upb/wire/reader.c

// Protocol Buffers - Google's data interchange format
// Copyright 2023 Google LLC.  All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd

#include "upb/wire/reader.h"

#include <stddef.h>
#include <stdint.h>

#include "upb/wire/eps_copy_input_stream.h"
#include "upb/wire/types.h"

// Must be last.
#include "upb/port/def.inc"

UPB_NOINLINE UPB_PRIVATE(_upb_WireReader_LongVarint)
    UPB_PRIVATE(_upb_WireReader_ReadLongVarint)(
        const char* ptr, uint64_t val, upb_EpsCopyInputStream* stream) {
  for (int i = 1; i < 10; i++) {
    uint64_t byte = (uint8_t)ptr[i];
    val += (byte - 1) << (i * 7);
    if (!(byte & 0x80)) {
      return (UPB_PRIVATE(_upb_WireReader_LongVarint)){ptr + i + 1, val};
    }
  }
  return (UPB_PRIVATE(_upb_WireReader_LongVarint)){
      UPB_PRIVATE(upb_EpsCopyInputStream_ReturnError)(stream), 0};
}

UPB_NOINLINE UPB_PRIVATE(_upb_WireReader_LongVarint)
    UPB_PRIVATE(_upb_WireReader_ReadLongTag)(const char* ptr, uint64_t val,
                                             upb_EpsCopyInputStream* stream) {
  for (int i = 1; i < 5; i++) {
    uint64_t byte = (uint8_t)ptr[i];
    val += (byte - 1) << (i * 7);
    if (!(byte & 0x80)) {
      if (val > UINT32_MAX) break;
      return (UPB_PRIVATE(_upb_WireReader_LongVarint)){ptr + i + 1, val};
    }
  }
  return (UPB_PRIVATE(_upb_WireReader_LongVarint)){
      UPB_PRIVATE(upb_EpsCopyInputStream_ReturnError)(stream), 0};
}

UPB_NOINLINE UPB_PRIVATE(_upb_WireReader_LongVarint)
    UPB_PRIVATE(_upb_WireReader_ReadLongSize)(const char* ptr, uint64_t val,
                                              upb_EpsCopyInputStream* stream) {
  for (int i = 1; i < 5; i++) {
    uint64_t byte = (uint8_t)ptr[i];
    val += (byte - 1) << (i * 7);
    if (!(byte & 0x80)) {
      if (val > INT32_MAX) break;
      return (UPB_PRIVATE(_upb_WireReader_LongVarint)){ptr + i + 1, val};
    }
  }
  return (UPB_PRIVATE(_upb_WireReader_LongVarint)){
      UPB_PRIVATE(upb_EpsCopyInputStream_ReturnError)(stream), 0};
}

const char* UPB_PRIVATE(_upb_WireReader_SkipGroup)(
    const char* ptr, uint32_t tag, int depth_limit,
    upb_EpsCopyInputStream* stream) {
  if (--depth_limit < 0) {
    return UPB_PRIVATE(upb_EpsCopyInputStream_ReturnError)(stream);
  }
  uint32_t end_group_tag = (tag & ~7ULL) | kUpb_WireType_EndGroup;
  while (!upb_EpsCopyInputStream_IsDone(stream, &ptr)) {
    uint32_t tag;
    ptr = upb_WireReader_ReadTag(ptr, &tag, stream);
    if (!ptr) break;
    if (tag == end_group_tag) return ptr;
    ptr = _upb_WireReader_SkipValue(ptr, tag, depth_limit, stream);
    if (!ptr) break;
  }
  // Encountered limit end before end group tag.
  return UPB_PRIVATE(upb_EpsCopyInputStream_ReturnError)(stream);
}