X-Git-Url: http://git.silcnet.org/gitweb/?a=blobdiff_plain;f=lib%2Fsilcutil%2Fsilcstack.h;h=f2663eef949e4b37b8774b9391d85ca56a301d48;hb=e7b6c157b80152bf9fb9266e6bdd93f9fb0db776;hp=8003666f9d9ff12478914d0c681cdcb9f8f07179;hpb=3d836f704311455db019d48b0666bb11a52a5a88;p=silc.git diff --git a/lib/silcutil/silcstack.h b/lib/silcutil/silcstack.h index 8003666f..f2663eef 100644 --- a/lib/silcutil/silcstack.h +++ b/lib/silcutil/silcstack.h @@ -4,7 +4,7 @@ Author: Pekka Riikonen - Copyright (C) 2003 - 2007 Pekka Riikonen + Copyright (C) 2003 - 2008 Pekka Riikonen This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -21,7 +21,7 @@ * * DESCRIPTION * - * Implementation of data stack which can be used to allocate memory from + * Implementation of data stack which can be used to do fast allocations from * the stack. Basically SilcStack is a pre-allocated memory pool system * which allows fast memory allocation for routines and applications that * frequently allocate small amounts of memory. Other advantage of this @@ -53,9 +53,10 @@ * silc_buffer_sstrformat, silc_buffer_senlarge, silc_mp_sinit, * silc_dlist_sinit, silc_hash_table_alloc * - * The SilcStack context is not thread-safe. If the same SilcStack must be - * used in multithreaded environment concurrency control must be employed. - * Each thread should allocate their own SilcStack. + * The SilcStack is not thread-safe so that same context could be used for + * allocations from multiple threads. It is however safe to create and use + * child stacks in a different thread from the parent stack. Each thread + * should allocate their own SilcStack, however they may be child stacks. * ***/ @@ -96,6 +97,22 @@ typedef struct SilcStackStruct *SilcStack; ***/ typedef struct SilcStackFrameStruct SilcStackFrame; +/****f* silcutil/SilcStackAPI/SilcStackOomHandler + * + * SYNOPSIS + * + * typedef void (*SilcStackOomHandler)(SilcStack stack, void *context); + * + * DESCRIPTION + * + * Callback of this type can be given to silc_stack_set_oom_handler + * to set Out of Memory handler to `stack'. If memory allocation from + * `stack' fails this callback is called to indicate error. The `context' + * is the context given to silc_stack_set_oom_handler. + * + ***/ +typedef void (*SilcStackOomHandler)(SilcStack stack, void *context); + /****f* silcutil/SilcStackAPI/silc_stack_alloc * * SYNOPSIS @@ -108,13 +125,12 @@ typedef struct SilcStackFrameStruct SilcStackFrame; * allocation by various routines. Returns the pointer to the stack * that must be freed with silc_stack_free function when it is not * needed anymore. If the `stack_size' is zero (0) by default a - * 2 kilobytes (2048 bytes) stack is allocated. If the `stack_size' - * is non-zero the byte value must be multiple by 8. + * 1 kilobyte (1024 bytes) stack is allocated. * * If `parent' is non-NULL the created stack is a child of the `parent' * stack. All of childs the memory is allocated from the `parent' and * will be returned back to the parent when the child is freed. Note - * that, even though child allocated memory from the parent, the parent's + * that, even though child allocates memory from the parent, the parent's * stack is not consumed. * * Returns NULL on error. @@ -134,7 +150,7 @@ SilcStack silc_stack_alloc(SilcUInt32 stack_size, SilcStack parent); * this and all allocated memory are freed. * * If `stack' is a child stack, its memory is returned back to its - * parent. + * parent. If `stack' is NULL this function does nothing. * ***/ void silc_stack_free(SilcStack stack); @@ -153,19 +169,15 @@ void silc_stack_free(SilcStack stack); * stack and all allocated memory is freed after the next silc_stack_pop * is called. This returns so called stack pointer for the new stack * frame, which the caller may use to check that all calls to - * silc_stack_pop has been made. This call may do a small memory - * allocation in some cases, but usually it does not allocate any memory. - * If this returns zero (0) the system is out of memory. + * silc_stack_pop has been made. * * If the `frame' is non-NULL then that SilcStackFrame is used as * stack frame. Usually `frame' is set to NULL by user. Statically * allocated SilcStackFrame should be used when using silc_stack_push * in recursive function and the recursion may become deep. In this * case using statically allocated SilcStackFrame is recommended since - * it assures that frames never run out and silc_stack_push never - * allocates any memory. If your routine is not recursive then - * setting `frame' to NULL is recommended, unless performance is - * critical. + * it assures that frames never run out. If your routine is not recursive + * then setting `frame' to NULL is recommended. * * This function is used when a routine is doing frequent allocations * from the stack. If the stack is not pushed and later popped all @@ -173,7 +185,8 @@ void silc_stack_free(SilcStack stack); * (it gets enlarged by normal memory allocation). By pushing and then * later popping the frequent allocations does not consume the stack. * - * If `stack' is NULL this call has no effect. + * If `stack' is NULL this call has no effect. This function does not + * allocate any memory. * * EXAMPLE * @@ -210,8 +223,8 @@ SilcUInt32 silc_stack_push(SilcStack stack, SilcStackFrame *frame); * * DESCRIPTION * - * Pop the top of the stack upwards which reveals the previous stack frame - * and becomes the top of the stack. After popping, memory allocated in + * Pop the top of the stack which removes the previous stack frame and + * becomes the top of the stack. After popping, memory allocated in * the old frame is freed. For each silc_stack_push call there must be * silc_stack_pop call to free all memory (in reality any memory is not * freed but within the stack it is). This returns the stack pointer of @@ -221,7 +234,8 @@ SilcUInt32 silc_stack_push(SilcStack stack, SilcStackFrame *frame); * silc_stack_pop has been called too many times. Application should * treat this as a fatal error, as it is a bug in the application code. * - * If `stack' is NULL this call has no effect. + * If `stack' is NULL this call has no effect. This function does not + * allocate any memory. * * EXAMPLE * @@ -246,7 +260,7 @@ SilcUInt32 silc_stack_pop(SilcStack stack); * * DESCRIPTION * - * Low level memory allocation routine. Allocates memor block of size of + * Low level memory allocation routine. Allocates memory block of size of * `size' from the `stack'. The allocated memory is aligned so it can be * used to allocate memory for structures, for example. Returns the * allocated memory address or NULL if memory could not be allocated from @@ -255,7 +269,8 @@ SilcUInt32 silc_stack_pop(SilcStack stack); * NOTES * * This function should be used only if low level memory allocation with - * SilcStack is needed. Instead, silc_smalloc, could be used. + * SilcStack is needed. Instead, silc_smalloc and silc_scalloc could + * be used. * ***/ void *silc_stack_malloc(SilcStack stack, SilcUInt32 size); @@ -265,26 +280,51 @@ void *silc_stack_malloc(SilcStack stack, SilcUInt32 size); * SYNOPSIS * * void *silc_stack_realloc(SilcStack stack, SilcUInt32 old_size, - * *void *ptr, SilcUInt32 size); + * void *ptr, SilcUInt32 size); * * DESCRIPTION * * Attempts to reallocate memory by changing the size of the `ptr' into * `size'. This routine works only if the previous allocation to `stack' * was `ptr'. If there is another memory allocation between allocating - * `ptr' and this call this routine will return NULL. NULL is also - * returned if the `size' does not fit into the current block. If NULL - * is returned the old memory remains intact. + * `ptr' and this call this routine will return NULL (and silc_errno is + * set to SILC_ERR_INVALID_ARGUMENT). NULL is also returned if the `size' + * does not fit into the current stack block. If NULL is returned the old + * memory remains intact. * * NOTES * * This function should be used only if low level memory allocation with - * SilcStack is needed. Instead, silc_srealloc, could be used. + * SilcStack is needed. Instead, silc_srealloc could be used. * ***/ void *silc_stack_realloc(SilcStack stack, SilcUInt32 old_size, void *ptr, SilcUInt32 size); +/****f* silcutil/SilcStackAPI/silc_stack_set_oom_handler + * + * SYNOPSIS + * + * void silc_stack_set_oom_handler(SilcStack stack, + * SilcStackOomHandler oom_handler, + * void *context); + * + * DESCRIPTION + * + * Sets Out of Memory handler `oom_handler' to `stack' to be called + * if memory allocation from `stack' fails. The `context' is delivered + * to `oom_handler'. + * + * Usually Out of Memory handler is set only when failed memory allocation + * is a fatal error. In this case the application would abort() inside + * the `oom_handler'. It may also be set if in case of failed allocation + * application wants to do clean up properly. + * + ***/ +void silc_stack_set_oom_handler(SilcStack stack, + SilcStackOomHandler oom_handler, + void *context); + /****f* silcutil/SilcStackAPI/silc_stack_set_alignment * * SYNOPSIS @@ -296,7 +336,7 @@ void *silc_stack_realloc(SilcStack stack, SilcUInt32 old_size, * Sets/changes the memory alignment in the `stack' to `alignment' which * is the alignment in bytes. By default, the SilcStack will use alignment * suited for the platform where it is used. This function can be used - * change this alignment, if such change is needed. You may check the + * to change this alignment, if such change is needed. You may check the * current alignment by calling silc_stack_get_alignment. * * NOTES @@ -325,6 +365,61 @@ void silc_stack_set_alignment(SilcStack stack, SilcUInt32 alignment); ***/ SilcUInt32 silc_stack_get_alignment(SilcStack stack); +/****f* silcutil/SilcStackAPI/silc_stack_purge + * + * SYNOPSIS + * + * SilcBool silc_stack_purge(SilcStack stack); + * + * DESCRIPTION + * + * Purges the `stack' from extra unused memory. This purges only `stack' + * and not its parent if `stack' is a child. This purges only large + * allocations. The 1024, 2048, 4096 and 8192 bytes of allocations remain. + * Call this multiple times to purge even more. Returns FALSE when there + * is no more to purge. This does not purge memory blocks that currently + * have allocations. No memory allocations from the stack are lost, so + * this is always safe to call. + * + ***/ +SilcBool silc_stack_purge(SilcStack stack); + +/****f* silcutil/SilcStackAPI/silc_stack_set_global + * + * SYNOPSIS + * + * void silc_stack_set_global(SilcStack stack); + * + * DESCRIPTION + * + * Sets global SilcStack `stack' that can be retrieved at any time + * by using silc_stack_get_global. The global stack is global only + * to the current thread. Each thread can have their own global stack. + * If each thread must have own stack this must be called in each + * thread. If the global stack has been set already, new call will + * replace the old one. + * + * This routine is provided only as a convenience function to store + * program's or thread's stack in one global place. It is not mandatory + * to call this function in order to use SilcStack. + * + ***/ +void silc_stack_set_global(SilcStack stack); + +/****f* silcutil/SilcStackAPI/silc_stack_get_global + * + * SYNOPSIS + * + * SilcStack silc_stack_get_global(void); + * + * DESCRIPTION + * + * Returns the thread's global stack that was set by calling the + * silc_stack_set_global or NULL if global stack has not been set. + * + ***/ +SilcStack silc_stack_get_global(void); + #include "silcstack_i.h" #endif /* SILCSTACK_H */