kc3-lang/libjpeg-turbo/jmemsys.h
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Hash : 19c791cd
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Date : 2018-03-08T10:55:20
Improve code formatting consistency With rare exceptions ... - Always separate line continuation characters by one space from preceding code. - Always use two-space indentation. Never use tabs. - Always use K&R-style conditional blocks. - Always surround operators with spaces, except in raw assembly code. - Always put a space after, but not before, a comma. - Never put a space between type casts and variables/function calls. - Never put a space between the function name and the argument list in function declarations and prototypes. - Always surround braces ('{' and '}') with spaces. - Always surround statements (if, for, else, catch, while, do, switch) with spaces. - Always attach pointer symbols ('*' and '**') to the variable or function name. - Always precede pointer symbols ('*' and '**') by a space in type casts. - Use the MIN() macro from jpegint.h within the libjpeg and TurboJPEG API libraries (using min() from tjutil.h is still necessary for TJBench.) - Where it makes sense (particularly in the TurboJPEG code), put a blank line after variable declaration blocks. - Always separate statements in one-liners by two spaces. The purpose of this was to ease maintenance on my part and also to make it easier for contributors to figure out how to format patch submissions. This was admittedly confusing (even to me sometimes) when we had 3 or 4 different style conventions in the same source tree. The new convention is more consistent with the formatting of other OSS code bases. This commit corrects deviations from the chosen formatting style in the libjpeg API code and reformats the TurboJPEG API code such that it conforms to the same standard. NOTES: - Although it is no longer necessary for the function name in function declarations to begin in Column 1 (this was historically necessary because of the ansi2knr utility, which allowed libjpeg to be built with non-ANSI compilers), we retain that formatting for the libjpeg code because it improves readability when using libjpeg's function attribute macros (GLOBAL(), etc.) - This reformatting project was accomplished with the help of AStyle and Uncrustify, although neither was completely up to the task, and thus a great deal of manual tweaking was required. Note to developers of code formatting utilities: the libjpeg-turbo code base is an excellent test bed, because AFAICT, it breaks every single one of the utilities that are currently available. - The legacy (MMX, SSE, 3DNow!) assembly code for i386 has been formatted to match the SSE2 code (refer to ff5685d5344273df321eb63a005eaae19d2496e3.) I hadn't intended to bother with this, but the Loongson MMI implementation demonstrated that there is still academic value to the MMX implementation, as an algorithmic model for other 64-bit vector implementations. Thus, it is desirable to improve its readability in the same manner as that of the SSE2 implementation.
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jmemsys.h
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/* * jmemsys.h * * This file was part of the Independent JPEG Group's software: * Copyright (C) 1992-1997, Thomas G. Lane. * It was modified by The libjpeg-turbo Project to include only code and * information relevant to libjpeg-turbo. * For conditions of distribution and use, see the accompanying README.ijg * file. * * This include file defines the interface between the system-independent * and system-dependent portions of the JPEG memory manager. No other * modules need include it. (The system-independent portion is jmemmgr.c; * there are several different versions of the system-dependent portion.) * * This file works as-is for the system-dependent memory managers supplied * in the IJG distribution. You may need to modify it if you write a * custom memory manager. If system-dependent changes are needed in * this file, the best method is to #ifdef them based on a configuration * symbol supplied in jconfig.h. */ /* * These two functions are used to allocate and release small chunks of * memory. (Typically the total amount requested through jpeg_get_small is * no more than 20K or so; this will be requested in chunks of a few K each.) * Behavior should be the same as for the standard library functions malloc * and free; in particular, jpeg_get_small must return NULL on failure. * On most systems, these ARE malloc and free. jpeg_free_small is passed the * size of the object being freed, just in case it's needed. */ EXTERN(void *) jpeg_get_small(j_common_ptr cinfo, size_t sizeofobject); EXTERN(void) jpeg_free_small(j_common_ptr cinfo, void *object, size_t sizeofobject); /* * These two functions are used to allocate and release large chunks of * memory (up to the total free space designated by jpeg_mem_available). * These are identical to the jpeg_get/free_small routines; but we keep them * separate anyway, in case a different allocation strategy is desirable for * large chunks. */ EXTERN(void *) jpeg_get_large(j_common_ptr cinfo, size_t sizeofobject); EXTERN(void) jpeg_free_large(j_common_ptr cinfo, void *object, size_t sizeofobject); /* * The macro MAX_ALLOC_CHUNK designates the maximum number of bytes that may * be requested in a single call to jpeg_get_large (and jpeg_get_small for that * matter, but that case should never come into play). This macro was needed * to model the 64Kb-segment-size limit of far addressing on 80x86 machines. * On machines with flat address spaces, any large constant may be used. * * NB: jmemmgr.c expects that MAX_ALLOC_CHUNK will be representable as type * size_t and will be a multiple of sizeof(align_type). */ #ifndef MAX_ALLOC_CHUNK /* may be overridden in jconfig.h */ #define MAX_ALLOC_CHUNK 1000000000L #endif /* * This routine computes the total space still available for allocation by * jpeg_get_large. If more space than this is needed, backing store will be * used. NOTE: any memory already allocated must not be counted. * * There is a minimum space requirement, corresponding to the minimum * feasible buffer sizes; jmemmgr.c will request that much space even if * jpeg_mem_available returns zero. The maximum space needed, enough to hold * all working storage in memory, is also passed in case it is useful. * Finally, the total space already allocated is passed. If no better * method is available, cinfo->mem->max_memory_to_use - already_allocated * is often a suitable calculation. * * It is OK for jpeg_mem_available to underestimate the space available * (that'll just lead to more backing-store access than is really necessary). * However, an overestimate will lead to failure. Hence it's wise to subtract * a slop factor from the true available space. 5% should be enough. * * On machines with lots of virtual memory, any large constant may be returned. * Conversely, zero may be returned to always use the minimum amount of memory. */ EXTERN(size_t) jpeg_mem_available(j_common_ptr cinfo, size_t min_bytes_needed, size_t max_bytes_needed, size_t already_allocated); /* * This structure holds whatever state is needed to access a single * backing-store object. The read/write/close method pointers are called * by jmemmgr.c to manipulate the backing-store object; all other fields * are private to the system-dependent backing store routines. */ #define TEMP_NAME_LENGTH 64 /* max length of a temporary file's name */ #ifdef USE_MSDOS_MEMMGR /* DOS-specific junk */ typedef unsigned short XMSH; /* type of extended-memory handles */ typedef unsigned short EMSH; /* type of expanded-memory handles */ typedef union { short file_handle; /* DOS file handle if it's a temp file */ XMSH xms_handle; /* handle if it's a chunk of XMS */ EMSH ems_handle; /* handle if it's a chunk of EMS */ } handle_union; #endif /* USE_MSDOS_MEMMGR */ #ifdef USE_MAC_MEMMGR /* Mac-specific junk */ #include <Files.h> #endif /* USE_MAC_MEMMGR */ typedef struct backing_store_struct *backing_store_ptr; typedef struct backing_store_struct { /* Methods for reading/writing/closing this backing-store object */ void (*read_backing_store) (j_common_ptr cinfo, backing_store_ptr info, void *buffer_address, long file_offset, long byte_count); void (*write_backing_store) (j_common_ptr cinfo, backing_store_ptr info, void *buffer_address, long file_offset, long byte_count); void (*close_backing_store) (j_common_ptr cinfo, backing_store_ptr info); /* Private fields for system-dependent backing-store management */ #ifdef USE_MSDOS_MEMMGR /* For the MS-DOS manager (jmemdos.c), we need: */ handle_union handle; /* reference to backing-store storage object */ char temp_name[TEMP_NAME_LENGTH]; /* name if it's a file */ #else #ifdef USE_MAC_MEMMGR /* For the Mac manager (jmemmac.c), we need: */ short temp_file; /* file reference number to temp file */ FSSpec tempSpec; /* the FSSpec for the temp file */ char temp_name[TEMP_NAME_LENGTH]; /* name if it's a file */ #else /* For a typical implementation with temp files, we need: */ FILE *temp_file; /* stdio reference to temp file */ char temp_name[TEMP_NAME_LENGTH]; /* name of temp file */ #endif #endif } backing_store_info; /* * Initial opening of a backing-store object. This must fill in the * read/write/close pointers in the object. The read/write routines * may take an error exit if the specified maximum file size is exceeded. * (If jpeg_mem_available always returns a large value, this routine can * just take an error exit.) */ EXTERN(void) jpeg_open_backing_store(j_common_ptr cinfo, backing_store_ptr info, long total_bytes_needed); /* * These routines take care of any system-dependent initialization and * cleanup required. jpeg_mem_init will be called before anything is * allocated (and, therefore, nothing in cinfo is of use except the error * manager pointer). It should return a suitable default value for * max_memory_to_use; this may subsequently be overridden by the surrounding * application. (Note that max_memory_to_use is only important if * jpeg_mem_available chooses to consult it ... no one else will.) * jpeg_mem_term may assume that all requested memory has been freed and that * all opened backing-store objects have been closed. */ EXTERN(long) jpeg_mem_init(j_common_ptr cinfo); EXTERN(void) jpeg_mem_term(j_common_ptr cinfo);