name.h

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#ifndef NDNDPDK_NDNI_NAME_H
#define NDNDPDK_NDNI_NAME_H

 
#include "common.h"
 
extern uint64_t LName_EmptyHash_;

typedef struct LName {
  const uint8_t* value;
  uint16_t length;
} LName;
 
__attribute__((nonnull)) static __rte_always_inline bool
LName_ParseVarNum_(LName name, uint16_t* restrict pos, uint16_t* restrict n, uint16_t minTail) {
  if (unlikely(*pos + 1 + minTail > name.length)) {
    return false;
  }
 
  *n = name.value[*pos];
  *pos += 1;
  if (likely(*n < 0xFD)) {
    return true;
  }
 
  if (unlikely(*n > 0xFD) || unlikely(*pos + 2 + minTail > name.length)) {
    return false;
  }
 
  *n = rte_be_to_cpu_16(*(unaligned_uint16_t*)&name.value[*pos]);
  *pos += 2;
  return true;
}

__attribute__((nonnull)) static inline bool
LName_Component(LName name, uint16_t* restrict pos, uint16_t* restrict type,
                uint16_t* restrict length) {
  return LName_ParseVarNum_(name, pos, type, 1) && likely(*type != 0) &&
         LName_ParseVarNum_(name, pos, length, 0) && *pos + *length <= name.length;
}

static inline int
LName_IsPrefix(LName a, LName b) {
  if (a.length > b.length || memcmp(a.value, b.value, a.length) != 0) {
    return -1;
  }
  return b.length - a.length;
}
 
static __rte_always_inline LName
LName_SliceByte_(LName name, uint16_t start, uint16_t end) {
  return (LName){.length = end - start, .value = RTE_PTR_ADD(name.value, start)};
}
 
static __rte_always_inline LName
LName_Slice_(LName name, uint16_t start, uint16_t end) {
  uint16_t i = 0, pos = 0, type = 0, length = 0;
  uint16_t posStart = likely(start == 0) ? 0 : name.length;
  uint16_t posEnd = name.length;
  while (likely(LName_Component(name, &pos, &type, &length))) {
    ++i;
    pos += length;
    if (i == start) {
      posStart = pos;
    } else if (i == end) {
      posEnd = pos;
      break;
    }
  }
  return LName_SliceByte_(name, posStart, posEnd);
}

static inline LName
LName_Slice(LName name, uint16_t start, uint16_t end) {
  if (unlikely(start >= end)) {
    return (LName){0};
  }
  return LName_Slice_(name, start, end);
}

uint64_t
LName_ComputeHash(LName name);

__attribute__((nonnull)) static inline int
LNamePrefixFilter_Find(LName name, int maxPrefix, const uint16_t* prefixL, const uint8_t* prefixV) {
  size_t offset = 0;
  for (int i = 0; i < maxPrefix; ++i) {
    if (prefixL[i] == UINT16_MAX) {
      break;
    }
 
    LName prefix = {
      .value = RTE_PTR_ADD(prefixV, offset),
      .length = prefixL[i],
    };
    if (LName_IsPrefix(prefix, name) >= 0) {
      return i;
    }
    offset += prefix.length;
  }
  return -1;
}

typedef struct __rte_packed_begin PName {
  const uint8_t* value; 
  uint16_t length;      
  uint16_t nComps;      
  struct {
    int16_t firstNonGeneric : 12; 
    bool hasDigestComp : 1;       
    bool hasHashes_ : 1;          
    uint32_t a_ : 2;
  } __rte_packed_end;
  uint16_t comp_[PNameCachedComponents]; 
  uint64_t hash_[PNameCachedComponents]; 
} PName;
// maximum component index must fit in firstNonGeneric
static_assert((NameMaxLength / 2) <= (1 << 11), "");

static __rte_always_inline LName
PName_ToLName(const PName* p) {
  static_assert(offsetof(LName, value) == offsetof(PName, value), "");
  static_assert(offsetof(LName, length) == offsetof(PName, length), "");
  return *(const LName*)p;
}

__attribute__((nonnull)) bool
PName_Parse(PName* p, LName l);
 
__attribute__((nonnull)) static __rte_noinline LName
PName_Slice_Uncached_(const PName* p, int16_t start, int16_t end) {
  return LName_Slice_(PName_ToLName(p), (uint16_t)start, (uint16_t)end);
}

__attribute__((nonnull)) static __rte_always_inline LName
PName_Slice(const PName* p, int16_t start, int16_t end) {
  if (unlikely(start < 0)) {
    start += p->nComps;
  }
  start = CLAMP(start, 0, (int16_t)p->nComps);
 
  if (unlikely(end < 0)) {
    end += p->nComps;
  }
  end = CLAMP(end, 0, (int16_t)p->nComps);
 
  if (unlikely(start >= end)) {
    return (LName){0};
  }
 
  if (unlikely(end > PNameCachedComponents)) {
    return PName_Slice_Uncached_(p, start, end);
  }
 
  return LName_SliceByte_(PName_ToLName(p), likely(start == 0) ? 0 : p->comp_[start - 1],
                          p->comp_[end - 1]);
}

__attribute__((nonnull)) static __rte_always_inline LName
PName_GetPrefix(const PName* p, int16_t n) {
  return PName_Slice(p, 0, n);
}
 
__attribute__((nonnull)) void
PName_PrepareHashes_(PName* p);

__attribute__((nonnull)) static inline uint64_t
PName_ComputePrefixHash(const PName* p, uint16_t i) {
  NDNDPDK_ASSERT(i <= p->nComps);
  if (unlikely(i == 0)) {
    return LName_EmptyHash_;
  }
  if (unlikely(i > PNameCachedComponents)) {
    return LName_ComputeHash(PName_GetPrefix(p, i));
  }
 
  if (!p->hasHashes_) {
    PName_PrepareHashes_((PName*)p);
  }
  return p->hash_[i - 1];
}

__attribute__((nonnull)) static inline uint64_t
PName_ComputeHash(const PName* p) {
  return PName_ComputePrefixHash(p, p->nComps);
}
 
#endif // NDNDPDK_NDNI_NAME_H