diff options
Diffstat (limited to 'upb/decode.c')
| -rw-r--r-- | upb/decode.c | 582 |
1 files changed, 582 insertions, 0 deletions
diff --git a/upb/decode.c b/upb/decode.c new file mode 100644 index 0000000..3c76e0f --- /dev/null +++ b/upb/decode.c @@ -0,0 +1,582 @@ + +#include "upb/upb.h" +#include "upb/decode.h" +#include "upb/structs.int.h" + +/* Maps descriptor type -> upb field type. */ +static const uint8_t upb_desctype_to_fieldtype[] = { + UPB_WIRE_TYPE_END_GROUP, /* ENDGROUP */ + 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 */ +}; + +/* Data pertaining to the parse. */ +typedef struct { + upb_env *env; + /* Current decoding pointer. Points to the beginning of a field until we + * have finished decoding the whole field. */ + const char *ptr; +} upb_decstate; + +/* Data pertaining to a single message frame. */ +typedef struct { + const char *limit; + int32_t group_number; /* 0 if we are not parsing a group. */ + + /* These members are unset for an unknown group frame. */ + char *msg; + const upb_msglayout_msginit_v1 *m; +} upb_decframe; + +#define CHK(x) if (!(x)) { return false; } + +static bool upb_skip_unknowngroup(upb_decstate *d, int field_number, + const char *limit); +static bool upb_decode_message(upb_decstate *d, const char *limit, + int group_number, char *msg, + const upb_msglayout_msginit_v1 *l); + +static bool upb_decode_varint(const char **ptr, const char *limit, + uint64_t *val) { + uint8_t byte; + int bitpos = 0; + const char *p = *ptr; + *val = 0; + + do { + CHK(bitpos < 70 && p < limit); + byte = *p; + *val |= (uint64_t)(byte & 0x7F) << bitpos; + p++; + bitpos += 7; + } while (byte & 0x80); + + *ptr = p; + return true; +} + +static bool upb_decode_varint32(const char **ptr, const char *limit, + uint32_t *val) { + uint64_t u64; + CHK(upb_decode_varint(ptr, limit, &u64) && u64 <= UINT32_MAX); + *val = u64; + return true; +} + +static bool upb_decode_64bit(const char **ptr, const char *limit, + uint64_t *val) { + CHK(limit - *ptr >= 8); + memcpy(val, *ptr, 8); + *ptr += 8; + return true; +} + +static bool upb_decode_32bit(const char **ptr, const char *limit, + uint32_t *val) { + CHK(limit - *ptr >= 4); + memcpy(val, *ptr, 4); + *ptr += 4; + return true; +} + +static bool upb_decode_tag(const char **ptr, const char *limit, + int *field_number, int *wire_type) { + uint32_t tag; + CHK(upb_decode_varint32(ptr, limit, &tag)); + *field_number = tag >> 3; + *wire_type = tag & 7; + return true; +} + +static int32_t upb_zzdecode_32(uint32_t n) { + return (n >> 1) ^ -(int32_t)(n & 1); +} + +static int64_t upb_zzdecode_64(uint64_t n) { + return (n >> 1) ^ -(int64_t)(n & 1); +} + +static bool upb_decode_string(const char **ptr, const char *limit, + upb_stringview *val) { + uint32_t len; + + CHK(upb_decode_varint32(ptr, limit, &len) && + len < INT32_MAX && + limit - *ptr >= (int32_t)len); + + *val = upb_stringview_make(*ptr, len); + *ptr += len; + return true; +} + +static void upb_set32(void *msg, size_t ofs, uint32_t val) { + memcpy((char*)msg + ofs, &val, sizeof(val)); +} + +static bool upb_append_unknown(upb_decstate *d, upb_decframe *frame, + const char *start) { + UPB_UNUSED(d); + UPB_UNUSED(frame); + UPB_UNUSED(start); + return true; +} + +static bool upb_skip_unknownfielddata(upb_decstate *d, upb_decframe *frame, + int field_number, int wire_type) { + switch (wire_type) { + case UPB_WIRE_TYPE_VARINT: { + uint64_t val; + return upb_decode_varint(&d->ptr, frame->limit, &val); + } + case UPB_WIRE_TYPE_32BIT: { + uint32_t val; + return upb_decode_32bit(&d->ptr, frame->limit, &val); + } + case UPB_WIRE_TYPE_64BIT: { + uint64_t val; + return upb_decode_64bit(&d->ptr, frame->limit, &val); + } + case UPB_WIRE_TYPE_DELIMITED: { + upb_stringview val; + return upb_decode_string(&d->ptr, frame->limit, &val); + } + case UPB_WIRE_TYPE_START_GROUP: + return upb_skip_unknowngroup(d, field_number, frame->limit); + case UPB_WIRE_TYPE_END_GROUP: + CHK(field_number == frame->group_number); + frame->limit = d->ptr; + return true; + } + return false; +} + +static bool upb_array_grow(upb_array *arr, size_t elements) { + size_t needed = arr->len + elements; + size_t new_size = UPB_MAX(arr->size, 8); + size_t new_bytes; + size_t old_bytes; + void *new_data; + + while (new_size < needed) { + new_size *= 2; + } + + old_bytes = arr->len * arr->element_size; + new_bytes = new_size * arr->element_size; + new_data = upb_realloc(arr->alloc, arr->data, old_bytes, new_bytes); + CHK(new_data); + + arr->data = new_data; + arr->size = new_size; + return true; +} + +static void *upb_array_reserve(upb_array *arr, size_t elements) { + if (arr->size - arr->len < elements) { + CHK(upb_array_grow(arr, elements)); + } + return (char*)arr->data + (arr->len * arr->element_size); +} + +static void *upb_array_add(upb_array *arr, size_t elements) { + void *ret = upb_array_reserve(arr, elements); + arr->len += elements; + return ret; +} + +static upb_array *upb_getarr(upb_decframe *frame, + const upb_msglayout_fieldinit_v1 *field) { + UPB_ASSERT(field->label == UPB_LABEL_REPEATED); + return *(upb_array**)&frame->msg[field->offset]; +} + +static upb_array *upb_getorcreatearr(upb_decstate *d, + upb_decframe *frame, + const upb_msglayout_fieldinit_v1 *field) { + upb_array *arr = upb_getarr(frame, field); + + if (!arr) { + arr = upb_env_malloc(d->env, sizeof(*arr)); + if (!arr) { + return NULL; + } + upb_array_init(arr, upb_desctype_to_fieldtype[field->type], + upb_arena_alloc(upb_env_arena(d->env))); + *(upb_array**)&frame->msg[field->offset] = arr; + } + + return arr; +} + +static void upb_sethasbit(upb_decframe *frame, + const upb_msglayout_fieldinit_v1 *field) { + UPB_ASSERT(field->hasbit != UPB_NO_HASBIT); + frame->msg[field->hasbit / 8] |= (1 << (field->hasbit % 8)); +} + +static void upb_setoneofcase(upb_decframe *frame, + const upb_msglayout_fieldinit_v1 *field) { + UPB_ASSERT(field->oneof_index != UPB_NOT_IN_ONEOF); + upb_set32(frame->msg, frame->m->oneofs[field->oneof_index].case_offset, + field->number); +} + +static char *upb_decode_prepareslot(upb_decstate *d, + upb_decframe *frame, + const upb_msglayout_fieldinit_v1 *field) { + char *field_mem = frame->msg + field->offset; + upb_array *arr; + + if (field->label == UPB_LABEL_REPEATED) { + arr = upb_getorcreatearr(d, frame, field); + field_mem = upb_array_reserve(arr, 1); + } + + return field_mem; +} + +static void upb_decode_setpresent(upb_decframe *frame, + const upb_msglayout_fieldinit_v1 *field) { + if (field->label == UPB_LABEL_REPEATED) { + upb_array *arr = upb_getarr(frame, field); + UPB_ASSERT(arr->len < arr->size); + arr->len++; + } else if (field->oneof_index != UPB_NOT_IN_ONEOF) { + upb_setoneofcase(frame, field); + } else if (field->hasbit != UPB_NO_HASBIT) { + upb_sethasbit(frame, field); + } +} + +static bool upb_decode_submsg(upb_decstate *d, + upb_decframe *frame, + const char *limit, + const upb_msglayout_fieldinit_v1 *field, + int group_number) { + char *submsg = *(void**)&frame->msg[field->offset]; + const upb_msglayout_msginit_v1 *subm; + + UPB_ASSERT(field->submsg_index != UPB_NO_SUBMSG); + subm = frame->m->submsgs[field->submsg_index]; + UPB_ASSERT(subm); + + if (!submsg) { + submsg = upb_env_malloc(d->env, upb_msg_sizeof((upb_msglayout *)subm)); + CHK(submsg); + submsg = upb_msg_init( + submsg, (upb_msglayout*)subm, upb_arena_alloc(upb_env_arena(d->env))); + *(void**)&frame->msg[field->offset] = submsg; + } + + upb_decode_message(d, limit, group_number, submsg, subm); + + return true; +} + +static bool upb_decode_varintfield(upb_decstate *d, upb_decframe *frame, + const char *field_start, + const upb_msglayout_fieldinit_v1 *field) { + uint64_t val; + void *field_mem; + + field_mem = upb_decode_prepareslot(d, frame, field); + CHK(field_mem); + CHK(upb_decode_varint(&d->ptr, frame->limit, &val)); + + switch ((upb_descriptortype_t)field->type) { + case UPB_DESCRIPTOR_TYPE_INT64: + case UPB_DESCRIPTOR_TYPE_UINT64: + memcpy(field_mem, &val, sizeof(val)); + break; + case UPB_DESCRIPTOR_TYPE_INT32: + case UPB_DESCRIPTOR_TYPE_UINT32: + case UPB_DESCRIPTOR_TYPE_ENUM: { + uint32_t val32 = val; + memcpy(field_mem, &val32, sizeof(val32)); + break; + } + case UPB_DESCRIPTOR_TYPE_BOOL: { + bool valbool = val != 0; + memcpy(field_mem, &valbool, sizeof(valbool)); + break; + } + case UPB_DESCRIPTOR_TYPE_SINT32: { + int32_t decoded = upb_zzdecode_32(val); + memcpy(field_mem, &decoded, sizeof(decoded)); + break; + } + case UPB_DESCRIPTOR_TYPE_SINT64: { + int64_t decoded = upb_zzdecode_64(val); + memcpy(field_mem, &decoded, sizeof(decoded)); + break; + } + default: + return upb_append_unknown(d, frame, field_start); + } + + upb_decode_setpresent(frame, field); + return true; +} + +static bool upb_decode_64bitfield(upb_decstate *d, upb_decframe *frame, + const char *field_start, + const upb_msglayout_fieldinit_v1 *field) { + void *field_mem; + uint64_t val; + + field_mem = upb_decode_prepareslot(d, frame, field); + CHK(field_mem); + CHK(upb_decode_64bit(&d->ptr, frame->limit, &val)); + + switch ((upb_descriptortype_t)field->type) { + case UPB_DESCRIPTOR_TYPE_DOUBLE: + case UPB_DESCRIPTOR_TYPE_FIXED64: + case UPB_DESCRIPTOR_TYPE_SFIXED64: + memcpy(field_mem, &val, sizeof(val)); + break; + default: + return upb_append_unknown(d, frame, field_start); + } + + upb_decode_setpresent(frame, field); + return true; +} + +static bool upb_decode_32bitfield(upb_decstate *d, upb_decframe *frame, + const char *field_start, + const upb_msglayout_fieldinit_v1 *field) { + void *field_mem; + uint32_t val; + + field_mem = upb_decode_prepareslot(d, frame, field); + CHK(field_mem); + CHK(upb_decode_32bit(&d->ptr, frame->limit, &val)); + + switch ((upb_descriptortype_t)field->type) { + case UPB_DESCRIPTOR_TYPE_FLOAT: + case UPB_DESCRIPTOR_TYPE_FIXED32: + case UPB_DESCRIPTOR_TYPE_SFIXED32: + memcpy(field_mem, &val, sizeof(val)); + break; + default: + return upb_append_unknown(d, frame, field_start); + } + + upb_decode_setpresent(frame, field); + return true; +} + +static bool upb_decode_fixedpacked(upb_array *arr, upb_stringview data, + int elem_size) { + int elements = data.size / elem_size; + void *field_mem; + + CHK((size_t)(elements * elem_size) == data.size); + field_mem = upb_array_add(arr, elements); + CHK(field_mem); + memcpy(field_mem, data.data, data.size); + return true; +} + +static bool upb_decode_toarray(upb_decstate *d, upb_decframe *frame, + const char *field_start, + const upb_msglayout_fieldinit_v1 *field, + upb_stringview val) { + upb_array *arr = upb_getorcreatearr(d, frame, field); + +#define VARINT_CASE(ctype, decode) { \ + const char *ptr = val.data; \ + const char *limit = ptr + val.size; \ + while (ptr < limit) { \ + uint64_t val; \ + void *field_mem; \ + ctype decoded; \ + CHK(upb_decode_varint(&ptr, limit, &val)); \ + decoded = (decode)(val); \ + field_mem = upb_array_add(arr, 1); \ + CHK(field_mem); \ + memcpy(field_mem, &decoded, sizeof(ctype)); \ + } \ + return true; \ +} + + switch ((upb_descriptortype_t)field->type) { + case UPB_DESCRIPTOR_TYPE_STRING: + case UPB_DESCRIPTOR_TYPE_BYTES: { + void *field_mem = upb_array_add(arr, 1); + CHK(field_mem); + memcpy(field_mem, &val, sizeof(val)); + return true; + } + case UPB_DESCRIPTOR_TYPE_FLOAT: + case UPB_DESCRIPTOR_TYPE_FIXED32: + case UPB_DESCRIPTOR_TYPE_SFIXED32: + return upb_decode_fixedpacked(arr, val, sizeof(int32_t)); + case UPB_DESCRIPTOR_TYPE_DOUBLE: + case UPB_DESCRIPTOR_TYPE_FIXED64: + case UPB_DESCRIPTOR_TYPE_SFIXED64: + return upb_decode_fixedpacked(arr, val, sizeof(int64_t)); + case UPB_DESCRIPTOR_TYPE_INT32: + case UPB_DESCRIPTOR_TYPE_UINT32: + case UPB_DESCRIPTOR_TYPE_ENUM: + /* TODO: proto2 enum field that isn't in the enum. */ + VARINT_CASE(uint32_t, uint32_t); + case UPB_DESCRIPTOR_TYPE_INT64: + case UPB_DESCRIPTOR_TYPE_UINT64: + VARINT_CASE(uint64_t, uint64_t); + case UPB_DESCRIPTOR_TYPE_BOOL: + VARINT_CASE(bool, bool); + case UPB_DESCRIPTOR_TYPE_SINT32: + VARINT_CASE(int32_t, upb_zzdecode_32); + case UPB_DESCRIPTOR_TYPE_SINT64: + VARINT_CASE(int64_t, upb_zzdecode_64); + case UPB_DESCRIPTOR_TYPE_MESSAGE: + CHK(val.size <= (size_t)(frame->limit - val.data)); + return upb_decode_submsg(d, frame, val.data + val.size, field, 0); + case UPB_DESCRIPTOR_TYPE_GROUP: + return upb_append_unknown(d, frame, field_start); + } +#undef VARINT_CASE + UPB_UNREACHABLE(); +} + +static bool upb_decode_delimitedfield(upb_decstate *d, upb_decframe *frame, + const char *field_start, + const upb_msglayout_fieldinit_v1 *field) { + upb_stringview val; + + CHK(upb_decode_string(&d->ptr, frame->limit, &val)); + + if (field->label == UPB_LABEL_REPEATED) { + return upb_decode_toarray(d, frame, field_start, field, val); + } else { + switch ((upb_descriptortype_t)field->type) { + case UPB_DESCRIPTOR_TYPE_STRING: + case UPB_DESCRIPTOR_TYPE_BYTES: { + void *field_mem = upb_decode_prepareslot(d, frame, field); + CHK(field_mem); + memcpy(field_mem, &val, sizeof(val)); + break; + } + case UPB_DESCRIPTOR_TYPE_MESSAGE: + CHK(val.size <= (size_t)(frame->limit - val.data)); + CHK(upb_decode_submsg(d, frame, val.data + val.size, field, 0)); + break; + default: + /* TODO(haberman): should we accept the last element of a packed? */ + return upb_append_unknown(d, frame, field_start); + } + upb_decode_setpresent(frame, field); + return true; + } +} + +static const upb_msglayout_fieldinit_v1 *upb_find_field( + const upb_msglayout_msginit_v1 *l, uint32_t field_number) { + /* Lots of optimization opportunities here. */ + int i; + for (i = 0; i < l->field_count; i++) { + if (l->fields[i].number == field_number) { + return &l->fields[i]; + } + } + + return NULL; /* Unknown field. */ +} + +static bool upb_decode_field(upb_decstate *d, upb_decframe *frame) { + int field_number; + int wire_type; + const char *field_start = d->ptr; + const upb_msglayout_fieldinit_v1 *field; + + CHK(upb_decode_tag(&d->ptr, frame->limit, &field_number, &wire_type)); + field = upb_find_field(frame->m, field_number); + + if (field) { + switch (wire_type) { + case UPB_WIRE_TYPE_VARINT: + return upb_decode_varintfield(d, frame, field_start, field); + case UPB_WIRE_TYPE_32BIT: + return upb_decode_32bitfield(d, frame, field_start, field); + case UPB_WIRE_TYPE_64BIT: + return upb_decode_64bitfield(d, frame, field_start, field); + case UPB_WIRE_TYPE_DELIMITED: + return upb_decode_delimitedfield(d, frame, field_start, field); + case UPB_WIRE_TYPE_START_GROUP: + CHK(field->type == UPB_DESCRIPTOR_TYPE_GROUP); + return upb_decode_submsg(d, frame, frame->limit, field, field_number); + case UPB_WIRE_TYPE_END_GROUP: + CHK(frame->group_number == field_number) + frame->limit = d->ptr; + return true; + default: + return false; + } + } else { + CHK(field_number != 0); + return upb_skip_unknownfielddata(d, frame, field_number, wire_type); + } +} + +static bool upb_skip_unknowngroup(upb_decstate *d, int field_number, + const char *limit) { + upb_decframe frame; + frame.msg = NULL; + frame.m = NULL; + frame.group_number = field_number; + frame.limit = limit; + + while (d->ptr < frame.limit) { + int wire_type; + int field_number; + + CHK(upb_decode_tag(&d->ptr, frame.limit, &field_number, &wire_type)); + CHK(upb_skip_unknownfielddata(d, &frame, field_number, wire_type)); + } + + return true; +} + +static bool upb_decode_message(upb_decstate *d, const char *limit, + int group_number, char *msg, + const upb_msglayout_msginit_v1 *l) { + upb_decframe frame; + frame.group_number = group_number; + frame.limit = limit; + frame.msg = msg; + frame.m = l; + + while (d->ptr < frame.limit) { + CHK(upb_decode_field(d, &frame)); + } + + return true; +} + +bool upb_decode(upb_stringview buf, void *msg, + const upb_msglayout_msginit_v1 *l, upb_env *env) { + upb_decstate state; + state.ptr = buf.data; + state.env = env; + + return upb_decode_message(&state, buf.data + buf.size, 0, msg, l); +} + +#undef CHK |