introduce linebuffer.[ch]

Makefile

@@ -2,7 +2,7 @@ CFLAGS := -O2 -pipe -Wall
 
 all: zyxel-revert compress decompress cfgpatch
 
-zyxel-revert: event.o filedata.o logging.o context.o serial.o statemachine.o xmodem.o zyxel-revert.o
+zyxel-revert: event.o filedata.o linebuffer.o logging.o context.o serial.o statemachine.o xmodem.o zyxel-revert.o
 	$(CC) $(CFLAGS) $^ -o $@
 
 compress: filedata.o lzsc.o romfile.o compress.o

context.c

@@ -18,8 +18,15 @@ struct context * create_context(const char *filename)
 
 	memset(ctx, 0, sizeof(struct context));
 
+	ctx->lbuf = create_linebuffer(256);
+	if (ctx->lbuf == NULL) {
+		free(ctx);
+		return NULL;
+	}
+
 	ctx->file = get_filedata(filename);
 	if (ctx->file == NULL) {
+		free(ctx->lbuf);
 		free(ctx);
 		return NULL;
 	}
@@ -36,6 +43,7 @@ int destroy_context(struct context *ctx)
 		ctx->dev_close(ctx);
 
 	free(ctx->file);
+	free(ctx->lbuf);
 	free(ctx);
 	return 0;
 }

context.h

@@ -2,6 +2,7 @@
 #define _CONTEXT_H_
 
 #include "filedata.h"
+#include "linebuffer.h"
 #include "list.h"
 
 struct context {
@@ -21,8 +22,7 @@ struct context {
 	int state;
 
 	/* line buffer */
-	char linebuf[256];
+	struct linebuffer *lbuf;
-	int linepos;
 
 	/* xmodem */
 	int lastpkt;

linebuffer.c

@@ -0,0 +1,68 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "linebuffer.h"
+
+struct linebuffer * create_linebuffer(int size)
+{
+	struct linebuffer *retval = malloc(sizeof(struct linebuffer) + size);
+	if (retval == NULL)
+		return NULL;
+
+	retval->size = size;
+	retval->pos = 0;
+	return retval;
+}
+
+int linebuffer_read(struct linebuffer *lbuf, int fd)
+{
+	char buf[32];
+	int len = read(fd, buf, sizeof(buf));
+	if (len <= 0)
+		return -1;
+
+	int i;
+	for (i = 0; i < len; i++) {
+		/* "understand" backspace */
+		if (buf[i] == 0x08 && lbuf->pos > 0) {
+			lbuf->pos--;
+
+		/* copy */
+		} else if (buf[i] >= ' ' || buf[i] == '\r') {
+			lbuf->data[lbuf->pos++] = buf[i];
+		}
+
+		if (lbuf->pos > lbuf->size)
+			return -1;
+	}
+
+	return 0;
+}
+
+char * linebuffer_get(struct linebuffer *lbuf)
+{
+	char *newline = memchr(lbuf->data, '\r', lbuf->pos);
+	if (newline == NULL)
+		return NULL;
+
+	char *retval = NULL;
+	*newline = '\0';
+
+	int len = newline - lbuf->data;
+	if (len > 0)
+		retval = strdup(lbuf->data);
+
+	lbuf->pos -= len +1;
+	memmove(lbuf->data, newline +1, lbuf->pos);
+
+	return retval;
+}
+
+int linebuffer_clear(struct linebuffer *lbuf)
+{
+	int oldpos = lbuf->pos;
+	lbuf->pos = 0;
+	return oldpos;
+}

linebuffer.h

@@ -0,0 +1,18 @@
+#ifndef _LINEBUFFER_H_
+#define _LINEBUFFER_H_
+
+struct linebuffer {
+	int size;
+	int pos;
+
+	char data[0];
+};
+
+struct linebuffer * create_linebuffer(int size);
+
+int linebuffer_read(struct linebuffer *lbuf, int fd);
+char * linebuffer_get(struct linebuffer *lbuf);
+
+int linebuffer_clear(struct linebuffer *lbuf);
+
+#endif /* _LINEBUFFER_H_ */

serial.c

@@ -55,9 +55,6 @@ static int setbaudrate(struct context *ctx, int baudrate)
 	cfsetispeed(&sdev->newtio, baudrate);
 	cfsetospeed(&sdev->newtio, baudrate);
 
-	/* flush linebuffer */
-	ctx->linepos = 0;
-
 	if (tcsetattr(ctx->fd, TCSANOW, &sdev->newtio) != 0) {
 		log_print(LOG_WARN, "open_serial(): tcsetattr()");
 		close(ctx->fd);

statemachine.c

@@ -6,6 +6,7 @@
 #include <termios.h>
 
 #include "context.h"
+#include "linebuffer.h"
 #include "logging.h"
 #include "xmodem.h"
 
@@ -39,57 +40,6 @@ enum {
 	MSG_BAUD_LOW,
 };
 
-static int my_readline(int fd, struct context *ctx, char **retval)
-{
-	char *newline = memchr(ctx->linebuf, '\r', ctx->linepos);
-	if (newline != NULL) {
-		int len = newline - ctx->linebuf;
-		*newline = '\0';
-		if (len > 0)
-			*retval = strdup(ctx->linebuf);
-
-		ctx->linepos -= len +1;
-		memmove(ctx->linebuf, newline +1, ctx->linepos);
-
-		newline = memchr(ctx->linebuf, '\r', ctx->linepos);
-		return ((*retval != NULL) ? 1 : 0) + ((newline != NULL) ? 1 : 0);
-	}
-
-	char buf[32];
-	int len = read(fd, buf, sizeof(buf));
-	if (len <= 0)
-		return -1;
-
-	int i, numlines = 0;
-	for (i = 0; i < len; i++) {
-		/* "understand" backspace */
-		if (buf[i] == 0x08 && ctx->linepos > 0) {
-			ctx->linepos--;
-
-		/* export buffer */
-		} else if (buf[i] == '\r') {
-			if (*retval == NULL) {
-				ctx->linebuf[ctx->linepos] = '\0';
-
-				if (ctx->linepos > 0)
-					*retval = strdup(ctx->linebuf);
-
-				ctx->linepos = 0;
-				numlines = 1;
-
-			} else {
-				ctx->linebuf[ctx->linepos++] = buf[i];
-				numlines++;
-			}
-
-		/* copy */
-		} else if (buf[i] >= ' ') {
-			ctx->linebuf[ctx->linepos++] = buf[i];
-		}
-	}
-	return numlines;
-}
-
 int statemachine_read(int fd, void *privdata)
 {
 	struct context *ctx = (struct context *)privdata;
@@ -101,15 +51,11 @@ int statemachine_read(int fd, void *privdata)
 		return 0;
 	}
 
-	int numlines;
+	if (linebuffer_read(ctx->lbuf, fd) < 0)
-	do {
+		return -1;
-		char *line = NULL;
-		numlines = my_readline(fd, ctx, &line);
-		if (numlines < 0)
-			return -1;
 
-		if (line == NULL)
+	char *line;
-			return 0;
+	while ((line = linebuffer_get(ctx->lbuf)) != NULL) {
 
 		log_print(LOG_DEBUG, "%s: '%s'", ctx->devname, line);
 
@@ -141,7 +87,7 @@ int statemachine_read(int fd, void *privdata)
 		/* follow device to high baudrate */
 		} else if (msg == MSG_BAUD_HIGH) {
 			ctx->dev_setbaudrate(ctx, B115200);
-			numlines = 0;
+			linebuffer_clear(ctx->lbuf);
 
 			ctx->state = STATE_XMODEM;
 			write(fd, "ATLC\r\n", 6);
@@ -154,11 +100,11 @@ int statemachine_read(int fd, void *privdata)
 		/* follow device to low baudrate */
 		} else if (msg == MSG_BAUD_LOW) {
 			ctx->dev_setbaudrate(ctx, B9600);
-			numlines = 0;
+			linebuffer_clear(ctx->lbuf);
 		}
 
 		free(line);
-	} while (numlines > 1);
+	};
 
 	return 0;
 }