用YACC实现的一个小的编译工具
源代码在线查看： text.c
/* text.c */ #define PRIVATE static #define PUBLIC #include /*============================================================================== * * FILL TEXT BUFFER * */ PRIVATE char *text; /* pointer to input buffer (dynamically allocated and resized */ PRIVATE textsize; /* current size of input buffer */ PRIVATE int textpos = 0; /* next free position in input buffer */ PUBLIC int startpos; /* start index of last item added to input buffer */ /* defined by StoreText, used in token descriptions */ PRIVATE int do_store = 1; /* StoreText and StoreChar have no effect if 'do_storing' is false */ /*------------------------------------------------------------------------------ * * StoreBegin() * * Initialize input to text buffer * */ #define PIECE 10000 PUBLIC StoreBegin() { text = (char *) malloc(PIECE); textsize = PIECE; } /*------------------------------------------------------------------------------ * * StoreChar(ch) * * store the character 'ch' into text buffer * (if 'do_store') * */ StoreChar(ch) char ch; { if (do_store) { if (textpos == textsize) { char *newtext; textsize = textsize+PIECE; newtext = (char *) realloc(text, textsize); if (! newtext) { printf("cannot allocate source buffer\n"); exit(1); } text = newtext; } text[textpos] = ch; textpos++; } } /*------------------------------------------------------------------------------ * * StoreText(txt) * * store the text to which 'txt' points into text buffer * (if 'do_store') * 'startpos' will point to the start of the entry * */ StoreText(txt) char *txt; { long pos; startpos = textpos; while(*txt) { StoreChar(*txt); txt++; } } /*------------------------------------------------------------------------------ * * StoreEnd() * * switch off 'do_store', * further additions to text buffer will have no effect * (used to suppress storing imported files) * */ StoreEnd() { do_store = 0; } /*============================================================================== * * PROCESS TEXT BUFFER * */ PRIVATE int linecount = 1; /* number of input lines already processed for output */ PRIVATE int outputlines = 0; /* number of lines already written to output */ PRIVATE int TxtPtr = 0; /* index of next character in input buffer */ /* that has to be written to output */ PRIVATE PutRange(); /*------------------------------------------------------------------------------ * * SkipTo(stop) * * Skip text[TextPtr .. stop], set TxtPtr to stop+1 * */ PUBLIC SkipTo(stop) int stop; { int pos; for (pos = TxtPtr; pos if (text[pos] == '\n') linecount++; } TxtPtr = stop+1; } /*------------------------------------------------------------------------------ * * EmitText(stop) * * Emit text[TxtPtr..stop], set TxtPtr to stop+1 * * Output text is preceeded and followed by by line pragmas * */ PUBLIC EmitText(stop) int stop; { char *name; get_basename(&name); Put("# line "); PutI(linecount); Put(" \""); Put(name); Put(".m\""); Nl(); PutRange(text+TxtPtr, text+stop); TxtPtr = stop+1; Nl(); Put("# line "); PutI(outputlines+2); Put(" \""); Put(name); Put(".cpp\""); Nl(); } /*------------------------------------------------------------------------------ * * EmitFinalText() * * Emit text[TxPtr..] * */ EmitFinalText() { char *name; get_basename(&name); Put("# line "); PutI(linecount); Put(" \""); Put(name); Put(".m\""); Nl(); PutRange(text+TxtPtr, text+textpos-1); } /*============================================================================== * * BASIC OUTPUT * */ #define OutBufSize 6000 #define FlushPos 5000 PRIVATE char OutBuf[OutBufSize]; PRIVATE char *OutBufPtr; PRIVATE FILE *OutFile; /*------------------------------------------------------------------------------ * * OpenOutputWithExtension(Name, Extension) * * open 'OutFile' with name 'Name' and extension 'Extension' for output * */ OpenOutputWithExtension(Name, Extension) char *Name; char *Extension; { char fullname[100]; sprintf(fullname, "%s.%s", Name, Extension); OutFile = fopen(fullname, "w"); if (OutFile == NULL) { printf("cannot open %s\n", Name); exit(1); } OutBufPtr = &OutBuf[0]; } /*------------------------------------------------------------------------------ * * CloseOutput() * * flush and close 'OutFile' * */ CloseOutput () { fwrite(OutBuf, 1, OutBufPtr - &OutBuf[0], OutFile); fclose(OutFile); } /*------------------------------------------------------------------------------ * * Put(Str) * * Emit string 'Str' * */ Put(Str) char *Str; { if (OutBufPtr > &OutBuf[FlushPos]) { fwrite(OutBuf, 1, OutBufPtr - &OutBuf[0], OutFile); OutBufPtr = &OutBuf[0]; } while(*Str) *OutBufPtr++ = *Str++; } /*------------------------------------------------------------------------------ * * PutI(N) * * Emit integer 'N' * */ PutI (N) long N; { if (OutBufPtr > &OutBuf[FlushPos]) { fwrite(OutBuf, 1, OutBufPtr - &OutBuf[0], OutFile); OutBufPtr = &OutBuf[0]; } if (N < 0) { *OutBufPtr++ = '-'; N = -N; } if (N < 10) { *OutBufPtr++ = N + '0'; } else if (N < 100) { *OutBufPtr++ = N/10 + '0'; *OutBufPtr++ = N%10 + '0'; } else { char buf[50]; register i; register n = N; i = 0; do { buf[++i] = (n % 10) + '0'; n = n / 10; } while (n); while (i) *OutBufPtr++ = buf[i--]; } } /*------------------------------------------------------------------------------ * * Nl() * * Emit newline * */ Nl () { if (OutBufPtr > &OutBuf[FlushPos]) { fwrite(OutBuf, 1, OutBufPtr - &OutBuf[0], OutFile); OutBufPtr = &OutBuf[0]; } *OutBufPtr++ = '\n'; outputlines++; } /*------------------------------------------------------------------------------ * * PutRange(start, stop) * * Emit the string ranging from pointer 'start' to pointer 'stop' * */ PRIVATE PutRange(start, stop) char *start, *stop; { char *pos; for (pos = start; pos if (OutBufPtr > &OutBuf[FlushPos]) { fwrite(OutBuf, 1, OutBufPtr - &OutBuf[0], OutFile); OutBufPtr = &OutBuf[0]; } if (*pos == '\n') { linecount++; outputlines++; } *OutBufPtr++ = *pos; } } /*============================================================================== * * SOURCE COORDINATES * */ #define FILECODE 1000000000 #define LINECODE 1000 /*------------------------------------------------------------------------------ * * SourceReference(pos) * */ SourceReference(pos) long pos; { long file, line; file = pos / FILECODE; pos = pos % FILECODE; line = pos / LINECODE; Nl(); Put("// GENERATED FROM SOURCE LINE "); PutI(line); Nl(); } /*------------------------------------------------------------------------------ * * PutPos(pos) * */ PutPos(pos) long pos; { long file, line; file = pos / FILECODE; pos = pos % FILECODE; line = pos / LINECODE; PutI(line); } /*----------------------------------------------------------------------------*/
