Separate field iterator logic from pb_decode to pb_common.

1 files changed, 31 insertions, 109 deletions

diff --git a/pb_decode.c b/pb_decode.c
index 4e187256..40da1aa4 100644
--- a/pb_decode.c
+++ b/pb_decode.c
@@ -15,36 +15,23 @@
 
 #include "pb.h"
 #include "pb_decode.h"
+#include "pb_common.h"
 
 /**************************************
  * Declarations internal to this file *
  **************************************/
 
-/* Iterator for pb_field_t list */
-typedef struct {
-    const pb_field_t *start; /* Start of the pb_field_t array */
-    const pb_field_t *pos; /* Current position of the iterator */
-    unsigned field_index; /* Zero-based index of the field. */
-    unsigned required_field_index; /* Zero-based index that counts only the required fields */
-    void *dest_struct; /* Pointer to the destination structure to decode to */
-    void *pData; /* Pointer where to store current field value */
-    void *pSize; /* Pointer where to store the size of current array field */
-} pb_field_iterator_t;
-
 typedef bool (*pb_decoder_t)(pb_istream_t *stream, const pb_field_t *field, void *dest) checkreturn;
 
 static bool checkreturn buf_read(pb_istream_t *stream, uint8_t *buf, size_t count);
 static bool checkreturn pb_decode_varint32(pb_istream_t *stream, uint32_t *dest);
 static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire_type, uint8_t *buf, size_t *size);
-static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct);
-static bool pb_field_next(pb_field_iterator_t *iter);
-static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag);
-static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
-static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
-static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
+static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iter_t *iter);
+static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iter_t *iter);
+static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iter_t *iter);
 static bool checkreturn default_extension_decoder(pb_istream_t *stream, pb_extension_t *extension, uint32_t tag, pb_wire_type_t wire_type);
-static bool checkreturn decode_extension(pb_istream_t *stream, uint32_t tag, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
-static bool checkreturn find_extension_field(pb_field_iterator_t *iter);
+static bool checkreturn decode_extension(pb_istream_t *stream, uint32_t tag, pb_wire_type_t wire_type, pb_field_iter_t *iter);
+static bool checkreturn find_extension_field(pb_field_iter_t *iter);
 static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct);
 static bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest);
 static bool checkreturn pb_dec_uvarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
@@ -338,75 +325,11 @@ void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream)
 #endif
 }
 
-static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct)
-{
-    iter->start = iter->pos = fields;
-    iter->field_index = 0;
-    iter->required_field_index = 0;
-    iter->pData = (char*)dest_struct + iter->pos->data_offset;
-    iter->pSize = (char*)iter->pData + iter->pos->size_offset;
-    iter->dest_struct = dest_struct;
-}
-
-static bool pb_field_next(pb_field_iterator_t *iter)
-{
-    bool notwrapped = true;
-    size_t prev_size = iter->pos->data_size;
-    
-    if (PB_ATYPE(iter->pos->type) == PB_ATYPE_STATIC &&
-        PB_HTYPE(iter->pos->type) == PB_HTYPE_REPEATED)
-    {
-        prev_size *= iter->pos->array_size;
-    }
-    else if (PB_ATYPE(iter->pos->type) == PB_ATYPE_POINTER)
-    {
-        prev_size = sizeof(void*);
-    }
-    
-    if (iter->pos->tag == 0)
-        return false; /* Only happens with empty message types */
-    
-    if (PB_HTYPE(iter->pos->type) == PB_HTYPE_REQUIRED)
-        iter->required_field_index++;
-    
-    iter->pos++;
-    iter->field_index++;
-    if (iter->pos->tag == 0)
-    {
-        iter->pos = iter->start;
-        iter->field_index = 0;
-        iter->required_field_index = 0;
-        iter->pData = iter->dest_struct;
-        prev_size = 0;
-        notwrapped = false;
-    }
-    
-    iter->pData = (char*)iter->pData + prev_size + iter->pos->data_offset;
-    iter->pSize = (char*)iter->pData + iter->pos->size_offset;
-    return notwrapped;
-}
-
-static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag)
-{
-    unsigned start = iter->field_index;
-    
-    do {
-        if (iter->pos->tag == tag &&
-            PB_LTYPE(iter->pos->type) != PB_LTYPE_EXTENSION)
-        {
-            return true;
-        }
-        (void)pb_field_next(iter);
-    } while (iter->field_index != start);
-    
-    return false;
-}
-
 /*************************
  * Decode a single field *
  *************************/
 
-static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
+static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iter_t *iter)
 {
     pb_type_t type;
     pb_decoder_t func;
@@ -504,7 +427,7 @@ static bool checkreturn allocate_field(pb_istream_t *stream, void *pData, size_t
 }
 
 /* Clear a newly allocated item in case it contains a pointer, or is a submessage. */
-static void initialize_pointer_field(void *pItem, pb_field_iterator_t *iter)
+static void initialize_pointer_field(void *pItem, pb_field_iter_t *iter)
 {
     if (PB_LTYPE(iter->pos->type) == PB_LTYPE_STRING ||
         PB_LTYPE(iter->pos->type) == PB_LTYPE_BYTES)
@@ -518,7 +441,7 @@ static void initialize_pointer_field(void *pItem, pb_field_iterator_t *iter)
 }
 #endif
 
-static bool checkreturn decode_pointer_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
+static bool checkreturn decode_pointer_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iter_t *iter)
 {
 #ifndef PB_ENABLE_MALLOC
     UNUSED(wire_type);
@@ -614,7 +537,7 @@ static bool checkreturn decode_pointer_field(pb_istream_t *stream, pb_wire_type_
 #endif
 }
 
-static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
+static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iter_t *iter)
 {
     pb_callback_t *pCallback = (pb_callback_t*)iter->pData;
     
@@ -661,7 +584,7 @@ static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type
     }
 }
 
-static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
+static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iter_t *iter)
 {
     switch (PB_ATYPE(iter->pos->type))
     {
@@ -685,16 +608,15 @@ static bool checkreturn default_extension_decoder(pb_istream_t *stream,
     pb_extension_t *extension, uint32_t tag, pb_wire_type_t wire_type)
 {
     const pb_field_t *field = (const pb_field_t*)extension->type->arg;
-    pb_field_iterator_t iter;
+    pb_field_iter_t iter;
     
     if (field->tag != tag)
         return true;
     
-    iter.start = field;
-    iter.pos = field;
-    iter.field_index = 0;
-    iter.required_field_index = 0;
-    iter.dest_struct = extension->dest;
+    /* Fake a field iterator for the extension field.
+     * It is not actually safe to advance this iterator, but decode_field
+     * will not even try to. */
+    pb_field_iter_begin(&iter, field, extension->dest);
     iter.pData = extension->dest;
     iter.pSize = &extension->found;
     
@@ -704,7 +626,7 @@ static bool checkreturn default_extension_decoder(pb_istream_t *stream,
 /* Try to decode an unknown field as an extension field. Tries each extension
  * decoder in turn, until one of them handles the field or loop ends. */
 static bool checkreturn decode_extension(pb_istream_t *stream,
-    uint32_t tag, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
+    uint32_t tag, pb_wire_type_t wire_type, pb_field_iter_t *iter)
 {
     pb_extension_t *extension = *(pb_extension_t* const *)iter->pData;
     size_t pos = stream->bytes_left;
@@ -729,15 +651,15 @@ static bool checkreturn decode_extension(pb_istream_t *stream,
 /* Step through the iterator until an extension field is found or until all
  * entries have been checked. There can be only one extension field per
  * message. Returns false if no extension field is found. */
-static bool checkreturn find_extension_field(pb_field_iterator_t *iter)
+static bool checkreturn find_extension_field(pb_field_iter_t *iter)
 {
-    unsigned start = iter->field_index;
+    const pb_field_t *start = iter->pos;
     
     do {
         if (PB_LTYPE(iter->pos->type) == PB_LTYPE_EXTENSION)
             return true;
-        (void)pb_field_next(iter);
-    } while (iter->field_index != start);
+        (void)pb_field_iter_next(iter);
+    } while (iter->pos != start);
     
     return false;
 }
@@ -745,8 +667,8 @@ static bool checkreturn find_extension_field(pb_field_iterator_t *iter)
 /* Initialize message fields to default values, recursively */
 static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct)
 {
-    pb_field_iterator_t iter;
-    pb_field_init(&iter, fields, dest_struct);
+    pb_field_iter_t iter;
+    pb_field_iter_begin(&iter, fields, dest_struct);
     
     do
     {
@@ -803,7 +725,7 @@ static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_str
         {
             /* Don't overwrite callback */
         }
-    } while (pb_field_next(&iter));
+    } while (pb_field_iter_next(&iter));
 }
 
 /*********************
@@ -814,9 +736,9 @@ bool checkreturn pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[
 {
     uint8_t fields_seen[(PB_MAX_REQUIRED_FIELDS + 7) / 8] = {0, 0, 0, 0, 0, 0, 0, 0};
     uint32_t extension_range_start = 0;
-    pb_field_iterator_t iter;
+    pb_field_iter_t iter;
     
-    pb_field_init(&iter, fields, dest_struct);
+    pb_field_iter_begin(&iter, fields, dest_struct);
     
     while (stream->bytes_left)
     {
@@ -832,7 +754,7 @@ bool checkreturn pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[
                 return false;
         }
         
-        if (!pb_field_find(&iter, tag))
+        if (!pb_field_iter_find(&iter, tag))
         {
             /* No match found, check if it matches an extension. */
             if (tag >= extension_range_start)
@@ -885,7 +807,7 @@ bool checkreturn pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[
         do {
             req_field_count = iter.required_field_index;
             last_type = iter.pos->type;
-        } while (pb_field_next(&iter));
+        } while (pb_field_iter_next(&iter));
         
         /* Fixup if last field was also required. */
         if (PB_HTYPE(last_type) == PB_HTYPE_REQUIRED && iter.pos->tag != 0)
@@ -936,8 +858,8 @@ bool pb_decode_delimited(pb_istream_t *stream, const pb_field_t fields[], void *
 #ifdef PB_ENABLE_MALLOC
 void pb_release(const pb_field_t fields[], void *dest_struct)
 {
-    pb_field_iterator_t iter;
-    pb_field_init(&iter, fields, dest_struct);
+    pb_field_iter_t iter;
+    pb_field_iter_begin(&iter, fields, dest_struct);
     
     do
     {
@@ -985,7 +907,7 @@ void pb_release(const pb_field_t fields[], void *dest_struct)
             pb_free(*(void**)iter.pData);
             *(void**)iter.pData = NULL;
         }
-    } while (pb_field_next(&iter));
+    } while (pb_field_iter_next(&iter));
 }
 #endif