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-rw-r--r--contrib/cvs/src/buffer.c1294
1 files changed, 1294 insertions, 0 deletions
diff --git a/contrib/cvs/src/buffer.c b/contrib/cvs/src/buffer.c
new file mode 100644
index 0000000..d6ea895
--- /dev/null
+++ b/contrib/cvs/src/buffer.c
@@ -0,0 +1,1294 @@
+/* Code for the buffer data structure. */
+
+#include <assert.h>
+#include "cvs.h"
+#include "buffer.h"
+
+#if defined (SERVER_SUPPORT) || defined (CLIENT_SUPPORT)
+
+/* 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
+
+/* Linked list of available buffer_data structures. */
+static struct buffer_data *free_buffer_data;
+
+/* Local functions. */
+static void allocate_buffer_datas PROTO((void));
+static struct buffer_data *get_buffer_data PROTO((void));
+
+/* Initialize a buffer structure. */
+
+struct buffer *
+buf_initialize (input, output, flush, block, shutdown, memory, closure)
+ int (*input) PROTO((void *, char *, int, int, int *));
+ int (*output) PROTO((void *, const char *, int, int *));
+ int (*flush) PROTO((void *));
+ int (*block) PROTO((void *, int));
+ int (*shutdown) PROTO((void *));
+ void (*memory) PROTO((struct buffer *));
+ void *closure;
+{
+ struct buffer *buf;
+
+ buf = (struct buffer *) xmalloc (sizeof (struct buffer));
+ buf->data = NULL;
+ buf->last = NULL;
+ buf->nonblocking = 0;
+ buf->input = input;
+ buf->output = output;
+ buf->flush = flush;
+ buf->block = block;
+ buf->shutdown = shutdown;
+ buf->memory_error = memory;
+ buf->closure = closure;
+ return buf;
+}
+
+/* Initialize a buffer structure which is not to be used for I/O. */
+
+struct buffer *
+buf_nonio_initialize (memory)
+ void (*memory) PROTO((struct buffer *));
+{
+ return (buf_initialize
+ ((int (*) PROTO((void *, char *, int, int, int *))) NULL,
+ (int (*) PROTO((void *, const char *, int, int *))) NULL,
+ (int (*) PROTO((void *))) NULL,
+ (int (*) PROTO((void *, int))) NULL,
+ (int (*) PROTO((void *))) NULL,
+ memory,
+ (void *) NULL));
+}
+
+/* Allocate more buffer_data structures. */
+
+static void
+allocate_buffer_datas ()
+{
+ struct buffer_data *alc;
+ char *space;
+ int i;
+
+ /* Allocate buffer_data structures in blocks of 16. */
+#define ALLOC_COUNT (16)
+
+ alc = ((struct buffer_data *)
+ malloc (ALLOC_COUNT * sizeof (struct buffer_data)));
+ space = (char *) valloc (ALLOC_COUNT * BUFFER_DATA_SIZE);
+ if (alc == NULL || space == NULL)
+ return;
+ for (i = 0; i < ALLOC_COUNT; i++, alc++, space += BUFFER_DATA_SIZE)
+ {
+ alc->next = free_buffer_data;
+ free_buffer_data = alc;
+ alc->text = space;
+ }
+}
+
+/* Get a new buffer_data structure. */
+
+static struct buffer_data *
+get_buffer_data ()
+{
+ struct buffer_data *ret;
+
+ if (free_buffer_data == NULL)
+ {
+ allocate_buffer_datas ();
+ if (free_buffer_data == NULL)
+ return NULL;
+ }
+
+ ret = free_buffer_data;
+ free_buffer_data = ret->next;
+ return ret;
+}
+
+/* See whether a buffer is empty. */
+
+int
+buf_empty_p (buf)
+ struct buffer *buf;
+{
+ struct buffer_data *data;
+
+ for (data = buf->data; data != NULL; data = data->next)
+ if (data->size > 0)
+ return 0;
+ return 1;
+}
+
+#ifdef SERVER_FLOWCONTROL
+/*
+ * Count how much data is stored in the buffer..
+ * Note that each buffer is a malloc'ed chunk BUFFER_DATA_SIZE.
+ */
+
+int
+buf_count_mem (buf)
+ struct buffer *buf;
+{
+ struct buffer_data *data;
+ int mem = 0;
+
+ for (data = buf->data; data != NULL; data = data->next)
+ mem += BUFFER_DATA_SIZE;
+
+ return mem;
+}
+#endif /* SERVER_FLOWCONTROL */
+
+/* Add data DATA of length LEN to BUF. */
+
+void
+buf_output (buf, data, len)
+ struct buffer *buf;
+ const char *data;
+ int len;
+{
+ if (buf->data != NULL
+ && (((buf->last->text + BUFFER_DATA_SIZE)
+ - (buf->last->bufp + buf->last->size))
+ >= len))
+ {
+ memcpy (buf->last->bufp + buf->last->size, data, len);
+ buf->last->size += len;
+ return;
+ }
+
+ while (1)
+ {
+ struct buffer_data *newdata;
+
+ newdata = get_buffer_data ();
+ if (newdata == NULL)
+ {
+ (*buf->memory_error) (buf);
+ return;
+ }
+
+ if (buf->data == NULL)
+ buf->data = newdata;
+ else
+ buf->last->next = newdata;
+ newdata->next = NULL;
+ buf->last = newdata;
+
+ newdata->bufp = newdata->text;
+
+ if (len <= BUFFER_DATA_SIZE)
+ {
+ newdata->size = len;
+ memcpy (newdata->text, data, len);
+ return;
+ }
+
+ newdata->size = BUFFER_DATA_SIZE;
+ memcpy (newdata->text, data, BUFFER_DATA_SIZE);
+
+ data += BUFFER_DATA_SIZE;
+ len -= BUFFER_DATA_SIZE;
+ }
+
+ /*NOTREACHED*/
+}
+
+/* Add a '\0' terminated string to BUF. */
+
+void
+buf_output0 (buf, string)
+ struct buffer *buf;
+ const char *string;
+{
+ buf_output (buf, string, strlen (string));
+}
+
+/* Add a single character to BUF. */
+
+void
+buf_append_char (buf, ch)
+ struct buffer *buf;
+ int ch;
+{
+ if (buf->data != NULL
+ && (buf->last->text + BUFFER_DATA_SIZE
+ != buf->last->bufp + buf->last->size))
+ {
+ *(buf->last->bufp + buf->last->size) = ch;
+ ++buf->last->size;
+ }
+ else
+ {
+ char b;
+
+ b = ch;
+ buf_output (buf, &b, 1);
+ }
+}
+
+/*
+ * Send all the output we've been saving up. Returns 0 for success or
+ * errno code. If the buffer has been set to be nonblocking, this
+ * will just write until the write would block.
+ */
+
+int
+buf_send_output (buf)
+ struct buffer *buf;
+{
+ if (buf->output == NULL)
+ abort ();
+
+ while (buf->data != NULL)
+ {
+ struct buffer_data *data;
+
+ data = buf->data;
+
+ if (data->size > 0)
+ {
+ int status, nbytes;
+
+ status = (*buf->output) (buf->closure, data->bufp, data->size,
+ &nbytes);
+ if (status != 0)
+ {
+ /* Some sort of error. Discard the data, and return. */
+
+ buf->last->next = free_buffer_data;
+ free_buffer_data = buf->data;
+ buf->data = NULL;
+ buf->last = NULL;
+
+ return status;
+ }
+
+ if (nbytes != data->size)
+ {
+ /* Not all the data was written out. This is only
+ permitted in nonblocking mode. Adjust the buffer,
+ and return. */
+
+ assert (buf->nonblocking);
+
+ data->size -= nbytes;
+ data->bufp += nbytes;
+
+ return 0;
+ }
+ }
+
+ buf->data = data->next;
+ data->next = free_buffer_data;
+ free_buffer_data = data;
+ }
+
+ buf->last = NULL;
+
+ return 0;
+}
+
+/*
+ * Flush any data queued up in the buffer. If BLOCK is nonzero, then
+ * if the buffer is in nonblocking mode, put it into blocking mode for
+ * the duration of the flush. This returns 0 on success, or an error
+ * code.
+ */
+
+int
+buf_flush (buf, block)
+ struct buffer *buf;
+ int block;
+{
+ int nonblocking;
+ int status;
+
+ if (buf->flush == NULL)
+ abort ();
+
+ nonblocking = buf->nonblocking;
+ if (nonblocking && block)
+ {
+ status = set_block (buf);
+ if (status != 0)
+ return status;
+ }
+
+ status = buf_send_output (buf);
+ if (status == 0)
+ status = (*buf->flush) (buf->closure);
+
+ if (nonblocking && block)
+ {
+ int blockstat;
+
+ blockstat = set_nonblock (buf);
+ if (status == 0)
+ status = blockstat;
+ }
+
+ return status;
+}
+
+/*
+ * Set buffer BUF to nonblocking I/O. Returns 0 for success or errno
+ * code.
+ */
+
+int
+set_nonblock (buf)
+ struct buffer *buf;
+{
+ int status;
+
+ if (buf->nonblocking)
+ return 0;
+ if (buf->block == NULL)
+ abort ();
+ status = (*buf->block) (buf->closure, 0);
+ if (status != 0)
+ return status;
+ buf->nonblocking = 1;
+ return 0;
+}
+
+/*
+ * Set buffer BUF to blocking I/O. Returns 0 for success or errno
+ * code.
+ */
+
+int
+set_block (buf)
+ struct buffer *buf;
+{
+ int status;
+
+ if (! buf->nonblocking)
+ return 0;
+ if (buf->block == NULL)
+ abort ();
+ status = (*buf->block) (buf->closure, 1);
+ if (status != 0)
+ return status;
+ buf->nonblocking = 0;
+ return 0;
+}
+
+/*
+ * Send a character count and some output. Returns errno code or 0 for
+ * success.
+ *
+ * Sending the count in binary is OK since this is only used on a pipe
+ * within the same system.
+ */
+
+int
+buf_send_counted (buf)
+ struct buffer *buf;
+{
+ int size;
+ struct buffer_data *data;
+
+ size = 0;
+ for (data = buf->data; data != NULL; data = data->next)
+ size += data->size;
+
+ data = get_buffer_data ();
+ if (data == NULL)
+ {
+ (*buf->memory_error) (buf);
+ return ENOMEM;
+ }
+
+ data->next = buf->data;
+ buf->data = data;
+ if (buf->last == NULL)
+ buf->last = data;
+
+ data->bufp = data->text;
+ data->size = sizeof (int);
+
+ *((int *) data->text) = size;
+
+ return buf_send_output (buf);
+}
+
+/*
+ * Send a special count. COUNT should be negative. It will be
+ * handled speciallyi by buf_copy_counted. This function returns 0 or
+ * an errno code.
+ *
+ * Sending the count in binary is OK since this is only used on a pipe
+ * within the same system.
+ */
+
+int
+buf_send_special_count (buf, count)
+ struct buffer *buf;
+ int count;
+{
+ struct buffer_data *data;
+
+ data = get_buffer_data ();
+ if (data == NULL)
+ {
+ (*buf->memory_error) (buf);
+ return ENOMEM;
+ }
+
+ data->next = buf->data;
+ buf->data = data;
+ if (buf->last == NULL)
+ buf->last = data;
+
+ data->bufp = data->text;
+ data->size = sizeof (int);
+
+ *((int *) data->text) = count;
+
+ return buf_send_output (buf);
+}
+
+/* Append a list of buffer_data structures to an buffer. */
+
+void
+buf_append_data (buf, data, last)
+ struct buffer *buf;
+ struct buffer_data *data;
+ struct buffer_data *last;
+{
+ if (data != NULL)
+ {
+ if (buf->data == NULL)
+ buf->data = data;
+ else
+ buf->last->next = data;
+ buf->last = last;
+ }
+}
+
+/*
+ * Copy the contents of file F into buffer_data structures. We can't
+ * copy directly into an buffer, because we want to handle failure and
+ * succeess differently. Returns 0 on success, or -2 if out of
+ * memory, or a status code on error. Since the caller happens to
+ * know the size of the file, it is passed in as SIZE. On success,
+ * this function sets *RETP and *LASTP, which may be passed to
+ * buf_append_data.
+ */
+
+int
+buf_read_file (f, size, retp, lastp)
+ FILE *f;
+ long size;
+ struct buffer_data **retp;
+ struct buffer_data **lastp;
+{
+ int status;
+
+ *retp = NULL;
+ *lastp = NULL;
+
+ while (size > 0)
+ {
+ struct buffer_data *data;
+ int get;
+
+ data = get_buffer_data ();
+ if (data == NULL)
+ {
+ status = -2;
+ goto error_return;
+ }
+
+ if (*retp == NULL)
+ *retp = data;
+ else
+ (*lastp)->next = data;
+ data->next = NULL;
+ *lastp = data;
+
+ data->bufp = data->text;
+ data->size = 0;
+
+ if (size > BUFFER_DATA_SIZE)
+ get = BUFFER_DATA_SIZE;
+ else
+ get = size;
+
+ errno = EIO;
+ if (fread (data->text, get, 1, f) != 1)
+ {
+ status = errno;
+ goto error_return;
+ }
+
+ data->size += get;
+ size -= get;
+ }
+
+ return 0;
+
+ error_return:
+ if (*retp != NULL)
+ {
+ (*lastp)->next = free_buffer_data;
+ free_buffer_data = *retp;
+ }
+ return status;
+}
+
+/*
+ * Copy the contents of file F into buffer_data structures. We can't
+ * copy directly into an buffer, because we want to handle failure and
+ * succeess differently. Returns 0 on success, or -2 if out of
+ * memory, or a status code on error. On success, this function sets
+ * *RETP and *LASTP, which may be passed to buf_append_data.
+ */
+
+int
+buf_read_file_to_eof (f, retp, lastp)
+ FILE *f;
+ struct buffer_data **retp;
+ struct buffer_data **lastp;
+{
+ int status;
+
+ *retp = NULL;
+ *lastp = NULL;
+
+ while (!feof (f))
+ {
+ struct buffer_data *data;
+ int get, nread;
+
+ data = get_buffer_data ();
+ if (data == NULL)
+ {
+ status = -2;
+ goto error_return;
+ }
+
+ if (*retp == NULL)
+ *retp = data;
+ else
+ (*lastp)->next = data;
+ data->next = NULL;
+ *lastp = data;
+
+ data->bufp = data->text;
+ data->size = 0;
+
+ get = BUFFER_DATA_SIZE;
+
+ errno = EIO;
+ nread = fread (data->text, 1, get, f);
+ if (nread == 0 && !feof (f))
+ {
+ status = errno;
+ goto error_return;
+ }
+
+ data->size = nread;
+ }
+
+ return 0;
+
+ error_return:
+ if (*retp != NULL)
+ {
+ (*lastp)->next = free_buffer_data;
+ free_buffer_data = *retp;
+ }
+ return status;
+}
+
+/* Return the number of bytes in a chain of buffer_data structures. */
+
+int
+buf_chain_length (buf)
+ struct buffer_data *buf;
+{
+ int size = 0;
+ while (buf)
+ {
+ size += buf->size;
+ buf = buf->next;
+ }
+ return size;
+}
+
+/*
+ * Read an arbitrary amount of data into an input buffer. The buffer
+ * will be in nonblocking mode, and we just grab what we can. Return
+ * 0 on success, or -1 on end of file, or -2 if out of memory, or an
+ * error code. If COUNTP is not NULL, *COUNTP is set to the number of
+ * bytes read.
+ */
+
+int
+buf_input_data (buf, countp)
+ struct buffer *buf;
+ int *countp;
+{
+ if (buf->input == NULL)
+ abort ();
+
+ if (countp != NULL)
+ *countp = 0;
+
+ while (1)
+ {
+ int get;
+ int status, nbytes;
+
+ if (buf->data == NULL
+ || (buf->last->bufp + buf->last->size
+ == buf->last->text + BUFFER_DATA_SIZE))
+ {
+ struct buffer_data *data;
+
+ data = get_buffer_data ();
+ if (data == NULL)
+ {
+ (*buf->memory_error) (buf);
+ return -2;
+ }
+
+ if (buf->data == NULL)
+ buf->data = data;
+ else
+ buf->last->next = data;
+ data->next = NULL;
+ buf->last = data;
+
+ data->bufp = data->text;
+ data->size = 0;
+ }
+
+ get = ((buf->last->text + BUFFER_DATA_SIZE)
+ - (buf->last->bufp + buf->last->size));
+
+ status = (*buf->input) (buf->closure,
+ buf->last->bufp + buf->last->size,
+ 0, get, &nbytes);
+ if (status != 0)
+ return status;
+
+ buf->last->size += nbytes;
+ if (countp != NULL)
+ *countp += nbytes;
+
+ if (nbytes < get)
+ {
+ /* If we did not fill the buffer, then presumably we read
+ all the available data. */
+ return 0;
+ }
+ }
+
+ /*NOTREACHED*/
+}
+
+/*
+ * Read a line (characters up to a \012) from an input buffer. (We
+ * use \012 rather than \n for the benefit of non Unix clients for
+ * which \n means something else). This returns 0 on success, or -1
+ * on end of file, or -2 if out of memory, or an error code. If it
+ * succeeds, it sets *LINE to an allocated buffer holding the contents
+ * of the line. The trailing \012 is not included in the buffer. If
+ * LENP is not NULL, then *LENP is set to the number of bytes read;
+ * strlen may not work, because there may be embedded null bytes.
+ */
+
+int
+buf_read_line (buf, line, lenp)
+ struct buffer *buf;
+ char **line;
+ int *lenp;
+{
+ if (buf->input == NULL)
+ abort ();
+
+ *line = NULL;
+
+ while (1)
+ {
+ int len, finallen = 0;
+ struct buffer_data *data;
+ char *nl;
+
+ /* See if there is a newline in BUF. */
+ len = 0;
+ for (data = buf->data; data != NULL; data = data->next)
+ {
+ nl = memchr (data->bufp, '\012', data->size);
+ if (nl != NULL)
+ {
+ finallen = nl - data->bufp;
+ len += finallen;
+ break;
+ }
+ len += data->size;
+ }
+
+ /* If we found a newline, copy the line into a memory buffer,
+ and remove it from BUF. */
+ if (data != NULL)
+ {
+ char *p;
+ struct buffer_data *nldata;
+
+ p = malloc (len + 1);
+ if (p == NULL)
+ return -2;
+ *line = p;
+
+ nldata = data;
+ data = buf->data;
+ while (data != nldata)
+ {
+ struct buffer_data *next;
+
+ memcpy (p, data->bufp, data->size);
+ p += data->size;
+ next = data->next;
+ data->next = free_buffer_data;
+ free_buffer_data = data;
+ data = next;
+ }
+
+ memcpy (p, data->bufp, finallen);
+ p[finallen] = '\0';
+
+ data->size -= finallen + 1;
+ data->bufp = nl + 1;
+ buf->data = data;
+
+ if (lenp != NULL)
+ *lenp = len;
+
+ return 0;
+ }
+
+ /* Read more data until we get a newline. */
+ while (1)
+ {
+ int size, status, nbytes;
+ char *mem;
+
+ if (buf->data == NULL
+ || (buf->last->bufp + buf->last->size
+ == buf->last->text + BUFFER_DATA_SIZE))
+ {
+ data = get_buffer_data ();
+ if (data == NULL)
+ {
+ (*buf->memory_error) (buf);
+ return -2;
+ }
+
+ if (buf->data == NULL)
+ buf->data = data;
+ else
+ buf->last->next = data;
+ data->next = NULL;
+ buf->last = data;
+
+ data->bufp = data->text;
+ data->size = 0;
+ }
+
+ mem = buf->last->bufp + buf->last->size;
+ size = (buf->last->text + BUFFER_DATA_SIZE) - mem;
+
+ /* We need to read at least 1 byte. We can handle up to
+ SIZE bytes. This will only be efficient if the
+ underlying communication stream does its own buffering,
+ or is clever about getting more than 1 byte at a time. */
+ status = (*buf->input) (buf->closure, mem, 1, size, &nbytes);
+ if (status != 0)
+ return status;
+
+ buf->last->size += nbytes;
+
+ /* Optimize slightly to avoid an unnecessary call to
+ memchr. */
+ if (nbytes == 1)
+ {
+ if (*mem == '\012')
+ break;
+ }
+ else
+ {
+ if (memchr (mem, '\012', nbytes) != NULL)
+ break;
+ }
+ }
+ }
+}
+
+/*
+ * Extract data from the input buffer BUF. This will read up to WANT
+ * bytes from the buffer. It will set *RETDATA to point at the bytes,
+ * and set *GOT to the number of bytes to be found there. Any buffer
+ * call which uses BUF may change the contents of the buffer at *DATA,
+ * so the data should be fully processed before any further calls are
+ * made. This returns 0 on success, or -1 on end of file, or -2 if
+ * out of memory, or an error code.
+ */
+
+int
+buf_read_data (buf, want, retdata, got)
+ struct buffer *buf;
+ int want;
+ char **retdata;
+ int *got;
+{
+ if (buf->input == NULL)
+ abort ();
+
+ while (buf->data != NULL && buf->data->size == 0)
+ {
+ struct buffer_data *next;
+
+ next = buf->data->next;
+ buf->data->next = free_buffer_data;
+ free_buffer_data = buf->data;
+ buf->data = next;
+ if (next == NULL)
+ buf->last = NULL;
+ }
+
+ if (buf->data == NULL)
+ {
+ struct buffer_data *data;
+ int get, status, nbytes;
+
+ data = get_buffer_data ();
+ if (data == NULL)
+ {
+ (*buf->memory_error) (buf);
+ return -2;
+ }
+
+ buf->data = data;
+ buf->last = data;
+ data->next = NULL;
+ data->bufp = data->text;
+ data->size = 0;
+
+ if (want < BUFFER_DATA_SIZE)
+ get = want;
+ else
+ get = BUFFER_DATA_SIZE;
+ status = (*buf->input) (buf->closure, data->bufp, get,
+ BUFFER_DATA_SIZE, &nbytes);
+ if (status != 0)
+ return status;
+
+ data->size = nbytes;
+ }
+
+ *retdata = buf->data->bufp;
+ if (want < buf->data->size)
+ {
+ *got = want;
+ buf->data->size -= want;
+ buf->data->bufp += want;
+ }
+ else
+ {
+ *got = buf->data->size;
+ buf->data->size = 0;
+ }
+
+ return 0;
+}
+
+/*
+ * Copy lines from an input buffer to an output buffer. This copies
+ * all complete lines (characters up to a newline) from INBUF to
+ * OUTBUF. Each line in OUTBUF is preceded by the character COMMAND
+ * and a space.
+ */
+
+void
+buf_copy_lines (outbuf, inbuf, command)
+ struct buffer *outbuf;
+ struct buffer *inbuf;
+ int command;
+{
+ while (1)
+ {
+ struct buffer_data *data;
+ struct buffer_data *nldata;
+ char *nl;
+ int len;
+
+ /* See if there is a newline in INBUF. */
+ nldata = NULL;
+ nl = NULL;
+ for (data = inbuf->data; data != NULL; data = data->next)
+ {
+ nl = memchr (data->bufp, '\n', data->size);
+ if (nl != NULL)
+ {
+ nldata = data;
+ break;
+ }
+ }
+
+ if (nldata == NULL)
+ {
+ /* There are no more lines in INBUF. */
+ return;
+ }
+
+ /* Put in the command. */
+ buf_append_char (outbuf, command);
+ buf_append_char (outbuf, ' ');
+
+ if (inbuf->data != nldata)
+ {
+ /*
+ * Simply move over all the buffers up to the one containing
+ * the newline.
+ */
+ for (data = inbuf->data; data->next != nldata; data = data->next)
+ ;
+ data->next = NULL;
+ buf_append_data (outbuf, inbuf->data, data);
+ inbuf->data = nldata;
+ }
+
+ /*
+ * If the newline is at the very end of the buffer, just move
+ * the buffer onto OUTBUF. Otherwise we must copy the data.
+ */
+ len = nl + 1 - nldata->bufp;
+ if (len == nldata->size)
+ {
+ inbuf->data = nldata->next;
+ if (inbuf->data == NULL)
+ inbuf->last = NULL;
+
+ nldata->next = NULL;
+ buf_append_data (outbuf, nldata, nldata);
+ }
+ else
+ {
+ buf_output (outbuf, nldata->bufp, len);
+ nldata->bufp += len;
+ nldata->size -= len;
+ }
+ }
+}
+
+/*
+ * Copy counted data from one buffer to another. The count is an
+ * integer, host size, host byte order (it is only used across a
+ * pipe). If there is enough data, it should be moved over. If there
+ * is not enough data, it should remain on the original buffer. A
+ * negative count is a special case. if one is seen, *SPECIAL is set
+ * to the (negative) count value and no additional data is gathered
+ * from the buffer; normally *SPECIAL is set to 0. This function
+ * returns the number of bytes it needs to see in order to actually
+ * copy something over.
+ */
+
+int
+buf_copy_counted (outbuf, inbuf, special)
+ struct buffer *outbuf;
+ struct buffer *inbuf;
+ int *special;
+{
+ *special = 0;
+
+ while (1)
+ {
+ struct buffer_data *data;
+ int need;
+ union
+ {
+ char intbuf[sizeof (int)];
+ int i;
+ } u;
+ char *intp;
+ int count;
+ struct buffer_data *start;
+ int startoff;
+ struct buffer_data *stop;
+ int stopwant;
+
+ /* See if we have enough bytes to figure out the count. */
+ need = sizeof (int);
+ intp = u.intbuf;
+ for (data = inbuf->data; data != NULL; data = data->next)
+ {
+ if (data->size >= need)
+ {
+ memcpy (intp, data->bufp, need);
+ break;
+ }
+ memcpy (intp, data->bufp, data->size);
+ intp += data->size;
+ need -= data->size;
+ }
+ if (data == NULL)
+ {
+ /* We don't have enough bytes to form an integer. */
+ return need;
+ }
+
+ count = u.i;
+ start = data;
+ startoff = need;
+
+ if (count < 0)
+ {
+ /* A negative COUNT is a special case meaning that we
+ don't need any further information. */
+ stop = start;
+ stopwant = 0;
+ }
+ else
+ {
+ /*
+ * We have an integer in COUNT. We have gotten all the
+ * data from INBUF in all buffers before START, and we
+ * have gotten STARTOFF bytes from START. See if we have
+ * enough bytes remaining in INBUF.
+ */
+ need = count - (start->size - startoff);
+ if (need <= 0)
+ {
+ stop = start;
+ stopwant = count;
+ }
+ else
+ {
+ for (data = start->next; data != NULL; data = data->next)
+ {
+ if (need <= data->size)
+ break;
+ need -= data->size;
+ }
+ if (data == NULL)
+ {
+ /* We don't have enough bytes. */
+ return need;
+ }
+ stop = data;
+ stopwant = need;
+ }
+ }
+
+ /*
+ * We have enough bytes. Free any buffers in INBUF before
+ * START, and remove STARTOFF bytes from START, so that we can
+ * forget about STARTOFF.
+ */
+ start->bufp += startoff;
+ start->size -= startoff;
+
+ if (start->size == 0)
+ start = start->next;
+
+ if (stop->size == stopwant)
+ {
+ stop = stop->next;
+ stopwant = 0;
+ }
+
+ while (inbuf->data != start)
+ {
+ data = inbuf->data;
+ inbuf->data = data->next;
+ data->next = free_buffer_data;
+ free_buffer_data = data;
+ }
+
+ /* If COUNT is negative, set *SPECIAL and get out now. */
+ if (count < 0)
+ {
+ *special = count;
+ return 0;
+ }
+
+ /*
+ * We want to copy over the bytes from START through STOP. We
+ * only want STOPWANT bytes from STOP.
+ */
+
+ if (start != stop)
+ {
+ /* Attach the buffers from START through STOP to OUTBUF. */
+ for (data = start; data->next != stop; data = data->next)
+ ;
+ inbuf->data = stop;
+ data->next = NULL;
+ buf_append_data (outbuf, start, data);
+ }
+
+ if (stopwant > 0)
+ {
+ buf_output (outbuf, stop->bufp, stopwant);
+ stop->bufp += stopwant;
+ stop->size -= stopwant;
+ }
+ }
+
+ /*NOTREACHED*/
+}
+
+/* Shut down a buffer. This returns 0 on success, or an errno code. */
+
+int
+buf_shutdown (buf)
+ struct buffer *buf;
+{
+ if (buf->shutdown)
+ return (*buf->shutdown) (buf->closure);
+ return 0;
+}
+
+/* The simplest type of buffer is one built on top of a stdio FILE.
+ For simplicity, and because it is all that is required, we do not
+ implement setting this type of buffer into nonblocking mode. The
+ closure field is just a FILE *. */
+
+static int stdio_buffer_input PROTO((void *, char *, int, int, int *));
+static int stdio_buffer_output PROTO((void *, const char *, int, int *));
+static int stdio_buffer_flush PROTO((void *));
+
+/* Initialize a buffer built on a stdio FILE. */
+
+struct buffer
+*stdio_buffer_initialize (fp, input, memory)
+ FILE *fp;
+ int input;
+ void (*memory) PROTO((struct buffer *));
+{
+ return buf_initialize (input ? stdio_buffer_input : NULL,
+ input ? NULL : stdio_buffer_output,
+ input ? NULL : stdio_buffer_flush,
+ (int (*) PROTO((void *, int))) NULL,
+ (int (*) PROTO((void *))) NULL,
+ memory,
+ (void *) fp);
+}
+
+/* The buffer input function for a buffer built on a stdio FILE. */
+
+static int
+stdio_buffer_input (closure, data, need, size, got)
+ void *closure;
+ char *data;
+ int need;
+ int size;
+ int *got;
+{
+ FILE *fp = (FILE *) closure;
+ int nbytes;
+
+ /* Since stdio does its own buffering, we don't worry about
+ getting more bytes than we need. */
+
+ if (need == 0 || need == 1)
+ {
+ int ch;
+
+ ch = getc (fp);
+
+ if (ch == EOF)
+ {
+ if (feof (fp))
+ return -1;
+ else if (errno == 0)
+ return EIO;
+ else
+ return errno;
+ }
+
+ *data = ch;
+ *got = 1;
+ return 0;
+ }
+
+ nbytes = fread (data, 1, need, fp);
+
+ if (nbytes == 0)
+ {
+ *got = 0;
+ if (feof (fp))
+ return -1;
+ else if (errno == 0)
+ return EIO;
+ else
+ return errno;
+ }
+
+ *got = nbytes;
+
+ return 0;
+}
+
+/* The buffer output function for a buffer built on a stdio FILE. */
+
+static int
+stdio_buffer_output (closure, data, have, wrote)
+ void *closure;
+ const char *data;
+ int have;
+ int *wrote;
+{
+ FILE *fp = (FILE *) closure;
+
+ *wrote = 0;
+
+ while (have > 0)
+ {
+ int nbytes;
+
+ nbytes = fwrite (data, 1, have, fp);
+
+ if (nbytes != have)
+ {
+ if (errno == 0)
+ return EIO;
+ else
+ return errno;
+ }
+
+ *wrote += nbytes;
+ have -= nbytes;
+ data += nbytes;
+ }
+
+ return 0;
+}
+
+/* The buffer flush function for a buffer built on a stdio FILE. */
+
+static int
+stdio_buffer_flush (closure)
+ void *closure;
+{
+ FILE *fp = (FILE *) closure;
+
+ if (fflush (fp) != 0)
+ {
+ if (errno == 0)
+ return EIO;
+ else
+ return errno;
+ }
+
+ return 0;
+}
+
+#endif /* defined (SERVER_SUPPORT) || defined (CLIENT_SUPPORT) */
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