/*

 * Copyright 2020 Google LLC

 *

 * 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

 */

#define REFTABLE_ALLOW_BANNED_ALLOCATORS

#include "basics.h"

#include "reftable-basics.h"

#include "reftable-error.h"

static void *(*reftable_malloc_ptr)(size_t sz);

static void *(*reftable_realloc_ptr)(void *, size_t);

static void (*reftable_free_ptr)(void *);

void *reftable_malloc(size_t sz)

{

  if (!sz)

    return NULL;

  if (reftable_malloc_ptr)

    return (*reftable_malloc_ptr)(sz);

  return malloc(sz);

}

void *reftable_realloc(void *p, size_t sz)

{

  if (!sz) {

    reftable_free(p);

    return NULL;

  }

  if (reftable_realloc_ptr)

    return (*reftable_realloc_ptr)(p, sz);

  return realloc(p, sz);

}

void reftable_free(void *p)

{

  if (reftable_free_ptr)

    reftable_free_ptr(p);

  else

    free(p);

}

void *reftable_calloc(size_t nelem, size_t elsize)

{

  void *p;

  if (nelem && elsize > SIZE_MAX / nelem)

    return NULL;

  p = reftable_malloc(nelem * elsize);

  if (!p)

    return NULL;

  memset(p, 0, nelem * elsize);

  return p;

}

char *reftable_strdup(const char *str)

{

  size_t len = strlen(str);

  char *result = reftable_malloc(len + 1);

  if (!result)

    return NULL;

  memcpy(result, str, len + 1);

  return result;

}

void reftable_set_alloc(void *(*malloc)(size_t),

      void *(*realloc)(void *, size_t), void (*free)(void *))

{

  reftable_malloc_ptr = malloc;

  reftable_realloc_ptr = realloc;

  reftable_free_ptr = free;

}

void reftable_buf_init(struct reftable_buf *buf)

{

  struct reftable_buf empty = REFTABLE_BUF_INIT;

  *buf = empty;

}

void reftable_buf_release(struct reftable_buf *buf)

{

  reftable_free(buf->buf);

  reftable_buf_init(buf);

}

void reftable_buf_reset(struct reftable_buf *buf)

{

  if (buf->alloc) {

    buf->len = 0;

    buf->buf[0] = '\0';

  }

}

int reftable_buf_setlen(struct reftable_buf *buf, size_t len)

{

  if (len > buf->len)

    return -1;

  if (len == buf->len)

    return 0;

  buf->buf[len] = '\0';

  buf->len = len;

  return 0;

}

int reftable_buf_cmp(const struct reftable_buf *a, const struct reftable_buf *b)

{

  size_t len = a->len < b->len ? a->len : b->len;

  if (len) {

    int cmp = memcmp(a->buf, b->buf, len);

    if (cmp)

      return cmp;

  }

  return a->len < b->len ? -1 : a->len != b->len;

}

int reftable_buf_add(struct reftable_buf *buf, const void *data, size_t len)

{

  size_t newlen = buf->len + len;

  if (newlen + 1 > buf->alloc) {

    if (REFTABLE_ALLOC_GROW(buf->buf, newlen + 1, buf->alloc))

      return REFTABLE_OUT_OF_MEMORY_ERROR;

  }

  memcpy(buf->buf + buf->len, data, len);

  buf->buf[newlen] = '\0';

  buf->len = newlen;

  return 0;

}

int reftable_buf_addstr(struct reftable_buf *buf, const char *s)

{

  return reftable_buf_add(buf, s, strlen(s));

}

char *reftable_buf_detach(struct reftable_buf *buf)

{

  char *result = buf->buf;

  reftable_buf_init(buf);

  return result;

}

size_t binsearch(size_t sz, int (*f)(size_t k, void *args), void *args)

{

  size_t lo = 0;

  size_t hi = sz;

  /* Invariants:

   *

   *  (hi == sz) || f(hi) == true

   *  (lo == 0 && f(0) == true) || fi(lo) == false

   */

  while (hi - lo > 1) {

    size_t mid = lo + (hi - lo) / 2;

    int ret = f(mid, args);

    if (ret < 0)

      return sz;

    if (ret > 0)

      hi = mid;

    else

      lo = mid;

  }

  if (lo)

    return hi;

  return f(0, args) ? 0 : 1;

}

void free_names(char **a)

{

  char **p;

  if (!a) {

    return;

  }

  for (p = a; *p; p++) {

    reftable_free(*p);

  }

  reftable_free(a);

}

size_t names_length(const char **names)

{

  const char **p = names;

  while (*p)

    p++;

  return p - names;

}

int parse_names(char *buf, int size, char ***out)

{

  char **names = NULL;

  size_t names_cap = 0;

  size_t names_len = 0;

  char *p = buf;

  char *end = buf + size;

  int err = 0;

  while (p < end) {

    char *next = strchr(p, '\n');

    if (!next) {

      err = REFTABLE_FORMAT_ERROR;

      goto done;

    } else if (next < end) {

      *next = '\0';

    } else {

      next = end;

    }

    if (p < next) {

      if (REFTABLE_ALLOC_GROW(names, names_len + 1,

            names_cap)) {

        err = REFTABLE_OUT_OF_MEMORY_ERROR;

        goto done;

      }

      names[names_len] = reftable_strdup(p);

      if (!names[names_len++]) {

        err = REFTABLE_OUT_OF_MEMORY_ERROR;

        goto done;

      }

    }

    p = next + 1;

  }

  if (REFTABLE_ALLOC_GROW(names, names_len + 1, names_cap)) {

    err = REFTABLE_OUT_OF_MEMORY_ERROR;

    goto done;

  }

  names[names_len] = NULL;

  *out = names;

  return 0;

done:

  for (size_t i = 0; i < names_len; i++)

    reftable_free(names[i]);

  reftable_free(names);

  return err;

}

int names_equal(const char **a, const char **b)

{

  size_t i = 0;

  for (; a[i] && b[i]; i++)

    if (strcmp(a[i], b[i]))

      return 0;

  return a[i] == b[i];

}

size_t common_prefix_size(struct reftable_buf *a, struct reftable_buf *b)

{

  size_t p = 0;

  for (; p < a->len && p < b->len; p++)

    if (a->buf[p] != b->buf[p])

      break;

  return p;

}

uint32_t hash_size(enum reftable_hash id)

{

  if (!id)

    return REFTABLE_HASH_SIZE_SHA1;

  switch (id) {

  case REFTABLE_HASH_SHA1:

    return REFTABLE_HASH_SIZE_SHA1;

  case REFTABLE_HASH_SHA256:

    return REFTABLE_HASH_SIZE_SHA256;

  }

  abort();

}