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Protocol Buffers - Google's data interchange format (grpc依赖) https://developers.google.com/protocol-buffers/
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protobuf/upb_parse.c

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/*
* upb - a minimalist implementation of protocol buffers.
*
* Copyright (c) 2008-2009 Joshua Haberman. See LICENSE for details.
*/
#include "upb_parse.h"
#include <assert.h>
#include <string.h>
#include "descriptor.h"
/* Branch prediction hints for GCC. */
#ifdef __GNUC__
#define likely(x) __builtin_expect((x),1)
#define unlikely(x) __builtin_expect((x),0)
#else
#define likely(x) (x)
#define unlikely(x) (x)
#endif
#define CHECK(func) do { \
upb_status_t status = func; \
if(status != UPB_STATUS_OK) return status; \
} while (0)
/* Lowest-level functions -- these read integers from the input buffer.
* To avoid branches, none of these do bounds checking. So we force clients
* to overallocate their buffers by >=9 bytes. */
static upb_status_t get_v_uint64_t(void *restrict *buf,
uint64_t *restrict val)
{
uint8_t *ptr = *buf, b;
uint32_t part0 = 0, part1 = 0, part2 = 0;
/* From the original proto2 implementation. */
b = *(ptr++); part0 = (b & 0x7F) ; if (!(b & 0x80)) goto done;
b = *(ptr++); part0 |= (b & 0x7F) << 7; if (!(b & 0x80)) goto done;
b = *(ptr++); part0 |= (b & 0x7F) << 14; if (!(b & 0x80)) goto done;
b = *(ptr++); part0 |= (b & 0x7F) << 21; if (!(b & 0x80)) goto done;
b = *(ptr++); part1 = (b & 0x7F) ; if (!(b & 0x80)) goto done;
b = *(ptr++); part1 |= (b & 0x7F) << 7; if (!(b & 0x80)) goto done;
b = *(ptr++); part1 |= (b & 0x7F) << 14; if (!(b & 0x80)) goto done;
b = *(ptr++); part1 |= (b & 0x7F) << 21; if (!(b & 0x80)) goto done;
b = *(ptr++); part2 = (b & 0x7F) ; if (!(b & 0x80)) goto done;
b = *(ptr++); part2 |= (b & 0x7F) << 7; if (!(b & 0x80)) goto done;
return UPB_ERROR_UNTERMINATED_VARINT;
done:
*buf = ptr;
*val = (uint64_t)part0 | ((uint64_t)part1 << 28) | ((uint64_t)part2 << 56);
return UPB_STATUS_OK;
}
static upb_status_t skip_v_uint64_t(void **buf)
{
for(int i = 0; i < 10; i++, *buf++) {
uint8_t *b = *buf;
if(!(*b & 0x80)) return UPB_STATUS_OK;
}
return UPB_ERROR_UNTERMINATED_VARINT;
}
static upb_status_t get_v_uint32_t(void *restrict *buf,
uint32_t *restrict val)
{
uint8_t *ptr = *buf, b;
uint32_t result;
/* From the original proto2 implementation. */
b = *(ptr++); result = (b & 0x7F) ; if (!(b & 0x80)) goto done;
b = *(ptr++); result |= (b & 0x7F) << 7; if (!(b & 0x80)) goto done;
b = *(ptr++); result |= (b & 0x7F) << 14; if (!(b & 0x80)) goto done;
b = *(ptr++); result |= (b & 0x7F) << 21; if (!(b & 0x80)) goto done;
b = *(ptr++); result = (b & 0x7F) << 28; if (!(b & 0x80)) goto done;
return UPB_ERROR_UNTERMINATED_VARINT;
done:
*buf = ptr;
*val = result;
return UPB_STATUS_OK;
}
#define SHL(val, bits) ((uint32_t)val << bits)
static upb_status_t get_f_uint32_t(void *restrict *buf,
uint32_t *restrict val)
{
uint8_t *b = *buf;
#if UPB_UNALIGNED_READS_OK
*val = *(uint32_t*)b;
#else
*val = SHL(b[0], 0) | SHL(b[1], 8) | SHL(b[2], 16) | SHL(b[3], 24);
#endif
b += sizeof(uint32_t);
*buf = b;
return UPB_STATUS_OK;
}
#undef SHL
static upb_status_t skip_f_uint32_t(void **buf)
{
*buf = (char*)*buf + sizeof(uint32_t);
return UPB_STATUS_OK;
}
static upb_status_t get_f_uint64_t(void *restrict *buf,
uint64_t *restrict val)
{
#if UPB_UNALIGNED_READS_OK
*val = *(uint64_t*)*buf;
*buf = (char*)*buf + sizeof(uint64_t);
#else
uint32_t lo32, hi32;
get_f_uint32_t(buf, &lo32);
get_f_uint32_t(buf, &hi32);
*val = lo32 | ((uint64_t)hi32 << 32);
#endif
return UPB_STATUS_OK;
}
static upb_status_t skip_f_uint64_t(void **buf)
{
*buf = (char*)*buf + sizeof(uint64_t);
return UPB_STATUS_OK;
}
static int32_t zz_decode_32(uint32_t n) { return (n >> 1) ^ -(int32_t)(n & 1); }
static int64_t zz_decode_64(uint64_t n) { return (n >> 1) ^ -(int64_t)(n & 1); }
/* Functions for reading wire values and converting them to values. These
* are generated with macros because they follow a higly consistent pattern. */
#define WVTOV(type, wire_t, val_t) \
static void wvtov_ ## type(wire_t s, val_t *d)
#define GET(type, v_or_f, wire_t, val_t, member_name) \
static upb_status_t get_ ## type(void **buf, union upb_value *d) { \
wire_t tmp; \
CHECK(get_ ## v_or_f ## _ ## wire_t(buf, &tmp)); \
wvtov_ ## type(tmp, &d->member_name); \
return UPB_STATUS_OK; \
}
#define T(type, v_or_f, wire_t, val_t, member_name) \
WVTOV(type, wire_t, val_t); /* prototype for GET below */ \
GET(type, v_or_f, wire_t, val_t, member_name) \
WVTOV(type, wire_t, val_t)
T(DOUBLE, f, uint64_t, double, _double) { memcpy(d, &s, sizeof(double)); }
T(FLOAT, f, uint32_t, float, _float) { memcpy(d, &s, sizeof(float)); }
T(INT32, v, uint32_t, int32_t, int32) { *d = (int32_t)s; }
T(INT64, v, uint64_t, int64_t, int64) { *d = (int64_t)s; }
T(UINT32, v, uint32_t, uint32_t, uint32) { *d = s; }
T(UINT64, v, uint64_t, uint64_t, uint64) { *d = s; }
T(SINT32, v, uint32_t, int32_t, int32) { *d = zz_decode_32(s); }
T(SINT64, v, uint64_t, int64_t, int64) { *d = zz_decode_64(s); }
T(FIXED32, f, uint32_t, uint32_t, uint32) { *d = s; }
T(FIXED64, f, uint64_t, uint64_t, uint64) { *d = s; }
T(SFIXED32, f, uint32_t, int32_t, int32) { *d = (int32_t)s; }
T(SFIXED64, f, uint64_t, int64_t, int64) { *d = (int64_t)s; }
T(BOOL, v, uint32_t, bool, _bool) { *d = (bool)s; }
T(ENUM, v, uint32_t, int32_t, int32) { *d = (int32_t)s; }
#undef WVTOV
#undef GET
#undef T
upb_wire_type_t upb_expected_wire_types[] = {
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_DOUBLE] = UPB_WIRE_TYPE_64BIT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_FLOAT] = UPB_WIRE_TYPE_32BIT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_INT64] = UPB_WIRE_TYPE_VARINT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_UINT64] = UPB_WIRE_TYPE_VARINT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_INT32] = UPB_WIRE_TYPE_VARINT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_FIXED64] = UPB_WIRE_TYPE_64BIT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_FIXED32] = UPB_WIRE_TYPE_32BIT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_BOOL] = UPB_WIRE_TYPE_VARINT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_STRING] = UPB_WIRE_TYPE_DELIMITED,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_BYTES] = UPB_WIRE_TYPE_DELIMITED,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_GROUP] = -1, /* TODO */
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_MESSAGE] = UPB_WIRE_TYPE_DELIMITED,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_UINT32] = UPB_WIRE_TYPE_VARINT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_ENUM] = UPB_WIRE_TYPE_VARINT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_SFIXED32] = UPB_WIRE_TYPE_32BIT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_SFIXED64] = UPB_WIRE_TYPE_64BIT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_SINT32] = UPB_WIRE_TYPE_VARINT,
[GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_SINT64] = UPB_WIRE_TYPE_VARINT,
};
upb_status_t upb_parse_tag(void **buf, struct upb_tag *tag)
{
uint32_t tag_int;
CHECK(get_v_uint32_t(buf, &tag_int));
tag->wire_type = (upb_wire_type_t)(tag_int & 0x07);
tag->field_number = tag_int >> 3;
return UPB_STATUS_OK;
}
upb_status_t upb_parse_wire_value(void *buf, size_t *offset,
upb_wire_type_t wt,
union upb_wire_value *wv)
{
#define READ(expr) CHECK(expr); *offset += ((char*)b-(char*)buf)
void *b = buf;
switch(wt) {
case UPB_WIRE_TYPE_VARINT: READ(get_v_uint64_t(&b, &wv->varint)); break;
case UPB_WIRE_TYPE_64BIT: READ(get_f_uint64_t(&b, &wv->_64bit)); break;
case UPB_WIRE_TYPE_32BIT: READ(get_f_uint32_t(&b, &wv->_32bit)); break;
case UPB_WIRE_TYPE_DELIMITED:
READ(get_v_uint32_t(&b, &wv->_32bit));
size_t new_offset = *offset + wv->_32bit;
if (new_offset < *offset) return UPB_ERROR_OVERFLOW;
*offset += new_offset;
break;
case UPB_WIRE_TYPE_START_GROUP:
case UPB_WIRE_TYPE_END_GROUP: break;
}
return UPB_STATUS_OK;
}
upb_status_t upb_skip_wire_value(void *buf, size_t *offset,
upb_wire_type_t wt)
{
void *b = buf;
switch(wt) {
case UPB_WIRE_TYPE_VARINT: READ(skip_v_uint64_t(&b)); break;
case UPB_WIRE_TYPE_64BIT: READ(skip_f_uint64_t(&b)); break;
case UPB_WIRE_TYPE_32BIT: READ(skip_f_uint32_t(&b)); break;
case UPB_WIRE_TYPE_DELIMITED: {
/* Have to get (not skip) the length to skip the bytes. */
uint32_t len;
READ(get_v_uint32_t(&b, &len));
size_t new_offset = *offset + len;
if (new_offset < *offset) return UPB_ERROR_OVERFLOW;
*offset += new_offset;
break;
}
case UPB_WIRE_TYPE_START_GROUP: /* TODO: skip to matching end group. */
case UPB_WIRE_TYPE_END_GROUP: break;
}
return UPB_STATUS_OK;
#undef READ
}
upb_status_t upb_parse_value(void **b, upb_field_type_t ft,
union upb_value *v)
{
#define CASE(t) \
case GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_ ## t: return get_ ## t(b, v);
switch(ft) {
CASE(DOUBLE) CASE(FLOAT) CASE(INT64) CASE(UINT64) CASE(INT32) CASE(FIXED64)
CASE(FIXED32) CASE(BOOL) CASE(UINT32) CASE(ENUM) CASE(SFIXED32)
CASE(SFIXED64) CASE(SINT32) CASE(SINT64)
case GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_BYTES:
case GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_STRING:
case GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_MESSAGE:
return get_UINT32(b, v);
default: return 0; /* Including GROUP -- groups have no value. */
}
#undef CASE
}
static void pop_stack_frame(struct upb_parse_state *s)
{
s->submsg_end_cb(s);
s->top--;
s->top = (struct upb_parse_stack_frame*)((char*)s->top - s->udata_size);
}
static upb_status_t push_stack_frame(struct upb_parse_state *s, size_t end,
void *user_field_desc)
{
s->top++;
s->top = (struct upb_parse_stack_frame*)((char*)s->top + s->udata_size);
if(unlikely(s->top > s->limit)) return UPB_ERROR_STACK_OVERFLOW;
s->top->end_offset = end;
s->submsg_start_cb(s, user_field_desc);
return UPB_STATUS_OK;
}
upb_status_t upb_parse(struct upb_parse_state *s, void *buf, size_t len,
size_t *read)
{
size_t start_offset = s->offset;
size_t end_offset = start_offset + len;
while(!s->done && s->offset < end_offset) {
while(s->offset >= s->top->end_offset) pop_stack_frame(s);
while(s->packed_end_offset > s->offset) {
/* Parse a packed field entry. */
}
struct upb_tag tag;
void *b = buf;
CHECK(upb_parse_tag(&b, &tag));
int tag_bytes = ((char*)b - (char*)buf);
s->offset += tag_bytes;
buf = b;
if(unlikely(tag.wire_type == UPB_WIRE_TYPE_END_GROUP)) {
if(unlikely(s->top->end_offset != 0)) return UPB_ERROR_SPURIOUS_END_GROUP;
pop_stack_frame(s);
continue;
}
void *user_field_desc;
upb_field_type_t ft = s->tag_cb(s, &tag, &user_field_desc);
if(ft == 0) {
CHECK(upb_skip_wire_value(b, &s->offset, tag.wire_type));
} else if(ft == GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_GROUP) {
/* No length specified, an "end group" tag will mark the end. */
push_stack_frame(s, 0, user_field_desc);
} else {
/* For all other cases we parse the next value. */
union upb_value v;
CHECK(upb_parse_value(&b, ft, &v));
if(ft == GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_MESSAGE) {
/* The value we parsed is the length of the submessage. */
push_stack_frame(s, s->offset + v.delim_len, user_field_desc);
} else if(ft == GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_STRING ||
ft == GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_BYTES) {
s->value_cb(s, &v, b, user_field_desc);
b = (char*)b + v.delim_len;
} else if(tag.wire_type == UPB_WIRE_TYPE_DELIMITED) {
/* Delimited data which is not a string, bytes, or a submessage.
* It must be a packed array. */
s->packed_type = ft;
s->packed_end_offset = s->offset + v.delim_len;
} else {
/* The common case: a simple value. */
CHECK(upb_parse_value(&b, ft, &v));
s->value_cb(s, &v, b, user_field_desc);
}
}
}
*read = s->offset - start_offset;
return UPB_STATUS_OK;
}