Use streq() instead of strcmp() == 0.
[cparser] / lexer.c
diff --git a/lexer.c b/lexer.c
index 4ff847d..daeda8a 100644 (file)
--- a/lexer.c
+++ b/lexer.c
@@ -19,6 +19,8 @@
  */
 #include <config.h>
 
+#include "adt/strutil.h"
+#include "input.h"
 #include "diagnostic.h"
 #include "lexer.h"
 #include "symbol_t.h"
 #include <strings.h>
 #endif
 
-//#define DEBUG_CHARS
-#define MAX_PUTBACK 3
+#define MAX_PUTBACK 16    // 3 would be enough, but 16 gives a nicer alignment
 #define BUF_SIZE    1024
 
-#if defined(_WIN32) || defined(__CYGWIN__)
-/* No strtold on windows and no replacement yet */
-#define strtold(s, e) strtod(s, e)
-#endif
-
-static utf32        c;
-token_t             lexer_token;
-symbol_t           *symbol_L;
-static FILE        *input;
-static utf32        buf[BUF_SIZE + MAX_PUTBACK];
-static const utf32 *bufend;
-static const utf32 *bufpos;
-static strset_t     stringset;
-bool                allow_dollar_in_symbol = true;
+static input_t           *input;
+static utf32              input_buf[BUF_SIZE + MAX_PUTBACK];
+static const utf32       *bufpos;
+static const utf32       *bufend;
+static utf32              c;
+static source_position_t  lexer_pos;
+token_t                   lexer_token;
+static symbol_t          *symbol_L;
+static strset_t           stringset;
+bool                      allow_dollar_in_symbol = true;
 
 /**
  * Prints a parse error message at the current token.
@@ -70,7 +67,7 @@ bool                allow_dollar_in_symbol = true;
  */
 static void parse_error(const char *msg)
 {
-       errorf(&lexer_token.source_position, "%s", msg);
+       errorf(&lexer_pos, "%s", msg);
 }
 
 /**
@@ -80,281 +77,23 @@ static void parse_error(const char *msg)
  */
 static NORETURN internal_error(const char *msg)
 {
-       internal_errorf(&lexer_token.source_position, "%s", msg);
-}
-
-static size_t read_block(unsigned char *const read_buf, size_t const n)
-{
-       size_t const s = fread(read_buf, 1, n, input);
-       if (s == 0) {
-               if (ferror(input))
-                       parse_error("read from input failed");
-               buf[MAX_PUTBACK] = EOF;
-               bufpos           = buf + MAX_PUTBACK;
-               bufend           = buf + MAX_PUTBACK + 1;
-       }
-       return s;
-}
-
-static void decode_iso_8859_1(void)
-{
-       unsigned char read_buf[BUF_SIZE];
-       size_t const s = read_block(read_buf, sizeof(read_buf));
-       if (s == 0)
-               return;
-
-       unsigned char const *src = read_buf;
-       unsigned char const *end = read_buf + s;
-       utf32               *dst = buf + MAX_PUTBACK;
-       while (src != end)
-               *dst++ = *src++;
-
-       bufpos = buf + MAX_PUTBACK;
-       bufend = dst;
-}
-
-static void decode_iso_8859_15(void)
-{
-       unsigned char read_buf[BUF_SIZE];
-       size_t const s = read_block(read_buf, sizeof(read_buf));
-       if (s == 0)
-               return;
-
-       unsigned char const *src = read_buf;
-       unsigned char const *end = read_buf + s;
-       utf32               *dst = buf + MAX_PUTBACK;
-       while (src != end) {
-               utf32 tc = *src++;
-               switch (tc) {
-                       case 0xA4: tc = 0x20AC; break; // €
-                       case 0xA6: tc = 0x0160; break; // Š
-                       case 0xA8: tc = 0x0161; break; // š
-                       case 0xB4: tc = 0x017D; break; // Ž
-                       case 0xB8: tc = 0x017E; break; // ž
-                       case 0xBC: tc = 0x0152; break; // Œ
-                       case 0xBD: tc = 0x0153; break; // œ
-                       case 0xBE: tc = 0x0178; break; // Ÿ
-               }
-               *dst++ = tc;
-       }
-
-       bufpos = buf + MAX_PUTBACK;
-       bufend = dst;
-}
-
-static void decode_utf8(void)
-{
-       static utf32  part_decoded_min_code;
-       static utf32  part_decoded_char;
-       static size_t part_decoded_rest_len;
-
-       do {
-               unsigned char read_buf[BUF_SIZE];
-               size_t const s = read_block(read_buf, sizeof(read_buf));
-               if (s == 0) {
-                       if (part_decoded_rest_len > 0)
-                               parse_error("incomplete input char at end of input");
-                       return;
-               }
-
-               unsigned char const *src = read_buf;
-               unsigned char const *end = read_buf + s;
-               utf32               *dst = buf + MAX_PUTBACK;
-               utf32                decoded;
-               utf32                min_code;
-
-               if (part_decoded_rest_len != 0) {
-                       min_code              = part_decoded_min_code;
-                       decoded               = part_decoded_char;
-                       size_t const rest_len = part_decoded_rest_len;
-                       part_decoded_rest_len = 0;
-                       switch (rest_len) {
-                               case 4:  goto realign;
-                               case 3:  goto three_more;
-                               case 2:  goto two_more;
-                               default: goto one_more;
-                       }
-               }
-
-               while (src != end) {
-                       if ((*src & 0x80) == 0) {
-                               decoded = *src++;
-                       } else if ((*src & 0xE0) == 0xC0) {
-                               min_code = 0x80;
-                               decoded  = *src++ & 0x1F;
-one_more:
-                               if (src == end) {
-                                       part_decoded_min_code = min_code;
-                                       part_decoded_char     = decoded;
-                                       part_decoded_rest_len = 1;
-                                       break;
-                               }
-                               if ((*src & 0xC0) == 0x80) {
-                                       decoded = (decoded << 6) | (*src++ & 0x3F);
-                               } else {
-                                       goto invalid_char;
-                               }
-                               if (decoded < min_code                      ||
-                                               decoded > 0x10FFFF                      ||
-                                               (0xD800 <= decoded && decoded < 0xE000) || // high/low surrogates
-                                               (0xFDD0 <= decoded && decoded < 0xFDF0) || // noncharacters
-                                               (decoded & 0xFFFE) == 0xFFFE) {            // noncharacters
-                                       parse_error("invalid byte sequence in input");
-                               }
-                       } else if ((*src & 0xF0) == 0xE0) {
-                               min_code = 0x800;
-                               decoded  = *src++ & 0x0F;
-two_more:
-                               if (src == end) {
-                                       part_decoded_min_code = min_code;
-                                       part_decoded_char     = decoded;
-                                       part_decoded_rest_len = 2;
-                                       break;
-                               }
-                               if ((*src & 0xC0) == 0x80) {
-                                       decoded = (decoded << 6) | (*src++ & 0x3F);
-                               } else {
-                                       goto invalid_char;
-                               }
-                               goto one_more;
-                       } else if ((*src & 0xF8) == 0xF0) {
-                               min_code = 0x10000;
-                               decoded  = *src++ & 0x07;
-three_more:
-                               if (src == end) {
-                                       part_decoded_min_code = min_code;
-                                       part_decoded_char     = decoded;
-                                       part_decoded_rest_len = 3;
-                                       break;
-                               }
-                               if ((*src & 0xC0) == 0x80) {
-                                       decoded = (decoded << 6) | (*src++ & 0x3F);
-                               } else {
-                                       goto invalid_char;
-                               }
-                               goto two_more;
-                       } else {
-invalid_char:
-                               parse_error("invalid byte sequence in input");
-realign:
-                               do {
-                                       ++src;
-                                       if (src == end) {
-                                               part_decoded_rest_len = 4;
-                                               break;
-                                       }
-                               } while ((*src & 0xC0) == 0x80 || (*src & 0xF8) == 0xF8);
-                               continue;
-                       }
-                       *dst++ = decoded;
-               }
-
-               bufpos = buf + MAX_PUTBACK;
-               bufend = dst;
-       } while (bufpos == bufend);
-}
-
-static void decode_windows_1252(void)
-{
-       unsigned char read_buf[BUF_SIZE];
-       size_t const s = read_block(read_buf, sizeof(read_buf));
-       if (s == 0)
-               return;
-
-       unsigned char const *src = read_buf;
-       unsigned char const *end = read_buf + s;
-       utf32               *dst = buf + MAX_PUTBACK;
-       while (src != end) {
-               utf32 tc = *src++;
-               switch (tc) {
-                       case 0x80: tc = 0x20AC; break; // €
-                       case 0x82: tc = 0x201A; break; // ‚
-                       case 0x83: tc = 0x0192; break; // ƒ
-                       case 0x84: tc = 0x201E; break; // „
-                       case 0x85: tc = 0x2026; break; // …
-                       case 0x86: tc = 0x2020; break; // †
-                       case 0x87: tc = 0x2021; break; // ‡
-                       case 0x88: tc = 0x02C6; break; // ˆ
-                       case 0x89: tc = 0x2030; break; // ‰
-                       case 0x8A: tc = 0x0160; break; // Š
-                       case 0x8B: tc = 0x2039; break; // ‹
-                       case 0x8C: tc = 0x0152; break; // Œ
-                       case 0x8E: tc = 0x017D; break; // Ž
-                       case 0x91: tc = 0x2018; break; // ‘
-                       case 0x92: tc = 0x2019; break; // ’
-                       case 0x93: tc = 0x201C; break; // “
-                       case 0x94: tc = 0x201D; break; // ”
-                       case 0x95: tc = 0x2022; break; // •
-                       case 0x96: tc = 0x2013; break; // –
-                       case 0x97: tc = 0x2014; break; // —
-                       case 0x98: tc = 0x02DC; break; // ˜
-                       case 0x99: tc = 0x2122; break; // ™
-                       case 0x9A: tc = 0x0161; break; // š
-                       case 0x9B: tc = 0x203A; break; // ›
-                       case 0x9C: tc = 0x0153; break; // œ
-                       case 0x9E: tc = 0x017E; break; // ž
-                       case 0x9F: tc = 0x0178; break; // Ÿ
-               }
-               *dst++ = tc;
-       }
-
-       bufpos = buf + MAX_PUTBACK;
-       bufend = dst;
-}
-
-typedef void (*decoder_t)(void);
-
-static decoder_t decoder = decode_utf8;
-
-typedef struct named_decoder_t {
-       char const *name;
-       decoder_t   decoder;
-} named_decoder_t;
-
-static named_decoder_t const decoders[] = {
-       { "CP819",           decode_iso_8859_1   }, // offical alias
-       { "IBM819",          decode_iso_8859_1   }, // offical alias
-       { "ISO-8859-1",      decode_iso_8859_1   }, // offical alias
-       { "ISO-8859-15",     decode_iso_8859_15  }, // offical name
-       { "ISO8859-1",       decode_iso_8859_1   },
-       { "ISO8859-15",      decode_iso_8859_15  },
-       { "ISO_8859-1",      decode_iso_8859_1   }, // offical alias
-       { "ISO_8859-15",     decode_iso_8859_15  }, // offical alias
-       { "ISO_8859-1:1987", decode_iso_8859_1   }, // offical name
-       { "Latin-9",         decode_iso_8859_15  }, // offical alias
-       { "UTF-8",           decode_utf8         }, // offical name
-       { "csISOLatin1",     decode_iso_8859_1   }, // offical alias
-       { "cp1252",          decode_windows_1252 },
-       { "iso-ir-100",      decode_iso_8859_1   }, // offical alias
-       { "l1",              decode_iso_8859_1   }, // offical alias
-       { "latin1",          decode_iso_8859_1   }, // offical alias
-       { "windows-1252",    decode_windows_1252 }, // official name
-
-       { NULL,              NULL                }
-};
-
-void select_input_encoding(char const* const encoding)
-{
-       for (named_decoder_t const *i = decoders; i->name != NULL; ++i) {
-               if (strcasecmp(encoding, i->name) != 0)
-                       continue;
-               decoder = i->decoder;
-               return;
-       }
-       fprintf(stderr, "error: input encoding \"%s\" not supported\n", encoding);
+       internal_errorf(&lexer_pos, "%s", msg);
 }
 
 static inline void next_real_char(void)
 {
        assert(bufpos <= bufend);
        if (bufpos >= bufend) {
-               if (input == NULL) {
+               size_t n = decode(input, input_buf+MAX_PUTBACK, BUF_SIZE);
+               if (n == 0) {
                        c = EOF;
                        return;
                }
-               decoder();
+               bufpos = input_buf + MAX_PUTBACK;
+               bufend = bufpos + n;
        }
        c = *bufpos++;
+       ++lexer_pos.colno;
 }
 
 /**
@@ -364,30 +103,24 @@ static inline void next_real_char(void)
  */
 static inline void put_back(utf32 const pc)
 {
-       assert(bufpos > buf);
-       *(--bufpos - buf + buf) = pc;
-
-#ifdef DEBUG_CHARS
-       printf("putback '%lc'\n", pc);
-#endif
+       *(--bufpos - input_buf + input_buf) = pc;
+       --lexer_pos.colno;
 }
 
 static inline void next_char(void);
 
-#define MATCH_NEWLINE(code)                   \
-       case '\r':                                \
-               next_char();                          \
-               if (c == '\n') {                      \
-                       next_char();                      \
-               }                                     \
-               lexer_token.source_position.linenr++; \
-               code                                  \
-       case '\n':                                \
-               next_char();                          \
-               lexer_token.source_position.linenr++; \
+#define MATCH_NEWLINE(code)  \
+       case '\r':               \
+               next_char();         \
+               if (c == '\n') {     \
+       case '\n':               \
+                       next_char();     \
+               }                    \
+               lexer_pos.lineno++;  \
+               lexer_pos.colno = 1; \
                code
 
-#define eat(c_type)  do { assert(c == c_type); next_char(); } while (0)
+#define eat(c_type) (assert(c == c_type), next_char())
 
 static void maybe_concat_lines(void)
 {
@@ -415,17 +148,17 @@ static inline void next_char(void)
        /* filter trigraphs */
        if (UNLIKELY(c == '\\')) {
                maybe_concat_lines();
-               goto end_of_next_char;
+               return;
        }
 
        if (LIKELY(c != '?'))
-               goto end_of_next_char;
+               return;
 
        next_real_char();
        if (LIKELY(c != '?')) {
                put_back(c);
                c = '?';
-               goto end_of_next_char;
+               return;
        }
 
        next_real_char();
@@ -445,11 +178,6 @@ static inline void next_char(void)
                c = '?';
                break;
        }
-
-end_of_next_char:;
-#ifdef DEBUG_CHARS
-       printf("nchar '%c'\n", c);
-#endif
 }
 
 #define SYMBOL_CHARS  \
@@ -549,14 +277,28 @@ end_symbol:
        char     *string = obstack_finish(&symbol_obstack);
        symbol_t *symbol = symbol_table_insert(string);
 
-       lexer_token.type   = symbol->ID;
-       lexer_token.symbol = symbol;
+       lexer_token.kind              = symbol->ID;
+       lexer_token.identifier.symbol = symbol;
 
        if (symbol->string != string) {
                obstack_free(&symbol_obstack, string);
        }
 }
 
+static string_t identify_string(char *string, size_t len)
+{
+       /* TODO hash */
+#if 0
+       const char *result = strset_insert(&stringset, concat);
+       if (result != concat) {
+               obstack_free(&symbol_obstack, concat);
+       }
+#else
+       const char *result = string;
+#endif
+       return (string_t) {result, len};
+}
+
 /**
  * parse suffixes like 'LU' or 'f' after numbers
  */
@@ -576,32 +318,16 @@ static void parse_number_suffix(void)
        }
 finish_suffix:
        if (obstack_object_size(&symbol_obstack) == 0) {
-               lexer_token.symbol = NULL;
+               lexer_token.number.suffix.begin = NULL;
+               lexer_token.number.suffix.size  = 0;
                return;
        }
 
        obstack_1grow(&symbol_obstack, '\0');
+       size_t    size   = obstack_object_size(&symbol_obstack);
        char     *string = obstack_finish(&symbol_obstack);
-       symbol_t *symbol = symbol_table_insert(string);
-
-       if (symbol->string != string) {
-               obstack_free(&symbol_obstack, string);
-       }
-       lexer_token.symbol = symbol;
-}
 
-static string_t identify_string(char *string, size_t len)
-{
-       /* TODO hash */
-#if 0
-       const char *result = strset_insert(&stringset, concat);
-       if (result != concat) {
-               obstack_free(&symbol_obstack, concat);
-       }
-#else
-       const char *result = string;
-#endif
-       return (string_t) {result, len};
+       lexer_token.number.suffix = identify_string(string, size);
 }
 
 /**
@@ -646,23 +372,23 @@ static void parse_number_hex(void)
                        next_char();
                }
        } else if (is_float) {
-               errorf(&lexer_token.source_position,
+               errorf(&lexer_token.base.source_position,
                       "hexadecimal floatingpoint constant requires an exponent");
        }
        obstack_1grow(&symbol_obstack, '\0');
 
        size_t  size   = obstack_object_size(&symbol_obstack) - 1;
        char   *string = obstack_finish(&symbol_obstack);
-       lexer_token.literal = identify_string(string, size);
+       lexer_token.number.number = identify_string(string, size);
 
-       lexer_token.type    =
+       lexer_token.kind    =
                is_float ? T_FLOATINGPOINT_HEXADECIMAL : T_INTEGER_HEXADECIMAL;
 
        if (!has_digits) {
-               errorf(&lexer_token.source_position, "invalid number literal '0x%S'",
-                      &lexer_token.literal);
-               lexer_token.literal.begin = "0";
-               lexer_token.literal.size  = 1;
+               errorf(&lexer_token.base.source_position,
+                      "invalid number literal '0x%S'", &lexer_token.number.number);
+               lexer_token.number.number.begin = "0";
+               lexer_token.number.number.size  = 1;
        }
 
        parse_number_suffix();
@@ -675,19 +401,7 @@ static void parse_number_hex(void)
  */
 static bool is_octal_digit(utf32 chr)
 {
-       switch (chr) {
-       case '0':
-       case '1':
-       case '2':
-       case '3':
-       case '4':
-       case '5':
-       case '6':
-       case '7':
-               return true;
-       default:
-               return false;
-       }
+       return '0' <= chr && chr <= '7';
 }
 
 /**
@@ -747,28 +461,28 @@ static void parse_number(void)
        obstack_1grow(&symbol_obstack, '\0');
        size_t  size   = obstack_object_size(&symbol_obstack) - 1;
        char   *string = obstack_finish(&symbol_obstack);
-       lexer_token.literal = identify_string(string, size);
+       lexer_token.number.number = identify_string(string, size);
 
        /* is it an octal number? */
        if (is_float) {
-               lexer_token.type = T_FLOATINGPOINT;
+               lexer_token.kind = T_FLOATINGPOINT;
        } else if (string[0] == '0') {
-               lexer_token.type = T_INTEGER_OCTAL;
+               lexer_token.kind = T_INTEGER_OCTAL;
 
                /* check for invalid octal digits */
                for (size_t i= 0; i < size; ++i) {
                        char t = string[i];
-                       if (t == '8' || t == '9')
-                               errorf(&lexer_token.source_position,
+                       if (t >= '8')
+                               errorf(&lexer_token.base.source_position,
                                       "invalid digit '%c' in octal number", t);
                }
        } else {
-               lexer_token.type = T_INTEGER;
+               lexer_token.kind = T_INTEGER;
        }
 
        if (!has_digits) {
-               errorf(&lexer_token.source_position, "invalid number literal '%S'",
-                      &lexer_token.literal);
+               errorf(&lexer_token.base.source_position, "invalid number literal '%S'",
+                      &lexer_token.number.number);
        }
 
        parse_number_suffix();
@@ -918,33 +632,11 @@ string_t make_string(const char *string)
        return identify_string(space, len);
 }
 
-static void grow_symbol(utf32 const tc)
-{
-       struct obstack *const o  = &symbol_obstack;
-       if (tc < 0x80U) {
-               obstack_1grow(o, tc);
-       } else if (tc < 0x800) {
-               obstack_1grow(o, 0xC0 | (tc >> 6));
-               obstack_1grow(o, 0x80 | (tc & 0x3F));
-       } else if (tc < 0x10000) {
-               obstack_1grow(o, 0xE0 | ( tc >> 12));
-               obstack_1grow(o, 0x80 | ((tc >>  6) & 0x3F));
-               obstack_1grow(o, 0x80 | ( tc        & 0x3F));
-       } else {
-               obstack_1grow(o, 0xF0 | ( tc >> 18));
-               obstack_1grow(o, 0x80 | ((tc >> 12) & 0x3F));
-               obstack_1grow(o, 0x80 | ((tc >>  6) & 0x3F));
-               obstack_1grow(o, 0x80 | ( tc        & 0x3F));
-       }
-}
-
 /**
  * Parse a string literal and set lexer_token.
  */
 static void parse_string_literal(void)
 {
-       const unsigned start_linenr = lexer_token.source_position.linenr;
-
        eat('"');
 
        while (true) {
@@ -952,19 +644,15 @@ static void parse_string_literal(void)
                case '\\': {
                        utf32 const tc = parse_escape_sequence();
                        if (tc >= 0x100) {
-                               warningf(&lexer_token.source_position,
-                                               "escape sequence out of range");
+                               warningf(WARN_OTHER, &lexer_pos, "escape sequence out of range");
                        }
                        obstack_1grow(&symbol_obstack, 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;
+                       errorf(&lexer_token.base.source_position, "string has no end");
+                       lexer_token.kind = T_ERROR;
                        return;
                }
 
@@ -973,7 +661,7 @@ static void parse_string_literal(void)
                        goto end_of_string;
 
                default:
-                       grow_symbol(c);
+                       obstack_grow_symbol(&symbol_obstack, c);
                        next_char();
                        break;
                }
@@ -988,8 +676,8 @@ end_of_string:
        const size_t  size   = (size_t)obstack_object_size(&symbol_obstack);
        char         *string = obstack_finish(&symbol_obstack);
 
-       lexer_token.type    = T_STRING_LITERAL;
-       lexer_token.literal = identify_string(string, size);
+       lexer_token.kind          = T_STRING_LITERAL;
+       lexer_token.string.string = identify_string(string, size);
 }
 
 /**
@@ -997,15 +685,13 @@ end_of_string:
  */
 static void parse_wide_character_constant(void)
 {
-       const unsigned start_linenr = lexer_token.source_position.linenr;
-
        eat('\'');
 
        while (true) {
                switch (c) {
                case '\\': {
                        const utf32 tc = parse_escape_sequence();
-                       grow_symbol(tc);
+                       obstack_grow_symbol(&symbol_obstack, tc);
                        break;
                }
 
@@ -1019,15 +705,14 @@ static void parse_wide_character_constant(void)
                        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;
+                       errorf(&lexer_token.base.source_position,
+                              "EOF while parsing character constant");
+                       lexer_token.kind = T_ERROR;
                        return;
                }
 
                default:
-                       grow_symbol(c);
+                       obstack_grow_symbol(&symbol_obstack, c);
                        next_char();
                        break;
                }
@@ -1038,8 +723,12 @@ end_of_wide_char_constant:;
        size_t  size   = (size_t) obstack_object_size(&symbol_obstack) - 1;
        char   *string = obstack_finish(&symbol_obstack);
 
-       lexer_token.type     = T_WIDE_CHARACTER_CONSTANT;
-       lexer_token.literal  = identify_string(string, size);
+       lexer_token.kind          = T_WIDE_CHARACTER_CONSTANT;
+       lexer_token.string.string = identify_string(string, size);
+
+       if (size == 0) {
+               errorf(&lexer_token.base.source_position, "empty character constant");
+       }
 }
 
 /**
@@ -1048,8 +737,8 @@ end_of_wide_char_constant:;
 static void parse_wide_string_literal(void)
 {
        parse_string_literal();
-       if (lexer_token.type == T_STRING_LITERAL)
-               lexer_token.type = T_WIDE_STRING_LITERAL;
+       if (lexer_token.kind == T_STRING_LITERAL)
+               lexer_token.kind = T_WIDE_STRING_LITERAL;
 }
 
 /**
@@ -1057,8 +746,6 @@ static void parse_wide_string_literal(void)
  */
 static void parse_character_constant(void)
 {
-       const unsigned start_linenr = lexer_token.source_position.linenr;
-
        eat('\'');
 
        while (true) {
@@ -1066,8 +753,7 @@ static void parse_character_constant(void)
                case '\\': {
                        utf32 const tc = parse_escape_sequence();
                        if (tc >= 0x100) {
-                               warningf(&lexer_token.source_position,
-                                               "escape sequence out of range");
+                               warningf(WARN_OTHER, &lexer_pos, "escape sequence out of range");
                        }
                        obstack_1grow(&symbol_obstack, tc);
                        break;
@@ -1083,16 +769,14 @@ static void parse_character_constant(void)
                        goto end_of_char_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;
+                       errorf(&lexer_token.base.source_position,
+                              "EOF while parsing character constant");
+                       lexer_token.kind = T_ERROR;
                        return;
                }
 
                default:
-                       grow_symbol(c);
+                       obstack_grow_symbol(&symbol_obstack, c);
                        next_char();
                        break;
 
@@ -1104,8 +788,12 @@ end_of_char_constant:;
        const size_t        size   = (size_t)obstack_object_size(&symbol_obstack)-1;
        char         *const string = obstack_finish(&symbol_obstack);
 
-       lexer_token.type    = T_CHARACTER_CONSTANT;
-       lexer_token.literal = identify_string(string, size);
+       lexer_token.kind          = T_CHARACTER_CONSTANT;
+       lexer_token.string.string = identify_string(string, size);
+
+       if (size == 0) {
+               errorf(&lexer_token.base.source_position, "empty character constant");
+       }
 }
 
 /**
@@ -1113,17 +801,13 @@ end_of_char_constant:;
  */
 static void skip_multiline_comment(void)
 {
-       unsigned start_linenr = lexer_token.source_position.linenr;
-
        while (true) {
                switch (c) {
                case '/':
                        next_char();
                        if (c == '*') {
                                /* nested comment, warn here */
-                               if (warning.comment) {
-                                       warningf(&lexer_token.source_position, "'/*' within comment");
-                               }
+                               warningf(WARN_COMMENT, &lexer_pos, "'/*' within comment");
                        }
                        break;
                case '*':
@@ -1137,10 +821,8 @@ static void skip_multiline_comment(void)
                MATCH_NEWLINE(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, "at end of file while looking for comment end");
+                       errorf(&lexer_token.base.source_position,
+                              "at end of file while looking for comment end");
                        return;
                }
 
@@ -1168,8 +850,7 @@ static void skip_line_comment(void)
                case '\\':
                        next_char();
                        if (c == '\n' || c == '\r') {
-                               if (warning.comment)
-                                       warningf(&lexer_token.source_position, "multi-line comment");
+                               warningf(WARN_COMMENT, &lexer_pos, "multi-line comment");
                                return;
                        }
                        break;
@@ -1198,56 +879,43 @@ static inline void next_pp_token(void)
  */
 static void eat_until_newline(void)
 {
-       while (pp_token.type != '\n' && pp_token.type != T_EOF) {
+       while (pp_token.kind != '\n' && pp_token.kind != T_EOF) {
                next_pp_token();
        }
 }
 
-/**
- * Handle the define directive.
- */
-static void define_directive(void)
-{
-       lexer_next_preprocessing_token();
-       if (lexer_token.type != T_IDENTIFIER) {
-               parse_error("expected identifier after #define\n");
-               eat_until_newline();
-       }
-}
-
-/**
- * Handle the ifdef directive.
- */
-static void ifdef_directive(int is_ifndef)
-{
-       (void) is_ifndef;
-       lexer_next_preprocessing_token();
-       //expect_identifier();
-       //extect_newline();
-}
-
-/**
- * Handle the endif directive.
- */
-static void endif_directive(void)
-{
-       //expect_newline();
-}
-
 /**
  * Parse the line directive.
  */
 static void parse_line_directive(void)
 {
-       if (pp_token.type != T_INTEGER) {
+       if (pp_token.kind != T_INTEGER) {
                parse_error("expected integer");
        } else {
-               lexer_token.source_position.linenr = atoi(pp_token.literal.begin);
+               /* use offset -1 as this is about the next line */
+               lexer_pos.lineno = atoi(pp_token.number.number.begin) - 1;
                next_pp_token();
        }
-       if (pp_token.type == T_STRING_LITERAL) {
-               lexer_token.source_position.input_name = pp_token.literal.begin;
+       if (pp_token.kind == T_STRING_LITERAL) {
+               lexer_pos.input_name = pp_token.string.string.begin;
+               lexer_pos.is_system_header = false;
                next_pp_token();
+
+               /* attempt to parse numeric flags as outputted by gcc preprocessor */
+               while (pp_token.kind == T_INTEGER) {
+                       /* flags:
+                        * 1 - indicates start of a new file
+                        * 2 - indicates return from a file
+                        * 3 - indicates system header
+                        * 4 - indicates implicit extern "C" in C++ mode
+                        *
+                        * currently we're only interested in "3"
+                        */
+                       if (streq(pp_token.number.number.begin, "3")) {
+                               lexer_pos.is_system_header = true;
+                       }
+                       next_pp_token();
+               }
        }
 
        eat_until_newline();
@@ -1281,13 +949,21 @@ static void parse_pragma(void)
        bool unknown_pragma = true;
 
        next_pp_token();
-       if (pp_token.symbol->pp_ID == TP_STDC) {
+       if (pp_token.kind != T_IDENTIFIER) {
+               warningf(WARN_UNKNOWN_PRAGMAS, &pp_token.base.source_position,
+                        "expected identifier after #pragma");
+               eat_until_newline();
+               return;
+       }
+
+       symbol_t *symbol = pp_token.identifier.symbol;
+       if (symbol->pp_ID == TP_STDC) {
                stdc_pragma_kind_t kind = STDC_UNKNOWN;
                /* a STDC pragma */
                if (c_mode & _C99) {
                        next_pp_token();
 
-                       switch (pp_token.symbol->pp_ID) {
+                       switch (pp_token.identifier.symbol->pp_ID) {
                        case TP_FP_CONTRACT:
                                kind = STDC_FP_CONTRACT;
                                break;
@@ -1303,7 +979,7 @@ static void parse_pragma(void)
                        if (kind != STDC_UNKNOWN) {
                                stdc_pragma_value_kind_t value = STDC_VALUE_UNKNOWN;
                                next_pp_token();
-                               switch (pp_token.symbol->pp_ID) {
+                               switch (pp_token.identifier.symbol->pp_ID) {
                                case TP_ON:
                                        value = STDC_VALUE_ON;
                                        break;
@@ -1319,7 +995,8 @@ static void parse_pragma(void)
                                if (value != STDC_VALUE_UNKNOWN) {
                                        unknown_pragma = false;
                                } else {
-                                       errorf(&pp_token.source_position, "bad STDC pragma argument");
+                                       errorf(&pp_token.base.source_position,
+                                              "bad STDC pragma argument");
                                }
                        }
                }
@@ -1327,8 +1004,9 @@ static void parse_pragma(void)
                unknown_pragma = true;
        }
        eat_until_newline();
-       if (unknown_pragma && warning.unknown_pragmas) {
-               warningf(&pp_token.source_position, "encountered unknown #pragma");
+       if (unknown_pragma) {
+               warningf(WARN_UNKNOWN_PRAGMAS, &pp_token.base.source_position,
+                        "encountered unknown #pragma");
        }
 }
 
@@ -1337,40 +1015,21 @@ static void parse_pragma(void)
  */
 static void parse_preprocessor_identifier(void)
 {
-       assert(pp_token.type == T_IDENTIFIER);
-       symbol_t *symbol = pp_token.symbol;
+       assert(pp_token.kind == T_IDENTIFIER);
+       symbol_t *symbol = pp_token.identifier.symbol;
 
        switch (symbol->pp_ID) {
-       case TP_include:
-               printf("include - enable header name parsing!\n");
-               break;
-       case TP_define:
-               define_directive();
-               break;
-       case TP_ifdef:
-               ifdef_directive(0);
-               break;
-       case TP_ifndef:
-               ifdef_directive(1);
-               break;
-       case TP_endif:
-               endif_directive();
-               break;
        case TP_line:
                next_pp_token();
                parse_line_directive();
                break;
-       case TP_if:
-       case TP_else:
-       case TP_elif:
-       case TP_undef:
-       case TP_error:
-               /* TODO; output the rest of the line */
-               parse_error("#error directive: ");
-               break;
        case TP_pragma:
                parse_pragma();
                break;
+       case TP_error:
+               /* TODO; output the rest of the line */
+               parse_error("#error directive");
+               break;
        }
 }
 
@@ -1381,7 +1040,7 @@ static void parse_preprocessor_directive(void)
 {
        next_pp_token();
 
-       switch (pp_token.type) {
+       switch (pp_token.kind) {
        case T_IDENTIFIER:
                parse_preprocessor_identifier();
                break;
@@ -1406,7 +1065,7 @@ static void parse_preprocessor_directive(void)
 #define MAYBE(ch, set_type)                                \
                                case ch:                                   \
                                        next_char();                           \
-                                       lexer_token.type = set_type;           \
+                                       lexer_token.kind = set_type;           \
                                        return;
 
 /* must use this as last thing */
@@ -1414,7 +1073,7 @@ static void parse_preprocessor_directive(void)
                                case ch:                                   \
                                        if (c_mode & mode) {                   \
                                                next_char();                       \
-                                               lexer_token.type = set_type;       \
+                                               lexer_token.kind = set_type;       \
                                                return;                            \
                                        }                                      \
                                        /* fallthrough */
@@ -1422,19 +1081,20 @@ static void parse_preprocessor_directive(void)
 #define ELSE_CODE(code)                                    \
                                default:                                   \
                                        code                                   \
+                                       return;                                \
                                }                                          \
                        } /* end of while (true) */                    \
-                       break;
 
 #define ELSE(set_type)                                     \
                ELSE_CODE(                                         \
-                       lexer_token.type = set_type;                   \
-                       return;                                        \
+                       lexer_token.kind = set_type;                   \
                )
 
 void lexer_next_preprocessing_token(void)
 {
        while (true) {
+               lexer_token.base.source_position = lexer_pos;
+
                switch (c) {
                case ' ':
                case '\t':
@@ -1442,14 +1102,14 @@ void lexer_next_preprocessing_token(void)
                        break;
 
                MATCH_NEWLINE(
-                       lexer_token.type = '\n';
+                       lexer_token.kind = '\n';
                        return;
                )
 
                SYMBOL_CHARS
                        parse_symbol();
                        /* might be a wide string ( L"string" ) */
-                       if (lexer_token.symbol == symbol_L) {
+                       if (lexer_token.identifier.symbol == symbol_L) {
                                switch (c) {
                                        case '"':  parse_wide_string_literal();     break;
                                        case '\'': parse_wide_character_constant(); break;
@@ -1483,8 +1143,7 @@ void lexer_next_preprocessing_token(void)
                                        ELSE_CODE(
                                                put_back(c);
                                                c = '.';
-                                               lexer_token.type = '.';
-                                               return;
+                                               lexer_token.kind = '.';
                                        )
                        ELSE('.')
                case '&':
@@ -1537,8 +1196,7 @@ void lexer_next_preprocessing_token(void)
                                                        ELSE_CODE(
                                                                put_back(c);
                                                                c = '%';
-                                                               lexer_token.type = '#';
-                                                               return;
+                                                               lexer_token.kind = '#';
                                                        )
                                        ELSE('#')
                        ELSE('%')
@@ -1594,19 +1252,19 @@ void lexer_next_preprocessing_token(void)
                case ';':
                case ',':
                case '\\':
-                       lexer_token.type = c;
+                       lexer_token.kind = c;
                        next_char();
                        return;
 
                case EOF:
-                       lexer_token.type = T_EOF;
+                       lexer_token.kind = T_EOF;
                        return;
 
                default:
 dollar_sign:
-                       errorf(&lexer_token.source_position, "unknown character '%c' found", c);
+                       errorf(&lexer_pos, "unknown character '%c' found", c);
                        next_char();
-                       lexer_token.type = T_ERROR;
+                       lexer_token.kind = T_ERROR;
                        return;
                }
        }
@@ -1616,12 +1274,12 @@ void lexer_next_token(void)
 {
        lexer_next_preprocessing_token();
 
-       while (lexer_token.type == '\n') {
+       while (lexer_token.kind == '\n') {
 newline_found:
                lexer_next_preprocessing_token();
        }
 
-       if (lexer_token.type == '#') {
+       if (lexer_token.kind == '#') {
                parse_preprocessor_directive();
                goto newline_found;
        }
@@ -1633,34 +1291,24 @@ void init_lexer(void)
        symbol_L = symbol_table_insert("L");
 }
 
-void lexer_open_stream(FILE *stream, const char *input_name)
+static void input_error(unsigned delta_lines, unsigned delta_cols,
+                        const char *message)
 {
-       input                                  = stream;
-       lexer_token.source_position.linenr     = 0;
-       lexer_token.source_position.input_name = input_name;
-
-       bufpos = NULL;
-       bufend = NULL;
-
-       /* place a virtual \n at the beginning so the lexer knows that we're
-        * at the beginning of a line */
-       c = '\n';
+       lexer_pos.lineno += delta_lines;
+       lexer_pos.colno  += delta_cols;
+       errorf(&lexer_pos, "%s", message);
 }
 
-void lexer_open_buffer(const char *buffer, size_t len, const char *input_name)
+void lexer_switch_input(input_t *new_input, const char *input_name)
 {
-       input                                  = NULL;
-       lexer_token.source_position.linenr     = 0;
-       lexer_token.source_position.input_name = input_name;
+       lexer_pos.lineno     = 0;
+       lexer_pos.colno      = 0;
+       lexer_pos.input_name = input_name;
 
-#if 0 // TODO
-       bufpos = buffer;
-       bufend = buffer + len;
-#else
-       (void)buffer;
-       (void)len;
-       panic("builtin lexing not done yet");
-#endif
+       set_input_error_callback(input_error);
+       input  = new_input;
+       bufpos = NULL;
+       bufend = NULL;
 
        /* place a virtual \n at the beginning so the lexer knows that we're
         * at the beginning of a line */
@@ -1675,7 +1323,7 @@ void exit_lexer(void)
 static __attribute__((unused))
 void dbg_pos(const source_position_t source_position)
 {
-       fprintf(stdout, "%s:%u\n", source_position.input_name,
-               source_position.linenr);
+       fprintf(stdout, "%s:%u:%u\n", source_position.input_name,
+               source_position.lineno, (unsigned)source_position.colno);
        fflush(stdout);
 }