cosmopolitan/third_party/lua/lzio.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set noet ft=c ts=2 sts=2 sw=2 fenc=utf-8                             :vi │
╚──────────────────────────────────────────────────────────────────────────────╝
│                                                                              │
│  Lua                                                                         │
│  Copyright © 2004-2021 Lua.org, PUC-Rio.                                     │
│                                                                              │
│  Permission is hereby granted, free of charge, to any person obtaining       │
│  a copy of this software and associated documentation files (the             │
│  "Software"), to deal in the Software without restriction, including         │
│  without limitation the rights to use, copy, modify, merge, publish,         │
│  distribute, sublicense, and/or sell copies of the Software, and to          │
│  permit persons to whom the Software is furnished to do so, subject to       │
│  the following conditions:                                                   │
│                                                                              │
│  The above copyright notice and this permission notice shall be              │
│  included in all copies or substantial portions of the Software.             │
│                                                                              │
│  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,             │
│  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF          │
│  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.      │
│  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY        │
│  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,        │
│  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE           │
│  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                      │
│                                                                              │
╚─────────────────────────────────────────────────────────────────────────────*/
#define lzio_c
#define LUA_CORE
#include "libc/str/str.h"
#include "third_party/lua/llimits.h"
#include "third_party/lua/lmem.h"
#include "third_party/lua/lprefix.h"
#include "third_party/lua/lstate.h"
#include "third_party/lua/lua.h"
#include "third_party/lua/lzio.h"

asm(".ident\t\"\\n\\n\
Lua 5.4.3 (MIT License)\\n\
Copyright 1994–2021 Lua.org, PUC-Rio.\"");
asm(".include \"libc/disclaimer.inc\"");


int luaZ_fill (ZIO *z) {
  size_t size;
  lua_State *L = z->L;
  const char *buff;
  lua_unlock(L);
  buff = z->reader(L, z->data, &size);
  lua_lock(L);
  if (buff == NULL || size == 0)
    return EOZ;
  z->n = size - 1;  /* discount char being returned */
  z->p = buff;
  return cast_uchar(*(z->p++));
}


void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
  z->L = L;
  z->reader = reader;
  z->data = data;
  z->n = 0;
  z->p = NULL;
}


/* --------------------------------------------------------------- read --- */
size_t luaZ_read (ZIO *z, void *b, size_t n) {
  while (n) {
    size_t m;
    if (z->n == 0) {  /* no bytes in buffer? */
      if (luaZ_fill(z) == EOZ)  /* try to read more */
        return n;  /* no more input; return number of missing bytes */
      else {
        z->n++;  /* luaZ_fill consumed first byte; put it back */
        z->p--;
      }
    }
    m = (n <= z->n) ? n : z->n;  /* min. between n and z->n */
    memcpy(b, z->p, m);
    z->n -= m;
    z->p += m;
    b = (char *)b + m;
    n -= m;
  }
  return 0;
}