hash http method and version and add tokens for fast parsing

1 files changed, 196 insertions, 2 deletions

diff --git a/fhp.c b/fhp.c
index 416d054..be4b7f3 100644
--- a/fhp.c
+++ b/fhp.c
@@ -170,6 +170,58 @@
   case ' ': \
   case '\t':
 
+//
+// hash functions (djb2)
+// (see http://aras-p.info/blog/2016/08/02/Hash-Functions-all-the-way-down/)
+//
+
+uint32_t
+fhp_hash_init(void) {
+  return 5381;
+}
+
+uint32_t
+fhp_hash_push(uint32_t hash, uint8_t * const buf, size_t len) {
+  for (size_t i = 0; i < len; i++)
+    hash = ((hash << 5) + hash) + buf[len];
+
+  return hash;
+}
+
+uint32_t
+fhp_hash_string(char * const str) {
+  uint32_t r = fhp_hash_init();
+  return fhp_hash_push(r, (uint8_t*) str, strlen(str));
+}
+
+uint32_t
+fhp_lc_hash_push(
+  uint32_t hash,
+  uint8_t * const buf,
+  size_t len
+) {
+  for (size_t i = 0; i < len; i++) {
+    uint8_t c = buf[len];
+
+    if (c >= 'A' && c <= 'Z')
+      c = (c - 'A') + 'a';
+
+    hash = ((hash << 5) + hash) + c;
+  }
+
+  return hash;
+}
+
+uint32_t
+fhp_lc_hash_string(char * const str) {
+  uint32_t r = fhp_hash_init();
+  return fhp_lc_hash_push(r, (uint8_t*) str, strlen(str));
+}
+
+//
+// error functions
+//
+
 static const char *
 fhp_errors[] = {
   "OK",
@@ -208,12 +260,24 @@ fhp_strerror(
   return FHP_OK;
 }
 
+//
+// token functions
+//
+
 static const char *
 fhp_tokens[] = {
   "METHOD_START",
   "METHOD_FRAGMENT",
   "METHOD_END",
 
+  "METHOD_GET",
+  "METHOD_POST",
+  "METHOD_HEAD",
+  "METHOD_PUT",
+  "METHOD_DELETE",
+  "METHOD_OPTIONS",
+  "METHOD_OTHER",
+
   "URL_START",
   "URL_FRAGMENT",
   "URL_END",
@@ -222,6 +286,10 @@ fhp_tokens[] = {
   "VERSION_FRAGMENT",
   "VERSION_END",
 
+  "VERSION_HTTP_10",
+  "VERSION_HTTP_11",
+  "VERSION_OTHER",
+
   "HEADER_NAME_START",
   "HEADER_NAME_FRAGMENT",
   "HEADER_NAME_END",
@@ -255,22 +323,92 @@ fhp_strtoken(
   return FHP_OK;
 }
 
-static fhp_t DEFAULT_CONTEXT = {
+//
+// string functions
+//
+
+static char * const
+fhp_strings[] = {
+  "GET",
+  "POST",
+  "HEAD",
+  "PUT",
+  "DELETE",
+  "OPTIONS",
+  "HTTP/1.0",
+  "HTTP/1.1",
+  "content-length",
+  "transfer-encoding",
+  "gzip",
+  "x-gzip",
+  "deflate",
+  "x-deflate",
+  "chunked",
+  NULL
+};
+
+typedef enum {
+  FHP_STR_GET,
+  FHP_STR_POST,
+  FHP_STR_HEAD,
+  FHP_STR_PUT,
+  FHP_STR_DELETE,
+  FHP_STR_OPTIONS,
+  FHP_STR_HTTP_10,
+  FHP_STR_HTTP_11,
+  FHP_STR_CONTENT_LENGTH,
+  FHP_STR_TRANSFER_ENCODING,
+  FHP_STR_GZIP,
+  FHP_STR_X_GZIP,
+  FHP_STR_DEFLATE,
+  FHP_STR_X_DEFLATE,
+  FHP_STR_CHUNKED,
+  FHP_STR_LAST
+} fhp_str_t;
+
+void
+fhp_env_init(fhp_env_t * const env) {
+  for (size_t i = 0; i < FHP_STR_LAST; i++)
+    env->hashes[i] = fhp_lc_hash_string(fhp_strings[i]);
+}
+
+static fhp_env_t fhp_default_env;
+
+fhp_env_t *
+fhp_get_default_env(void) {
+  static fhp_env_t *r = NULL;
+
+  if (!r) {
+    r = &fhp_default_env;
+    fhp_env_init(r);
+  }
+
+  return r;
+}
+
+//
+// context functions
+//
+
+static const fhp_t DEFAULT_CONTEXT = {
   .state = FHP_STATE_INIT,
   .user_data = NULL,
   .cb = NULL,
   .err = FHP_OK,
   .ofs = 0,
   .buf_len = 0,
+  .is_hashing = false,
 };
 
 fhp_err_t
 fhp_init(
   fhp_t * const fhp,
+  fhp_env_t * const env,
   fhp_cb_t cb,
   void * const user_data
 ) {
   *fhp = DEFAULT_CONTEXT;
+  fhp->env = env ? env : fhp_get_default_env();
   fhp->user_data = user_data;
   fhp->cb = cb;
 
@@ -294,6 +432,10 @@ fhp_buf_flush(
     if (!fhp->cb(fhp, token, fhp->buf, fhp->buf_len))
       return false;
 
+    // update buffer hash
+    if (fhp->is_hashing)
+      fhp->buf_hash = fhp_hash_push(fhp->buf_hash, fhp->buf, fhp->buf_len);
+
     // clear buffer
     fhp_buf_clear(fhp);
   }
@@ -336,6 +478,10 @@ retry:
       if (!fhp->cb(fhp, FHP_TOKEN_METHOD_START, 0, 0))
         return FHP_ERR_CB;
 
+      // enable buffer hashing
+      fhp->is_hashing = true;
+      fhp->buf_hash = fhp_hash_init();
+
       // set state
       fhp->state = FHP_STATE_METHOD;
       goto retry;
@@ -359,10 +505,33 @@ retry:
       if (!fhp_buf_flush(fhp, FHP_TOKEN_METHOD_FRAGMENT))
         return FHP_ERR_CB;
 
+      // disable buffer hashing
+      fhp->is_hashing = false;
+
       // send end token
       if (!fhp->cb(fhp, FHP_TOKEN_METHOD_END, 0, 0))
         return FHP_ERR_CB;
 
+      // get method token
+      fhp->http_method = FHP_TOKEN_METHOD_OTHER;
+      if (fhp->buf_hash == fhp->env->hashes[FHP_STR_GET]) {
+        fhp->http_method = FHP_TOKEN_METHOD_GET;
+      } else if (fhp->buf_hash == fhp->env->hashes[FHP_STR_POST]) {
+        fhp->http_method = FHP_TOKEN_METHOD_POST;
+      } else if (fhp->buf_hash == fhp->env->hashes[FHP_STR_HEAD]) {
+        fhp->http_method = FHP_TOKEN_METHOD_HEAD;
+      } else if (fhp->buf_hash == fhp->env->hashes[FHP_STR_PUT]) {
+        fhp->http_method = FHP_TOKEN_METHOD_PUT;
+      } else if (fhp->buf_hash == fhp->env->hashes[FHP_STR_DELETE]) {
+        fhp->http_method = FHP_TOKEN_METHOD_DELETE;
+      } else if (fhp->buf_hash == fhp->env->hashes[FHP_STR_OPTIONS]) {
+        fhp->http_method = FHP_TOKEN_METHOD_OPTIONS;
+      }
+
+      // send method token
+      if (!fhp->cb(fhp, fhp->http_method, 0, 0))
+        return FHP_ERR_CB;
+
       // set state
       fhp->state = FHP_STATE_METHOD_END;
       goto retry;
@@ -464,6 +633,11 @@ retry:
       if (!fhp->cb(fhp, FHP_TOKEN_VERSION_START, 0, 0))
         return FHP_ERR_CB;
 
+      // enable buffer hashing
+      fhp->is_hashing = true;
+      fhp->buf_hash = fhp_hash_init();
+
+      // set state
       fhp->state = FHP_STATE_VERSION;
       goto retry;
     }
@@ -481,6 +655,21 @@ retry:
       if (!fhp->cb(fhp, FHP_TOKEN_VERSION_END, 0, 0))
         return FHP_ERR_CB;
 
+      // disable buffer hashing
+      fhp->is_hashing = false;
+
+      // get version token
+      fhp->http_version = FHP_TOKEN_VERSION_OTHER;
+      if (fhp->buf_hash == fhp->env->hashes[FHP_STR_HTTP_10]) {
+        fhp->http_version = FHP_TOKEN_VERSION_HTTP_10;
+      } else if (fhp->buf_hash == fhp->env->hashes[FHP_STR_HTTP_11]) {
+        fhp->http_version = FHP_TOKEN_VERSION_HTTP_11;
+      }
+
+      // send version token
+      if (!fhp->cb(fhp, fhp->http_version, 0, 0))
+        return FHP_ERR_CB;
+
       // set state
       fhp->state = FHP_STATE_VERSION_END;
       goto retry;
@@ -761,7 +950,12 @@ fhp_push(
   return FHP_OK;
 }
 
+fhp_env_t *
+fhp_get_env(fhp_t * const fhp) {
+  return fhp->env;
+}
+
 void *
-fhp_user_data(fhp_t * const fhp) {
+fhp_get_user_data(fhp_t * const fhp) {
   return fhp->user_data;
 }