some refactoring in preparation for a preprocessor
[cparser] / lexer.c
diff --git a/lexer.c b/lexer.c
index 1300b3d..3ba2c37 100644 (file)
--- a/lexer.c
+++ b/lexer.c
@@ -1,20 +1,53 @@
+/*
+ * This file is part of cparser.
+ * Copyright (C) 2007-2008 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"
 #include "adt/strset.h"
 #include "adt/util.h"
+#include "types.h"
+#include "type_t.h"
+#include "target_architecture.h"
+#include "parser.h"
+#include "warning.h"
+#include "lang_features.h"
 
 #include <assert.h>
 #include <errno.h>
 #include <string.h>
+#include <stdbool.h>
 #include <ctype.h>
 
 //#define DEBUG_CHARS
 #define MAX_PUTBACK 3
 
+#ifdef _WIN32
+/* No strtold on windows and no replacement yet */
+#define strtold(s, e) strtod(s, e)
+#endif
+
 static int         c;
 token_t            lexer_token;
 symbol_t          *symbol_L;
@@ -24,27 +57,20 @@ static const char *bufend;
 static const char *bufpos;
 static strset_t    stringset;
 
-static void error_prefix_at(const char *input_name, unsigned linenr)
-{
-       fprintf(stderr, "%s:%u: Error: ", input_name, linenr);
-}
-
-static void error_prefix(void)
-{
-       error_prefix_at(lexer_token.source_position.input_name,
-                       lexer_token.source_position.linenr);
-}
-
+/**
+ * Prints a parse error message at the current token.
+ *
+ * @param msg   the error message
+ */
 static void parse_error(const char *msg)
 {
-       error_prefix();
-       fprintf(stderr, "%s\n", msg);
+       errorf(lexer_token.source_position,  "%s", msg);
 }
 
 static inline void next_real_char(void)
 {
-       bufpos++;
-       if(bufpos >= bufend) {
+       assert(bufpos <= bufend);
+       if (bufpos >= bufend) {
                size_t s = fread(buf + MAX_PUTBACK, 1, sizeof(buf) - MAX_PUTBACK,
                                 input);
                if(s == 0) {
@@ -54,20 +80,18 @@ static inline void next_real_char(void)
                bufpos = buf + MAX_PUTBACK;
                bufend = buf + MAX_PUTBACK + s;
        }
-       c = *(bufpos);
+       c = *bufpos++;
 }
 
+/**
+ * Put a character back into the buffer.
+ *
+ * @param pc  the character to put back
+ */
 static inline void put_back(int pc)
 {
-       assert(bufpos >= buf);
-       assert(bufpos < buf+MAX_PUTBACK || *bufpos == pc);
-
-       char *p = buf + (bufpos - buf);
-       *p = pc;
-
-       /* going backwards in the buffer is legal as long as it's not more often
-        * than MAX_PUTBACK */
-       bufpos--;
+       assert(bufpos > buf);
+       *(--bufpos - buf + buf) = (char) pc;
 
 #ifdef DEBUG_CHARS
        printf("putback '%c'\n", pc);
@@ -83,11 +107,11 @@ static inline void next_char(void);
                        next_char();                      \
                }                                     \
                lexer_token.source_position.linenr++; \
-               code;                                 \
+               code                                  \
        case '\n':                                \
                next_char();                          \
                lexer_token.source_position.linenr++; \
-               code;
+               code
 
 #define eat(c_type)  do { assert(c == c_type); next_char(); } while(0)
 
@@ -106,11 +130,14 @@ 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();
 
-#if 0
        /* filter trigraphs */
        if(UNLIKELY(c == '\\')) {
                maybe_concat_lines();
@@ -139,19 +166,15 @@ static inline void next_char(void)
        case '>': c = '}'; break;
        case '-': c = '~'; break;
        default:
-               put_back('?');
                put_back(c);
+               put_back('?');
                c = '?';
                break;
        }
 
-end_of_next_char:
-#endif
-       (void) maybe_concat_lines;
+end_of_next_char:;
 #ifdef DEBUG_CHARS
        printf("nchar '%c'\n", c);
-#else
-       ;
 #endif
 }
 
@@ -222,19 +245,23 @@ 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, c);
+       obstack_1grow(&symbol_obstack, (char) c);
        next_char();
 
        while(1) {
                switch(c) {
                DIGITS
                SYMBOL_CHARS
-                       obstack_1grow(&symbol_obstack, c);
+                       obstack_1grow(&symbol_obstack, (char) c);
                        next_char();
                        break;
 
@@ -257,181 +284,334 @@ end_symbol:
        }
 }
 
-static void parse_integer_suffix(void)
+static void parse_integer_suffix(bool is_oct_hex)
 {
-       if(c == 'U' || c == 'U') {
-               /* TODO do something with the suffixes... */
+       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;
                        next_char();
+                       lexer_token.datatype = type_unsigned_long;
+               }
+       }
+
+       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;
                }
+
+               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;
        }
 }
 
 static void parse_floating_suffix(void)
 {
        switch(c) {
-       /* TODO: do something usefull with the suffixes... */
+       /* TODO: do something useful 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;
+       }
+}
+
+/**
+ * A replacement for strtoull. Only those parts needed for
+ * our parser are implemented.
+ */
+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;
 }
 
+/**
+ * Parses a hex number including hex floats and set the
+ * lexer_token.
+ */
 static void parse_number_hex(void)
 {
        assert(c == 'x' || c == 'X');
        next_char();
 
-       if (!isdigit(c) &&
-               !('A' <= c && c <= 'F') &&
-               !('a' <= c && c <= 'f')) {
-               parse_error("premature end of hex number literal");
-               lexer_token.type = T_ERROR;
-               return;
-       }
-
-       int value = 0;
-       while(1) {
-               if (isdigit(c)) {
-                       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 {
-                       parse_integer_suffix();
-
-                       lexer_token.type       = T_INTEGER;
-                       lexer_token.v.intvalue = value;
-                       return;
-               }
+       while(isxdigit(c)) {
+               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') {
                next_char();
                panic("Hex floating point numbers not implemented yet");
        }
-}
-
-static void parse_number_oct(void)
-{
-       int value = 0;
-       while(c >= '0' && c <= '7') {
-               value = 8 * value + c - '0';
-               next_char();
-       }
-       if (c == '8' || c == '9') {
-               parse_error("invalid octal number");
+       if(*string == '\0') {
+               parse_error("invalid hex number");
                lexer_token.type = T_ERROR;
-               return;
        }
 
+       const char *endptr;
        lexer_token.type       = T_INTEGER;
-       lexer_token.v.intvalue = value;
+       lexer_token.v.intvalue = parse_int_string(string, &endptr, 16);
+       if(*endptr != '\0') {
+               parse_error("hex number literal too long");
+       }
 
-       parse_integer_suffix();
+       obstack_free(&symbol_obstack, string);
+       parse_integer_suffix(true);
 }
 
-static void parse_floatingpoint_exponent(long double value)
+/**
+ * Returns true if the given char is a octal digit.
+ *
+ * @param char  the character to check
+ */
+static inline bool is_octal_digit(int chr)
 {
-       unsigned int expo = 0;
-       long double  factor = 10.;
-
-       if(c == '-') {
-               next_char();
-               factor = 0.1;
-       } else if(c == '+') {
-               next_char();
-       }
-
-       while(c >= '0' && c <= '9') {
-               expo = 10 * expo + (c - '0');
-               next_char();
-       }
-
-       while(1) {
-               if(expo & 1)
-                       value *= factor;
-               expo >>= 1;
-               if(expo == 0)
-                       break;
-               factor *= factor;
+       switch(chr) {
+       case '0':
+       case '1':
+       case '2':
+       case '3':
+       case '4':
+       case '5':
+       case '6':
+       case '7':
+               return true;
+       default:
+               return false;
        }
-
-       lexer_token.type         = T_FLOATINGPOINT;
-       lexer_token.v.floatvalue = value;
-
-       parse_floating_suffix();
 }
 
-static void parse_floatingpoint_fract(int integer_part)
+/**
+ * Parses a octal number and set the lexer_token.
+ */
+static void parse_number_oct(void)
 {
-       long double value  = integer_part;
-       long double factor = 1.;
-
-       while(c >= '0' && c <= '9') {
-               factor *= 0.1;
-               value  += (c - '0') * factor;
+       while(is_octal_digit(c)) {
+               obstack_1grow(&symbol_obstack, (char) c);
                next_char();
        }
+       obstack_1grow(&symbol_obstack, '\0');
+       char *string = obstack_finish(&symbol_obstack);
 
-       if(c == 'e' || c == 'E') {
-               next_char();
-               parse_floatingpoint_exponent(value);
-               return;
+       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");
        }
 
-       lexer_token.type         = T_FLOATINGPOINT;
-       lexer_token.v.floatvalue = value;
-
-       parse_floating_suffix();
+       obstack_free(&symbol_obstack, string);
+       parse_integer_suffix(true);
 }
 
+/**
+ * Parses a decimal including float number and set the
+ * lexer_token.
+ */
 static void parse_number_dec(void)
 {
-       int value = 0;
-
+       bool is_float = false;
        while(isdigit(c)) {
-               value = 10 * value + c - '0';
+               obstack_1grow(&symbol_obstack, (char) c);
                next_char();
        }
 
        if(c == '.') {
+               obstack_1grow(&symbol_obstack, '.');
                next_char();
-               parse_floatingpoint_fract(value);
-               return;
+
+               while(isdigit(c)) {
+                       obstack_1grow(&symbol_obstack, (char) c);
+                       next_char();
+               }
+               is_float = true;
        }
        if(c == 'e' || c == 'E') {
+               obstack_1grow(&symbol_obstack, 'e');
                next_char();
-               parse_floatingpoint_exponent(value);
-               return;
+
+               if(c == '-' || c == '+') {
+                       obstack_1grow(&symbol_obstack, (char) c);
+                       next_char();
+               }
+
+               while(isdigit(c)) {
+                       obstack_1grow(&symbol_obstack, (char) c);
+                       next_char();
+               }
+               is_float = true;
        }
-       parse_integer_suffix();
 
-       lexer_token.type       = T_INTEGER;
-       lexer_token.v.intvalue = value;
+       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");
+               }
+
+               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");
+               }
+
+               parse_integer_suffix(false);
+       }
+       obstack_free(&symbol_obstack, string);
 }
 
+/**
+ * Parses a number and sets the lexer_token.
+ */
 static void parse_number(void)
 {
        if (c == '0') {
@@ -451,23 +631,17 @@ static void parse_number(void)
                        case '7':
                                parse_number_oct();
                                break;
-                       case '.':
-                               next_char();
-                               parse_floatingpoint_fract(0);
-                               break;
-                       case 'e':
-                       case 'E':
-                               parse_floatingpoint_exponent(0);
-                               break;
                        case '8':
                        case '9':
                                next_char();
                                parse_error("invalid octal number");
                                lexer_token.type = T_ERROR;
                                return;
+                       case '.':
+                       case 'e':
+                       case 'E':
                        default:
-                               put_back(c);
-                               c = '0';
+                               obstack_1grow(&symbol_obstack, '0');
                                parse_number_dec();
                                return;
                }
@@ -476,38 +650,83 @@ static void parse_number(void)
        }
 }
 
-static int parse_octal_sequence(void)
-{
-       int value = 0;
-       while(1) {
-               if(c < '0' || c > '7')
-                       break;
-               value = 8 * value + c - '0';
-               next_char();
+/**
+ * Returns the value of a digit.
+ * The only portable way to do it ...
+ */
+static int digit_value(int digit) {
+       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:
+               panic("wrong character given");
        }
+}
 
-       return value;
+/**
+ * Parses an octal character sequence.
+ *
+ * @param first_digit  the already read first digit
+ */
+static int parse_octal_sequence(const int first_digit)
+{
+       assert(is_octal_digit(first_digit));
+       int value = digit_value(first_digit);
+       if (!is_octal_digit(c)) return value;
+       value = 8 * value + digit_value(c);
+       next_char();
+       if (!is_octal_digit(c)) return value;
+       value = 8 * value + digit_value(c);
+       next_char();
+
+       if(char_is_signed) {
+               return (signed char) value;
+       } else {
+               return (unsigned char) value;
+       }
 }
 
+/**
+ * Parses a hex character sequence.
+ */
 static int 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;
-               }
+       while(isxdigit(c)) {
+               value = 16 * value + digit_value(c);
                next_char();
        }
 
-       return value;
+       if(char_is_signed) {
+               return (signed char) value;
+       } else {
+               return (unsigned char) value;
+       }
 }
 
+/**
+ * Parse an escape sequence.
+ */
 static int parse_escape_sequence(void)
 {
        eat('\\');
@@ -517,7 +736,7 @@ static int parse_escape_sequence(void)
 
        switch(ec) {
        case '"':  return '"';
-       case '\'': return'\'';
+       case '\'': return '\'';
        case '\\': return '\\';
        case '?': return '\?';
        case 'a': return '\a';
@@ -537,7 +756,7 @@ static int parse_escape_sequence(void)
        case '5':
        case '6':
        case '7':
-               return parse_octal_sequence();
+               return parse_octal_sequence(ec);
        case EOF:
                parse_error("reached end of file while parsing escape sequence");
                return EOF;
@@ -547,53 +766,113 @@ static int parse_escape_sequence(void)
        }
 }
 
-const char *concat_strings(const char *s1, const char *s2)
+/**
+ * Concatenate two strings.
+ */
+string_t concat_strings(const string_t *const s1, const string_t *const s2)
 {
-       size_t  len1   = strlen(s1);
-       size_t  len2   = strlen(s2);
+       const size_t len1 = s1->size - 1;
+       const size_t len2 = s2->size - 1;
 
-       char   *concat = obstack_alloc(&symbol_obstack, len1 + len2 + 1);
-       memcpy(concat, s1, len1);
-       memcpy(concat + len1, s2, len2 + 1);
+       char *const concat = obstack_alloc(&symbol_obstack, len1 + len2 + 1);
+       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 result;
+#else
+       return (string_t){ concat, len1 + len2 + 1 };
+#endif
+}
+
+/**
+ * Concatenate a string and a wide string.
+ */
+wide_string_t concat_string_wide_string(const string_t *const s1, const wide_string_t *const s2)
+{
+       const size_t len1 = s1->size - 1;
+       const size_t len2 = s2->size - 1;
+
+       wchar_rep_t *const concat = obstack_alloc(&symbol_obstack, (len1 + len2 + 1) * sizeof(*concat));
+       const char *const src = s1->begin;
+       for (size_t i = 0; i != len1; ++i) {
+               concat[i] = src[i];
+       }
+       memcpy(concat + len1, s2->begin, (len2 + 1) * sizeof(*concat));
+
+       return (wide_string_t){ concat, len1 + len2 + 1 };
 }
 
+/**
+ * Concatenate two wide strings.
+ */
+wide_string_t concat_wide_strings(const wide_string_t *const s1, const wide_string_t *const s2)
+{
+       const size_t len1 = s1->size - 1;
+       const size_t len2 = s2->size - 1;
+
+       wchar_rep_t *const concat = obstack_alloc(&symbol_obstack, (len1 + len2 + 1) * sizeof(*concat));
+       memcpy(concat,        s1->begin, len1       * sizeof(*concat));
+       memcpy(concat + len1, s2->begin, (len2 + 1) * sizeof(*concat));
+
+       return (wide_string_t){ concat, len1 + len2 + 1 };
+}
+
+/**
+ * Concatenate a wide string and a string.
+ */
+wide_string_t concat_wide_string_string(const wide_string_t *const s1, const string_t *const s2)
+{
+       const size_t len1 = s1->size - 1;
+       const size_t len2 = s2->size - 1;
+
+       wchar_rep_t *const concat = obstack_alloc(&symbol_obstack, (len1 + len2 + 1) * sizeof(*concat));
+       memcpy(concat, s1->begin, len1 * sizeof(*concat));
+       const char *const src = s2->begin;
+       for (size_t i = 0; i != len2 + 1; ++i) {
+               concat[i] = src[i];
+       }
+
+       return (wide_string_t){ concat, len1 + len2 + 1 };
+}
+
+/**
+ * Parse a string literal and set lexer_token.
+ */
 static void parse_string_literal(void)
 {
-       unsigned    start_linenr = lexer_token.source_position.linenr;
-       char       *string;
-       const char *result;
+       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, tc);
+                       obstack_1grow(&symbol_obstack, (char) 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, c);
+                       obstack_1grow(&symbol_obstack, (char) c);
                        next_char();
                        break;
                }
@@ -605,28 +884,158 @@ end_of_string:
 
        /* add finishing 0 to the string */
        obstack_1grow(&symbol_obstack, '\0');
-       string = obstack_finish(&symbol_obstack);
+       const size_t      size   = (size_t)obstack_object_size(&symbol_obstack);
+       const char *const 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;
+}
+
+/**
+ * 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('\'');
+
+       while(1) {
+               switch(c) {
+               case '\\': {
+                       wchar_rep_t tc = parse_escape_sequence();
+                       obstack_grow(&symbol_obstack, &tc, sizeof(tc));
+                       break;
+               }
+
+               MATCH_NEWLINE(
+                       parse_error("newline while parsing character constant");
+                       break;
+               )
+
+               case '\'':
+                       next_char();
+                       goto end_of_wide_char_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: {
+                       wchar_rep_t tc = (wchar_rep_t) c;
+                       obstack_grow(&symbol_obstack, &tc, sizeof(tc));
+                       next_char();
+                       break;
+               }
+               }
+       }
+
+end_of_wide_char_constant:;
+       size_t             size   = (size_t) obstack_object_size(&symbol_obstack);
+       const wchar_rep_t *string = obstack_finish(&symbol_obstack);
 
-       lexer_token.type     = T_STRING_LITERAL;
-       lexer_token.v.string = result;
+       lexer_token.type                = T_WIDE_CHARACTER_CONSTANT;
+       lexer_token.v.wide_string.begin = string;
+       lexer_token.v.wide_string.size  = size;
+       lexer_token.datatype            = type_wchar_t;
 }
 
+/**
+ * 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: {
+                       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: {
+                       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 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();
+               case '\\': {
+                       int tc = parse_escape_sequence();
+                       obstack_1grow(&symbol_obstack, (char) tc);
                        break;
+               }
 
                MATCH_NEWLINE(
                        parse_error("newline while parsing character constant");
@@ -637,35 +1046,48 @@ 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();
-                       }
+                       obstack_1grow(&symbol_obstack, (char) c);
+                       next_char();
                        break;
+
                }
        }
 
-end_of_char_constant:
-       lexer_token.type       = T_INTEGER;
-       lexer_token.v.intvalue = found_char;
+end_of_char_constant:;
+       const size_t      size   = (size_t)obstack_object_size(&symbol_obstack);
+       const char *const string = obstack_finish(&symbol_obstack);
+
+       lexer_token.type           = T_CHARACTER_CONSTANT;
+       lexer_token.v.string.begin = string;
+       lexer_token.v.string.size  = size;
+       lexer_token.datatype       = type_int;
 }
 
+/**
+ * Skip a multiline comment.
+ */
 static void skip_multiline_comment(void)
 {
        unsigned start_linenr = lexer_token.source_position.linenr;
 
        while(1) {
                switch(c) {
+               case '/':
+                       next_char();
+                       if (c == '*') {
+                               /* TODO: nested comment, warn here */
+                       }
+                       break;
                case '*':
                        next_char();
                        if(c == '/') {
@@ -676,11 +1098,13 @@ 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();
@@ -689,6 +1113,9 @@ static void skip_multiline_comment(void)
        }
 }
 
+/**
+ * Skip a single line comment.
+ */
 static void skip_line_comment(void)
 {
        while(1) {
@@ -707,14 +1134,21 @@ 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) {
@@ -722,14 +1156,9 @@ static void eat_until_newline(void)
        }
 }
 
-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();
@@ -739,6 +1168,9 @@ static void define_directive(void)
        }
 }
 
+/**
+ * Handle the ifdef directive.
+ */
 static void ifdef_directive(int is_ifndef)
 {
        (void) is_ifndef;
@@ -747,27 +1179,114 @@ 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) {
                parse_error("expected integer");
        } else {
-               lexer_token.source_position.linenr = pp_token.v.intvalue - 1;
+               lexer_token.source_position.linenr = (unsigned int)(pp_token.v.intvalue - 1);
                next_pp_token();
        }
        if(pp_token.type == T_STRING_LITERAL) {
-               lexer_token.source_position.input_name = pp_token.v.string;
+               lexer_token.source_position.input_name = pp_token.v.string.begin;
                next_pp_token();
        }
 
        eat_until_newline();
 }
 
+/**
+ * STDC pragmas.
+ */
+typedef enum {
+       STDC_UNKNOWN,
+       STDC_FP_CONTRACT,
+       STDC_FENV_ACCESS,
+       STDC_CX_LIMITED_RANGE
+} stdc_pragma_kind_t;
+
+/**
+ * STDC pragma values.
+ */
+typedef enum {
+       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.v.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.v.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.v.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);
@@ -798,13 +1317,18 @@ 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:
+               parse_pragma();
                break;
        }
 }
 
+/**
+ * Parse a preprocessor directive.
+ */
 static void parse_preprocessor_directive(void)
 {
        next_pp_token();
@@ -816,6 +1340,9 @@ static void parse_preprocessor_directive(void)
        case T_INTEGER:
                parse_line_directive();
                break;
+       case '\n':
+               /* NULL directive, see ยง 6.10.7 */
+               break;
        default:
                parse_error("invalid preprocessor directive");
                eat_until_newline();
@@ -864,10 +1391,13 @@ void lexer_next_preprocessing_token(void)
                SYMBOL_CHARS
                        parse_symbol();
                        /* might be a wide string ( L"string" ) */
-                       if(c == '"' && (lexer_token.type == T_IDENTIFIER &&
-                          lexer_token.v.symbol == symbol_L)) {
-                               parse_string_literal();
-                               return;
+                       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();
+                               }
                        }
                        return;
 
@@ -885,6 +1415,21 @@ 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':
+                                       put_back(c);
+                                       c = '.';
+                                       parse_number_dec();
+                                       return;
+
                                case '.':
                                        MAYBE_PROLOG
                                        MAYBE('.', T_DOTDOTDOT)
@@ -935,25 +1480,25 @@ 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
@@ -979,7 +1524,7 @@ void lexer_next_preprocessing_token(void)
                        ELSE('|')
                case ':':
                        MAYBE_PROLOG
-                       MAYBE('>', T_COLONGREATER)
+                       MAYBE('>', ']')
                        ELSE(':')
                case '=':
                        MAYBE_PROLOG
@@ -1011,8 +1556,7 @@ void lexer_next_preprocessing_token(void)
 
                default:
                        next_char();
-                       error_prefix();
-                       fprintf(stderr, "unknown character '%c' found\n", c);
+                       errorf(lexer_token.source_position, "unknown character '%c' found\n", c);
                        lexer_token.type = T_ERROR;
                        return;
                }
@@ -1048,6 +1592,8 @@ void lexer_open_stream(FILE *stream, const char *input_name)
        lexer_token.source_position.input_name = input_name;
 
        symbol_L = symbol_table_insert("L");
+       bufpos = NULL;
+       bufend = NULL;
 
        /* place a virtual \n at the beginning so the lexer knows that we're
         * at the beginning of a line */
@@ -1062,7 +1608,7 @@ void exit_lexer(void)
 static __attribute__((unused))
 void dbg_pos(const source_position_t source_position)
 {
-       fprintf(stdout, "%s:%d\n", source_position.input_name,
+       fprintf(stdout, "%s:%u\n", source_position.input_name,
                source_position.linenr);
        fflush(stdout);
 }