mirror of https://github.com/lua/lua
80 lines
1.6 KiB
C
80 lines
1.6 KiB
C
/*
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** $Id: lzio.c,v 1.21 2002/08/06 17:26:45 roberto Exp roberto $
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** a generic input stream interface
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** See Copyright Notice in lua.h
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*/
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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 "lzio.h"
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int luaZ_fill (ZIO *z) {
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size_t size;
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const char *buff = z->reader(NULL, z->data, &size);
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if (buff == NULL || size == 0) return EOZ;
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z->n = size - 1;
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z->p = buff;
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return *(z->p++);
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}
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int luaZ_lookahead (ZIO *z) {
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if (z->n == 0) {
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int c = luaZ_fill(z);
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if (c == EOZ) return c;
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z->n++;
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z->p--;
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}
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return *z->p;
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}
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void luaZ_init (ZIO *z, lua_Chunkreader reader, void *data, const char *name) {
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z->reader = reader;
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z->data = data;
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z->name = name;
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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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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 (z->n == 0) {
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if (luaZ_fill(z) == EOZ)
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return n; /* return number of missing bytes */
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else {
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++z->n; /* filbuf removed first byte; put back it */
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--z->p;
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}
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}
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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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/* ------------------------------------------------------------------------ */
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char *luaZ_openspace (lua_State *L, Mbuffer *buff, size_t n) {
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if (n > buff->buffsize) {
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if (n < LUA_MINBUFFER) n = LUA_MINBUFFER;
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luaM_reallocvector(L, buff->buffer, buff->buffsize, n, char);
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buff->buffsize = n;
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}
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return buff->buffer;
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}
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