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/*
* Copyright (c) 2009-2021, Google LLC
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Google LLC nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL Google LLC BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Internal implementation details of the decoder that are shared between
* decode.c and decode_fast.c.
*/
#ifndef UPB_DECODE_INT_H_
#define UPB_DECODE_INT_H_
#include <setjmp.h>
#include "third_party/utf8_range/utf8_range.h"
#include "upb/decode.h"
#include "upb/msg_internal.h"
#include "upb/upb_internal.h"
/* Must be last. */
#include "upb/port_def.inc"
#define DECODE_NOGROUP (uint32_t) - 1
typedef struct upb_Decoder {
const char* end; /* Can read up to 16 bytes slop beyond this. */
const char* limit_ptr; /* = end + UPB_MIN(limit, 0) */
upb_Message* unknown_msg; /* If non-NULL, add unknown data at buffer flip. */
const char* unknown; /* Start of unknown data. */
const upb_ExtensionRegistry*
extreg; /* For looking up extensions during the parse. */
int limit; /* Submessage limit relative to end. */
int depth; /* Tracks recursion depth to bound stack usage. */
uint32_t end_group; /* field number of END_GROUP tag, else DECODE_NOGROUP */
uint16_t options;
bool missing_required;
char patch[32];
upb_Arena arena;
jmp_buf err;
#ifndef NDEBUG
const char* debug_tagstart;
const char* debug_valstart;
#endif
} upb_Decoder;
/* Error function that will abort decoding with longjmp(). We can't declare this
* UPB_NORETURN, even though it is appropriate, because if we do then compilers
* will "helpfully" refuse to tailcall to it
* (see: https://stackoverflow.com/a/55657013), which will defeat a major goal
* of our optimizations. That is also why we must declare it in a separate file,
* otherwise the compiler will see that it calls longjmp() and deduce that it is
* noreturn. */
const char* fastdecode_err(upb_Decoder* d, int status);
extern const uint8_t upb_utf8_offsets[];
UPB_INLINE
bool decode_verifyutf8_inl(const char* ptr, int len) {
const char* end = ptr + len;
// Check 8 bytes at a time for any non-ASCII char.
while (end - ptr >= 8) {
uint64_t data;
memcpy(&data, ptr, 8);
if (data & 0x8080808080808080) goto non_ascii;
ptr += 8;
}
// Check one byte at a time for non-ASCII.
while (ptr < end) {
if (*ptr & 0x80) goto non_ascii;
ptr++;
}
return true;
non_ascii:
return utf8_range2((const unsigned char*)ptr, end - ptr) == 0;
}
const char* decode_checkrequired(upb_Decoder* d, const char* ptr,
const upb_Message* msg,
const upb_MiniTable* l);
/* x86-64 pointers always have the high 16 bits matching. So we can shift
* left 8 and right 8 without loss of information. */
UPB_INLINE intptr_t decode_totable(const upb_MiniTable* tablep) {
return ((intptr_t)tablep << 8) | tablep->table_mask;
}
UPB_INLINE const upb_MiniTable* decode_totablep(intptr_t table) {
return (const upb_MiniTable*)(table >> 8);
}
UPB_INLINE
const char* decode_isdonefallback_inl(upb_Decoder* d, const char* ptr,
int overrun, int* status) {
if (overrun < d->limit) {
/* Need to copy remaining data into patch buffer. */
UPB_ASSERT(overrun < 16);
if (d->unknown_msg) {
if (!_upb_Message_AddUnknown(d->unknown_msg, d->unknown, ptr - d->unknown,
&d->arena)) {
*status = kUpb_DecodeStatus_OutOfMemory;
return NULL;
}
d->unknown = &d->patch[0] + overrun;
}
memset(d->patch + 16, 0, 16);
memcpy(d->patch, d->end, 16);
ptr = &d->patch[0] + overrun;
d->end = &d->patch[16];
d->limit -= 16;
d->limit_ptr = d->end + d->limit;
d->options &= ~kUpb_DecodeOption_AliasString;
UPB_ASSERT(ptr < d->limit_ptr);
return ptr;
} else {
*status = kUpb_DecodeStatus_Malformed;
return NULL;
}
}
const char* decode_isdonefallback(upb_Decoder* d, const char* ptr, int overrun);
UPB_INLINE
bool decode_isdone(upb_Decoder* d, const char** ptr) {
int overrun = *ptr - d->end;
if (UPB_LIKELY(*ptr < d->limit_ptr)) {
return false;
} else if (UPB_LIKELY(overrun == d->limit)) {
return true;
} else {
*ptr = decode_isdonefallback(d, *ptr, overrun);
return false;
}
}
#if UPB_FASTTABLE
UPB_INLINE
const char* fastdecode_tagdispatch(upb_Decoder* d, const char* ptr,
upb_Message* msg, intptr_t table,
uint64_t hasbits, uint64_t tag) {
const upb_MiniTable* table_p = decode_totablep(table);
uint8_t mask = table;
uint64_t data;
size_t idx = tag & mask;
UPB_ASSUME((idx & 7) == 0);
idx >>= 3;
data = table_p->fasttable[idx].field_data ^ tag;
UPB_MUSTTAIL return table_p->fasttable[idx].field_parser(d, ptr, msg, table,
hasbits, data);
}
#endif
UPB_INLINE uint32_t fastdecode_loadtag(const char* ptr) {
uint16_t tag;
memcpy(&tag, ptr, 2);
return tag;
}
UPB_INLINE void decode_checklimit(upb_Decoder* d) {
UPB_ASSERT(d->limit_ptr == d->end + UPB_MIN(0, d->limit));
}
UPB_INLINE int decode_pushlimit(upb_Decoder* d, const char* ptr, int size) {
int limit = size + (int)(ptr - d->end);
int delta = d->limit - limit;
decode_checklimit(d);
d->limit = limit;
d->limit_ptr = d->end + UPB_MIN(0, limit);
decode_checklimit(d);
return delta;
}
UPB_INLINE void decode_poplimit(upb_Decoder* d, const char* ptr,
int saved_delta) {
UPB_ASSERT(ptr - d->end == d->limit);
decode_checklimit(d);
d->limit += saved_delta;
d->limit_ptr = d->end + UPB_MIN(0, d->limit);
decode_checklimit(d);
}
#include "upb/port_undef.inc"
#endif /* UPB_DECODE_INT_H_ */
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