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Diffstat (limited to 'contrib/cvs/src/zlib.c')
| -rw-r--r-- | contrib/cvs/src/zlib.c | 429 |
1 files changed, 429 insertions, 0 deletions
diff --git a/contrib/cvs/src/zlib.c b/contrib/cvs/src/zlib.c new file mode 100644 index 0000000000000..02ad70c2f5345 --- /dev/null +++ b/contrib/cvs/src/zlib.c @@ -0,0 +1,429 @@ +/* zlib.c --- interface to the zlib compression library + Ian Lance Taylor <ian@cygnus.com> + + This file is part of GNU CVS. + + GNU CVS is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by the + Free Software Foundation; either version 2, or (at your option) any + later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. */ + +/* The routines in this file are the interface between the CVS + client/server support and the zlib compression library. */ + +#include <assert.h> +#include "cvs.h" +#include "buffer.h" + +#if defined (SERVER_SUPPORT) || defined (CLIENT_SUPPORT) + +#include "zlib.h" + +/* OS/2 doesn't have EIO. FIXME: this whole notion of turning + a different error into EIO strikes me as pretty dubious. */ +#if !defined (EIO) +#define EIO EBADPOS +#endif + +/* The compression interface is built upon the buffer data structure. + We provide a buffer type which compresses or decompresses the data + which passes through it. An input buffer decompresses the data + read from an underlying buffer, and an output buffer compresses the + data before writing it to an underlying buffer. */ + +/* This structure is the closure field of the buffer. */ + +struct compress_buffer +{ + /* The underlying buffer. */ + struct buffer *buf; + /* The compression information. */ + z_stream zstr; +}; + +static void compress_error PROTO((int, int, z_stream *, const char *)); +static int compress_buffer_input PROTO((void *, char *, int, int, int *)); +static int compress_buffer_output PROTO((void *, const char *, int, int *)); +static int compress_buffer_flush PROTO((void *)); +static int compress_buffer_block PROTO((void *, int)); +static int compress_buffer_shutdown_input PROTO((void *)); +static int compress_buffer_shutdown_output PROTO((void *)); + +/* Report an error from one of the zlib functions. */ + +static void +compress_error (status, zstatus, zstr, msg) + int status; + int zstatus; + z_stream *zstr; + const char *msg; +{ + int hold_errno; + const char *zmsg; + char buf[100]; + + hold_errno = errno; + + zmsg = zstr->msg; + if (zmsg == NULL) + { + sprintf (buf, "error %d", zstatus); + zmsg = buf; + } + + error (status, + zstatus == Z_ERRNO ? hold_errno : 0, + "%s: %s", msg, zmsg); +} + +/* Create a compression buffer. */ + +struct buffer * +compress_buffer_initialize (buf, input, level, memory) + struct buffer *buf; + int input; + int level; + void (*memory) PROTO((struct buffer *)); +{ + struct compress_buffer *n; + int zstatus; + + n = (struct compress_buffer *) xmalloc (sizeof *n); + memset (n, 0, sizeof *n); + + n->buf = buf; + + if (input) + zstatus = inflateInit (&n->zstr); + else + zstatus = deflateInit (&n->zstr, level); + if (zstatus != Z_OK) + compress_error (1, zstatus, &n->zstr, "compression initialization"); + + /* There may already be data buffered on BUF. For an output + buffer, this is OK, because these routines will just use the + buffer routines to append data to the (uncompressed) data + already on BUF. An input buffer expects to handle a single + buffer_data of buffered input to be uncompressed, so that is OK + provided there is only one buffer. At present that is all + there ever will be; if this changes, compress_buffer_input must + be modified to handle multiple input buffers. */ + assert (! input || buf->data == NULL || buf->data->next == NULL); + + return buf_initialize (input ? compress_buffer_input : NULL, + input ? NULL : compress_buffer_output, + input ? NULL : compress_buffer_flush, + compress_buffer_block, + (input + ? compress_buffer_shutdown_input + : compress_buffer_shutdown_output), + memory, + n); +} + +/* Input data from a compression buffer. */ + +static int +compress_buffer_input (closure, data, need, size, got) + void *closure; + char *data; + int need; + int size; + int *got; +{ + struct compress_buffer *cb = (struct compress_buffer *) closure; + struct buffer_data *bd; + + if (cb->buf->input == NULL) + abort (); + + /* We use a single buffer_data structure to buffer up data which + the z_stream structure won't use yet. We can safely store this + on cb->buf->data, because we never call the buffer routines on + cb->buf; we only call the buffer input routine, since that + gives us the semantics we want. As noted in + compress_buffer_initialize, the buffer_data structure may + already exist, and hold data which was already read and + buffered before the decompression began. */ + bd = cb->buf->data; + if (bd == NULL) + { + bd = ((struct buffer_data *) malloc (sizeof (struct buffer_data))); + if (bd == NULL) + return -2; + bd->text = (char *) malloc (BUFFER_DATA_SIZE); + if (bd->text == NULL) + { + free (bd); + return -2; + } + bd->bufp = bd->text; + bd->size = 0; + cb->buf->data = bd; + } + + cb->zstr.avail_out = size; + cb->zstr.next_out = (Bytef *) data; + + while (1) + { + int zstatus, sofar, status, nread; + + /* First try to inflate any data we already have buffered up. + This is useful even if we don't have any buffered data, + because there may be data buffered inside the z_stream + structure. */ + + cb->zstr.avail_in = bd->size; + cb->zstr.next_in = (Bytef *) bd->bufp; + + do + { + zstatus = inflate (&cb->zstr, Z_NO_FLUSH); + if (zstatus == Z_STREAM_END) + break; + if (zstatus != Z_OK && zstatus != Z_BUF_ERROR) + { + compress_error (0, zstatus, &cb->zstr, "inflate"); + return EIO; + } + } while (cb->zstr.avail_in > 0 + && cb->zstr.avail_out > 0); + + bd->size = cb->zstr.avail_in; + bd->bufp = (char *) cb->zstr.next_in; + + if (zstatus == Z_STREAM_END) + return -1; + + /* If we have obtained NEED bytes, then return, unless NEED is + zero and we haven't obtained anything at all. If NEED is + zero, we will keep reading from the underlying buffer until + we either can't read anything, or we have managed to + inflate at least one byte. */ + sofar = size - cb->zstr.avail_out; + if (sofar > 0 && sofar >= need) + break; + + /* All our buffered data should have been processed at this + point. */ + assert (bd->size == 0); + + /* This will work well in the server, because this call will + do an unblocked read and fetch all the available data. In + the client, this will read a single byte from the stdio + stream, which will cause us to call inflate once per byte. + It would be more efficient if we could make a call which + would fetch all the available bytes, and at least one byte. */ + + status = (*cb->buf->input) (cb->buf->closure, bd->text, + need > 0 ? 1 : 0, + BUFFER_DATA_SIZE, &nread); + if (status != 0) + return status; + + /* If we didn't read anything, then presumably the buffer is + in nonblocking mode, and we should just get out now with + whatever we've inflated. */ + if (nread == 0) + { + assert (need == 0); + break; + } + + bd->bufp = bd->text; + bd->size = nread; + } + + *got = size - cb->zstr.avail_out; + + return 0; +} + +/* Output data to a compression buffer. */ + +static int +compress_buffer_output (closure, data, have, wrote) + void *closure; + const char *data; + int have; + int *wrote; +{ + struct compress_buffer *cb = (struct compress_buffer *) closure; + + cb->zstr.avail_in = have; + cb->zstr.next_in = (unsigned char *) data; + + while (cb->zstr.avail_in > 0) + { + char buffer[BUFFER_DATA_SIZE]; + int zstatus; + + cb->zstr.avail_out = BUFFER_DATA_SIZE; + cb->zstr.next_out = (unsigned char *) buffer; + + zstatus = deflate (&cb->zstr, Z_NO_FLUSH); + if (zstatus != Z_OK) + { + compress_error (0, zstatus, &cb->zstr, "deflate"); + return EIO; + } + + if (cb->zstr.avail_out != BUFFER_DATA_SIZE) + buf_output (cb->buf, buffer, + BUFFER_DATA_SIZE - cb->zstr.avail_out); + } + + *wrote = have; + + /* We will only be here because buf_send_output was called on the + compression buffer. That means that we should now call + buf_send_output on the underlying buffer. */ + return buf_send_output (cb->buf); +} + +/* Flush a compression buffer. */ + +static int +compress_buffer_flush (closure) + void *closure; +{ + struct compress_buffer *cb = (struct compress_buffer *) closure; + + cb->zstr.avail_in = 0; + cb->zstr.next_in = NULL; + + while (1) + { + char buffer[BUFFER_DATA_SIZE]; + int zstatus; + + cb->zstr.avail_out = BUFFER_DATA_SIZE; + cb->zstr.next_out = (unsigned char *) buffer; + + zstatus = deflate (&cb->zstr, Z_SYNC_FLUSH); + + /* The deflate function will return Z_BUF_ERROR if it can't do + anything, which in this case means that all data has been + flushed. */ + if (zstatus == Z_BUF_ERROR) + break; + + if (zstatus != Z_OK) + { + compress_error (0, zstatus, &cb->zstr, "deflate flush"); + return EIO; + } + + if (cb->zstr.avail_out != BUFFER_DATA_SIZE) + buf_output (cb->buf, buffer, + BUFFER_DATA_SIZE - cb->zstr.avail_out); + + /* If the deflate function did not fill the output buffer, + then all data has been flushed. */ + if (cb->zstr.avail_out > 0) + break; + } + + /* Now flush the underlying buffer. Note that if the original + call to buf_flush passed 1 for the BLOCK argument, then the + buffer will already have been set into blocking mode, so we + should always pass 0 here. */ + return buf_flush (cb->buf, 0); +} + +/* The block routine for a compression buffer. */ + +static int +compress_buffer_block (closure, block) + void *closure; + int block; +{ + struct compress_buffer *cb = (struct compress_buffer *) closure; + + if (block) + return set_block (cb->buf); + else + return set_nonblock (cb->buf); +} + +/* Shut down an input buffer. */ + +static int +compress_buffer_shutdown_input (closure) + void *closure; +{ + struct compress_buffer *cb = (struct compress_buffer *) closure; + int zstatus; + + /* Pick up any trailing data, such as the checksum. */ + while (1) + { + int status, nread; + char buf[100]; + + status = compress_buffer_input (cb, buf, 0, sizeof buf, &nread); + if (status == -1) + break; + if (status != 0) + return status; + } + + zstatus = inflateEnd (&cb->zstr); + if (zstatus != Z_OK) + { + compress_error (0, zstatus, &cb->zstr, "inflateEnd"); + return EIO; + } + + return buf_shutdown (cb->buf); +} + +/* Shut down an output buffer. */ + +static int +compress_buffer_shutdown_output (closure) + void *closure; +{ + struct compress_buffer *cb = (struct compress_buffer *) closure; + int zstatus, status; + + do + { + char buffer[BUFFER_DATA_SIZE]; + + cb->zstr.avail_out = BUFFER_DATA_SIZE; + cb->zstr.next_out = (unsigned char *) buffer; + + zstatus = deflate (&cb->zstr, Z_FINISH); + if (zstatus != Z_OK && zstatus != Z_STREAM_END) + { + compress_error (0, zstatus, &cb->zstr, "deflate finish"); + return EIO; + } + + if (cb->zstr.avail_out != BUFFER_DATA_SIZE) + buf_output (cb->buf, buffer, + BUFFER_DATA_SIZE - cb->zstr.avail_out); + } while (zstatus != Z_STREAM_END); + + zstatus = deflateEnd (&cb->zstr); + if (zstatus != Z_OK) + { + compress_error (0, zstatus, &cb->zstr, "deflateEnd"); + return EIO; + } + + status = buf_flush (cb->buf, 1); + if (status != 0) + return status; + + return buf_shutdown (cb->buf); +} + +#endif /* defined (SERVER_SUPPORT) || defined (CLIENT_SUPPORT) */ |