From: Eric S. Raymond <esr@thyrsus.com>
Date: Fri, 26 Sep 2014 21:01:31 +0000 (-0400)
Subject: Set the end pointer when erroring out.
X-Git-Tag: 1.2~1
X-Git-Url: http://thyrsus.com/gitweb/?a=commitdiff_plain;h=cd8f3b96266c5c5cd9ee2484b8db8acceebd9443;p=microjson.git

Set the end pointer when erroring out.
---

diff --git a/mjson.asc b/mjson.asc
index 0479000..0826f22 100644
--- a/mjson.asc
+++ b/mjson.asc
@@ -47,6 +47,9 @@ The two main functions return 0 for success, a nonzero error code for
 failure.  The function +json_error_string()+ maps error codes to
 explanatory messages.
 
+When an error is returned and the end pointer argument
+is non-null, it is filled with the value of the buffer
+pointer at the time the error was thrown. 
 == BUGS ==
 A backslash escape of "\0000" in a string value will drop a NUL in the 
 string that is likely to confuse C code looking at the storage.  In
diff --git a/mjson.c b/mjson.c
index 799fa34..25fd00b 100644
--- a/mjson.c
+++ b/mjson.c
@@ -237,6 +237,8 @@ static int json_internal_read_object(const char *cp,
 	    else {
 		json_debug_trace((1,
 				  "Non-WS when expecting object start.\n"));
+		if (end)
+		    *end = cp;
 		return JSON_ERR_OBSTART;
 	    }
 	    break;
@@ -250,12 +252,17 @@ static int json_internal_read_object(const char *cp,
 		break;
 	    else {
 		json_debug_trace((1, "Non-WS when expecting attribute.\n"));
+		if (end)
+		    *end = cp;
 		return JSON_ERR_ATTRSTART;
 	    }
 	    break;
 	case in_attr:
-	    if (pattr == NULL)
+	    if (pattr == NULL) {
+		if (end)
+		    *end = cp;
 		return JSON_ERR_NULLPTR;
+	    }
 	    if (*cp == '"') {
 		*pattr++ = '\0';
 		json_debug_trace((1, "Collected attribute name %s\n",
@@ -284,6 +291,8 @@ static int json_internal_read_object(const char *cp,
 		pval = valbuf;
 	    } else if (pattr >= attrbuf + JSON_ATTR_MAX - 1) {
 		json_debug_trace((1, "Attribute name too long.\n"));
+		if (end)
+		    *end = cp;
 		return JSON_ERR_ATTRLEN;
 	    } else
 		*pattr++ = *cp;
@@ -295,6 +304,8 @@ static int json_internal_read_object(const char *cp,
 		if (cursor->type != t_array) {
 		    json_debug_trace((1,
 				      "Saw [ when not expecting array.\n"));
+		    if (end)
+			*end = cp;
 		    return JSON_ERR_NOARRAY;
 		}
 		substatus = json_read_array(cp, &cursor->addr.array, &cp);
@@ -304,6 +315,8 @@ static int json_internal_read_object(const char *cp,
 	    } else if (cursor->type == t_array) {
 		json_debug_trace((1,
 				  "Array element was specified, but no [.\n"));
+		if (end)
+		    *end = cp;
 		return JSON_ERR_NOBRAK;
 	    } else if (*cp == '"') {
 		value_quoted = true;
@@ -317,8 +330,11 @@ static int json_internal_read_object(const char *cp,
 	    }
 	    break;
 	case in_val_string:
-	    if (pval == NULL)
+	    if (pval == NULL) {
+		if (end)
+		    *end = cp;
 		return JSON_ERR_NULLPTR;
+	    }
 	    if (*cp == '\\')
 		state = in_escape;
 	    else if (*cp == '"') {
@@ -328,13 +344,18 @@ static int json_internal_read_object(const char *cp,
 	    } else if (pval > valbuf + JSON_VAL_MAX - 1
 		       || pval > valbuf + maxlen) {
 		json_debug_trace((1, "String value too long.\n"));
+		if (end)
+		    *end = cp;
 		return JSON_ERR_STRLONG;	/*  */
 	    } else
 		*pval++ = *cp;
 	    break;
 	case in_escape:
-	    if (pval == NULL)
+	    if (pval == NULL) {
+		if (end)
+		    *end = cp;
 		return JSON_ERR_NULLPTR;
+	    }
 	    switch (*cp) {
 	    case 'b':
 		*pval++ = '\b';
@@ -365,8 +386,11 @@ static int json_internal_read_object(const char *cp,
 	    state = in_val_string;
 	    break;
 	case in_val_token:
-	    if (pval == NULL)
+	    if (pval == NULL) {
+		if (end)
+		    *end = cp;
 		return JSON_ERR_NULLPTR;
+	    }
 	    if (isspace((unsigned char) *cp) || *cp == ',' || *cp == '}') {
 		*pval = '\0';
 		json_debug_trace((1, "Collected token value %s.\n", valbuf));
@@ -375,6 +399,8 @@ static int json_internal_read_object(const char *cp,
 		    --cp;
 	    } else if (pval > valbuf + JSON_VAL_MAX - 1) {
 		json_debug_trace((1, "Token value too long.\n"));
+		if (end)
+		    *end = cp;
 		return JSON_ERR_TOKLONG;
 	    } else
 		*pval++ = *cp;
@@ -414,6 +440,8 @@ static int json_internal_read_object(const char *cp,
 		    && cursor->type != t_ignore && cursor->map == 0)) {
 		json_debug_trace((1,
 				  "Saw quoted value when expecting non-string.\n"));
+		if (end)
+		    *end = cp;
 		return JSON_ERR_QNONSTRING;
 	    }
 	    if (!value_quoted
@@ -421,6 +449,8 @@ static int json_internal_read_object(const char *cp,
 		    || cursor->map != 0)) {
 		json_debug_trace((1,
 				  "Didn't see quoted value when expecting string.\n"));
+		if (end)
+		    *end = cp;
 		return JSON_ERR_NONQSTRING;
 	    }
 	    if (cursor->map != 0) {
@@ -430,6 +460,8 @@ static int json_internal_read_object(const char *cp,
 		    }
 		json_debug_trace((1, "Invalid enumerated value string %s.\n",
 				  valbuf));
+		if (end)
+		    *end = cp;
 		return JSON_ERR_BADENUM;
 	      foundit:
 		(void)snprintf(valbuf, sizeof(valbuf), "%d", mp->value);
@@ -470,8 +502,11 @@ static int json_internal_read_object(const char *cp,
 		    }
 		    break;
 		case t_character:
-		    if (strlen(valbuf) > 1)
+		    if (strlen(valbuf) > 1) {
+			if (end)
+			    *end = cp;
 			return JSON_ERR_STRLONG;
+		    }
 		    else
 			lptr[0] = valbuf[0];
 		    break;
@@ -485,6 +520,8 @@ static int json_internal_read_object(const char *cp,
 			json_debug_trace((1,
 					  "Required attribute value %s not present.\n",
 					  cursor->dflt.check));
+			if (end)
+			    *end = cp;
 			return JSON_ERR_CHECKFAIL;
 		    }
 		    break;
@@ -500,6 +537,8 @@ static int json_internal_read_object(const char *cp,
 		goto good_parse;
 	    } else {
 		json_debug_trace((1, "Garbage while expecting comma or }\n"));
+		if (end)
+		    *end = cp;
 		return JSON_ERR_BADTRAIL;
 	    }
 	    break;