c-json-stdout: fixed broken buffering

Signed-off-by: Toni Uhlig <matzeton@googlemail.com>

1 files changed, 56 insertions, 54 deletions

diff --git a/examples/c-json-stdout/c-json-stdout.c b/examples/c-json-stdout/c-json-stdout.c
index d3a312030..c6594588b 100644
--- a/examples/c-json-stdout/c-json-stdout.c
+++ b/examples/c-json-stdout/c-json-stdout.c
@@ -23,7 +23,7 @@ int main(void)
     uint8_t buf[NETWORK_BUFFER_MAX_SIZE];
     size_t buf_used = 0;
     size_t json_start = 0;
-    unsigned long long int buf_wanted = 0;
+    unsigned long long int json_bytes = 0;
 #ifdef USE_JSON
     jsmn_parser parser;
     jsmntok_t tokens[128];
@@ -60,78 +60,80 @@ int main(void)
         }
 
         buf_used += bytes_read;
-        if (buf_wanted == 0)
+        while (json_bytes == 0 && buf_used >= nDPIsrvd_JSON_BYTES + 1)
         {
+            if (buf[nDPIsrvd_JSON_BYTES] != '{')
+            {
+                fprintf(stderr, "BUG: JSON invalid opening character: '%c'", buf[nDPIsrvd_JSON_BYTES]);
+                exit(1);
+            }
+
             char * json_str_start = NULL;
-            errno = 0;
-            /* the first bytes are the textual representation of the following JSON string */
-            buf_wanted = strtoull((char *)buf, &json_str_start, 10);
+            json_bytes = strtoull((char *)buf, &json_str_start, 10);
+            json_bytes += (uint8_t *)json_str_start - buf;
             json_start = (uint8_t *)json_str_start - buf;
-            buf_wanted += json_start;
 
             if (errno == ERANGE)
             {
-                buf_used = 0;
-                buf_wanted = 0;
-                fprintf(stderr, "Size of JSON exceeds limit\n");
-                continue;
+                fprintf(stderr, "BUG: Size of JSON exceeds limit");
+                exit(1);
             }
             if ((uint8_t *)json_str_start == buf)
             {
-                fprintf(stderr, "Missing size before JSON string: %.*s\n", (int)buf_used, buf);
-                buf_used = 0;
-                buf_wanted = 0;
-                continue;
+                fprintf(stderr, "BUG: Missing size before JSON string: \"%.*s\"", nDPIsrvd_JSON_BYTES, buf);
+                exit(1);
             }
-            if (buf_wanted > sizeof(buf))
+            if (json_bytes > sizeof(buf))
             {
-                fprintf(stderr, "BUG: JSON string too big: %llu > %zu\n", buf_wanted, sizeof(buf));
-                buf_used = 0;
-                buf_wanted = 0;
-                continue;
+                fprintf(stderr, "BUG: JSON string too big: %llu > %zu", json_bytes, sizeof(buf));
+                exit(1);
+            }
+            if (json_bytes > buf_used)
+            {
+                break;
             }
-        }
 
-        /* buffered enough data (full JSON String) ? */
-        if (buf_wanted > buf_used)
-        {
-            continue;
-        }
-        /* after buffering complete, last character should always be a '}' (end of object) */
-        if (buf[buf_wanted - 1] != '}')
-        {
-            fprintf(stderr, "Invalid JSON string: %.*s\n", (int)buf_wanted, buf);
-            buf_used = 0;
-            buf_wanted = 0;
-            continue;
-        }
+            if (buf[json_bytes - 1] != '}')
+            {
+                fprintf(stderr, "BUG: Invalid JSON string: %.*s", (int)json_bytes, buf);
+                exit(1);
+            }
 
 #ifdef USE_JSON
-        int r;
-        jsmn_init(&parser);
-        r = jsmn_parse(&parser, (char *)(buf + json_start), buf_wanted - json_start,
-                       tokens, sizeof(tokens) / sizeof(tokens[0]));
-        if (r < 0 || tokens[0].type != JSMN_OBJECT) {
-            fprintf(stderr, "JSON parsing failed with return value %d at position %u\n", r, parser.pos);
-            fprintf(stderr, "JSON string: '%.*s'\n", (int)(buf_wanted - json_start), (char *)(buf + json_start));
-        }
+            int r;
+            jsmn_init(&parser);
+            r = jsmn_parse(&parser,
+                           (char *)(buf + json_start),
+                           json_bytes - json_start,
+                           tokens,
+                           sizeof(tokens) / sizeof(tokens[0]));
+            if (r < 0 || tokens[0].type != JSMN_OBJECT)
+            {
+                fprintf(stderr, "JSON parsing failed with return value %d at position %u\n", r, parser.pos);
+                fprintf(stderr, "JSON string: '%.*s'\n", (int)(json_bytes - json_start), (char *)(buf + json_start));
+            }
 
-        for (int i = 1; i < r; i++) {
-            if (i % 2 ==  1) {
-                printf("[%.*s : ", tokens[i].end - tokens[i].start,
-                       (char *)(buf + json_start) + tokens[i].start);
-            } else {
-                printf("%.*s] ", tokens[i].end - tokens[i].start,
-                       (char *)(buf + json_start) + tokens[i].start);
+            for (int i = 1; i < r; i++)
+            {
+                if (i % 2 == 1)
+                {
+                    printf("[%.*s : ", tokens[i].end - tokens[i].start, (char *)(buf + json_start) + tokens[i].start);
+                }
+                else
+                {
+                    printf("%.*s] ", tokens[i].end - tokens[i].start, (char *)(buf + json_start) + tokens[i].start);
+                }
             }
-        }
-        printf("EoF\n");
+            printf("EoF\n");
 #else
-        printf("RECV[%llu,%zd]: '%.*s'\n\n", buf_wanted, bytes_read, (int)buf_wanted, buf);
+            printf("RECV[%llu,%zd]: '%.*s'\n\n", buf_wanted, bytes_read, (int)buf_wanted, buf);
 #endif
-        memmove(buf, buf + buf_wanted, buf_used - buf_wanted);
-        buf_used -= buf_wanted;
-        buf_wanted = 0;
+
+            memmove(buf, buf + json_bytes, buf_used - json_bytes);
+            buf_used -= json_bytes;
+            json_bytes = 0;
+            json_start = 0;
+        }
     }
 
     return 0;