ifupdown: save some 100+ bytes of code in addstr()

git-svn-id: svn://busybox.net/trunk/busybox@16646 69ca8d6d-28ef-0310-b511-8ec308f3f277

1 files changed, 35 insertions, 45 deletions

diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index f72e653b3..d4e49c4c1 100644
--- a/networking/ifupdown.c
+++ b/networking/ifupdown.c
@@ -125,6 +125,7 @@ static int count_netmask_bits(char *dotted_quad)
         /* Found a netmask...  Check if it is dotted quad */
         if (sscanf(dotted_quad, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
                 return -1;
+        // FIXME: will be confused by e.g. 255.0.255.0
         result = count_bits(a);
         result += count_bits(b);
         result += count_bits(c);
@@ -133,32 +134,27 @@ static int count_netmask_bits(char *dotted_quad)
 }
 #endif
 
-static void addstr(char **buf, size_t *len, size_t *pos, const char *str, size_t str_length)
+static void addstr(char **bufp, const char *str, size_t str_length)
 {
-        if (*pos + str_length >= *len) {
-                char *newbuf;
-
-                newbuf = xrealloc(*buf, *len * 2 + str_length + 1);
-                *buf = newbuf;
-                *len = *len * 2 + str_length + 1;
-        }
-
-        while (str_length-- >= 1) {
-                (*buf)[(*pos)++] = *str;
-                str++;
-        }
-        (*buf)[*pos] = '\0';
+        /* xasprintf trick will be smaller, but we are often
+         * called with str_length == 1 - don't want to have
+         * THAT much of malloc/freeing! */
+        char *buf = *bufp;
+        int len = (buf ? strlen(buf) : 0);
+        str_length++;
+        buf = xrealloc(buf, len + str_length);
+        /* copies at most str_length-1 chars! */
+        safe_strncpy(buf + len, str, str_length);
+        *bufp = buf;
 }
 
 static int strncmpz(const char *l, const char *r, size_t llen)
 {
         int i = strncmp(l, r, llen);
 
-        if (i == 0) {
+        if (i == 0)
                 return -r[llen];
-        } else {
-                return i;
-        }
+        return i;
 }
 
 static char *get_var(const char *id, size_t idlen, struct interface_defn_t *ifd)
@@ -168,31 +164,27 @@ static char *get_var(const char *id, size_t idlen, struct interface_defn_t *ifd)
         if (strncmpz(id, "iface", idlen) == 0) {
                 char *result;
                 static char label_buf[20];
-                strncpy(label_buf, ifd->iface, 19);
-                label_buf[19]=0;
+                safe_strncpy(label_buf, ifd->iface, sizeof(label_buf));
                 result = strchr(label_buf, ':');
                 if (result) {
-                        *result=0;
+                        *result = '\0';
                 }
                 return label_buf;
-        } else if (strncmpz(id, "label", idlen) == 0) {
+        }
+        if (strncmpz(id, "label", idlen) == 0) {
                 return ifd->iface;
-        } else {
-                for (i = 0; i < ifd->n_options; i++) {
-                        if (strncmpz(id, ifd->option[i].name, idlen) == 0) {
-                                return ifd->option[i].value;
-                        }
+        }
+        for (i = 0; i < ifd->n_options; i++) {
+                if (strncmpz(id, ifd->option[i].name, idlen) == 0) {
+                        return ifd->option[i].value;
                 }
         }
-
         return NULL;
 }
 
 static char *parse(const char *command, struct interface_defn_t *ifd)
 {
-
         char *result = NULL;
-        size_t pos = 0, len = 0;
         size_t old_pos[MAX_OPT_DEPTH] = { 0 };
         int okay[MAX_OPT_DEPTH] = { 1 };
         int opt_depth = 1;
@@ -200,26 +192,26 @@ static char *parse(const char *command, struct interface_defn_t *ifd)
         while (*command) {
                 switch (*command) {
                 default:
-                        addstr(&result, &len, &pos, command, 1);
+                        addstr(&result, command, 1);
                         command++;
                         break;
                 case '\\':
                         if (command[1]) {
-                                addstr(&result, &len, &pos, command + 1, 1);
+                                addstr(&result, command + 1, 1);
                                 command += 2;
                         } else {
-                                addstr(&result, &len, &pos, command, 1);
+                                addstr(&result, command, 1);
                                 command++;
                         }
                         break;
                 case '[':
                         if (command[1] == '[' && opt_depth < MAX_OPT_DEPTH) {
-                                old_pos[opt_depth] = pos;
+                                old_pos[opt_depth] = strlen(result);
                                 okay[opt_depth] = 1;
                                 opt_depth++;
                                 command += 2;
                         } else {
-                                addstr(&result, &len, &pos, "[", 1);
+                                addstr(&result, "[", 1);
                                 command++;
                         }
                         break;
@@ -227,12 +219,11 @@ static char *parse(const char *command, struct interface_defn_t *ifd)
                         if (command[1] == ']' && opt_depth > 1) {
                                 opt_depth--;
                                 if (!okay[opt_depth]) {
-                                        pos = old_pos[opt_depth];
-                                        result[pos] = '\0';
+                                        result[old_pos[opt_depth]] = '\0';
                                 }
                                 command += 2;
                         } else {
-                                addstr(&result, &len, &pos, "]", 1);
+                                addstr(&result, "]", 1);
                                 command++;
                         }
                         break;
@@ -252,18 +243,17 @@ static char *parse(const char *command, struct interface_defn_t *ifd)
                                 varvalue = get_var(command, nextpercent - command, ifd);
 
                                 if (varvalue) {
-                                        addstr(&result, &len, &pos, varvalue, strlen(varvalue));
+                                        addstr(&result, varvalue, strlen(varvalue));
                                 } else {
 #ifdef CONFIG_FEATURE_IFUPDOWN_IP
                                         /* Sigh...  Add a special case for 'ip' to convert from
                                          * dotted quad to bit count style netmasks.  */
                                         if (strncmp(command, "bnmask", 6)==0) {
-                                                int res;
+                                                unsigned res;
                                                 varvalue = get_var("netmask", 7, ifd);
-                                                if (varvalue && (res=count_netmask_bits(varvalue)) > 0) {
-                                                        char argument[255];
-                                                        sprintf(argument, "%d", res);
-                                                        addstr(&result, &len, &pos, argument, strlen(argument));
+                                                if (varvalue && (res = count_netmask_bits(varvalue)) > 0) {
+                                                        const char *argument = utoa(res);
+                                                        addstr(&result, argument, strlen(argument));
                                                         command = nextpercent + 1;
                                                         break;
                                                 }
@@ -567,7 +557,7 @@ static char *next_word(char **buf)
         unsigned short length;
         char *word;
 
-        if ((buf == NULL) || (*buf == NULL) || (**buf == '\0')) {
+        if (!buf || !*buf || !**buf) {
                 return NULL;
         }