textfile.cpp

MONA是为数不多的C++语言编写的一个很小的操作系统

#include	"compiler.h"
#include	"dosio.h"
#include	"textfile.h"


TEXTFILEH textfile_open(const char *filename, UINT buffersize) {

	FILEH		fh;
	TEXTFILEH	ret;

	if (buffersize < 256) {
		buffersize = 256;
	}
	fh = file_open_rb(filename);
	if (fh != FILEH_INVALID) {
		ret = (TEXTFILEH)malloc(sizeof(_TEXTFILE) + buffersize);
		if (ret) {
			memset(ret, 0, sizeof(_TEXTFILE) + buffersize);
			ret->fh = (long)fh;
			ret->buffersize = buffersize;
			return(ret);
		}
		file_close(fh);
	}
	return(NULL);
}


void textfile_close(TEXTFILEH fh) {

	if (fh) {
		file_close((FILEH)fh->fh);
		free(fh);
	}
}


static BOOL getnextstring(TEXTFILEH fh) {

	UINT	rsize;

	if (!fh) {
		return(FAILURE);
	}
	if (file_seek((FILEH)fh->fh, fh->fhpos, 0) != fh->fhpos) {
		return(FAILURE);
	}
	rsize = file_read((FILEH)fh->fh, fh + 1, fh->buffersize);
	if (rsize == (UINT)-1) {
		return(FAILURE);
	}
	fh->fhpos += rsize;
	fh->pos = 0;
	fh->remain = rsize;
	return(SUCCESS);
}


BOOL textfile_read(TEXTFILEH fh, char *buffer, UINT size) {

	char	c = '\0';
	char	*p;
	BOOL	crlf;
	BOOL	ret = FAILURE;

	if ((fh) && (size > 0)) {
		size--;
		crlf = FALSE;
		do {
			if ((!fh->remain) && (getnextstring(fh))) {
				return(FAILURE);
			}
			if (!fh->remain) {
				break;
			}
			ret = SUCCESS;
			p = (char *)(fh + 1);
			p += fh->pos;
			while((fh->remain) && (size)) {
				c = *p++;
				fh->pos++;
				fh->remain--;
				if ((c == 0x0d) || (c == 0x0a)) {
					crlf = TRUE;
					break;
				}
				*buffer++ = c;
				size--;
			}
			if (!crlf) {
				while((fh->remain) && (size)) {
					c = *p++;
					fh->pos++;
					fh->remain--;
					if ((c == 0x0d) || (c == 0x0a)) {
						crlf = TRUE;
						break;
					}
				}
			}
		} while(!crlf);
		if ((crlf) && (c == 0x0d)) {
			if ((!fh->remain) && (getnextstring(fh))) {
				return(FAILURE);
			}
			if (fh->remain) {
				p = (char *)(fh + 1);
				p += fh->pos;
				if (*p == 0x0a) {
					fh->pos++;
					fh->remain--;
				}
			}
		}
		*buffer = '\0';
	}
	return(ret);
}