diff options
Diffstat (limited to 'upb/decode.c')
-rw-r--r-- | upb/decode.c | 385 |
1 files changed, 385 insertions, 0 deletions
diff --git a/upb/decode.c b/upb/decode.c new file mode 100644 index 0000000..f28642b --- /dev/null +++ b/upb/decode.c @@ -0,0 +1,385 @@ + +#include "upb/decode.h" + +typedef enum { + UPB_WIRE_TYPE_VARINT = 0, + UPB_WIRE_TYPE_64BIT = 1, + UPB_WIRE_TYPE_DELIMITED = 2, + UPB_WIRE_TYPE_START_GROUP = 3, + UPB_WIRE_TYPE_END_GROUP = 4, + UPB_WIRE_TYPE_32BIT = 5 +} upb_wiretype_t; + +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; + +#define CHK(x) if (!(x)) { return false; } + +static void upb_decode_seterr(upb_env *env, const char *msg) { + upb_status status = UPB_STATUS_INIT; + upb_status_seterrmsg(&status, msg); + upb_env_reporterror(env, &status); +} + +static bool upb_decode_varint(const char **ptr, const char *limit, + uint64_t *val) { + uint8_t byte = 0x80; + int bitpos = 0; + const char *p = *ptr; + *val = 0; + + while (byte & 0x80) { + if (bitpos == 70 || p == limit) { + return false; + } + + byte = *p; + *val |= (uint64_t)(byte & 0x7F) << bitpos; + p++; + bitpos += 7; + } + + *ptr = p; + return true; +} + +static bool upb_decode_varint32(const char **ptr, const char *limit, + uint32_t *val) { + uint64_t u64; + if (!upb_decode_varint(ptr, limit, &u64) || u64 > UINT32_MAX) { + return false; + } else { + *val = u64; + 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_64bit(const char **ptr, const char *limit, + uint64_t *val) { + if (limit - *ptr < 8) { + return false; + } else { + memcpy(val, *ptr, 8); + *ptr += 8; + return true; + } +} + +static bool upb_decode_32bit(const char **ptr, const char *limit, + uint32_t *val) { + if (limit - *ptr < 4) { + return false; + } else { + memcpy(val, *ptr, 4); + *ptr += 4; + return true; + } +} + +static int32_t upb_zzdec_32(uint32_t n) { + return (n >> 1) ^ -(int32_t)(n & 1); +} + +static int64_t upb_zzdec_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; + + if (!upb_decode_varint32(ptr, limit, &len) || + limit - *ptr < len) { + return false; + } + + *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_unknownfield(const char **ptr, const char *start, + const char *limit, char *msg) { + UPB_UNUSED(limit); + UPB_UNUSED(msg); + *ptr = limit; + return true; +} + +static bool upb_decode_unknownfielddata(upb_decstate *d, const char *ptr, + const char *limit, char *msg, + const upb_msglayout_msginit_v1 *l) { + do { + switch (wire_type) { + case UPB_WIRE_TYPE_VARINT: + CHK(upb_decode_varint(&ptr, limit, &val)); + break; + case UPB_WIRE_TYPE_32BIT: + CHK(upb_decode_32bit(&ptr, limit, &val)); + break; + case UPB_WIRE_TYPE_64BIT: + CHK(upb_decode_64bit(&ptr, limit, &val)); + break; + case UPB_WIRE_TYPE_DELIMITED: { + upb_stringview val; + CHK(upb_decode_string(&ptr, limit, &val)); + } + case UPB_WIRE_TYPE_START_GROUP: + depth++; + continue; + case UPB_WIRE_TYPE_END_GROUP: + depth--; + continue; + } + + UPB_ASSERT(depth == 0); + upb_append_unknown(msg, l, d->ptr, ptr); + d->ptr = ptr; + return true; + } while (true); +} + +static bool upb_decode_field(upb_decstate *d, const char *limit, char *msg, + const upb_msglayout_msginit_v1 *l) { + uint32_t tag; + uint32_t wire_type; + uint32_t field_number; + const char *ptr = d->ptr; + const upb_msglayout_fieldinit_v1 *f; + + if (!upb_decode_varint32(&ptr, limit, &tag)) { + upb_decode_seterr(env, "Error decoding tag.\n"); + return false; + } + + wire_type = tag & 0x7; + field_number = tag >> 3; + + if (field_number == 0) { + return false; + } + + f = upb_find_field(l, field_number); + + if (f) { + return upb_decode_knownfield(d, ptr, limit, msg, l, f); + } else { + return upb_decode_unknownfield(d, ptr, limit, msg, l); + } + + if (f->label == UPB_LABEL_REPEATED) { + arr = upb_getarray(msg, f, env); + } + + switch (wire_type) { + case UPB_WIRE_TYPE_VARINT: { + uint64_t val; + if (!upb_decode_varint(&ptr, limit, &val)) { + upb_decode_seterr(env, "Error decoding varint value.\n"); + return false; + } + + if (!f) { + return upb_append_unknown(ptr, field_start, ptr, msg); + } + + if (f->label == UPB_LABEL_REPEATED) { + upb_array *arr = upb_getarray(msg, f, env); + switch (f->type) { + case UPB_DESCRIPTOR_TYPE_INT64: + case UPB_DESCRIPTOR_TYPE_UINT64: + memcpy(arr->data, &val, sizeof(val)); + arr->len++; + break; + case UPB_DESCRIPTOR_TYPE_INT32: + case UPB_DESCRIPTOR_TYPE_UINT32: + case UPB_DESCRIPTOR_TYPE_ENUM: { + uint32_t val32 = val; + memcpy(arr->data, &val32, sizeof(val32)); + arr->len++; + break; + } + case UPB_DESCRIPTOR_TYPE_SINT32: { + int32_t decoded = upb_zzdec_32(val); + memcpy(arr->data, &decoded, sizeof(decoded)); + arr->len++; + break; + } + case UPB_DESCRIPTOR_TYPE_SINT64: { + int64_t decoded = upb_zzdec_64(val); + memcpy(arr->data, &decoded, sizeof(decoded)); + arr->len++; + break; + } + default: + return upb_append_unknown(ptr, field_start, ptr, msg); + } + } else { + switch (f->type) { + case UPB_DESCRIPTOR_TYPE_INT64: + case UPB_DESCRIPTOR_TYPE_UINT64: + memcpy(msg + f->offset, &val, sizeof(val)); + break; + case UPB_DESCRIPTOR_TYPE_INT32: + case UPB_DESCRIPTOR_TYPE_UINT32: + case UPB_DESCRIPTOR_TYPE_ENUM: { + uint32_t val32 = val; + memcpy(msg + f->offset, &val32, sizeof(val32)); + break; + } + case UPB_DESCRIPTOR_TYPE_SINT32: { + int32_t decoded = upb_zzdec_32(val); + memcpy(msg + f->offset, &decoded, sizeof(decoded)); + break; + } + case UPB_DESCRIPTOR_TYPE_SINT64: { + int64_t decoded = upb_zzdec_64(val); + memcpy(msg + f->offset, &decoded, sizeof(decoded)); + break; + } + default: + return upb_append_unknown(ptr, field_start, ptr, msg); + } + } + + break; + } + case UPB_WIRE_TYPE_64BIT: { + uint64_t val; + if (!upb_decode_64bit(&ptr, limit, &val)) { + upb_decode_seterr(env, "Error decoding 64bit value.\n"); + return false; + } + + if (!f) { + return upb_append_unknown(ptr, field_start, ptr, msg); + } + + switch (f->type) { + case UPB_DESCRIPTOR_TYPE_DOUBLE: + case UPB_DESCRIPTOR_TYPE_FIXED64: + case UPB_DESCRIPTOR_TYPE_SFIXED64: + memcpy(msg + f->offset, &val, sizeof(val)); + default: + return upb_append_unknown(ptr, field_start, ptr, msg); + } + + break; + } + case UPB_WIRE_TYPE_32BIT: { + uint32_t val; + if (!upb_decode_32bit(&ptr, limit, &val)) { + upb_decode_seterr(env, "Error decoding 32bit value.\n"); + return false; + } + + if (!f) { + return upb_append_unknown(ptr, field_start, ptr, msg); + } + + switch (f->type) { + case UPB_DESCRIPTOR_TYPE_FLOAT: + case UPB_DESCRIPTOR_TYPE_FIXED32: + case UPB_DESCRIPTOR_TYPE_SFIXED32: + memcpy(msg + f->offset, &val, sizeof(val)); + default: + return upb_append_unknown(ptr, field_start, ptr, msg); + } + + break; + } + case UPB_WIRE_TYPE_DELIMITED: { + upb_stringview val; + if (!upb_decode_string(&ptr, limit, &val)) { + upb_decode_seterr(env, "Error decoding delimited value.\n"); + return false; + } + + if (!f) { + return upb_append_unknown(ptr, field_start, ptr, msg); + } + + switch (f->type) { + case UPB_DESCRIPTOR_TYPE_STRING: + case UPB_DESCRIPTOR_TYPE_BYTES: + memcpy(msg + f->offset, &val, sizeof(val)); + break; + case UPB_DESCRIPTOR_TYPE_INT64: + case UPB_DESCRIPTOR_TYPE_UINT64: { + memcpy(msg + f->offset, &val, sizeof(val)); + break; + case UPB_DESCRIPTOR_TYPE_INT32: + case UPB_DESCRIPTOR_TYPE_UINT32: + case UPB_DESCRIPTOR_TYPE_ENUM: { + uint32_t val32 = val; + memcpy(msg + f->offset, &val32, sizeof(val32)); + break; + } + case UPB_DESCRIPTOR_TYPE_SINT32: { + int32_t decoded = upb_zzdec_32(val); + memcpy(msg + f->offset, &decoded, sizeof(decoded)); + break; + } + case UPB_DESCRIPTOR_TYPE_SINT64: + case UPB_DESCRIPTOR_TYPE_FLOAT: + case UPB_DESCRIPTOR_TYPE_FIXED32: + case UPB_DESCRIPTOR_TYPE_SFIXED32: + /* + case UPB_DESCRIPTOR_TYPE_MESSAGE: { + upb_decode_message(val, + } + */ + default: + return upb_append_unknown(ptr, field_start, ptr, msg); + } + + break; + } + } + + if (f->oneof_index != UPB_NOT_IN_ONEOF) { + upb_set32(msg, l->oneofs[f->oneof_index].case_offset, f->number); + } + + d->ptr = ptr; + return true; +} + +static bool upb_decode_message(upb_decstate *d, upb_stringview buf, + char *msg, const upb_msglayout_msginit_v1 *l) { + const char *limit = ptr + buf.size; + + while (d->ptr < limit) { + if (!upb_decode_field(&ptr, limit, msg, l, env)) { + return false; + } + } + + return true; +} + +bool upb_decode(upb_stringview buf, void *msg, + const upb_msglayout_msginit_v1 *l, upb_env *env) { + return upb_decode_message(buf, msg, l, env); +} |