mirror of
https://github.com/scummvm/scummvm.git
synced 2026-06-20 05:45:29 +00:00
Pawel Kolodziejski
470 lines
10 KiB
C++
470 lines
10 KiB
C++
/*
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** $Id$
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** Lexical Analizer
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** See Copyright Notice in lua.h
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*/
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#include "engine/lua/lauxlib.h"
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#include "engine/lua/llex.h"
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#include "engine/lua/lmem.h"
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#include "engine/lua/lobject.h"
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#include "engine/lua/lparser.h"
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#include "engine/lua/lstate.h"
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#include "engine/lua/lstring.h"
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#include "engine/lua/luadebug.h"
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#include "engine/lua/lzio.h"
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int32 lua_debug = 0;
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#define next(LS) (LS->current = zgetc(LS->lex_z))
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#define save(c) luaL_addchar(c)
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#define save_and_next(LS) (save(LS->current), next(LS))
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const char *reserved [] = { "and", "do", "else", "elseif", "end", "function",
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"if", "local", "nil", "not", "or", "repeat", "return", "then",
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"until", "while"
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};
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void luaX_init() {
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uint32 i;
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for (i = 0; i < (sizeof(reserved) / sizeof(reserved[0])); i++) {
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TaggedString *ts = luaS_new(reserved[i]);
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ts->head.marked = FIRST_RESERVED + i; // reserved word (always > 255)
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}
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}
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void luaX_syntaxerror(LexState *ls, const char *s, const char *token) {
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if (token[0] == 0)
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token = "<eof>";
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luaL_verror("%.100s;\n last token read: `%.50s' at line %d in chunk `%.50s'",
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s, token, ls->linenumber, zname(ls->lex_z));
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}
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void luaX_error(LexState *ls, const char *s) {
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save(0);
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luaX_syntaxerror(ls, s, luaL_buffer());
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}
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void luaX_token2str (LexState *, int32 token, char *s) {
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if (token < 255) {
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s[0] = token;
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s[1] = 0;
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} else
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strcpy(s, reserved[token - FIRST_RESERVED]);
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}
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static void luaX_invalidchar(LexState *ls, int32 c) {
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char buff[10];
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sprintf(buff, "0x%X", (int)c);
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luaX_syntaxerror(ls, "invalid control char", buff);
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}
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static void firstline(LexState *LS) {
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int32 c = zgetc(LS->lex_z);
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if (c == '#')
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while ((c = zgetc(LS->lex_z)) != '\n' && c != EOZ) // skip first line
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zungetc(LS->lex_z);
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}
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void luaX_setinput(LexState *LS, ZIO *z) {
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LS->current = '\n';
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LS->linenumber = 0;
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LS->iflevel = 0;
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LS->ifstate[0].skip = 0;
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LS->ifstate[0].elsepart = 1; // to avoid a free $else
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LS->lex_z = z;
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LS->fs = NULL;
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firstline(LS);
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luaL_resetbuffer();
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}
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/*
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** =======================================================
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** PRAGMAS
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** =======================================================
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*/
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#define PRAGMASIZE 20
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static void skipspace(LexState *LS) {
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while (LS->current == ' ' || LS->current == '\t' || LS->current == '\r')
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next(LS);
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}
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static int32 checkcond(LexState *LS, char *buff) {
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static const char *opts[] = { "nil", "1", NULL };
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int32 i = luaL_findstring(buff, opts);
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if (i >= 0)
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return i;
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else if (isalpha((byte)buff[0]) || buff[0] == '_')
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return luaS_globaldefined(buff);
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else {
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luaX_syntaxerror(LS, "invalid $if condition", buff);
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return 0; // to avoid warnings
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}
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}
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static void readname(LexState *LS, char *buff) {
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int32 i = 0;
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skipspace(LS);
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while (isalnum(LS->current) || LS->current == '_') {
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if (i >= PRAGMASIZE) {
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buff[PRAGMASIZE] = 0;
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luaX_syntaxerror(LS, "pragma too long", buff);
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}
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buff[i++] = LS->current;
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next(LS);
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}
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buff[i] = 0;
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}
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static void inclinenumber (LexState *LS);
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static void ifskip (LexState *LS) {
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while (LS->ifstate[LS->iflevel].skip) {
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if (LS->current == '\n')
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inclinenumber(LS);
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else if (LS->current == EOZ)
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luaX_error(LS, "input ends inside a $if");
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else
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next(LS);
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}
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}
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static void inclinenumber (LexState *LS) {
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static const char *pragmas [] =
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{ "debug", "nodebug", "endinput", "end", "ifnot", "if", "else", NULL };
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next(LS); // skip '\n'
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++LS->linenumber;
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if (LS->current == '$') { // is a pragma?
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char buff[PRAGMASIZE + 1];
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int32 ifnot = 0;
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int32 skip = LS->ifstate[LS->iflevel].skip;
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next(LS); // skip $
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readname(LS, buff);
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switch (luaL_findstring(buff, pragmas)) {
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case 0: // debug
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if (!skip)
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lua_debug = 1;
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break;
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case 1: // nodebug
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if (!skip)
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lua_debug = 0;
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break;
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case 2: // endinput
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if (!skip) {
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LS->current = EOZ;
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LS->iflevel = 0; // to allow $endinput inside a $if
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}
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break;
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case 3: // end
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if (LS->iflevel-- == 0)
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luaX_syntaxerror(LS, "unmatched $end", "$end");
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break;
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case 4: // ifnot
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ifnot = 1;
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// go through
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case 5: // if
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if (LS->iflevel == MAX_IFS - 1)
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luaX_syntaxerror(LS, "too many nested $ifs", "$if");
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readname(LS, buff);
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LS->iflevel++;
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LS->ifstate[LS->iflevel].elsepart = 0;
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LS->ifstate[LS->iflevel].condition = checkcond(LS, buff) ? !ifnot : ifnot;
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LS->ifstate[LS->iflevel].skip = skip || !LS->ifstate[LS->iflevel].condition;
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break;
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case 6: // else
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if (LS->ifstate[LS->iflevel].elsepart)
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luaX_syntaxerror(LS, "unmatched $else", "$else");
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LS->ifstate[LS->iflevel].elsepart = 1;
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LS->ifstate[LS->iflevel].skip = LS->ifstate[LS->iflevel - 1].skip || LS->ifstate[LS->iflevel].condition;
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break;
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default:
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luaX_syntaxerror(LS, "unknown pragma", buff);
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}
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skipspace(LS);
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if (LS->current == '\n') // pragma must end with a '\n' ...
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inclinenumber(LS);
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else if (LS->current != EOZ) // or eof
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luaX_syntaxerror(LS, "invalid pragma format", buff);
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ifskip(LS);
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}
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}
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/*
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** =======================================================
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** LEXICAL ANALIZER
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** =======================================================
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*/
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static int32 read_long_string(LexState *LS) {
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int32 cont = 0;
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while (1) {
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switch (LS->current) {
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case EOZ:
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luaX_error(LS, "unfinished long string");
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return EOS; // to avoid warnings
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case '[':
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save_and_next(LS);
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if (LS->current == '[') {
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cont++;
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save_and_next(LS);
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}
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continue;
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case ']':
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save_and_next(LS);
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if (LS->current == ']') {
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if (cont == 0)
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goto endloop;
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cont--;
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save_and_next(LS);
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}
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continue;
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case '\n':
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save('\n');
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inclinenumber(LS);
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continue;
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default:
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save_and_next(LS);
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}
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}
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endloop:
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save_and_next(LS); // pass the second ']'
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LS->seminfo.ts = luaS_newlstr(L->Mbuffbase + 2, L->Mbuffnext - (L->Mbuffbase - L->Mbuffer) - 4);
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return STRING;
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}
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int32 luaX_lex (LexState *LS) {
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double a;
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luaL_resetbuffer();
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while (1) {
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switch (LS->current) {
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case ' ':
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case '\t':
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case '\r': // CR: to avoid problems with DOS
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next(LS);
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continue;
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case '\n':
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inclinenumber(LS);
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continue;
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case '-':
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save_and_next(LS);
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if (LS->current != '-')
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return '-';
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do {
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next(LS);
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} while (LS->current != '\n' && LS->current != EOZ);
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luaL_resetbuffer();
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continue;
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case '[':
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save_and_next(LS);
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if (LS->current != '[')
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return '[';
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else {
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save_and_next(LS); // pass the second '['
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return read_long_string(LS);
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}
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case '=':
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save_and_next(LS);
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if (LS->current != '=')
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return '=';
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else {
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save_and_next(LS);
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return EQ;
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}
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case '<':
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save_and_next(LS);
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if (LS->current != '=')
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return '<';
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else {
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save_and_next(LS);
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return LE;
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}
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case '>':
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save_and_next(LS);
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if (LS->current != '=')
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return '>';
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else {
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save_and_next(LS);
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return GE;
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}
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case '~':
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save_and_next(LS);
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if (LS->current != '=')
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return '~';
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else {
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save_and_next(LS);
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return NE;
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}
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case '"':
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case '\'':
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{
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int32 del = LS->current;
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save_and_next(LS);
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while (LS->current != del) {
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switch (LS->current) {
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case EOZ:
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case '\n':
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luaX_error(LS, "unfinished string");
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return EOS; // to avoid warnings
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case '\\':
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next(LS); // do not save the '\'
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switch (LS->current) {
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case 'a':
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save('\a');
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next(LS);
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break;
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case 'b':
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save('\b');
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next(LS);
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break;
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case 'f':
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save('\f');
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next(LS);
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break;
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case 'n':
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save('\n');
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next(LS);
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break;
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case 'r':
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save('\r');
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next(LS);
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break;
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case 't':
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save('\t');
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next(LS);
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break;
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case 'v':
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save('\v');
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next(LS);
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break;
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case '\n':
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save('\n');
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inclinenumber(LS);
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break;
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default :
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{
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if (isdigit(LS->current)) {
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int32 c = 0;
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int32 i = 0;
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do {
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c = 10 * c + (LS->current - '0');
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next(LS);
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} while (++i < 3 && isdigit(LS->current));
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if (c >= 256)
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luaX_error(LS, "escape sequence too large");
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save(c);
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} else { // handles \, ", ', and ?
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save(LS->current);
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next(LS);
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}
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break;
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}
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}
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break;
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default:
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save_and_next(LS);
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}
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}
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save_and_next(LS); // skip delimiter
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LS->seminfo.ts = luaS_newlstr(L->Mbuffbase + 1,
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L->Mbuffnext - (L->Mbuffbase - L->Mbuffer) - 2);
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return STRING;
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}
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case '.':
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save_and_next(LS);
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if (LS->current == '.') {
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save_and_next(LS);
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if (LS->current == '.') {
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save_and_next(LS);
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return DOTS; // ...
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} else
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return CONC; // ..
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} else if (!isdigit(LS->current))
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return '.';
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// LS->current is a digit: goes through to number/
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a = 0.0;
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goto fraction;
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case '0':
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case '1':
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case '2':
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case '3':
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case '4':
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case '5':
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case '6':
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case '7':
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case '8':
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case '9':
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a = 0.0;
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do {
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a = 10.0 * a + (LS->current - '0');
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save_and_next(LS);
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} while (isdigit(LS->current));
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if (LS->current == '.') {
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save_and_next(LS);
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if (LS->current == '.') {
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save('.');
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luaX_error(LS, "ambiguous syntax (decimal point x string concatenation)");
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}
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}
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fraction:
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{
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double da = 0.1;
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while (isdigit(LS->current)) {
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a += (LS->current - '0') * da;
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da /= 10.0;
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save_and_next(LS);
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}
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if (toupper(LS->current) == 'E') {
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int32 e = 0;
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int32 neg;
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double ea;
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save_and_next(LS);
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neg = (LS->current == '-');
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if (LS->current == '+' || LS->current == '-')
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save_and_next(LS);
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if (!isdigit(LS->current))
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luaX_error(LS, "invalid numeral format");
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do {
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e = 10 * e + (LS->current - '0');
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save_and_next(LS);
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} while (isdigit(LS->current));
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for (ea = neg ? 0.1 : 10.0; e > 0; e >>= 1) {
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if (e & 1)
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a *= ea;
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ea *= ea;
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}
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}
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LS->seminfo.r = (real)a;
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return NUMBER;
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}
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case EOZ:
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if (LS->iflevel > 0)
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luaX_error(LS, "input ends inside a $if");
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return EOS;
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default:
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if (LS->current != '_' && !isalpha(LS->current)) {
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int32 c = LS->current;
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if (iscntrl(c))
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luaX_invalidchar(LS, c);
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save_and_next(LS);
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return c;
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} else { // identifier or reserved word
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TaggedString *ts;
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do {
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save_and_next(LS);
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} while (isalnum(LS->current) || LS->current == '_');
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save(0);
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ts = luaS_new(L->Mbuffbase);
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if (ts->head.marked >= 'A')
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return ts->head.marked; // reserved word
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LS->seminfo.ts = ts;
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return NAME;
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}
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}
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}
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}
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