X-Git-Url: http://mj.ucw.cz/gitweb/?a=blobdiff_plain;ds=sidebyside;f=ucw%2Ffastbuf.h;h=4f0d99d3190be67c6fad8ae22e4e11a46760167d;hb=06cac26f0d8895b5cb8fbe03ca96444dc4ac8d51;hp=90c7648eafeac8ff28509a07892a198d7fec5e80;hpb=681b277c0aabea785a21e109dc07338847c0cb32;p=libucw.git

diff --git a/ucw/fastbuf.h b/ucw/fastbuf.h
index 90c7648e..4f0d99d3 100644
--- a/ucw/fastbuf.h
+++ b/ucw/fastbuf.h
@@ -1,7 +1,7 @@
 /*
  *	UCW Library -- Fast Buffered I/O
  *
- *	(c) 1997--2008 Martin Mares <mj@ucw.cz>
+ *	(c) 1997--2011 Martin Mares <mj@ucw.cz>
  *	(c) 2004 Robert Spalek <robert@ucw.cz>
  *
  *	This software may be freely distributed and used according to the terms
@@ -101,6 +101,7 @@
  *
  *   - Initialization:
  *     * out: `buffer <= bstop <= bptr <= bufend` (flushed).
+ *     * @fb_tie() should be called on the newly created fastbuf.
  *
  *   - `refill`:
  *     * in: `buffer <= bstop <= bptr <= bufend` (reading or flushed).
@@ -128,7 +129,6 @@
  * for how it works.
  **/
 struct fastbuf {
-  byte is_fastbuf[0];				/* Dummy field for checking of type casts */
   byte *bptr, *bstop;				/* State of the buffer */
   byte *buffer, *bufend;			/* Start and end of the buffer */
   char *name;					/* File name (used for error messages) */
@@ -143,8 +143,6 @@ struct fastbuf {
   struct resource *res;				/* The fastbuf can be tied to a resource pool */
 };
 
-void fb_tie(struct fastbuf *b);			/* Tie fastbuf to a resource if there is an active pool */
-
 /**
  * Fastbuf flags
  */
@@ -153,13 +151,14 @@ enum fb_flags {
   FB_DIE_ON_EOF = 0x2,				/* Most of read operations throw "fb.eof" on EOF */
 };
 
+/** Tie a fastbuf to a resource in the current resource pool. Returns the pointer to the same fastbuf. **/
+struct fastbuf *fb_tie(struct fastbuf *b);	/* Tie fastbuf to a resource if there is an active pool */
+
 /***
  * === Fastbuf on files [[fbparam]]
  *
  * If you want to use fastbufs to access files, you can choose one of several
  * back-ends and set their parameters.
- *
- * All file fastbufs are tied to resources automatically.
  ***/
 
 /**
@@ -195,7 +194,7 @@ extern struct fb_params fbpar_def;	/** The default `fb_params` **/
  * Use @params to select the fastbuf back-end and its parameters or
  * pass NULL if you are fine with defaults.
  *
- * Dies if the file does not exist.
+ * Raises `ucw.fb.open` if the file does not exist.
  **/
 struct fastbuf *bopen_file(const char *name, int mode, struct fb_params *params);
 struct fastbuf *bopen_file_try(const char *name, int mode, struct fb_params *params); /** Like bopen_file(), but returns NULL on failure. **/
@@ -306,8 +305,6 @@ void bclose_file_helper(struct fastbuf *f, int fd, int is_temp_file);
  *
  * The `fblim` back-end reads from a file handle, but at most a given
  * number of bytes. This is frequently used for reading from sockets.
- *
- * All such fastbufs are tied to resources automatically.
  ***/
 
 struct fastbuf *bopen_limited_fd(int fd, uns bufsize, uns limit); /** Create a fastbuf which reads at most @limit bytes from @fd. **/
@@ -322,8 +319,6 @@ struct fastbuf *bopen_limited_fd(int fd, uns bufsize, uns limit); /** Create a f
  * First, you use @fbmem_create() to create the stream and the fastbuf
  * used for writing to it. Then you can call @fbmem_clone_read() to get
  * an arbitrary number of fastbuf for reading from the stream.
- *
- * All in-memory fastbufs are tied to resources automatically.
  ***/
 
 struct fastbuf *fbmem_create(uns blocksize);		/** Create stream and return its writing fastbuf. **/
@@ -353,7 +348,7 @@ void fbbuf_init_read(struct fastbuf *f, byte *buffer, uns size, uns can_overwrit
 /**
  * Creates a write-only fastbuf which writes into a provided memory buffer.
  * The fastbuf structure is allocated by the caller and pointed to by @f.
- * An attempt to write behind the end of the buffer dies.
+ * An attempt to write behind the end of the buffer causes the `ucw.fb.write` exception.
  *
  * Data are written directly into the buffer, so it is not necessary to call @bflush()
  * at any moment.
@@ -376,14 +371,22 @@ static inline uns fbbuf_count_written(struct fastbuf *f) /** Calculates, how man
  * size and it is expanded to accomodate all data.
  *
  * At every moment, you can use `fastbuf->buffer` to gain access to the stream.
- *
- * All fastbufs of this type are tied to resources automatically.
  ***/
 
+struct mempool;
+
 struct fastbuf *fbgrow_create(unsigned basic_size);	/** Create the growing buffer pre-allocated to @basic_size bytes. **/
+struct fastbuf *fbgrow_create_mp(struct mempool *mp, unsigned basic_size); /** Create the growing buffer pre-allocated to @basic_size bytes. **/
 void fbgrow_reset(struct fastbuf *b);			/** Reset stream and prepare for writing. **/
 void fbgrow_rewind(struct fastbuf *b);			/** Prepare for reading (of already written data). **/
 
+/**
+ * Can be used in any state of @b (for example when writing or after
+ * @fbgrow_rewind()) to return the pointer to internal buffer and its length in
+ * bytes. The returned buffer can be invalidated by further requests.
+ **/
+uns fbgrow_get_buf(struct fastbuf *b, byte **buf);
+
 /***
  * === Fastbuf on memory pools [[fbpool]]
  *
@@ -391,7 +394,6 @@ void fbgrow_rewind(struct fastbuf *b);			/** Prepare for reading (of already wri
  * buffer, but this time the buffer is allocated from within a memory pool.
  ***/
 
-struct mempool;
 struct fbpool { /** Structure for fastbufs & mempools. **/
   struct fastbuf fb;
   struct mempool *mp;
@@ -434,8 +436,6 @@ void *fbpool_end(struct fbpool *fb);
  *
  * Please note that initialization of the clones is not thread-safe,
  * so you have to serialize it yourself.
- *
- * The atomic fastbufs are tied to resources automatically.
  ***/
 
 struct fb_atomic {
@@ -444,7 +444,6 @@ struct fb_atomic {
   byte *expected_max_bptr;
   uns slack_size;
 };
-#define FB_ATOMIC(f) ((struct fb_atomic *)(f)->is_fastbuf)
 
 /**
  * Open an atomic fastbuf.
@@ -474,6 +473,53 @@ static inline void fbatomic_commit(struct fastbuf *b)
     fbatomic_internal_write(b);
 }
 
+/***
+ * === Fastbufs atop other fastbufs [[fbmulti]]
+ *
+ * Imagine some code which does massive string processing. It takes an input
+ * buffer, writes a part of it into an output buffer, then some other string
+ * and then the remaining part of the input buffer. Or anything else where you
+ * copy all the data at each stage of the complicated process.
+ *
+ * This backend takes multiple fastbufs and concatenates them formally into
+ * one. You may then read them consecutively as they were one fastbuf at all.
+ *
+ * This backend is read-only.
+ *
+ * This backend is seekable iff all of the supplied fastbufs are seekable.
+ *
+ * You aren't allowed to do anything with the underlying buffers while these
+ * are connected into fbmulti.
+ *
+ * The fbmulti is inited by @fbmulti_create(). It returns an empty fbmulti.
+ * Then you call @fbmulti_append() for each fbmulti.
+ *
+ * If @bclose() is called on fbmulti, all the underlying buffers get closed
+ * recursively.
+ *
+ * If you want to keep an underlying fastbuf open after @bclose, just remove it
+ * by @fbmulti_remove where the second parameter is a pointer to the removed
+ * fastbuf. If you pass NULL, all the underlying fastbufs are removed.
+ *
+ * After @fbmulti_remove, the state of the fbmulti is undefined. The only allowed
+ * operation is either another @fbmulti_remove or @bclose on the fbmulti.
+ ***/
+
+/**
+ * Create an empty fbmulti
+ **/
+struct fastbuf *fbmulti_create(void);
+
+/**
+ * Append a fb to fbmulti
+ **/
+void fbmulti_append(struct fastbuf *f, struct fastbuf *fb);
+
+/**
+ * Remove a fb from fbmulti
+ **/
+void fbmulti_remove(struct fastbuf *f, struct fastbuf *fb);
+
 /*** === Configuring stream parameters [[bconfig]] ***/
 
 enum bconfig_type {			/** Parameters that could be configured. **/
@@ -567,7 +613,7 @@ static inline uns bread(struct fastbuf *f, void *b, uns l)
 /**
  * Reads exactly @l bytes of data into @b.
  * If at the end of file, it returns 0.
- * If there are data, but less than @l, it dies.
+ * If there are data, but less than @l, it raises `ucw.fb.eof`.
  */
 static inline uns breadb(struct fastbuf *f, void *b, uns l)
 {
@@ -596,7 +642,7 @@ static inline void bwrite(struct fastbuf *f, const void *b, uns l) /** Writes bu
 /**
  * Reads a line into @b and strips trailing `\n`.
  * Returns pointer to the terminating 0 or NULL on `EOF`.
- * Dies if the line is longer than @l.
+ * Raises `ucw.fb.toolong` if the line is longer than @l.
  **/
 char *bgets(struct fastbuf *f, char *b, uns l);
 char *bgets0(struct fastbuf *f, char *b, uns l);	/** The same as @bgets(), but for 0-terminated strings. **/
@@ -610,7 +656,7 @@ struct mempool;
 struct bb_t;
 /**
  * Read a string, strip the trailing `\n` and store it into growing buffer @b.
- * Dies if the line is longer than @limit.
+ * Raises `ucw.fb.toolong` if the line is longer than @limit.
  **/
 uns bgets_bb(struct fastbuf *f, struct bb_t *b, uns limit);
 /**