ref: 20a1d2268d69a0bbe66d0f21999649133878377c
dir: /sys/src/libflate/inflatezlibblock.c/
#include <u.h> #include <libc.h> #include <flate.h> #include "zlib.h" typedef struct Block Block; struct Block { uchar *pos; uchar *limit; }; static int blgetc(void *vb) { Block *b; b = vb; if(b->pos >= b->limit) return -1; return *b->pos++; } static int blwrite(void *vb, void *buf, int n) { Block *b; b = vb; if(n > b->limit - b->pos) n = b->limit - b->pos; memmove(b->pos, buf, n); b->pos += n; return n; } int inflatezlibblock(uchar *dst, int dsize, uchar *src, int ssize) { Block bd, bs; int ok; if(ssize < 6) return FlateInputFail; if(((src[0] << 8) | src[1]) % 31) return FlateCorrupted; if((src[0] & ZlibMeth) != ZlibDeflate || (src[0] & ZlibCInfo) > ZlibWin32k) return FlateCorrupted; bs.pos = src + 2; bs.limit = src + ssize - 6; bd.pos = dst; bd.limit = dst + dsize; ok = inflate(&bd, blwrite, &bs, blgetc); if(ok != FlateOk) return ok; if(adler32(1, dst, bd.pos - dst) != ((bs.pos[0] << 24) | (bs.pos[1] << 16) | (bs.pos[2] << 8) | bs.pos[3])) return FlateCorrupted; return bd.pos - dst; }