diff options
Diffstat (limited to 'buffer.c')
| -rw-r--r-- | buffer.c | 61 |
1 files changed, 48 insertions, 13 deletions
@@ -1,4 +1,4 @@ -/* $OpenBSD: buffer.c,v 1.26 2006/03/25 13:17:01 djm Exp $ */ +/* $OpenBSD: buffer.c,v 1.27 2006/04/16 00:48:52 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -18,6 +18,10 @@ #include "buffer.h" #include "log.h" +#define BUFFER_MAX_CHUNK 0x100000 +#define BUFFER_MAX_LEN 0xa00000 +#define BUFFER_ALLOCSZ 0x008000 + /* Initializes the buffer structure. */ void @@ -66,6 +70,23 @@ buffer_append(Buffer *buffer, const void *data, u_int len) memcpy(p, data, len); } +static int +buffer_compact(Buffer *buffer) +{ + /* + * If the buffer is quite empty, but all data is at the end, move the + * data to the beginning. + */ + if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) { + memmove(buffer->buf, buffer->buf + buffer->offset, + buffer->end - buffer->offset); + buffer->end -= buffer->offset; + buffer->offset = 0; + return (1); + } + return (0); +} + /* * Appends space to the buffer, expanding the buffer if necessary. This does * not actually copy the data into the buffer, but instead returns a pointer @@ -93,20 +114,13 @@ restart: buffer->end += len; return p; } - /* - * If the buffer is quite empty, but all data is at the end, move the - * data to the beginning and retry. - */ - if (buffer->offset > MIN(buffer->alloc, BUFFER_MAX_CHUNK)) { - memmove(buffer->buf, buffer->buf + buffer->offset, - buffer->end - buffer->offset); - buffer->end -= buffer->offset; - buffer->offset = 0; + + /* Compact data back to the start of the buffer if necessary */ + if (buffer_compact(buffer)) goto restart; - } - /* Increase the size of the buffer and retry. */ - newlen = buffer->alloc + len + 32768; + /* Increase the size of the buffer and retry. */ + newlen = roundup(buffer->alloc + len, BUFFER_ALLOCSZ); if (newlen > BUFFER_MAX_LEN) fatal("buffer_append_space: alloc %u not supported", newlen); @@ -116,6 +130,27 @@ restart: /* NOTREACHED */ } +/* + * Check whether an allocation of 'len' will fit in the buffer + * This must follow the same math as buffer_append_space + */ +int +buffer_check_alloc(Buffer *buffer, u_int len) +{ + if (buffer->offset == buffer->end) { + buffer->offset = 0; + buffer->end = 0; + } + restart: + if (buffer->end + len < buffer->alloc) + return (1); + if (buffer_compact(buffer)) + goto restart; + if (roundup(buffer->alloc + len, BUFFER_ALLOCSZ) <= BUFFER_MAX_LEN) + return (1); + return (0); +} + /* Returns the number of bytes of data in the buffer. */ u_int |