diff options
Diffstat (limited to 'core/upb_def.c')
-rw-r--r-- | core/upb_def.c | 65 |
1 files changed, 63 insertions, 2 deletions
diff --git a/core/upb_def.c b/core/upb_def.c index e117455..1c8fbdc 100644 --- a/core/upb_def.c +++ b/core/upb_def.c @@ -12,6 +12,16 @@ #define CHECKSRC(x) if(!(x)) goto src_err #define CHECK(x) if(!(x)) goto err +/* Rounds p up to the next multiple of t. */ +static size_t upb_align_up(size_t val, size_t align) { + return val % align == 0 ? val : val + align - (val % align); +} + +static int upb_div_round_up(int numerator, int denominator) { + /* cf. http://stackoverflow.com/questions/17944/how-to-round-up-the-result-of-integer-division */ + return numerator > 0 ? (numerator - 1) / denominator + 1 : 0; +} + // A little dynamic array for storing a growing list of upb_defs. typedef struct { upb_def **defs; @@ -409,6 +419,19 @@ src_err: /* upb_msgdef *****************************************************************/ +static int upb_compare_typed_fields(upb_fielddef *f1, upb_fielddef *f2) { + // Sort by data size (ascending) to reduce padding. + size_t size1 = upb_types[f1->type].size; + size_t size2 = upb_types[f2->type].size; + if (size1 != size2) return size1 - size2; + // Otherwise return in number order (just so we get a reproduceable order. + return f1->number - f2->number; +} + +static int upb_compare_fields(const void *f1, const void *f2) { + return upb_compare_typed_fields(*(void**)f1, *(void**)f2); +} + // Processes a google.protobuf.DescriptorProto, adding defs to "defs." static bool upb_addmsg(upb_src *src, upb_deflist *defs, upb_status *status) { @@ -418,7 +441,6 @@ static bool upb_addmsg(upb_src *src, upb_deflist *defs, upb_status *status) upb_inttable_init(&m->itof, 4, sizeof(upb_itof_ent)); upb_strtable_init(&m->ntof, 4, sizeof(upb_ntof_ent)); int32_t start_count = defs->len; - upb_fielddef *f; while((f = upb_src_getdef(src)) != NULL) { switch(f->number) { @@ -451,6 +473,45 @@ static bool upb_addmsg(upb_src *src, upb_deflist *defs, upb_status *status) upb_seterr(status, UPB_STATUS_ERROR, "Encountered message with no name."); goto err; } + + + // Create an ordering over the fields. + upb_field_count_t n = upb_msgdef_numfields(m); + upb_fielddef **sorted_fields = malloc(sizeof(upb_fielddef*) * n); + upb_field_count_t field = 0; + upb_msg_iter i; + for (i = upb_msg_begin(m); !upb_msg_done(i); i = upb_msg_next(m, i)) { + sorted_fields[field++]= upb_msg_iter_field(i); + } + qsort(sorted_fields, n, sizeof(*sorted_fields), upb_compare_fields); + + // Assign offsets in the msg. + m->set_flags_bytes = upb_div_round_up(n, 8); + m->size = sizeof(upb_atomic_refcount_t) + m->set_flags_bytes; + + size_t max_align = 0; + for (int i = 0; i < n; i++) { + upb_fielddef *f = sorted_fields[i]; + upb_type_info *type_info = &upb_types[f->type]; + + // This identifies the set bit. When we implement is_initialized (a + // general check about whether all required bits are set) we will probably + // want to use a different ordering that puts all the required bits + // together. + f->field_index = i; + + // General alignment rules are: each member must be at an address that is a + // multiple of that type's alignment. Also, the size of the structure as a + // whole must be a multiple of the greatest alignment of any member. + size_t offset = upb_align_up(m->size, type_info->align); + // Offsets are relative to the end of the refcount. + f->byte_offset = offset - sizeof(upb_atomic_refcount_t); + m->size = offset + type_info->size; + max_align = UPB_MAX(max_align, type_info->align); + } + + if (max_align > 0) m->size = upb_align_up(m->size, max_align); + upb_deflist_qualify(defs, m->base.fqname, start_count); upb_deflist_push(defs, UPB_UPCAST(m)); return true; @@ -664,7 +725,7 @@ bool upb_resolverefs(upb_strtable *tmptab, upb_strtable *symtab, } // Check the type of the found def. - upb_field_type_t expected = upb_issubmsg(f) ? UPB_DEF_MSG : UPB_DEF_ENUM; + upb_fieldtype_t expected = upb_issubmsg(f) ? UPB_DEF_MSG : UPB_DEF_ENUM; if(found->def->type != expected) { upb_seterr(status, UPB_STATUS_ERROR, "Unexpected type"); return false; |