- implemented most cases of -W traditional (preprocessor missing)
[cparser] / lexer.c
diff --git a/lexer.c b/lexer.c
index e8c183c..779f4b3 100644 (file)
--- a/lexer.c
+++ b/lexer.c
@@ -1,7 +1,27 @@
+/*
+ * 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"
@@ -11,6 +31,8 @@
 #include "type_t.h"
 #include "target_architecture.h"
 #include "parser.h"
+#include "warning.h"
+#include "lang_features.h"
 
 #include <assert.h>
 #include <errno.h>
 #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;
@@ -42,28 +56,37 @@ static char        buf[1024 + MAX_PUTBACK];
 static const char *bufend;
 static const char *bufpos;
 static strset_t    stringset;
+bool               allow_dollar_in_symbol = true;
 
-static void error_prefix_at(const char *input_name, unsigned linenr)
-{
-       fprintf(stderr, "%s:%u: Error: ", input_name, linenr);
-}
-
-static void error_prefix(void)
+/**
+ * Prints a parse error message at the current token.
+ *
+ * @param msg   the error message
+ */
+static void parse_error(const char *msg)
 {
-       error_prefix_at(lexer_token.source_position.input_name,
-                       lexer_token.source_position.linenr);
+       errorf(&lexer_token.source_position, "%s", msg);
 }
 
-static void parse_error(const char *msg)
+/**
+ * Prints an internal error message at the current token.
+ *
+ * @param msg   the error message
+ */
+static NORETURN internal_error(const char *msg)
 {
-       error_prefix();
-       fprintf(stderr, "%s\n", msg);
+       internal_errorf(&lexer_token.source_position, "%s", msg);
 }
 
 static inline void next_real_char(void)
 {
        assert(bufpos <= bufend);
        if (bufpos >= bufend) {
+               if (input == NULL) {
+                       c = EOF;
+                       return;
+               }
+
                size_t s = fread(buf + MAX_PUTBACK, 1, sizeof(buf) - MAX_PUTBACK,
                                 input);
                if(s == 0) {
@@ -76,10 +99,15 @@ static inline void next_real_char(void)
        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);
-       *(--bufpos - buf + buf) = pc;
+       *(--bufpos - buf + buf) = (char) pc;
 
 #ifdef DEBUG_CHARS
        printf("putback '%c'\n", pc);
@@ -95,11 +123,11 @@ 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)
 
@@ -118,6 +146,10 @@ 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();
@@ -163,6 +195,7 @@ end_of_next_char:;
 }
 
 #define SYMBOL_CHARS  \
+       case '$': if (!allow_dollar_in_symbol) goto dollar_sign; \
        case 'a':         \
        case 'b':         \
        case 'c':         \
@@ -229,6 +262,10 @@ 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;
@@ -246,6 +283,7 @@ static void parse_symbol(void)
                        break;
 
                default:
+dollar_sign:
                        goto end_symbol;
                }
        }
@@ -266,60 +304,78 @@ end_symbol:
 
 static void parse_integer_suffix(bool is_oct_hex)
 {
-       bool is_unsigned  = false;
-       bool min_long     = false;
-       bool min_longlong = false;
-
-       if(c == 'U' || c == 'u') {
-               is_unsigned = true;
+       bool is_unsigned     = false;
+       bool min_long        = false;
+       bool min_longlong    = false;
+       bool not_traditional = false;
+       int  pos             = 0;
+       char suffix[4];
+
+       if (c == 'U' || c == 'u') {
+               not_traditional = true;
+               suffix[pos++]   = toupper(c);
+               is_unsigned     = true;
                next_char();
-               if(c == 'L' || c == 'l') {
+               if (c == 'L' || c == 'l') {
+                       suffix[pos++] = toupper(c);
                        min_long = true;
                        next_char();
-                       if(c == 'L' || c == 'l') {
+                       if (c == 'L' || c == 'l') {
+                               suffix[pos++] = toupper(c);
                                min_longlong = true;
                                next_char();
                        }
                }
-       } else if(c == 'l' || c == 'L') {
+       } else if (c == 'l' || c == 'L') {
+               suffix[pos++] = toupper(c);
                min_long = true;
                next_char();
-               if(c == 'l' || c == 'L') {
-                       min_longlong = true;
+               if (c == 'l' || c == 'L') {
+                       not_traditional = true;
+                       suffix[pos++]   = toupper(c);
+                       min_longlong    = true;
                        next_char();
-                       if(c == 'u' || c == 'U') {
-                               is_unsigned = true;
+                       if (c == 'u' || c == 'U') {
+                               suffix[pos++] = toupper(c);
+                               is_unsigned   = true;
                                next_char();
                        }
-               } else if(c == 'u' || c == 'U') {
-                       is_unsigned = true;
+               } else if (c == 'u' || c == 'U') {
+                       not_traditional = true;
+                       suffix[pos++]   = toupper(c);
+                       is_unsigned     = true;
                        next_char();
                        lexer_token.datatype = type_unsigned_long;
                }
        }
 
-       if(!is_unsigned) {
+       if (warning.traditional && not_traditional) {
+               suffix[pos] = '\0';
+               warningf(&lexer_token.source_position,
+                       "traditional C rejects the '%s' suffix", suffix);
+       }
+       if (!is_unsigned) {
                long long v = lexer_token.v.intvalue;
-               if(!min_long) {
-                       if(v >= TARGET_INT_MIN && v <= TARGET_INT_MAX) {
+               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) {
+                       } 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) {
+               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) {
+                       } else if (is_oct_hex && v >= 0 && (unsigned long long)v <= (unsigned long long)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) {
+               if (is_oct_hex && uv > (unsigned long long) TARGET_LONGLONG_MAX) {
                        lexer_token.datatype = type_unsigned_long_long;
                        return;
                }
@@ -327,11 +383,11 @@ static void parse_integer_suffix(bool is_oct_hex)
                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) {
+               if (!min_long && v <= TARGET_UINT_MAX) {
                        lexer_token.datatype = type_unsigned_int;
                        return;
                }
-               if(!min_longlong && v <= TARGET_ULONG_MAX) {
+               if (!min_longlong && v <= TARGET_ULONG_MAX) {
                        lexer_token.datatype = type_unsigned_long;
                        return;
                }
@@ -342,14 +398,22 @@ static void parse_integer_suffix(bool is_oct_hex)
 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':
+               if (warning.traditional) {
+                       warningf(&lexer_token.source_position,
+                               "traditional C rejects the 'F' suffix");
+               }
                next_char();
                lexer_token.datatype = type_float;
                break;
        case 'l':
        case 'L':
+               if (warning.traditional) {
+                       warningf(&lexer_token.source_position,
+                               "traditional C rejects the 'F' suffix");
+               }
                next_char();
                lexer_token.datatype = type_long_double;
                break;
@@ -443,43 +507,107 @@ end:
        return v;
 }
 
+/**
+ * Parses a hex number including hex floats and set the
+ * lexer_token.
+ */
 static void parse_number_hex(void)
 {
+       bool is_float = false;
        assert(c == 'x' || c == 'X');
        next_char();
 
+       obstack_1grow(&symbol_obstack, '0');
+       obstack_1grow(&symbol_obstack, 'x');
+
        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') {
+       if (c == '.') {
+               obstack_1grow(&symbol_obstack, (char) c);
                next_char();
-               panic("Hex floating point numbers not implemented yet");
+
+               while (isxdigit(c)) {
+                       obstack_1grow(&symbol_obstack, (char) c);
+                       next_char();
+               }
+               is_float = true;
+       }
+       if (c == 'p' || c == 'P') {
+               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();
+               }
+               is_float = true;
        }
+
+       obstack_1grow(&symbol_obstack, '\0');
+       char *string = obstack_finish(&symbol_obstack);
        if(*string == '\0') {
                parse_error("invalid hex number");
                lexer_token.type = T_ERROR;
+               obstack_free(&symbol_obstack, string);
+               return;
        }
 
-       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");
+       if (is_float) {
+               char *endptr;
+               lexer_token.type         = T_FLOATINGPOINT;
+               lexer_token.v.floatvalue = strtold(string, &endptr);
+
+               if(*endptr != '\0') {
+                       parse_error("invalid hex float literal");
+               }
+
+               parse_floating_suffix();
+       } else {
+               const char *endptr;
+               lexer_token.type       = T_INTEGER;
+               lexer_token.v.intvalue = parse_int_string(string + 2, &endptr, 16);
+               if(*endptr != '\0') {
+                       parse_error("hex number literal too long");
+               }
+               parse_integer_suffix(true);
        }
 
        obstack_free(&symbol_obstack, string);
-       parse_integer_suffix(true);
 }
 
+/**
+ * Returns true if the given char is a octal digit.
+ *
+ * @param char  the character to check
+ */
 static inline bool is_octal_digit(int 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;
+       }
 }
 
+/**
+ * Parses a octal number and set the lexer_token.
+ */
 static void parse_number_oct(void)
 {
        while(is_octal_digit(c)) {
@@ -500,26 +628,30 @@ static void parse_number_oct(void)
        parse_integer_suffix(true);
 }
 
+/**
+ * Parses a decimal including float number and set the
+ * lexer_token.
+ */
 static void parse_number_dec(void)
 {
        bool is_float = false;
-       while(isdigit(c)) {
+       while (isdigit(c)) {
                obstack_1grow(&symbol_obstack, (char) c);
                next_char();
        }
 
-       if(c == '.') {
+       if (c == '.') {
                obstack_1grow(&symbol_obstack, '.');
                next_char();
 
-               while(isdigit(c)) {
+               while (isdigit(c)) {
                        obstack_1grow(&symbol_obstack, (char) c);
                        next_char();
                }
                is_float = true;
        }
        if(c == 'e' || c == 'E') {
-               obstack_1grow(&symbol_obstack, 'e');
+               obstack_1grow(&symbol_obstack, (char) c);
                next_char();
 
                if(c == '-' || c == '+') {
@@ -561,6 +693,9 @@ static void parse_number_dec(void)
        obstack_free(&symbol_obstack, string);
 }
 
+/**
+ * Parses a number and sets the lexer_token.
+ */
 static void parse_number(void)
 {
        if (c == '0') {
@@ -599,38 +734,83 @@ static void parse_number(void)
        }
 }
 
+/**
+ * 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:
+               internal_error("wrong character given");
+       }
+}
+
+/**
+ * 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 = first_digit - '0';
+       int 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;
+
+       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 (char_type)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('\\');
@@ -638,7 +818,7 @@ static int parse_escape_sequence(void)
        int ec = c;
        next_char();
 
-       switch(ec) {
+       switch (ec) {
        case '"':  return '"';
        case '\'': return '\'';
        case '\\': return '\\';
@@ -664,37 +844,115 @@ static int parse_escape_sequence(void)
        case EOF:
                parse_error("reached end of file while parsing escape sequence");
                return EOF;
+       case 'e':
+               if (c_mode & _GNUC)
+                       return 27;   /* hopefully 27 is ALWAYS the code for ESACAPE */
+               /*fallthrough*/
        default:
                parse_error("unknown escape sequence");
                return EOF;
        }
 }
 
-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 (warning.traditional) {
+               warningf(&lexer_token.source_position,
+                       "traditional C rejects string constant concatenation");
+       }
+#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));
+       if (warning.traditional) {
+               warningf(&lexer_token.source_position,
+                       "traditional C rejects string constant concatenation");
+       }
+
+       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));
+       if (warning.traditional) {
+               warningf(&lexer_token.source_position,
+                       "traditional C rejects string constant concatenation");
+       }
+
+       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];
+       }
+       if (warning.traditional) {
+               warningf(&lexer_token.source_position,
+                       "traditional C rejects string constant concatenation");
+       }
+
+       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) {
@@ -704,12 +962,14 @@ static void parse_string_literal(void)
                        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();
@@ -728,28 +988,40 @@ 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 = result;
+       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('\'');
 
-       int found_char = 0;
        while(1) {
                switch(c) {
-               case '\\':
-                       found_char = parse_escape_sequence();
+               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");
@@ -760,30 +1032,39 @@ 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();
-                       }
+               default: {
+                       wchar_rep_t tc = (wchar_rep_t) c;
+                       obstack_grow(&symbol_obstack, &tc, sizeof(tc));
+                       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);
+       assert(size % sizeof(wchar_rep_t) == 0);
+       size /= sizeof(wchar_rep_t);
+
+       const wchar_rep_t *string = obstack_finish(&symbol_obstack);
+
+       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;
@@ -793,29 +1074,31 @@ static void parse_wide_string_literal(void)
 
        while(1) {
                switch(c) {
-                       case '\\': {
-                               wchar_rep_t tc = parse_escape_sequence();
-                               obstack_grow(&symbol_obstack, &tc, sizeof(tc));
-                               break;
-                       }
+               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 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;
+               case '"':
+                       next_char();
+                       goto end_of_string;
 
-                       default: {
-                               wchar_rep_t tc = c;
-                               obstack_grow(&symbol_obstack, &tc, sizeof(tc));
-                               next_char();
-                               break;
-                       }
+               default: {
+                       wchar_rep_t tc = c;
+                       obstack_grow(&symbol_obstack, &tc, sizeof(tc));
+                       next_char();
+                       break;
+               }
                }
        }
 
@@ -844,16 +1127,22 @@ end_of_string:;
        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");
@@ -864,36 +1153,51 @@ 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;
-       lexer_token.datatype   = type_int;
+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 == '*') {
+                               /* nested comment, warn here */
+                               if (warning.comment) {
+                                       warningf(&lexer_token.source_position, "'/*' within comment");
+                               }
+                       }
+                       break;
                case '*':
                        next_char();
                        if(c == '/') {
@@ -904,11 +1208,13 @@ 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();
@@ -917,6 +1223,9 @@ static void skip_multiline_comment(void)
        }
 }
 
+/**
+ * Skip a single line comment.
+ */
 static void skip_line_comment(void)
 {
        while(1) {
@@ -928,6 +1237,15 @@ 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;
@@ -935,14 +1253,21 @@ 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) {
@@ -950,14 +1275,9 @@ 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();
@@ -967,6 +1287,9 @@ static void define_directive(void)
        }
 }
 
+/**
+ * Handle the ifdef directive.
+ */
 static void ifdef_directive(int is_ifndef)
 {
        (void) is_ifndef;
@@ -975,11 +1298,17 @@ 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) {
@@ -989,13 +1318,94 @@ static void parse_line_directive(void)
                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_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.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);
@@ -1026,15 +1436,18 @@ 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:
-               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();
@@ -1046,6 +1459,9 @@ 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();
@@ -1066,7 +1482,7 @@ static void parse_preprocessor_directive(void)
 
 #define ELSE_CODE(code)                                    \
                                default:                                   \
-                                       code;                                  \
+                                       code                                   \
                                }                                          \
                        } /* end of while(1) */                        \
                        break;
@@ -1118,16 +1534,7 @@ 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();
@@ -1183,25 +1590,25 @@ 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
@@ -1227,7 +1634,7 @@ void lexer_next_preprocessing_token(void)
                        ELSE('|')
                case ':':
                        MAYBE_PROLOG
-                       MAYBE('>', T_COLONGREATER)
+                       MAYBE('>', ']')
                        ELSE(':')
                case '=':
                        MAYBE_PROLOG
@@ -1258,9 +1665,9 @@ 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;
                }
@@ -1270,15 +1677,13 @@ 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;
        }
@@ -1287,6 +1692,7 @@ 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)
@@ -1295,7 +1701,6 @@ 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;
 
@@ -1304,6 +1709,20 @@ 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;
+
+       bufpos = buffer;
+       bufend = buffer + len;
+
+       /* 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);