol_obstack, (char) c);
                        next_char();
-                       lexer_token.datatype = type_unsigned_long;
+                       break;
+               default:
+               dollar_sign:
+                       goto finish_suffix;
                }
        }
+finish_suffix:
+       if (obstack_object_size(&symbol_obstack) == 0) {
+               lexer_token.symbol = NULL;
+               return;
+       }
 
-       if(!is_unsigned) {
-               long long v = lexer_token.v.intvalue;
-               if(!min_long) {
-                       if(v >= TARGET_INT_MIN && v <= TARGET_INT_MAX) {
-                               lexer_token.datatype = type_int;
-                               return;
-                       } else if(is_oct_hex && v >= 0 && v <= TARGET_UINT_MAX) {
-                               lexer_token.datatype = type_unsigned_int;
-                               return;
-                       }
-               }
-               if(!min_longlong) {
-                       if(v >= TARGET_LONG_MIN && v <= TARGET_LONG_MAX) {
-                               lexer_token.datatype = type_long;
-                               return;
-                       } else if(is_oct_hex && v >= 0 && v <= TARGET_ULONG_MAX) {
-                               lexer_token.datatype = type_unsigned_long;
-                               return;
-                       }
-               }
-               unsigned long long uv = (unsigned long long) v;
-               if(is_oct_hex && uv > (unsigned long long) TARGET_LONGLONG_MAX) {
-                       lexer_token.datatype = type_unsigned_long_long;
-                       return;
-               }
+       obstack_1grow(&symbol_obstack, '\0');
+       char     *string = obstack_finish(&symbol_obstack);
+       symbol_t *symbol = symbol_table_insert(string);
 
-               lexer_token.datatype = type_long_long;
-       } else {
-               unsigned long long v = (unsigned long long) lexer_token.v.intvalue;
-               if(!min_long && v <= TARGET_UINT_MAX) {
-                       lexer_token.datatype = type_unsigned_int;
-                       return;
-               }
-               if(!min_longlong && v <= TARGET_ULONG_MAX) {
-                       lexer_token.datatype = type_unsigned_long;
-                       return;
-               }
-               lexer_token.datatype = type_unsigned_long_long;
+       if (symbol->string != string) {
+               obstack_free(&symbol_obstack, string);
        }
+       lexer_token.symbol = symbol;
 }
 
-static void parse_floating_suffix(void)
+static string_t identify_string(char *string, size_t len)
 {
-       switch(c) {
-       /* TODO: do something usefull with the suffixes... */
-       case 'f':
-       case 'F':
-               next_char();
-               lexer_token.datatype = type_float;
-               break;
-       case 'l':
-       case 'L':
-               next_char();
-               lexer_token.datatype = type_long_double;
-               break;
-       default:
-               lexer_token.datatype = type_double;
-               break;
+       /* TODO hash */
+#if 0
+       const char *result = strset_insert(&stringset, concat);
+       if (result != concat) {
+               obstack_free(&symbol_obstack, concat);
        }
+#else
+       const char *result = string;
+#endif
+       return (string_t) {result, len};
 }
 
 /**
- * A replacement for strtoull. Only those parts needed for
- * our parser are implemented.
+ * Parses a hex number including hex floats and set the
+ * lexer_token.
  */
-static unsigned long long parse_int_string(const char *s, const char **endptr, int base) {
-       unsigned long long v = 0;
-
-       switch (base) {
-       case 16:
-               for (;; ++s) {
-                       /* check for overrun */
-                       if (v >= 0x1000000000000000ULL)
-                               break;
-                       switch (tolower(*s)) {
-                       case '0': v <<= 4; break;
-                       case '1': v <<= 4; v |= 0x1; break;
-                       case '2': v <<= 4; v |= 0x2; break;
-                       case '3': v <<= 4; v |= 0x3; break;
-                       case '4': v <<= 4; v |= 0x4; break;
-                       case '5': v <<= 4; v |= 0x5; break;
-                       case '6': v <<= 4; v |= 0x6; break;
-                       case '7': v <<= 4; v |= 0x7; break;
-                       case '8': v <<= 4; v |= 0x8; break;
-                       case '9': v <<= 4; v |= 0x9; break;
-                       case 'a': v <<= 4; v |= 0xa; break;
-                       case 'b': v <<= 4; v |= 0xb; break;
-                       case 'c': v <<= 4; v |= 0xc; break;
-                       case 'd': v <<= 4; v |= 0xd; break;
-                       case 'e': v <<= 4; v |= 0xe; break;
-                       case 'f': v <<= 4; v |= 0xf; break;
-                       default:
-                               goto end;
-                       }
-               }
-               break;
-       case 8:
-               for (;; ++s) {
-                       /* check for overrun */
-                       if (v >= 0x2000000000000000ULL)
-                               break;
-                       switch (tolower(*s)) {
-                       case '0': v <<= 3; break;
-                       case '1': v <<= 3; v |= 1; break;
-                       case '2': v <<= 3; v |= 2; break;
-                       case '3': v <<= 3; v |= 3; break;
-                       case '4': v <<= 3; v |= 4; break;
-                       case '5': v <<= 3; v |= 5; break;
-                       case '6': v <<= 3; v |= 6; break;
-                       case '7': v <<= 3; v |= 7; break;
-                       default:
-                               goto end;
-                       }
-               }
-               break;
-       case 10:
-               for (;; ++s) {
-                       /* check for overrun */
-                       if (v > 0x1999999999999999ULL)
-                               break;
-                       switch (tolower(*s)) {
-                       case '0': v *= 10; break;
-                       case '1': v *= 10; v += 1; break;
-                       case '2': v *= 10; v += 2; break;
-                       case '3': v *= 10; v += 3; break;
-                       case '4': v *= 10; v += 4; break;
-                       case '5': v *= 10; v += 5; break;
-                       case '6': v *= 10; v += 6; break;
-                       case '7': v *= 10; v += 7; break;
-                       case '8': v *= 10; v += 8; break;
-                       case '9': v *= 10; v += 9; break;
-                       default:
-                               goto end;
-                       }
-               }
-               break;
-       default:
-               assert(0);
-               break;
-       }
-end:
-       *endptr = s;
-       return v;
-}
-
 static void parse_number_hex(void)
 {
-       assert(c == 'x' || c == 'X');
-       next_char();
+       bool is_float   = false;
+       bool has_digits = false;
 
-       while(isxdigit(c)) {
+       assert(obstack_object_size(&symbol_obstack) == 0);
+       while (isxdigit(c)) {
+               has_digits = true;
                obstack_1grow(&symbol_obstack, (char) c);
                next_char();
        }
-       obstack_1grow(&symbol_obstack, '\0');
-       char *string = obstack_finish(&symbol_obstack);
 
-       if(c == '.' || c == 'p' || c == 'P') {
+       if (c == '.') {
+               is_float = true;
+               obstack_1grow(&symbol_obstack, (char) c);
                next_char();
-               panic("Hex floating point numbers not implemented yet");
+
+               while (isxdigit(c)) {
+                       has_digits = true;
+                       obstack_1grow(&symbol_obstack, (char) c);
+                       next_char();
+               }
        }
-       if(*string == '\0') {
-               parse_error("invalid hex number");
-               lexer_token.type = T_ERROR;
+       if (c == 'p' || c == 'P') {
+               is_float = true;
+               obstack_1grow(&symbol_obstack, (char) c);
+               next_char();
+
+               if (c == '-' || c == '+') {
+                       obstack_1grow(&symbol_obstack, (char) c);
+                       next_char();
+               }
+
+               while (isxdigit(c)) {
+                       obstack_1grow(&symbol_obstack, (char) c);
+                       next_char();
+               }
+       } else if (is_float) {
+               errorf(&lexer_token.source_position,
+                      "hexadecimal floatingpoint constant requires an exponent");
        }
 
-       const char *endptr;
-       lexer_token.type       = T_INTEGER;
-       lexer_token.v.intvalue = parse_int_string(string, &endptr, 16);
-       if(*endptr != '\0') {
-               parse_error("hex number literal too long");
+       size_t  size   = obstack_object_size(&symbol_obstack);
+       char   *string = obstack_finish(&symbol_obstack);
+       lexer_token.literal = identify_string(string, size);
+
+       lexer_token.type    =
+               is_float ? T_FLOATINGPOINT_HEXADECIMAL : T_INTEGER_HEXADECIMAL;
+
+       if (!has_digits) {
+               errorf(&lexer_token.source_position, "invalid number literal '0x%S'",
+                      &lexer_token.literal);
+               lexer_token.literal.begin = "0";
+               lexer_token.literal.size  = 1;
        }
 
-       obstack_free(&symbol_obstack, string);
-       parse_integer_suffix(true);
+       parse_number_suffix();
 }
 
-static inline bool is_octal_digit(int chr)
+/**
+ * Returns true if the given char is a octal digit.
+ *
+ * @param char  the character to check
+ */
+static bool is_octal_digit(utf32 chr)
 {
-       return '0' <= chr && chr <= '7';
+       switch (chr) {
+       case '0':
+       case '1':
+       case '2':
+       case '3':
+       case '4':
+       case '5':
+       case '6':
+       case '7':
+               return true;
+       default:
+               return false;
+       }
 }
 
-static void parse_number_oct(void)
+/**
+ * Parses a number and sets the lexer_token.
+ */
+static void parse_number(void)
 {
-       while(is_octal_digit(c)) {
-               obstack_1grow(&symbol_obstack, (char) c);
-               next_char();
-       }
-       obstack_1grow(&symbol_obstack, '\0');
-       char *string = obstack_finish(&symbol_obstack);
+       bool is_float   = false;
+       bool has_digits = false;
 
-       const char *endptr;
-       lexer_token.type       = T_INTEGER;
-       lexer_token.v.intvalue = parse_int_string(string, &endptr, 8);
-       if(*endptr != '\0') {
-               parse_error("octal number literal too long");
+       assert(obstack_object_size(&symbol_obstack) == 0);
+       if (c == '0') {
+               next_char();
+               if (c == 'x' || c == 'X') {
+                       next_char();
+                       parse_number_hex();
+                       return;
+               } else {
+                       has_digits = true;
+               }
+               obstack_1grow(&symbol_obstack, '0');
        }
 
-       obstack_free(&symbol_obstack, string);
-       parse_integer_suffix(true);
-}
-
-static void parse_number_dec(void)
-{
-       bool is_float = false;
-       while(isdigit(c)) {
+       while (isdigit(c)) {
+               has_digits = true;
                obstack_1grow(&symbol_obstack, (char) c);
                next_char();
        }
 
-       if(c == '.') {
+       if (c == '.') {
+               is_float = true;
                obstack_1grow(&symbol_obstack, '.');
                next_char();
 
-               while(isdigit(c)) {
+               while (isdigit(c)) {
+                       has_digits = true;
                        obstack_1grow(&symbol_obstack, (char) c);
                        next_char();
                }
-               is_float = true;
        }
-       if(c == 'e' || c == 'E') {
+       if (c == 'e' || c == 'E') {
+               is_float = true;
                obstack_1grow(&symbol_obstack, 'e');
                next_char();
 
-               if(c == '-' || c == '+') {
+               if (c == '-' || c == '+') {
                        obstack_1grow(&symbol_obstack, (char) c);
                        next_char();
                }
 
-               while(isdigit(c)) {
+               while (isdigit(c)) {
                        obstack_1grow(&symbol_obstack, (char) c);
                        next_char();
                }
-               is_float = true;
        }
 
-       obstack_1grow(&symbol_obstack, '\0');
-       char *string = obstack_finish(&symbol_obstack);
-
-       if(is_float) {
-               char *endptr;
-               lexer_token.type         = T_FLOATINGPOINT;
-               lexer_token.v.floatvalue = strtold(string, &endptr);
-
-               if(*endptr != '\0') {
-                       parse_error("invalid number literal");
+       size_t  size   = obstack_object_size(&symbol_obstack);
+       char   *string = obstack_finish(&symbol_obstack);
+       lexer_token.literal = identify_string(string, size);
+
+       /* is it an octal number? */
+       if (is_float) {
+               lexer_token.type = T_FLOATINGPOINT;
+       } else if (string[0] == '0') {
+               lexer_token.type = T_INTEGER_OCTAL;
+
+               /* check for invalid octal digits */
+               for (size_t i= 0; i < size; ++i) {
+                       char t = string[i];
+                       if (t == '8' || t == '9')
+                               errorf(&lexer_token.source_position,
+                                      "invalid digit '%c' in octal number", t);
                }
-
-               parse_floating_suffix();
        } else {
-               const char *endptr;
-               lexer_token.type       = T_INTEGER;
-               lexer_token.v.intvalue = parse_int_string(string, &endptr, 10);
-
-               if(*endptr != '\0') {
-                       parse_error("invalid number literal");
-               }
+               lexer_token.type = T_INTEGER;
+       }
 
-               parse_integer_suffix(false);
+       if (!has_digits) {
+               errorf(&lexer_token.source_position, "invalid number literal '%S'",
+                      &lexer_token.literal);
        }
-       obstack_free(&symbol_obstack, string);
+
+       parse_number_suffix();
 }
 
-static void parse_number(void)
+/**
+ * Returns the value of a digit.
+ * The only portable way to do it ...
+ */
+static int digit_value(utf32 const digit)
 {
-       if (c == '0') {
-               next_char();
-               switch (c) {
-                       case 'X':
-                       case 'x':
-                               parse_number_hex();
-                               break;
-                       case '0':
-                       case '1':
-                       case '2':
-                       case '3':
-                       case '4':
-                       case '5':
-                       case '6':
-                       case '7':
-                               parse_number_oct();
-                               break;
-                       case '8':
-                       case '9':
-                               next_char();
-                               parse_error("invalid octal number");
-                               lexer_token.type = T_ERROR;
-                               return;
-                       case '.':
-                       case 'e':
-                       case 'E':
-                       default:
-                               obstack_1grow(&symbol_obstack, '0');
-                               parse_number_dec();
-                               return;
-               }
-       } else {
-               parse_number_dec();
+       switch (digit) {
+       case '0': return 0;
+       case '1': return 1;
+       case '2': return 2;
+       case '3': return 3;
+       case '4': return 4;
+       case '5': return 5;
+       case '6': return 6;
+       case '7': return 7;
+       case '8': return 8;
+       case '9': return 9;
+       case 'a':
+       case 'A': return 10;
+       case 'b':
+       case 'B': return 11;
+       case 'c':
+       case 'C': return 12;
+       case 'd':
+       case 'D': return 13;
+       case 'e':
+       case 'E': return 14;
+       case 'f':
+       case 'F': return 15;
+       default:
+               internal_error("wrong character given");
        }
 }
 
-static int parse_octal_sequence(const int first_digit)
+/**
+ * Parses an octal character sequence.
+ *
+ * @param first_digit  the already read first digit
+ */
+static utf32 parse_octal_sequence(utf32 const first_digit)
 {
        assert(is_octal_digit(first_digit));
-       int value = first_digit - '0';
+       utf32 value = digit_value(first_digit);
        if (!is_octal_digit(c)) return value;
-       value = 8 * value + c - '0';
+       value = 8 * value + digit_value(c);
        next_char();
        if (!is_octal_digit(c)) return value;
-       value = 8 * value + c - '0';
+       value = 8 * value + digit_value(c);
        next_char();
-       return (char_type)value;
+       return value;
 }
 
-static int parse_hex_sequence(void)
+/**
+ * Parses a hex character sequence.
+ */
+static utf32 parse_hex_sequence(void)
 {
-       int value = 0;
-       while(1) {
-               if (c >= '0' && c <= '9') {
-                       value = 16 * value + c - '0';
-               } else if ('A' <= c && c <= 'F') {
-                       value = 16 * value + c - 'A' + 10;
-               } else if ('a' <= c && c <= 'f') {
-                       value = 16 * value + c - 'a' + 10;
-               } else {
-                       break;
-               }
+       utf32 value = 0;
+       while (isxdigit(c)) {
+               value = 16 * value + digit_value(c);
                next_char();
        }
-
-       return (char_type)value;
+       return value;
 }
 
-static int parse_escape_sequence(void)
+/**
+ * Parse an escape sequence.
+ */
+static utf32 parse_escape_sequence(void)
 {
        eat('\\');
 
-       int ec = c;
+       utf32 const ec = c;
        next_char();
 
-       switch(ec) {
+       switch (ec) {
        case '"':  return '"';
        case '\'': return '\'';
        case '\\': return '\\';
@@ -679,12 +873,28 @@ static int parse_escape_sequence(void)
        case EOF:
                parse_error("reached end of file while parsing escape sequence");
                return EOF;
-       default:
-               parse_error("unknown escape sequence");
+       /* \E is not documented, but handled, by GCC.  It is acceptable according
+        * to §6.11.4, whereas \e is not. */
+       case 'E':
+       case 'e':
+               if (c_mode & _GNUC)
+                       return 27;   /* hopefully 27 is ALWAYS the code for ESCAPE */
+               break;
+       case 'u':
+       case 'U':
+               parse_error("universal character parsing not implemented yet");
                return EOF;
+       default:
+               break;
        }
+       /* §6.4.4.4:8 footnote 64 */
+       parse_error("unknown escape sequence");
+       return EOF;
 }
 
+/**
+ * Concatenate two strings.
+ */
 string_t concat_strings(const string_t *const s1, const string_t *const s2)
 {
        const size_t len1 = s1->size - 1;
@@ -694,46 +904,74 @@ string_t concat_strings(const string_t *const s1, const string_t *const s2)
        memcpy(concat, s1->begin, len1);
        memcpy(concat + len1, s2->begin, len2 + 1);
 
-#if 0 /* TODO hash */
-       const char *result = strset_insert(&stringset, concat);
-       if(result != concat) {
-               obstack_free(&symbol_obstack, concat);
-       }
+       return identify_string(concat, len1 + len2 + 1);
+}
 
-       return result;
-#else
-       return (string_t){ concat, len1 + len2 + 1 };
-#endif
+string_t make_string(const char *string)
+{
+       size_t      len   = strlen(string) + 1;
+       char *const space = obstack_alloc(&symbol_obstack, len);
+       memcpy(space, string, len);
+
+       return identify_string(space, len);
 }
 
+static void grow_symbol(utf32 const tc)
+{
+       struct obstack *const o  = &symbol_obstack;
+       if (tc < 0x80U) {
+               obstack_1grow(o, tc);
+       } else if (tc < 0x800) {
+               obstack_1grow(o, 0xC0 | (tc >> 6));
+               obstack_1grow(o, 0x80 | (tc & 0x3F));
+       } else if (tc < 0x10000) {
+               obstack_1grow(o, 0xE0 | ( tc >> 12));
+               obstack_1grow(o, 0x80 | ((tc >>  6) & 0x3F));
+               obstack_1grow(o, 0x80 | ( tc        & 0x3F));
+       } else {
+               obstack_1grow(o, 0xF0 | ( tc >> 18));
+               obstack_1grow(o, 0x80 | ((tc >> 12) & 0x3F));
+               obstack_1grow(o, 0x80 | ((tc >>  6) & 0x3F));
+               obstack_1grow(o, 0x80 | ( tc        & 0x3F));
+       }
+}
+
+/**
+ * Parse a string literal and set lexer_token.
+ */
 static void parse_string_literal(void)
 {
        const unsigned start_linenr = lexer_token.source_position.linenr;
 
-       assert(c == '"');
-       next_char();
+       eat('"');
 
-       int tc;
-       while(1) {
-               switch(c) {
-               case '\\':
-                       tc = parse_escape_sequence();
-                       obstack_1grow(&symbol_obstack, (char) tc);
+       while (true) {
+               switch (c) {
+               case '\\': {
+                       utf32 const tc = parse_escape_sequence();
+                       if (tc >= 0x100) {
+                               warningf(&lexer_token.source_position,
+                                               "escape sequence out of range");
+                       }
+                       obstack_1grow(&symbol_obstack, tc);
                        break;
+               }
 
-               case EOF:
-                       error_prefix_at(lexer_token.source_position.input_name,
-                                       start_linenr);
-                       fprintf(stderr, "string has no end\n");
+               case EOF: {
+                       source_position_t source_position;
+                       source_position.input_name = lexer_token.source_position.input_name;
+                       source_position.linenr     = start_linenr;
+                       errorf(&source_position, "string has no end");
                        lexer_token.type = T_ERROR;
                        return;
+               }
 
                case '"':
                        next_char();
                        goto end_of_string;
 
                default:
-                       obstack_1grow(&symbol_obstack, (char) c);
+                       grow_symbol(c);
                        next_char();
                        break;
                }
@@ -745,34 +983,29 @@ end_of_string:
 
        /* add finishing 0 to the string */
        obstack_1grow(&symbol_obstack, '\0');
-       const size_t      size   = (size_t)obstack_object_size(&symbol_obstack);
-       const char *const string = obstack_finish(&symbol_obstack);
+       const size_t  size   = (size_t)obstack_object_size(&symbol_obstack);
+       char         *string = obstack_finish(&symbol_obstack);
 
-#if 0 /* TODO hash */
-       /* check if there is already a copy of the string */
-       result = strset_insert(&stringset, string);
-       if(result != string) {
-               obstack_free(&symbol_obstack, string);
-       }
-#else
-       const char *const result = string;
-#endif
-
-       lexer_token.type           = T_STRING_LITERAL;
-       lexer_token.v.string.begin = result;
-       lexer_token.v.string.size  = size;
+       lexer_token.type    = T_STRING_LITERAL;
+       lexer_token.literal = identify_string(string, size);
 }
 
+/**
+ * Parse a wide character constant and set lexer_token.
+ */
 static void parse_wide_character_constant(void)
 {
+       const unsigned start_linenr = lexer_token.source_position.linenr;
+
        eat('\'');
 
-       int found_char = 0;
-       while(1) {
-               switch(c) {
-               case '\\':
-                       found_char = parse_escape_sequence();
+       while (true) {
+               switch (c) {
+               case '\\': {
+                       const utf32 tc = parse_escape_sequence();
+                       grow_symbol(tc);
                        break;
+               }
 
                MATCH_NEWLINE(
                        parse_error("newline while parsing character constant");
@@ -783,100 +1016,59 @@ static void parse_wide_character_constant(void)
                        next_char();
                        goto end_of_wide_char_constant;
 
-               case EOF:
-                       parse_error("EOF while parsing character constant");
+               case EOF: {
+                       source_position_t source_position = lexer_token.source_position;
+                       source_position.linenr = start_linenr;
+                       errorf(&source_position, "EOF while parsing character constant");
                        lexer_token.type = T_ERROR;
                        return;
+               }
 
                default:
-                       if(found_char != 0) {
-                               parse_error("more than 1 characters in character "
-                                           "constant");
-                               goto end_of_wide_char_constant;
-                       } else {
-                               found_char = c;
-                               next_char();
-                       }
+                       grow_symbol(c);
+                       next_char();
                        break;
                }
        }
 
-end_of_wide_char_constant:
-       lexer_token.type       = T_INTEGER;
-       lexer_token.v.intvalue = found_char;
-       lexer_token.datatype   = type_wchar_t;
+end_of_wide_char_constant:;
+       size_t  size   = (size_t) obstack_object_size(&symbol_obstack);
+       char   *string = obstack_finish(&symbol_obstack);
+
+       lexer_token.type     = T_WIDE_CHARACTER_CONSTANT;
+       lexer_token.literal  = identify_string(string, size);
 }
 
+/**
+ * Parse a wide string literal and set lexer_token.
+ */
 static void parse_wide_string_literal(void)
 {
-       const unsigned start_linenr = lexer_token.source_position.linenr;
-
-       assert(c == '"');
-       next_char();
-
-       while(1) {
-               switch(c) {
-                       case '\\': {
-                               wchar_rep_t tc = parse_escape_sequence();
-                               obstack_grow(&symbol_obstack, &tc, sizeof(tc));
-                               break;
-                       }
-
-                       case EOF:
-                               error_prefix_at(lexer_token.source_position.input_name,
-                                               start_linenr);
-                               fprintf(stderr, "string has no end\n");
-                               lexer_token.type = T_ERROR;
-                               return;
-
-                       case '"':
-                               next_char();
-                               goto end_of_string;
-
-                       default: {
-                               wchar_rep_t tc = c;
-                               obstack_grow(&symbol_obstack, &tc, sizeof(tc));
-                               next_char();
-                               break;
-                       }
-               }
-       }
-
-end_of_string:;
-
-       /* TODO: concatenate multiple strings separated by whitespace... */
-
-       /* add finishing 0 to the string */
-       wchar_rep_t nul = L'\0';
-       obstack_grow(&symbol_obstack, &nul, sizeof(nul));
-       const size_t             size   = (size_t)obstack_object_size(&symbol_obstack) / sizeof(wchar_rep_t);
-       const wchar_rep_t *const string = obstack_finish(&symbol_obstack);
-
-#if 0 /* TODO hash */
-       /* check if there is already a copy of the string */
-       const wchar_rep_t *const result = strset_insert(&stringset, string);
-       if(result != string) {
-               obstack_free(&symbol_obstack, string);
-       }
-#else
-       const wchar_rep_t *const result = string;
-#endif
-
-       lexer_token.type                = T_WIDE_STRING_LITERAL;
-       lexer_token.v.wide_string.begin = result;
-       lexer_token.v.wide_string.size  = size;
+       parse_string_literal();
+       if (lexer_token.type == T_STRING_LITERAL)
+               lexer_token.type = T_WIDE_STRING_LITERAL;
 }
 
+/**
+ * Parse a character constant and set lexer_token.
+ */
 static void parse_character_constant(void)
 {
+       const unsigned start_linenr = lexer_token.source_position.linenr;
+
        eat('\'');
 
-       int found_char = 0;
-       while(1) {
-               switch(c) {
-               case '\\':
-                       found_char = parse_escape_sequence();
+       while (true) {
+               switch (c) {
+               case '\\': {
+                       utf32 const tc = parse_escape_sequence();
+                       if (tc >= 0x100) {
+                               warningf(&lexer_token.source_position,
+                                               "escape sequence out of range");
+                       }
+                       obstack_1grow(&symbol_obstack, tc);
                        break;
+               }
 
                MATCH_NEWLINE(
                        parse_error("newline while parsing character constant");
@@ -887,45 +1079,52 @@ static void parse_character_constant(void)
                        next_char();
                        goto end_of_char_constant;
 
-               case EOF:
-                       parse_error("EOF while parsing character constant");
+               case EOF: {
+                       source_position_t source_position;
+                       source_position.input_name = lexer_token.source_position.input_name;
+                       source_position.linenr     = start_linenr;
+                       errorf(&source_position, "EOF while parsing character constant");
                        lexer_token.type = T_ERROR;
                        return;
+               }
 
                default:
-                       if(found_char != 0) {
-                               parse_error("more than 1 characters in character "
-                                           "constant");
-                               goto end_of_char_constant;
-                       } else {
-                               found_char = c;
-                               next_char();
-                       }
+                       grow_symbol(c);
+                       next_char();
                        break;
+
                }
        }
 
-end_of_char_constant:
-       lexer_token.type       = T_INTEGER;
-       lexer_token.v.intvalue = found_char;
-       lexer_token.datatype   = type_int;
+end_of_char_constant:;
+       const size_t        size   = (size_t)obstack_object_size(&symbol_obstack);
+       char         *const string = obstack_finish(&symbol_obstack);
+
+       lexer_token.type    = T_CHARACTER_CONSTANT;
+       lexer_token.literal = identify_string(string, size);
 }
 
+/**
+ * Skip a multiline comment.
+ */
 static void skip_multiline_comment(void)
 {
        unsigned start_linenr = lexer_token.source_position.linenr;
 
-       while(1) {
-               switch(c) {
+       while (true) {
+               switch (c) {
                case '/':
                        next_char();
                        if (c == '*') {
-                               /* TODO: nested comment, warn here */
+                               /* nested comment, warn here */
+                               if (warning.comment) {
+                                       warningf(&lexer_token.source_position, "'/*' within comment");
+                               }
                        }
                        break;
                case '*':
                        next_char();
-                       if(c == '/') {
+                       if (c == '/') {
                                next_char();
                                return;
                        }
@@ -933,11 +1132,13 @@ static void skip_multiline_comment(void)
 
                MATCH_NEWLINE(break;)
 
-               case EOF:
-                       error_prefix_at(lexer_token.source_position.input_name,
-                                       start_linenr);
-                       fprintf(stderr, "at end of file while looking for comment end\n");
+               case EOF: {
+                       source_position_t source_position;
+                       source_position.input_name = lexer_token.source_position.input_name;
+                       source_position.linenr     = start_linenr;
+                       errorf(&source_position, "at end of file while looking for comment end");
                        return;
+               }
 
                default:
                        next_char();
@@ -946,10 +1147,13 @@ static void skip_multiline_comment(void)
        }
 }
 
+/**
+ * Skip a single line comment.
+ */
 static void skip_line_comment(void)
 {
-       while(1) {
-               switch(c) {
+       while (true) {
+               switch (c) {
                case EOF:
                        return;
 
@@ -957,6 +1161,15 @@ static void skip_line_comment(void)
                case '\r':
                        return;
 
+               case '\\':
+                       next_char();
+                       if (c == '\n' || c == '\r') {
+                               if (warning.comment)
+                                       warningf(&lexer_token.source_position, "multi-line comment");
+                               return;
+                       }
+                       break;
+
                default:
                        next_char();
                        break;
@@ -964,38 +1177,43 @@ static void skip_line_comment(void)
        }
 }
 
+/** The current preprocessor token. */
 static token_t pp_token;
 
+/**
+ * Read the next preprocessor token.
+ */
 static inline void next_pp_token(void)
 {
        lexer_next_preprocessing_token();
        pp_token = lexer_token;
 }
 
+/**
+ * Eat all preprocessor tokens until newline.
+ */
 static void eat_until_newline(void)
 {
-       while(pp_token.type != '\n' && pp_token.type != T_EOF) {
+       while (pp_token.type != '\n' && pp_token.type != T_EOF) {
                next_pp_token();
        }
 }
 
-static void error_directive(void)
-{
-       error_prefix();
-       fprintf(stderr, "#error directive: \n");
-
-       /* parse pp-tokens until new-line */
-}
-
+/**
+ * Handle the define directive.
+ */
 static void define_directive(void)
 {
        lexer_next_preprocessing_token();
-       if(lexer_token.type != T_IDENTIFIER) {
+       if (lexer_token.type != T_IDENTIFIER) {
                parse_error("expected identifier after #define\n");
                eat_until_newline();
        }
 }
 
+/**
+ * Handle the ifdef directive.
+ */
 static void ifdef_directive(int is_ifndef)
 {
        (void) is_ifndef;
@@ -1004,33 +1222,121 @@ static void ifdef_directive(int is_ifndef)
        //extect_newline();
 }
 
+/**
+ * Handle the endif directive.
+ */
 static void endif_directive(void)
 {
        //expect_newline();
 }
 
+/**
+ * Parse the line directive.
+ */
 static void parse_line_directive(void)
 {
-       if(pp_token.type != T_INTEGER) {
+       if (pp_token.type != T_INTEGER) {
                parse_error("expected integer");
        } else {
-               lexer_token.source_position.linenr = (unsigned int)(pp_token.v.intvalue - 1);
+               lexer_token.source_position.linenr = atoi(pp_token.literal.begin);
                next_pp_token();
        }
-       if(pp_token.type == T_STRING_LITERAL) {
-               lexer_token.source_position.input_name = pp_token.v.string.begin;
+       if (pp_token.type == T_STRING_LITERAL) {
+               lexer_token.source_position.input_name = pp_token.literal.begin;
                next_pp_token();
        }
 
        eat_until_newline();
 }
 
+/**
+ * STDC pragmas.
+ */
+typedef enum stdc_pragma_kind_t {
+       STDC_UNKNOWN,
+       STDC_FP_CONTRACT,
+       STDC_FENV_ACCESS,
+       STDC_CX_LIMITED_RANGE
+} stdc_pragma_kind_t;
+
+/**
+ * STDC pragma values.
+ */
+typedef enum stdc_pragma_value_kind_t {
+       STDC_VALUE_UNKNOWN,
+       STDC_VALUE_ON,
+       STDC_VALUE_OFF,
+       STDC_VALUE_DEFAULT
+} stdc_pragma_value_kind_t;
+
+/**
+ * Parse a pragma directive.
+ */
+static void parse_pragma(void)
+{
+       bool unknown_pragma = true;
+
+       next_pp_token();
+       if (pp_token.symbol->pp_ID == TP_STDC) {
+               stdc_pragma_kind_t kind = STDC_UNKNOWN;
+               /* a STDC pragma */
+               if (c_mode & _C99) {
+                       next_pp_token();
+
+                       switch (pp_token.symbol->pp_ID) {
+                       case TP_FP_CONTRACT:
+                               kind = STDC_FP_CONTRACT;
+                               break;
+                       case TP_FENV_ACCESS:
+                               kind = STDC_FENV_ACCESS;
+                               break;
+                       case TP_CX_LIMITED_RANGE:
+                               kind = STDC_CX_LIMITED_RANGE;
+                               break;
+                       default:
+                               break;
+                       }
+                       if (kind != STDC_UNKNOWN) {
+                               stdc_pragma_value_kind_t value = STDC_VALUE_UNKNOWN;
+                               next_pp_token();
+                               switch (pp_token.symbol->pp_ID) {
+                               case TP_ON:
+                                       value = STDC_VALUE_ON;
+                                       break;
+                               case TP_OFF:
+                                       value = STDC_VALUE_OFF;
+                                       break;
+                               case TP_DEFAULT:
+                                       value = STDC_VALUE_DEFAULT;
+                                       break;
+                               default:
+                                       break;
+                               }
+                               if (value != STDC_VALUE_UNKNOWN) {
+                                       unknown_pragma = false;
+                               } else {
+                                       errorf(&pp_token.source_position, "bad STDC pragma argument");
+                               }
+                       }
+               }
+       } else {
+               unknown_pragma = true;
+       }
+       eat_until_newline();
+       if (unknown_pragma && warning.unknown_pragmas) {
+               warningf(&pp_token.source_position, "encountered unknown #pragma");
+       }
+}
+
+/**
+ * Parse a preprocessor non-null directive.
+ */
 static void parse_preprocessor_identifier(void)
 {
        assert(pp_token.type == T_IDENTIFIER);
-       symbol_t *symbol = pp_token.v.symbol;
+       symbol_t *symbol = pp_token.symbol;
 
-       switch(symbol->pp_ID) {
+       switch (symbol->pp_ID) {
        case TP_include:
                printf("include - enable header name parsing!\n");
                break;
@@ -1055,28 +1361,32 @@ static void parse_preprocessor_identifier(void)
        case TP_elif:
        case TP_undef:
        case TP_error:
-               error_directive();
+               /* TODO; output the rest of the line */
+               parse_error("#error directive: ");
                break;
        case TP_pragma:
-               if (warning.unknown_pragmas) {
-                       warningf(lexer_token.source_position, "encountered unknown #pragma");
-               }
-               eat_until_newline();
+               parse_pragma();
                break;
        }
 }
 
+/**
+ * Parse a preprocessor directive.
+ */
 static void parse_preprocessor_directive(void)
 {
        next_pp_token();
 
-       switch(pp_token.type) {
+       switch (pp_token.type) {
        case T_IDENTIFIER:
                parse_preprocessor_identifier();
                break;
        case T_INTEGER:
                parse_line_directive();
                break;
+       case '\n':
+               /* NULL directive, see §6.10.7 */
+               break;
        default:
                parse_error("invalid preprocessor directive");
                eat_until_newline();
@@ -1086,8 +1396,8 @@ static void parse_preprocessor_directive(void)
 
 #define MAYBE_PROLOG                                       \
                        next_char();                                   \
-                       while(1) {                                     \
-                               switch(c) {
+                       while (true) {                                 \
+                               switch (c) {
 
 #define MAYBE(ch, set_type)                                \
                                case ch:                                   \
@@ -1095,11 +1405,21 @@ static void parse_preprocessor_directive(void)
                                        lexer_token.type = set_type;           \
                                        return;
 
+/* must use this as last thing */
+#define MAYBE_MODE(ch, set_type, mode)                     \
+                               case ch:                                   \
+                                       if (c_mode & mode) {                   \
+                                               next_char();                       \
+                                               lexer_token.type = set_type;       \
+                                               return;                            \
+                                       }                                      \
+                                       /* fallthrough */
+
 #define ELSE_CODE(code)                                    \
                                default:                                   \
-                                       code;                                  \
+                                       code                                   \
                                }                                          \
-                       } /* end of while(1) */                        \
+                       } /* end of while (true) */                    \
                        break;
 
 #define ELSE(set_type)                                     \
@@ -1110,8 +1430,8 @@ static void parse_preprocessor_directive(void)
 
 void lexer_next_preprocessing_token(void)
 {
-       while(1) {
-               switch(c) {
+       while (true) {
+               switch (c) {
                case ' ':
                case '\t':
                        next_char();
@@ -1125,12 +1445,10 @@ void lexer_next_preprocessing_token(void)
                SYMBOL_CHARS
                        parse_symbol();
                        /* might be a wide string ( L"string" ) */
-                       if(lexer_token.type == T_IDENTIFIER &&
-                           lexer_token.v.symbol == symbol_L) {
-                           if(c == '"') {
-                                       parse_wide_string_literal();
-                               } else if(c == '\'') {
-                                       parse_wide_character_constant();
+                       if (lexer_token.symbol == symbol_L) {
+                               switch (c) {
+                                       case '"':  parse_wide_string_literal();     break;
+                                       case '\'': parse_wide_character_constant(); break;
                                }
                        }
                        return;
@@ -1149,19 +1467,10 @@ void lexer_next_preprocessing_token(void)
 
                case '.':
                        MAYBE_PROLOG
-                               case '0':
-                               case '1':
-                               case '2':
-                               case '3':
-                               case '4':
-                               case '5':
-                               case '6':
-                               case '7':
-                               case '8':
-                               case '9':
+                               DIGITS
                                        put_back(c);
                                        c = '.';
-                                       parse_number_dec();
+                                       parse_number();
                                        return;
 
                                case '.':
@@ -1214,25 +1523,25 @@ void lexer_next_preprocessing_token(void)
                        ELSE('/')
                case '%':
                        MAYBE_PROLOG
-                       MAYBE('>', T_PERCENTGREATER)
+                       MAYBE('>', '}')
                        MAYBE('=', T_PERCENTEQUAL)
                                case ':':
                                        MAYBE_PROLOG
                                                case '%':
                                                        MAYBE_PROLOG
-                                                       MAYBE(':', T_PERCENTCOLONPERCENTCOLON)
+                                                       MAYBE(':', T_HASHHASH)
                                                        ELSE_CODE(
                                                                put_back(c);
                                                                c = '%';
-                                                               lexer_token.type = T_PERCENTCOLON;
+                                                               lexer_token.type = '#';
                                                                return;
                                                        )
-                                       ELSE(T_PERCENTCOLON)
+                                       ELSE('#')
                        ELSE('%')
                case '<':
                        MAYBE_PROLOG
-                       MAYBE(':', T_LESSCOLON)
-                       MAYBE('%', T_LESSPERCENT)
+                       MAYBE(':', '[')
+                       MAYBE('%', '{')
                        MAYBE('=', T_LESSEQUAL)
                                case '<':
                                        MAYBE_PROLOG
@@ -1258,7 +1567,8 @@ void lexer_next_preprocessing_token(void)
                        ELSE('|')
                case ':':
                        MAYBE_PROLOG
-                       MAYBE('>', T_COLONGREATER)
+                       MAYBE('>', ']')
+                       MAYBE_MODE(':', T_COLONCOLON, _CXX)
                        ELSE(':')
                case '=':
                        MAYBE_PROLOG
@@ -1289,9 +1599,9 @@ void lexer_next_preprocessing_token(void)
                        return;
 
                default:
+dollar_sign:
+                       errorf(&lexer_token.source_position, "unknown character '%c' found", c);
                        next_char();
-                       error_prefix();
-                       fprintf(stderr, "unknown character '%c' found\n", c);
                        lexer_token.type = T_ERROR;
                        return;
                }
@@ -1301,15 +1611,13 @@ void lexer_next_preprocessing_token(void)
 void lexer_next_token(void)
 {
        lexer_next_preprocessing_token();
-       if(lexer_token.type != '\n')
-               return;
 
+       while (lexer_token.type == '\n') {
 newline_found:
-       do {
                lexer_next_preprocessing_token();
-       } while(lexer_token.type == '\n');
+       }
 
-       if(lexer_token.type == '#') {
+       if (lexer_token.type == '#') {
                parse_preprocessor_directive();
                goto newline_found;
        }
@@ -1318,6 +1626,7 @@ newline_found:
 void init_lexer(void)
 {
        strset_init(&stringset);
+       symbol_L = symbol_table_insert("L");
 }
 
 void lexer_open_stream(FILE *stream, const char *input_name)
@@ -1326,7 +1635,6 @@ void lexer_open_stream(FILE *stream, const char *input_name)
        lexer_token.source_position.linenr     = 0;
        lexer_token.source_position.input_name = input_name;
 
-       symbol_L = symbol_table_insert("L");
        bufpos = NULL;
        bufend = NULL;
 
@@ -1335,6 +1643,26 @@ void lexer_open_stream(FILE *stream, const char *input_name)
        c = '\n';
 }
 
+void lexer_open_buffer(const char *buffer, size_t len, const char *input_name)
+{
+       input                                  = NULL;
+       lexer_token.source_position.linenr     = 0;
+       lexer_token.source_position.input_name = input_name;
+
+#if 0 // TODO
+       bufpos = buffer;
+       bufend = buffer + len;
+#else
+       (void)buffer;
+       (void)len;
+       panic("builtin lexing not done yet");
+#endif
+
+       /* place a virtual \n at the beginning so the lexer knows that we're
+        * at the beginning of a line */
+       c = '\n';
+}
+
 void exit_lexer(void)
 {
        strset_destroy(&stringset);