89 lines
1.7 KiB
C
89 lines
1.7 KiB
C
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/*
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** $Id: lzio.c $
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** Buffered streams
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** See Copyright Notice in lua.h
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*/
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#define lzio_c
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#define LUA_CORE
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#include "lprefix.h"
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#include <string.h>
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#include "lua.h"
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#include "llimits.h"
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#include "lmem.h"
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#include "lstate.h"
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#include "lzio.h"
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int luaZ_fill (ZIO *z) {
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size_t size;
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lua_State *L = z->L;
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const char *buff;
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lua_unlock(L);
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buff = z->reader(L, z->data, &size);
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lua_lock(L);
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if (buff == NULL || size == 0)
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return EOZ;
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z->n = size - 1; /* discount char being returned */
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z->p = buff;
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return cast_uchar(*(z->p++));
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}
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void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) {
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z->L = L;
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z->reader = reader;
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z->data = data;
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z->n = 0;
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z->p = NULL;
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}
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/* --------------------------------------------------------------- read --- */
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static int checkbuffer (ZIO *z) {
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if (z->n == 0) { /* no bytes in buffer? */
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if (luaZ_fill(z) == EOZ) /* try to read more */
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return 0; /* no more input */
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else {
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z->n++; /* luaZ_fill consumed first byte; put it back */
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z->p--;
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}
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}
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return 1; /* now buffer has something */
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}
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size_t luaZ_read (ZIO *z, void *b, size_t n) {
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while (n) {
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size_t m;
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if (!checkbuffer(z))
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return n; /* no more input; return number of missing bytes */
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m = (n <= z->n) ? n : z->n; /* min. between n and z->n */
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memcpy(b, z->p, m);
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z->n -= m;
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z->p += m;
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b = (char *)b + m;
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n -= m;
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}
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return 0;
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}
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const void *luaZ_getaddr (ZIO* z, size_t n) {
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const void *res;
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if (!checkbuffer(z))
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return NULL; /* no more input */
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if (z->n < n) /* not enough bytes? */
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return NULL; /* block not whole; cannot give an address */
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res = z->p; /* get block address */
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z->n -= n; /* consume these bytes */
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z->p += n;
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return res;
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}
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