From 14e416355f83cf0a1b871eedec2c92b86dbe76d6 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Tue, 5 Sep 2023 15:30:45 -0300 Subject: Added suport for Fixed Buffers A fixed buffer keeps a binary chunk "forever", so that the program does not need to copy some of its parts when loading it. --- lzio.c | 36 ++++++++++++++++++++++++++++-------- 1 file changed, 28 insertions(+), 8 deletions(-) (limited to 'lzio.c') diff --git a/lzio.c b/lzio.c index cd0a02d5..78f7ac83 100644 --- a/lzio.c +++ b/lzio.c @@ -45,17 +45,25 @@ void luaZ_init (lua_State *L, ZIO *z, lua_Reader reader, void *data) { /* --------------------------------------------------------------- read --- */ + +static int checkbuffer (ZIO *z) { + if (z->n == 0) { /* no bytes in buffer? */ + if (luaZ_fill(z) == EOZ) /* try to read more */ + return 0; /* no more input */ + else { + z->n++; /* luaZ_fill consumed first byte; put it back */ + z->p--; + } + } + return 1; /* now buffer has something */ +} + + 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--; - } - } + if (!checkbuffer(z)) + return n; /* no more input; return number of missing bytes */ m = (n <= z->n) ? n : z->n; /* min. between n and z->n */ memcpy(b, z->p, m); z->n -= m; @@ -66,3 +74,15 @@ size_t luaZ_read (ZIO *z, void *b, size_t n) { return 0; } + +const void *luaZ_getaddr (ZIO* z, size_t n) { + const void *res; + if (!checkbuffer(z)) + return NULL; /* no more input */ + if (z->n < n) /* not enough bytes? */ + return NULL; /* block not whole; cannot give an address */ + res = z->p; /* get block address */ + z->n -= n; /* consume these bytes */ + z->p += n; + return res; +} -- cgit v1.2.3-55-g6feb