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protobuf/upb/decode.c

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#include <setjmp.h>
#include <string.h>
#include "upb/decode.h"
#include "upb/upb.h"
#include "upb/port_def.inc"
/* Maps descriptor type -> upb field type. */
static const uint8_t desctype_to_fieldtype[] = {
-1, /* invalid descriptor type */
UPB_TYPE_DOUBLE, /* DOUBLE */
UPB_TYPE_FLOAT, /* FLOAT */
UPB_TYPE_INT64, /* INT64 */
UPB_TYPE_UINT64, /* UINT64 */
UPB_TYPE_INT32, /* INT32 */
UPB_TYPE_UINT64, /* FIXED64 */
UPB_TYPE_UINT32, /* FIXED32 */
UPB_TYPE_BOOL, /* BOOL */
UPB_TYPE_STRING, /* STRING */
UPB_TYPE_MESSAGE, /* GROUP */
UPB_TYPE_MESSAGE, /* MESSAGE */
UPB_TYPE_BYTES, /* BYTES */
UPB_TYPE_UINT32, /* UINT32 */
UPB_TYPE_ENUM, /* ENUM */
UPB_TYPE_INT32, /* SFIXED32 */
UPB_TYPE_INT64, /* SFIXED64 */
UPB_TYPE_INT32, /* SINT32 */
UPB_TYPE_INT64, /* SINT64 */
};
/* Maps descriptor type -> upb map size. */
static const uint8_t desctype_to_mapsize[] = {
-1, /* invalid descriptor type */
8, /* DOUBLE */
4, /* FLOAT */
8, /* INT64 */
8, /* UINT64 */
4, /* INT32 */
8, /* FIXED64 */
4, /* FIXED32 */
1, /* BOOL */
UPB_MAPTYPE_STRING, /* STRING */
sizeof(void *), /* GROUP */
sizeof(void *), /* MESSAGE */
UPB_MAPTYPE_STRING, /* BYTES */
4, /* UINT32 */
4, /* ENUM */
4, /* SFIXED32 */
8, /* SFIXED64 */
4, /* SINT32 */
8, /* SINT64 */
};
static const unsigned fixed32_ok = (1 << UPB_DTYPE_FLOAT) |
(1 << UPB_DTYPE_FIXED32) |
(1 << UPB_DTYPE_SFIXED32);
static const unsigned fixed64_ok = (1 << UPB_DTYPE_DOUBLE) |
(1 << UPB_DTYPE_FIXED64) |
(1 << UPB_DTYPE_SFIXED64);
/* Op: an action to be performed for a wire-type/field-type combination. */
#define OP_SCALAR_LG2(n) (n)
#define OP_FIXPCK_LG2(n) (n + 4)
#define OP_VARPCK_LG2(n) (n + 8)
#define OP_STRING 4
#define OP_SUBMSG 5
static const int8_t varint_ops[19] = {
-1, /* field not found */
-1, /* DOUBLE */
-1, /* FLOAT */
OP_SCALAR_LG2(3), /* INT64 */
OP_SCALAR_LG2(3), /* UINT64 */
OP_SCALAR_LG2(2), /* INT32 */
-1, /* FIXED64 */
-1, /* FIXED32 */
OP_SCALAR_LG2(0), /* BOOL */
-1, /* STRING */
-1, /* GROUP */
-1, /* MESSAGE */
-1, /* BYTES */
OP_SCALAR_LG2(2), /* UINT32 */
OP_SCALAR_LG2(2), /* ENUM */
-1, /* SFIXED32 */
-1, /* SFIXED64 */
OP_SCALAR_LG2(2), /* SINT32 */
OP_SCALAR_LG2(3), /* SINT64 */
};
static const int8_t delim_ops[37] = {
/* For non-repeated field type. */
-1, /* field not found */
-1, /* DOUBLE */
-1, /* FLOAT */
-1, /* INT64 */
-1, /* UINT64 */
-1, /* INT32 */
-1, /* FIXED64 */
-1, /* FIXED32 */
-1, /* BOOL */
OP_STRING, /* STRING */
-1, /* GROUP */
OP_SUBMSG, /* MESSAGE */
OP_STRING, /* BYTES */
-1, /* UINT32 */
-1, /* ENUM */
-1, /* SFIXED32 */
-1, /* SFIXED64 */
-1, /* SINT32 */
-1, /* SINT64 */
/* For repeated field type. */
OP_FIXPCK_LG2(3), /* REPEATED DOUBLE */
OP_FIXPCK_LG2(2), /* REPEATED FLOAT */
OP_VARPCK_LG2(3), /* REPEATED INT64 */
OP_VARPCK_LG2(3), /* REPEATED UINT64 */
OP_VARPCK_LG2(2), /* REPEATED INT32 */
OP_FIXPCK_LG2(3), /* REPEATED FIXED64 */
OP_FIXPCK_LG2(2), /* REPEATED FIXED32 */
OP_VARPCK_LG2(0), /* REPEATED BOOL */
OP_STRING, /* REPEATED STRING */
OP_SUBMSG, /* REPEATED GROUP */
OP_SUBMSG, /* REPEATED MESSAGE */
OP_STRING, /* REPEATED BYTES */
OP_VARPCK_LG2(2), /* REPEATED UINT32 */
OP_VARPCK_LG2(2), /* REPEATED ENUM */
OP_FIXPCK_LG2(2), /* REPEATED SFIXED32 */
OP_FIXPCK_LG2(3), /* REPEATED SFIXED64 */
OP_VARPCK_LG2(2), /* REPEATED SINT32 */
OP_VARPCK_LG2(3), /* REPEATED SINT64 */
};
/* Data pertaining to the parse. */
typedef struct {
const char *limit; /* End of delimited region or end of buffer. */
upb_arena *arena;
int depth;
uint32_t end_group; /* Set to field number of END_GROUP tag, if any. */
jmp_buf err;
} upb_decstate;
typedef union {
bool bool_val;
int32_t int32_val;
int64_t int64_val;
uint32_t uint32_val;
uint64_t uint64_val;
upb_strview str_val;
} wireval;
static const char *decode_msg(upb_decstate *d, const char *ptr, upb_msg *msg,
const upb_msglayout *layout);
UPB_NORETURN static void decode_err(upb_decstate *d) { longjmp(d->err, 1); }
static bool decode_reserve(upb_decstate *d, upb_array *arr, int elem) {
bool need_realloc = arr->size - arr->len < elem;
if (need_realloc && !_upb_array_realloc(arr, arr->len + elem, d->arena)) {
decode_err(d);
}
return need_realloc;
}
UPB_NOINLINE
static const char *decode_longvarint64(upb_decstate *d, const char *ptr,
const char *limit, uint64_t *val) {
uint8_t byte;
int bitpos = 0;
uint64_t out = 0;
do {
if (bitpos >= 70 || ptr == limit) decode_err(d);
byte = *ptr;
out |= (uint64_t)(byte & 0x7F) << bitpos;
ptr++;
bitpos += 7;
} while (byte & 0x80);
*val = out;
return ptr;
}
UPB_FORCEINLINE
static const char *decode_varint64(upb_decstate *d, const char *ptr,
const char *limit, uint64_t *val) {
if (UPB_LIKELY(ptr < limit && (*ptr & 0x80) == 0)) {
*val = (uint8_t)*ptr;
return ptr + 1;
} else {
return decode_longvarint64(d, ptr, limit, val);
}
}
static const char *decode_varint32(upb_decstate *d, const char *ptr,
const char *limit, uint32_t *val) {
uint64_t u64;
ptr = decode_varint64(d, ptr, limit, &u64);
if (u64 > UINT32_MAX) decode_err(d);
*val = (uint32_t)u64;
return ptr;
}
static void decode_munge(int type, wireval *val) {
switch (type) {
case UPB_DESCRIPTOR_TYPE_BOOL:
val->bool_val = val->uint64_val != 0;
break;
case UPB_DESCRIPTOR_TYPE_SINT32: {
uint32_t n = val->uint32_val;
val->int32_val = (n >> 1) ^ -(int32_t)(n & 1);
break;
}
case UPB_DESCRIPTOR_TYPE_SINT64: {
uint64_t n = val->uint64_val;
val->int64_val = (n >> 1) ^ -(int64_t)(n & 1);
break;
}
}
}
static const upb_msglayout_field *upb_find_field(const upb_msglayout *l,
uint32_t field_number) {
static upb_msglayout_field none = {0};
/* Lots of optimization opportunities here. */
int i;
if (l == NULL) return &none;
for (i = 0; i < l->field_count; i++) {
if (l->fields[i].number == field_number) {
return &l->fields[i];
}
}
return &none; /* Unknown field. */
}
static upb_msg *decode_newsubmsg(upb_decstate *d, const upb_msglayout *layout,
const upb_msglayout_field *field) {
const upb_msglayout *subl = layout->submsgs[field->submsg_index];
return _upb_msg_new(subl, d->arena);
}
static void decode_tosubmsg(upb_decstate *d, upb_msg *submsg,
const upb_msglayout *layout,
const upb_msglayout_field *field, upb_strview val) {
const upb_msglayout *subl = layout->submsgs[field->submsg_index];
const char *saved_limit = d->limit;
if (--d->depth < 0) decode_err(d);
d->limit = val.data + val.size;
decode_msg(d, val.data, submsg, subl);
d->limit = saved_limit;
if (d->end_group != 0) decode_err(d);
d->depth++;
}
static const char *decode_group(upb_decstate *d, const char *ptr,
upb_msg *submsg, const upb_msglayout *subl,
uint32_t number) {
if (--d->depth < 0) decode_err(d);
ptr = decode_msg(d, ptr, submsg, subl);
if (d->end_group != number) decode_err(d);
d->end_group = 0;
d->depth++;
return ptr;
}
static const char *decode_togroup(upb_decstate *d, const char *ptr,
upb_msg *submsg, const upb_msglayout *layout,
const upb_msglayout_field *field) {
const upb_msglayout *subl = layout->submsgs[field->submsg_index];
return decode_group(d, ptr, submsg, subl, field->number);
}
static const char *decode_toarray(upb_decstate *d, const char *ptr,
upb_msg *msg, const upb_msglayout *layout,
const upb_msglayout_field *field, wireval val,
int op) {
upb_array **arrp = UPB_PTR_AT(msg, field->offset, void);
upb_array *arr = *arrp;
void *mem;
if (!arr) {
upb_fieldtype_t type = desctype_to_fieldtype[field->descriptortype];
arr = _upb_array_new(d->arena, type);
if (!arr) decode_err(d);
*arrp = arr;
}
decode_reserve(d, arr, 1);
switch (op) {
case OP_SCALAR_LG2(0):
case OP_SCALAR_LG2(2):
case OP_SCALAR_LG2(3):
/* Append scalar value. */
mem = UPB_PTR_AT(_upb_array_ptr(arr), arr->len << op, void);
arr->len++;
memcpy(mem, &val, 1 << op);
return ptr;
case OP_STRING:
/* Append string. */
mem =
UPB_PTR_AT(_upb_array_ptr(arr), arr->len * sizeof(upb_strview), void);
arr->len++;
memcpy(mem, &val, sizeof(upb_strview));
return ptr;
case OP_SUBMSG: {
/* Append submessage / group. */
upb_msg *submsg = decode_newsubmsg(d, layout, field);
*UPB_PTR_AT(_upb_array_ptr(arr), arr->len * sizeof(void *), upb_msg *) =
submsg;
arr->len++;
if (UPB_UNLIKELY(field->descriptortype == UPB_DTYPE_GROUP)) {
ptr = decode_togroup(d, ptr, submsg, layout, field);
} else {
decode_tosubmsg(d, submsg, layout, field, val.str_val);
}
return ptr;
}
case OP_FIXPCK_LG2(2):
case OP_FIXPCK_LG2(3): {
/* Fixed packed. */
int lg2 = op - OP_FIXPCK_LG2(0);
int mask = (1 << lg2) - 1;
int count = val.str_val.size >> lg2;
if ((val.str_val.size & mask) != 0) {
decode_err(d); /* Length isn't a round multiple of elem size. */
}
decode_reserve(d, arr, count);
mem = UPB_PTR_AT(_upb_array_ptr(arr), arr->len << lg2, void);
arr->len += count;
memcpy(mem, val.str_val.data, val.str_val.size);
return ptr;
}
case OP_VARPCK_LG2(0):
case OP_VARPCK_LG2(2):
case OP_VARPCK_LG2(3): {
/* Varint packed. */
int lg2 = op - OP_VARPCK_LG2(0);
int scale = 1 << lg2;
const char *ptr = val.str_val.data;
const char *end = ptr + val.str_val.size;
char *out = UPB_PTR_AT(_upb_array_ptr(arr), arr->len << lg2, void);
while (ptr < end) {
wireval elem;
ptr = decode_varint64(d, ptr, end, &elem.uint64_val);
decode_munge(field->descriptortype, &elem);
if (decode_reserve(d, arr, 1)) {
out = UPB_PTR_AT(_upb_array_ptr(arr), arr->len << lg2, void);
}
arr->len++;
memcpy(out, &elem, scale);
out += scale;
}
if (ptr != end) decode_err(d);
return ptr;
}
default:
UPB_UNREACHABLE();
}
}
static void decode_tomap(upb_decstate *d, upb_msg *msg,
const upb_msglayout *layout,
const upb_msglayout_field *field, wireval val) {
upb_map **map_p = UPB_PTR_AT(msg, field->offset, upb_map *);
upb_map *map = *map_p;
upb_map_entry ent;
const upb_msglayout *entry = layout->submsgs[field->submsg_index];
if (!map) {
/* Lazily create map. */
const upb_msglayout *entry = layout->submsgs[field->submsg_index];
const upb_msglayout_field *key_field = &entry->fields[0];
const upb_msglayout_field *val_field = &entry->fields[1];
char key_size = desctype_to_mapsize[key_field->descriptortype];
char val_size = desctype_to_mapsize[val_field->descriptortype];
UPB_ASSERT(key_field->offset == 0);
UPB_ASSERT(val_field->offset == sizeof(upb_strview));
map = _upb_map_new(d->arena, key_size, val_size);
*map_p = map;
}
/* Parse map entry. */
memset(&ent, 0, sizeof(ent));
if (entry->fields[1].descriptortype == UPB_DESCRIPTOR_TYPE_MESSAGE ||
entry->fields[1].descriptortype == UPB_DESCRIPTOR_TYPE_GROUP) {
/* Create proactively to handle the case where it doesn't appear. */
ent.v.val.val = (uint64_t)_upb_msg_new(entry->submsgs[0], d->arena);
}
decode_tosubmsg(d, &ent.k, layout, field, val.str_val);
/* Insert into map. */
_upb_map_set(map, &ent.k, map->key_size, &ent.v, map->val_size, d->arena);
}
static const char *decode_tomsg(upb_decstate *d, const char *ptr, upb_msg *msg,
const upb_msglayout *layout,
const upb_msglayout_field *field, wireval val,
int op) {
void *mem = UPB_PTR_AT(msg, field->offset, void);
int type = field->descriptortype;
/* Set presence if necessary. */
if (field->presence < 0) {
/* Oneof case */
*UPB_PTR_AT(msg, -field->presence, int32_t) = field->number;
} else if (field->presence > 0) {
/* Hasbit */
uint32_t hasbit = field->presence;
*UPB_PTR_AT(msg, hasbit / 8, uint8_t) |= (1 << (hasbit % 8));
}
/* Store into message. */
switch (op) {
case OP_SUBMSG: {
upb_msg **submsgp = mem;
upb_msg *submsg = *submsgp;
if (!submsg) {
submsg = decode_newsubmsg(d, layout, field);
*submsgp = submsg;
}
if (UPB_UNLIKELY(type == UPB_DTYPE_GROUP)) {
ptr = decode_togroup(d, ptr, submsg, layout, field);
} else {
decode_tosubmsg(d, submsg, layout, field, val.str_val);
}
break;
}
case OP_STRING:
memcpy(mem, &val, sizeof(upb_strview));
break;
case OP_SCALAR_LG2(3):
memcpy(mem, &val, 8);
break;
case OP_SCALAR_LG2(2):
memcpy(mem, &val, 4);
break;
case OP_SCALAR_LG2(0):
memcpy(mem, &val, 1);
break;
default:
UPB_UNREACHABLE();
}
return ptr;
}
static const char *decode_msg(upb_decstate *d, const char *ptr, upb_msg *msg,
const upb_msglayout *layout) {
while (ptr < d->limit) {
uint32_t tag;
const upb_msglayout_field *field;
int field_number;
int wire_type;
const char *field_start = ptr;
wireval val;
int op;
ptr = decode_varint32(d, ptr, d->limit, &tag);
field_number = tag >> 3;
wire_type = tag & 7;
field = upb_find_field(layout, field_number);
switch (wire_type) {
case UPB_WIRE_TYPE_VARINT:
ptr = decode_varint64(d, ptr, d->limit, &val.uint64_val);
op = varint_ops[field->descriptortype];
decode_munge(field->descriptortype, &val);
break;
case UPB_WIRE_TYPE_32BIT:
if (d->limit - ptr < 4) decode_err(d);
memcpy(&val, ptr, 4);
ptr += 4;
op = OP_SCALAR_LG2(2);
if (((1 << field->descriptortype) & fixed32_ok) == 0) goto unknown;
break;
case UPB_WIRE_TYPE_64BIT:
if (d->limit - ptr < 8) decode_err(d);
memcpy(&val, ptr, 8);
ptr += 8;
op = OP_SCALAR_LG2(3);
if (((1 << field->descriptortype) & fixed64_ok) == 0) goto unknown;
break;
case UPB_WIRE_TYPE_DELIMITED: {
uint32_t size;
int ndx = field->descriptortype;
if (_upb_isrepeated(field)) ndx += 18;
ptr = decode_varint32(d, ptr, d->limit, &size);
if (size >= INT32_MAX || (size_t)(d->limit - ptr) < size) {
decode_err(d); /* Length overflow. */
}
val.str_val.data = ptr;
val.str_val.size = size;
ptr += size;
op = delim_ops[ndx];
break;
}
case UPB_WIRE_TYPE_START_GROUP:
val.int32_val = field_number;
op = OP_SUBMSG;
if (field->descriptortype != UPB_DTYPE_GROUP) goto unknown;
break;
case UPB_WIRE_TYPE_END_GROUP:
d->end_group = field_number;
return ptr;
default:
decode_err(d);
}
if (op >= 0) {
/* Parse, using op for dispatch. */
switch (field->label) {
case UPB_LABEL_REPEATED:
case _UPB_LABEL_PACKED:
ptr = decode_toarray(d, ptr, msg, layout, field, val, op);
break;
case _UPB_LABEL_MAP:
decode_tomap(d, msg, layout, field, val);
break;
default:
ptr = decode_tomsg(d, ptr, msg, layout, field, val, op);
break;
}
} else {
unknown:
/* Skip unknown field. */
if (field_number == 0) decode_err(d);
if (wire_type == UPB_WIRE_TYPE_START_GROUP) {
ptr = decode_group(d, ptr, NULL, NULL, field_number);
}
if (msg) {
if (!_upb_msg_addunknown(msg, field_start, ptr - field_start,
d->arena)) {
decode_err(d);
}
}
}
}
if (ptr != d->limit) decode_err(d);
return ptr;
}
bool upb_decode(const char *buf, size_t size, void *msg, const upb_msglayout *l,
upb_arena *arena) {
upb_decstate state;
state.limit = buf + size;
state.arena = arena;
state.depth = 64;
state.end_group = 0;
if (setjmp(state.err)) return false;
if (size == 0) return true;
decode_msg(&state, buf, msg, l);
return state.end_group == 0;
}
#undef OP_SCALAR_LG2
#undef OP_FIXPCK_LG2
#undef OP_VARPCK_LG2
#undef OP_STRING
#undef OP_SUBMSG