Add a growable sprintf memory buffer library

git-svn-id: svn://svn.berlios.de/openocd/trunk@2381 b42882b7-edfa-0310-969c-e2dbd0fdcd60

src/helper/membuf.h

@@ -0,0 +1,118 @@
+#ifndef HELPER_MEMBUF_H
+#define HELPER_MEMBUF_H
+
+/** @file */
+
+/** @page MEMBUF - an auto-growing string buffer
+ *
+ * With OpenOCD often, one must write code that sends text to
+ * different places.. the historical command_ctx, or JIM output,
+ * and/or other places.
+ *
+ * This is a simple 'string buffer' that auto-grows.
+ *
+ * More correctly put, this is a "memory buffer"
+ * it may contain binary data 
+ * 
+ * Note: Internally the buffer always has a 'null terminator'
+ */
+
+/* contents of this structure are 'opaque' */
+struct membuf;
+  
+
+/** Create a new membuf
+ * By default the memory buffer has "some non-zero-size"
+ * (couple hundred bytes, exact amount is opaque)
+ */
+struct membuf *membuf_new(void);
+
+/** delete (destroy) the mem buffer
+ * @param pBuf - buffer to release
+ */
+void membuf_delete( struct membuf *pBuf );
+
+
+/** grow/shrink a membuf by specified amount.
+ * @param pBuf   - the buffer 
+ * @param amount - the amount to grow or shrink by.
+ *
+ * Symantics of 'realloc()' return NULL on failure
+ */
+struct membuf *membuf_grow( struct membuf *pBuf, int amount );
+
+/** how long is this buffer (memlen(), strlen())
+ * @param pBuf - the buffer
+ * 
+ * @returns: length of current buffer.
+ */
+size_t membuf_len( struct membuf *pBuf );
+
+
+/** reset an membuf to zero length.
+ * @param pBuf - buffer to reset
+ *
+ * Note this does not 'release' the memory buffer
+ */
+void membuf_reset( struct membuf *pBuf );
+
+
+/** sprintf() to the string buffer
+ * @param pBuf - buffer to capture sprintf() data into
+ * @param fmt  - printf format
+ *
+ * Returns 0 on success
+ * Returns non-zero on failure
+ */
+int membuf_sprintf( struct membuf *pBuf , const char *fmt, ... );
+
+/** vsprintf() to the string buffer
+ * @param pBuf - buffer to capture sprintf() data into
+ * @param fmt  - printf format
+ * @param ap   - va_list for fmt
+ *
+ * Returns 0 on success
+ * Returns non-zero on failure
+ */
+int membuf_vsprintf( struct membuf *pBuf , const char *fmt, va_list ap);
+
+/** Tokenize lines using strtok() 
+ * @param pBuf - buffer to tokenize
+ * @param delim - delimiter parameter for strtok_r()
+ * 
+ * Identical to "strtok()" - pass "pBuff=NULL" on second call
+ *
+ * NOTE: This call is <b>destructive</b> to the buffer.
+ */
+const char *membuf_strtok( struct membuf *pBuf, const char *delim, void **pSave );
+
+/** Return pointer to the memory in the buffer
+ * @param pBuf - buffer
+ *
+ * NOTE: Thou shall not modify this pointer, it is <b>CONST</b>
+ */
+const void *membuf_datapointer( struct membuf *pBuf );
+
+
+/** Append data to the buffer
+ * @param pBuf  - buffer to append
+ * @param pData - pointer to data to append
+ * @param len   - length of data to append
+ *
+ * Modified symantics of "memcpy()".  On memory allocation failure
+ * returns NULL.  On success, returns pointer to orginal membuf.
+ */
+struct membuf *membuf_append( struct membuf *pBuf, const void *pData, size_t len );
+
+
+/** Append string to the buffer
+ * @param pBuf  - buffer to append
+ * @param str   - string to append
+ *
+ * Modified symantics of "strcat()".  On memory allocation failure
+ * returns NULL.  On success, returns pointer to orginal membuf.
+ */
+struct membuf *membuf_strcat( struct membuf *pBuf, const char *s );
+
+
+#endif