process_macros: reduce heap usage and fragmentation

2 files changed, 103 insertions, 109 deletions

diff --git a/avr/cli.c b/avr/cli.c
index 08e7038..b310f79 100644
--- a/avr/cli.c
+++ b/avr/cli.c
@@ -43,114 +43,107 @@ static int cli_parse_line(char *line, char *argv[])
 	return nargs;
 }
 
-static void process_macros(const char *input, char *output)
+static
+void append_char(uint_fast8_t pass, char **p, char c)
 {
-	char c, prev;
-	const char *varname_start = NULL;
-#if 0 && (CONFIG_SYS_CBSIZE < __UINT_FAST8_MAX__)
-	uint_fast8_t inputcnt = strlen(input);
-	uint_fast8_t outputcnt = CONFIG_SYS_CBSIZE;
-#else
-	int inputcnt = strlen(input);
-	int outputcnt = CONFIG_SYS_CBSIZE;
-#endif
-	uint_fast8_t state = 0;		/* 0 = waiting for '$'  */
-
-	/* 1 = waiting for '{' */
-	/* 2 = waiting for '}' */
-	/* 3 = waiting for '''  */
-	char *output_start = output;
-
-	debug_parser("[PROCESS_MACROS] INPUT len %d: \"%s\"\n", strlen(input),
-		     input);
-
-	prev = '\0';		/* previous character   */
-
-	while (inputcnt && outputcnt) {
-		c = *input++;
-		inputcnt--;
-
-		if (state != 3) {
-			/* remove one level of escape characters */
-			if ((c == '\\') && (prev != '\\')) {
-				if (inputcnt-- == 0)
-					break;
-				prev = c;
-				c = *input++;
-			}
+
+	if (pass) {
+		**p = c;
+	}
+	++(*p);
+}
+
+static
+char *process_macros(char *input, char *output)
+{
+	char c, prev, *inp, *outp;
+	const char *varname = NULL;
+
+	for(uint_fast8_t pass = 0; pass < 2; pass++)
+	{
+		uint_fast8_t state = 0;		/* 0 = waiting for '$'  */
+		/* 1 = waiting for '{' */
+		/* 2 = waiting for '}' */
+		/* 3 = waiting for ''' */
+
+		if (pass == 0) {
+			outp = output;
+		} else {
+			int outputlen = outp - output;
+			outp = xrealloc(output, outputlen);
+			output = outp;
 		}
 
-		switch (state) {
-		case 0:	/* Waiting for (unescaped) $    */
-			if ((c == '\'') && (prev != '\\')) {
-				state = 3;
-				break;
-			}
-			if ((c == '$') && (prev != '\\')) {
-				state++;
-			} else {
-				*(output++) = c;
-				outputcnt--;
-			}
-			break;
-		case 1:	/* Waiting for (        */
-			if (c == '{') {
-				state++;
-				varname_start = input;
-			} else {
-				state = 0;
-				*(output++) = '$';
-				outputcnt--;
-
-				if (outputcnt) {
-					*(output++) = c;
-					outputcnt--;
+		inp = input;
+		prev = '\0';		/* previous character   */
+
+		debug_parser("[PROCESS_MACROS] INPUT len %d: \"%s\"\n", strlen(inp),
+			     inp);
+
+		while ((c = *inp++) != '\0') {
+
+			if (state != 3) {
+				/* remove one level of escape characters */
+				if ((c == '\\') && (prev != '\\')) {
+					if (*inp == '\0')
+						break;
+					prev = c;
+					c = *inp++;
 				}
 			}
-			break;
-		case 2:	/* Waiting for )        */
-			if (c == '}') {
-				char envname[CONFIG_SYS_ENV_NAMELEN+1], *envval;
-				/* Varname # of chars */
-				uint_fast8_t envcnt = input - varname_start - 1;
-				if (envcnt > CONFIG_SYS_ENV_NAMELEN)
-					envcnt = CONFIG_SYS_ENV_NAMELEN;
-
-				memcpy(envname, varname_start, envcnt);
-				envname[envcnt] = '\0';
-
-				/* Get its value */
-				envval = getenv(envname);
-
-				/* Copy into the line if it exists */
-				if (envval != NULL)
-					while ((*envval) && outputcnt) {
-						*(output++) = *(envval++);
-						outputcnt--;
-					}
-				/* Look for another '$' */
-				state = 0;
-			}
-			break;
-		case 3:	/* Waiting for '        */
-			if ((c == '\'') && (prev != '\\')) {
-				state = 0;
-			} else {
-				*(output++) = c;
-				outputcnt--;
+
+			switch (state) {
+			case 0:	/* Waiting for (unescaped) $    */
+				if ((c == '\'') && (prev != '\\')) {
+					state = 3;
+					break;
+				}
+				if ((c == '$') && (prev != '\\'))
+					state++;
+				else
+					append_char(pass, &outp, c);
+				break;
+			case 1:	/* Waiting for {        */
+				if (c == '{') {
+					state++;
+					varname = inp;
+				} else {
+					state = 0;
+					append_char(pass, &outp, '$');
+					append_char(pass, &outp, c);
+				}
+				break;
+			case 2:	/* Waiting for }        */
+				if (c == '}') {
+					/* Terminate variable name */
+					*(inp-1) = '\0';
+					const char *envval = getenv(varname);
+					*(inp-1) = '}';
+					/* Copy into the line if it exists */
+					if (envval != NULL)
+						while (*envval)
+							append_char(pass, &outp, *(envval++));
+					/* Look for another '$' */
+					state = 0;
+				}
+				break;
+			case 3:	/* Waiting for '        */
+				if ((c == '\'') && (prev != '\\'))
+					state = 0;
+				else
+					append_char(pass, &outp, c);
+				break;
 			}
-			break;
+			prev = c;
 		}
-		prev = c;
-	}
 
-	if (outputcnt)
-		*output = 0;
-	else
-		*(output - 1) = 0;
+		append_char(pass, &outp, 0);
+	}
 
 	debug_parser("[PROCESS_MACROS] OUTPUT len %d: \"%s\"\n",
-		     strlen(output_start), output_start);
+		     strlen(output), output);
+
+	return output;
 }
 
 /**
@@ -174,7 +167,7 @@ static int cli_run_command(const char *cmd, int flag)
 	char *cmdbuf;			/* working copy of cmd		*/
 	char *token;			/* start of token in cmdbuf	*/
 	char *sep;			/* end of token (separator) in cmdbuf */
-	char *finaltoken;
+	char *finaltoken = NULL;	/* token after macro expansion	*/
 	char *str;
 	char *argv[CONFIG_SYS_MAXARGS + 1];	/* NULL terminated	*/
 	int argc;
@@ -190,8 +183,7 @@ static int cli_run_command(const char *cmd, int flag)
 		return -1;	/* empty command */
 
 	cmdbuf = strdup(cmd);
-	finaltoken = xmalloc(CONFIG_SYS_CBSIZE);
-	if (!finaltoken)
+	if (!cmdbuf)
 		return -1;	/* not enough memory */
 
 	str = cmdbuf;
@@ -231,7 +223,7 @@ static int cli_run_command(const char *cmd, int flag)
 		debug_parser("token: \"%s\"\n", token);
 
 		/* find macros in this token and replace them */
-		process_macros(token, finaltoken);
+		finaltoken = process_macros(token, finaltoken);
 
 		/* Extract arguments */
 		argc = cli_parse_line(finaltoken, argv);
diff --git a/avr/debug.c b/avr/debug.c
index 16df702..47b11b0 100644
--- a/avr/debug.c
+++ b/avr/debug.c
@@ -23,7 +23,7 @@ static uint8_t ram_read_byte(const uint8_t *p)
 	return *p;
 }
 
-void dump_mem(const uint8_t *startaddr, int len, 
+void dump_mem(const uint8_t *startaddr, int len,
 		uint8_t (*readfkt)(const uint8_t *), char *title)
 {
 	uint8_t buf[16];
@@ -33,12 +33,12 @@ void dump_mem(const uint8_t *startaddr, int len,
 	const uint8_t *addr = (uint8_t *) ((size_t) startaddr & ~0x0f);
 	len += pre;
 	uint8_t i;
-	
+
 	if (title && *title) {
 		printf_P(PSTR("%s\n"),title);
 		indent = "    ";
 	}
-		
+
 	while (len) {
 		if (len < 16)
 			llen = len;
@@ -100,7 +100,7 @@ command_ret_t do_dump_mem(cmd_tbl_t *cmdtp, int flag, int argc, char * const arg
 //	static const uint8_t *addr;
 //	static uint16_t length = 128;
 	uint8_t (*readhow)(const uint8_t *);
-		
+
 	(void) cmdtp; (void) flag;
 
 	if (argc < 2)
@@ -108,7 +108,7 @@ command_ret_t do_dump_mem(cmd_tbl_t *cmdtp, int flag, int argc, char * const arg
 
 	const uint8_t *addr;
 	uint16_t length = 128;
-	
+
 	if (strchr(argv[0],'r') != NULL)
 		readhow = ram_read_byte;
 	else if (strchr(argv[0],'e') != NULL)
@@ -182,7 +182,7 @@ command_ret_t do_eep_cp(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[
 /*------------------------------------------------------------------------------*/
 
 
-#if 0
+#if 1
 
 struct __freelist {
 	size_t sz;
@@ -201,6 +201,8 @@ printfreelist(const char * title)
 	int i;
 	unsigned int freesum = 0;
 
+/* TODO: printf_P */
+
 	if (!__flp) {
 		printf("%s no free list\n", title ? title : "");
 	} else {
@@ -215,7 +217,7 @@ printfreelist(const char * title)
 			freesum += fp1->sz;
 		}
 	}
-	
+
 	freesum +=  (size_t) STACK_POINTER() - __malloc_margin - (size_t) __brkval;
 
 	printf("SP: %04x, __brkval: %04x, Total free: %04u\n",