mirror of
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synced 2024-11-23 02:03:55 +08:00
55ac40f859
Several definitions that don't need to be "global" (that is, that concerns only specific parts of the code) moved out of llimits.h, to more appropriate places.
90 lines
1.8 KiB
C
90 lines
1.8 KiB
C
/*
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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 "lapi.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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