// Start of util.h.
//
// Various helper functions that are useful in all generated C code.

static const char *fut_progname = "(embedded Futhark)";

static void futhark_panic(int eval, const char *fmt, ...) {
  va_list ap;
  va_start(ap, fmt);
  fprintf(stderr, "%s: ", fut_progname);
  vfprintf(stderr, fmt, ap);
  va_end(ap);
  exit(eval);
}

// For generating arbitrary-sized error messages.  It is the callers
// responsibility to free the buffer at some point.
static char* msgprintf(const char *s, ...) {
  va_list vl;
  va_start(vl, s);
  size_t needed = 1 + (size_t)vsnprintf(NULL, 0, s, vl);
  char *buffer = (char*) malloc(needed);
  va_start(vl, s); // Must re-init.
  vsnprintf(buffer, needed, s, vl);
  return buffer;
}

// Read a file into a NUL-terminated string; returns NULL on error.
static void* slurp_file(const char *filename, size_t *size) {
  unsigned char *s;
  FILE *f = fopen(filename, "rb"); // To avoid Windows messing with linebreaks.
  if (f == NULL) return NULL;
  fseek(f, 0, SEEK_END);
  size_t src_size = ftell(f);
  fseek(f, 0, SEEK_SET);
  s = (unsigned char*) malloc(src_size + 1);
  if (fread(s, 1, src_size, f) != src_size) {
    free(s);
    s = NULL;
  } else {
    s[src_size] = '\0';
  }
  fclose(f);

  if (size) {
    *size = src_size;
  }

  return s;
}

// Dump 'n' bytes from 'buf' into the file at the designated location.
// Returns 0 on success.
static int dump_file(const char *file, const void *buf, size_t n) {
  FILE *f = fopen(file, "w");

  if (f == NULL) {
    return 1;
  }

  if (fwrite(buf, sizeof(char), n, f) != n) {
    return 1;
  }

  if (fclose(f) != 0) {
    return 1;
  }

  return 0;
}

struct str_builder {
  char *str;
  size_t capacity; // Size of buffer.
  size_t used; // Bytes used, *not* including final zero.
};

static void str_builder_init(struct str_builder *b) {
  b->capacity = 10;
  b->used = 0;
  b->str = malloc(b->capacity);
  b->str[0] = 0;
}

static void str_builder(struct str_builder *b, const char *s, ...) {
  va_list vl;
  va_start(vl, s);
  size_t needed = (size_t)vsnprintf(NULL, 0, s, vl);

  while (b->capacity < b->used + needed + 1) {
    b->capacity *= 2;
    b->str = realloc(b->str, b->capacity);
  }

  va_start(vl, s); // Must re-init.
  vsnprintf(b->str+b->used, b->capacity-b->used, s, vl);
  b->used += needed;
}

// End of util.h.