X-Git-Url: https://git.distorted.org.uk/~mdw/become/blobdiff_plain/fe59d3d70fc7337b7a50c4fcff72d20967672157..f60a34341fee6aafd5b878dce23b80af7c60064d:/src/sym.c diff --git a/src/sym.c b/src/sym.c deleted file mode 100644 index 99ec187..0000000 --- a/src/sym.c +++ /dev/null @@ -1,707 +0,0 @@ -/* -*-c-*- - * - * $Id: sym.c,v 1.4 1998/01/12 16:46:28 mdw Exp $ - * - * Symbol table management - * - * (c) 1998 Straylight - */ - -/*----- Licensing notice --------------------------------------------------* - * - * This file is part of `become' - * - * `Become' is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * `Become' is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with `become'; if not, write to the Free Software Foundation, - * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. - */ - -/*----- Revision history --------------------------------------------------* - * - * $Log: sym.c,v $ - * Revision 1.4 1998/01/12 16:46:28 mdw - * Fix copyright date. - * - * Revision 1.3 1997/08/20 16:22:59 mdw - * Patch memory leak. - * - * Revision 1.2 1997/08/04 10:24:25 mdw - * Sources placed under CVS control. - * - * Revision 1.1 1997/07/21 13:47:44 mdw - * Initial revision - * - */ - -/*----- Header files ------------------------------------------------------*/ - -/* --- ANSI headers --- */ - -#include -#include -#include - -/* --- Local headers --- */ - -#include "sym.h" -#include "utils.h" - -/*----- Tuning parameters -------------------------------------------------*/ - -/* --- Initial hash table size --- * - * - * This is the initial @mask@ value. It must be of the form %$2^n - 1$%, - * so that it can be used to mask of the bottom bits of a hash value. - */ - -#define sym__iSize 255 /* Size of a new hash table */ - -/* --- Maximum load factor --- * - * - * This parameter controls how much the table has to be loaded before the - * table is extended. The number of elements %$n$%, the number of bins %$b$% - * and the limit %$l$% satisfy the relation %$n < bl$%; if a new item is - * added to the table and this relation is found to be false, the table is - * doubled in size. - * - * The parameter @sym__limFactor@ is the value of %$l$% multiplied by 256; - * fixed point arithmetic is used to calculate the allowable load. Note - * that the exact calculation of this criterion isn't important; what's more - * significant is that the parameter allows tuning of the rehashing process. - * - * The current value is %$3 \over 4$%, which appears to be reasonable on the - * face of things. - */ - -#define sym__limFactor 0x0C0 /* Load factor for growing table */ - -/*----- CRC table ---------------------------------------------------------*/ - -/*****************************************************************/ -/* */ -/* CRC LOOKUP TABLE */ -/* ================ */ -/* */ -/* The following CRC lookup table was generated automagically */ -/* by `crcgen', which is based on the Rocksoft^tm Model CRC */ -/* Algorithm Table Generation Program. The model parameters */ -/* supplied to `crcgen' were: */ -/* */ -/* Width : 32 bits */ -/* Poly : 0x04C11DB7 */ -/* Init : 0xFFFFFFFF */ -/* XorOut : 0xFFFFFFFF */ -/* Reverse : Yes */ -/* Check : 0xCBF43926 */ -/* */ -/* For more information on the Rocksoft^tm Model CRC Algorithm, */ -/* see the document titled `A Painless Guide to CRC Error */ -/* Detection Algorithms' by Ross Williams */ -/* (ross@@guest.adelaide.edu.au.). This document is likely to be */ -/* in the FTP archive `ftp.adelaide.edu.au/pub/rocksoft'. */ -/* */ -/*****************************************************************/ - -static unsigned long sym__crcTable[256] = { - 0x00000000L, 0x77073096L, 0xEE0E612CL, 0x990951BAL, - 0x076DC419L, 0x706AF48FL, 0xE963A535L, 0x9E6495A3L, - 0x0EDB8832L, 0x79DCB8A4L, 0xE0D5E91EL, 0x97D2D988L, - 0x09B64C2BL, 0x7EB17CBDL, 0xE7B82D07L, 0x90BF1D91L, - 0x1DB71064L, 0x6AB020F2L, 0xF3B97148L, 0x84BE41DEL, - 0x1ADAD47DL, 0x6DDDE4EBL, 0xF4D4B551L, 0x83D385C7L, - 0x136C9856L, 0x646BA8C0L, 0xFD62F97AL, 0x8A65C9ECL, - 0x14015C4FL, 0x63066CD9L, 0xFA0F3D63L, 0x8D080DF5L, - 0x3B6E20C8L, 0x4C69105EL, 0xD56041E4L, 0xA2677172L, - 0x3C03E4D1L, 0x4B04D447L, 0xD20D85FDL, 0xA50AB56BL, - 0x35B5A8FAL, 0x42B2986CL, 0xDBBBC9D6L, 0xACBCF940L, - 0x32D86CE3L, 0x45DF5C75L, 0xDCD60DCFL, 0xABD13D59L, - 0x26D930ACL, 0x51DE003AL, 0xC8D75180L, 0xBFD06116L, - 0x21B4F4B5L, 0x56B3C423L, 0xCFBA9599L, 0xB8BDA50FL, - 0x2802B89EL, 0x5F058808L, 0xC60CD9B2L, 0xB10BE924L, - 0x2F6F7C87L, 0x58684C11L, 0xC1611DABL, 0xB6662D3DL, - 0x76DC4190L, 0x01DB7106L, 0x98D220BCL, 0xEFD5102AL, - 0x71B18589L, 0x06B6B51FL, 0x9FBFE4A5L, 0xE8B8D433L, - 0x7807C9A2L, 0x0F00F934L, 0x9609A88EL, 0xE10E9818L, - 0x7F6A0DBBL, 0x086D3D2DL, 0x91646C97L, 0xE6635C01L, - 0x6B6B51F4L, 0x1C6C6162L, 0x856530D8L, 0xF262004EL, - 0x6C0695EDL, 0x1B01A57BL, 0x8208F4C1L, 0xF50FC457L, - 0x65B0D9C6L, 0x12B7E950L, 0x8BBEB8EAL, 0xFCB9887CL, - 0x62DD1DDFL, 0x15DA2D49L, 0x8CD37CF3L, 0xFBD44C65L, - 0x4DB26158L, 0x3AB551CEL, 0xA3BC0074L, 0xD4BB30E2L, - 0x4ADFA541L, 0x3DD895D7L, 0xA4D1C46DL, 0xD3D6F4FBL, - 0x4369E96AL, 0x346ED9FCL, 0xAD678846L, 0xDA60B8D0L, - 0x44042D73L, 0x33031DE5L, 0xAA0A4C5FL, 0xDD0D7CC9L, - 0x5005713CL, 0x270241AAL, 0xBE0B1010L, 0xC90C2086L, - 0x5768B525L, 0x206F85B3L, 0xB966D409L, 0xCE61E49FL, - 0x5EDEF90EL, 0x29D9C998L, 0xB0D09822L, 0xC7D7A8B4L, - 0x59B33D17L, 0x2EB40D81L, 0xB7BD5C3BL, 0xC0BA6CADL, - 0xEDB88320L, 0x9ABFB3B6L, 0x03B6E20CL, 0x74B1D29AL, - 0xEAD54739L, 0x9DD277AFL, 0x04DB2615L, 0x73DC1683L, - 0xE3630B12L, 0x94643B84L, 0x0D6D6A3EL, 0x7A6A5AA8L, - 0xE40ECF0BL, 0x9309FF9DL, 0x0A00AE27L, 0x7D079EB1L, - 0xF00F9344L, 0x8708A3D2L, 0x1E01F268L, 0x6906C2FEL, - 0xF762575DL, 0x806567CBL, 0x196C3671L, 0x6E6B06E7L, - 0xFED41B76L, 0x89D32BE0L, 0x10DA7A5AL, 0x67DD4ACCL, - 0xF9B9DF6FL, 0x8EBEEFF9L, 0x17B7BE43L, 0x60B08ED5L, - 0xD6D6A3E8L, 0xA1D1937EL, 0x38D8C2C4L, 0x4FDFF252L, - 0xD1BB67F1L, 0xA6BC5767L, 0x3FB506DDL, 0x48B2364BL, - 0xD80D2BDAL, 0xAF0A1B4CL, 0x36034AF6L, 0x41047A60L, - 0xDF60EFC3L, 0xA867DF55L, 0x316E8EEFL, 0x4669BE79L, - 0xCB61B38CL, 0xBC66831AL, 0x256FD2A0L, 0x5268E236L, - 0xCC0C7795L, 0xBB0B4703L, 0x220216B9L, 0x5505262FL, - 0xC5BA3BBEL, 0xB2BD0B28L, 0x2BB45A92L, 0x5CB36A04L, - 0xC2D7FFA7L, 0xB5D0CF31L, 0x2CD99E8BL, 0x5BDEAE1DL, - 0x9B64C2B0L, 0xEC63F226L, 0x756AA39CL, 0x026D930AL, - 0x9C0906A9L, 0xEB0E363FL, 0x72076785L, 0x05005713L, - 0x95BF4A82L, 0xE2B87A14L, 0x7BB12BAEL, 0x0CB61B38L, - 0x92D28E9BL, 0xE5D5BE0DL, 0x7CDCEFB7L, 0x0BDBDF21L, - 0x86D3D2D4L, 0xF1D4E242L, 0x68DDB3F8L, 0x1FDA836EL, - 0x81BE16CDL, 0xF6B9265BL, 0x6FB077E1L, 0x18B74777L, - 0x88085AE6L, 0xFF0F6A70L, 0x66063BCAL, 0x11010B5CL, - 0x8F659EFFL, 0xF862AE69L, 0x616BFFD3L, 0x166CCF45L, - 0xA00AE278L, 0xD70DD2EEL, 0x4E048354L, 0x3903B3C2L, - 0xA7672661L, 0xD06016F7L, 0x4969474DL, 0x3E6E77DBL, - 0xAED16A4AL, 0xD9D65ADCL, 0x40DF0B66L, 0x37D83BF0L, - 0xA9BCAE53L, 0xDEBB9EC5L, 0x47B2CF7FL, 0x30B5FFE9L, - 0xBDBDF21CL, 0xCABAC28AL, 0x53B39330L, 0x24B4A3A6L, - 0xBAD03605L, 0xCDD70693L, 0x54DE5729L, 0x23D967BFL, - 0xB3667A2EL, 0xC4614AB8L, 0x5D681B02L, 0x2A6F2B94L, - 0xB40BBE37L, 0xC30C8EA1L, 0x5A05DF1BL, 0x2D02EF8DL, -}; - -/*****************************************************************/ -/* End of CRC Lookup Table */ -/*****************************************************************/ - -/* --- Work out the CRC of a bytestring --- */ - -#define sym__crc(s_, l_, hv_) do { \ - unsigned long h_ = 0xFFFFFFFFL; \ - const char *p_ = s_; \ - const char *e_ = (s_) + (l_); \ - \ - while (p_ < e_) \ - h_ = (h_ >> 8) ^ (sym__crcTable[(*p_++ ^ h_) & 0xFF]); \ - hv_ = ~h_ & 0xFFFFFFFFL; \ -} while (0) - -/*----- Main code ---------------------------------------------------------*/ - -#ifndef DEBUG_CRC - -/* --- @sym_createTable@ --- * - * - * Arguments: @sym_table *t@ = symbol table to initialise - * - * Returns: --- - * - * Use: Initialises the given symbol table. - */ - -void sym_createTable(sym_table *t) -{ - size_t i; - - t->mask = sym__iSize; - t->c = (sym__iSize * sym__limFactor) >> 8; - t->a = xmalloc((t->mask + 1) * sizeof(sym_base *)); - - for (i = 0; i < sym__iSize + 1; i++) - t->a[i] = 0; -} - -/* --- @sym_destroyTable@ --- * - * - * Arguments: @sym_table *t@ = pointer to symbol table in question - * - * Returns: --- - * - * Use: Destroys a symbol table, freeing all the memory it used to - * occupy. - */ - -void sym_destroyTable(sym_table *t) -{ - size_t i; - sym_base *p, *q; - - for (i = 0; i <= t->mask; i++) { - p = t->a[i]; - while (p) { - q = p->next; - free(p->name); - free(p); - p = q; - } - } - free(t->a); -} - -/* --- @sym_find@ --- * - * - * Arguments: @sym_table *t@ = pointer to symbol table in question - * @const char *n@ = pointer to symbol table to look up - * @long l@ = length of the name string or negative to measure - * @size_t sz@ = size of desired symbol object, or zero - * @unsigned *f@ = pointer to a flag, or null. - * - * Returns: The address of a @sym_base@ structure, or null if not found - * and @sz@ is zero. - * - * Use: Looks up a symbol in a given symbol table. The name is - * passed by the address of its first character. The length - * may be given, in which case the name may contain arbitrary - * binary data, or it may be given as a negative number, in - * which case the length of the name is calculated as - * @strlen(n)@. - * - * The return value is the address of a pointer to a @sym_base@ - * block (which may have other things on the end, as above). If - * the symbol could be found, the return value points to the - * symbol block. If the symbol wasn't there, then if @sz@ is - * nonzero, a new symbol is created and its address is returned; - * otherwise a null pointer is returned. - * - * The value of @*f@ indicates whether a new symbol entry was - * created: a nonzero value indicates that an old value was - * found. - */ - -void *sym_find(sym_table *t, const char *n, long l, size_t sz, unsigned *f) -{ - unsigned long hash; /* Hash value for user's name */ - size_t len = l < 0 ? strlen(n) + 1 : l; /* Find length of user's name */ - sym_base *bin; /* Bin containing our item */ - sym_base *p, *q; /* Pointer wandering through list */ - - /* --- Find the correct bin --- */ - - sym__crc(n, len, hash); /* Find hash value for this name */ - bin = p = (sym_base *)(t->a + (hash & t->mask)); - - /* --- Search the bin list --- */ - - while (p->next) { - if (hash == p->next->hash && /* Check hash values first */ - len == p->next->len && /* Then compare string lengths */ - !memcmp(n, p->next->name, len)) /* And finally compare the strings */ - { - /* --- Found a match --- * - * - * As a minor, and probably pointless, tweak, move the item to the - * front of its bin list. - */ - - q = p->next; /* Find the actual symbol block */ - p->next = q->next; /* Extract block from bin list */ - q->next = bin->next; /* Set up symbol's next pointer */ - bin->next = q; /* And reinsert the block */ - - /* --- Return the block --- */ - - if (f) *f = 1; /* Didn't fail to find the item */ - return (q); /* And return the block */ - } - - p = p->next; /* Move onto the next item */ - } - - /* --- Couldn't find the item there --- */ - - if (f) *f = 0; /* Failed to find the block */ - if (!sz) return (0); /* Return zero if not creating */ - - /* --- Create a new symbol block and initialise it --- */ - - p = xmalloc(sz); /* Create a new symbol block */ - p->next = bin->next; /* Set up the next pointer */ - p->hash = hash; /* Set up the hash value too */ - p->name = xmalloc(len); /* Allocate a block for the name */ - p->len = len; /* And set up the string length */ - memcpy(p->name, n, len); /* And copy the string over */ - - bin->next = p; /* Put the pointer into the bin */ - - /* --- Consider growing the array --- */ - - if (!--t->c) { - unsigned long m = t->mask + 1; /* Next set bit in has word */ - sym_base *p, *q, *r; /* More useful pointers */ - size_t i, lim; /* Loop counter and limit */ - - /* --- Update values in the anchor block --- */ - - t->c = ((t->mask + 1) * sym__limFactor) >> 8; /* Set load value */ - t->mask = (t->mask + 1) * 2 - 1; /* Set the new mask value */ - t->a = xrealloc(t->a, (t->mask + 1) * sizeof(sym_base *)); - - /* --- Now wander through the table rehashing things --- * - * - * This loop is very careful to avoid problems with aliasing. The items - * are dealt with from the end backwards to avoid overwriting bins before - * they've been processed. - */ - - lim = (t->mask + 1) >> 1; - for (i = 0; i < lim; i++) { - /* --- Some initialisation --- */ - - r = t->a[i]; /* Find the list we're dissecting */ - p = (sym_base *)(t->a + i); /* Find bit-clear list */ - q = (sym_base *)(t->a + i + lim); /* And the bit-set lsit */ - - /* --- Now go through the @r@ list --- */ - - while (r) { - if (r->hash & m) /* Is the next bit set? */ - q = q->next = r; /* Yes, so fit up previous link */ - else - p = p->next = r; /* No, so fit up previous link */ - r = r->next; /* Move onto the next item */ - } - p->next = q->next = 0; /* Null terminate the new lists */ - } - } - - /* --- Finished that, so return the new symbol block --- */ - - return (p); -} - -/* --- @sym_remove@ --- * - * - * Arguments: @sym_table *i@ = pointer to a symbol table object - * @void *b@ = pointer to symbol table entry - * - * Returns: --- - * - * Use: Removes the object from the symbol table. The space occupied - * by the object and its name is freed; anything else attached - * to the entry should already be gone by this point. - */ - -void sym_remove(sym_table *t, void *b) -{ - /* --- A quick comment --- * - * - * Since the @sym_base@ block contains the hash, finding the element in the - * bin list is really quick -- it's not worth bothering with things like - * doubly linked lists. - */ - - sym_base *p = b; - sym_base *bin = (sym_base *)(t->a + (p->hash & t->mask)); - - /* --- Find the item in the bin list --- */ - - while (bin->next) { - if (bin->next == p) - break; - bin = bin->next; - } - if (!bin->next) - return; - - /* --- Now just remove the item from the list and free it --- * - * - * Oh, and bump the load counter. - */ - - bin->next = p->next; - free(p->name); - free(p); - t->c++; -} - -/* --- @sym_createIter@ --- * - * - * Arguments: @sym_iter *i@ = pointer to an iterator object - * @sym_table *t@ = pointer to a symbol table object - * - * Returns: --- - * - * Use: Creates a new symbol table iterator which may be used to - * iterate through a symbol table. - */ - -void sym_createIter(sym_iter *i, sym_table *t) -{ - i->t = t; - i->i = 0; - i->n = 0; -} - -/* --- @sym_next@ --- * - * - * Arguments: @sym_iter *i@ = pointer to iterator object - * - * Returns: Pointer to the next symbol found, or null when finished. - * - * Use: Returns the next symbol from the table. Symbols are not - * returned in any particular order. - */ - -void *sym_next(sym_iter *i) -{ - sym_base *p; - - /* --- Find the next item --- */ - - while (!i->n) { - if (i->i > i->t->mask) - return (0); - i->n = i->t->a[i->i++]; - } - - /* --- Update the iterator block --- */ - - p = i->n; - i->n = p->next; - - /* --- Done --- */ - - return (p); -} - -#endif - -/*----- CRC test code -----------------------------------------------------*/ - -#ifdef DEBUG_CRC - -int main(void) -{ - unsigned long h; - sym__crc("123456789", 9, h); - printf("crc check == %04x\n", h); - return (0); -} - -#endif - -/*----- Symbol table test code --------------------------------------------*/ - -#ifdef TEST_RIG - -#include -#include - -#include "dbutils.h" - -typedef struct sym_word { - sym_base base; - size_t i; -} sym_word; - - -/* --- What it does --- * - * - * Reads the file /usr/dict/words (change to some other file full of - * interesting and appropriate bits of text to taste) into a big buffer and - * picks apart into lines. Then picks lines at random and enters them into - * the symbol table. - */ - -int main(void) -{ - char *buff, *p, *lim; - size_t sz, done; - FILE *fp; - int i; - char **line; - sym_word **flag; - sym_table tbl; - int entries; - - /* --- Initialise for reading the file --- */ - - sz = BUFSIZ; - buff = xmalloc(sz + 1); - done = 0; - - if ((fp = fopen("/usr/dict/words", "r")) == 0) - fprintf(stderr, "buggered ;-( (%s)\n", strerror(errno)); - - /* --- Read buffers of text --- * - * - * Read a buffer. If more to come, double the buffer size and try again. - * This is the method I recommended to comp.lang.c, so I may as well try - * it. - */ - - for (;;) { - i = fread(buff + done, 1, sz - done, fp); - done += i; - if (done != sz) - break; - sz <<= 1; - buff = xrealloc(buff, sz + 1); - } - - /* --- Count the lines --- */ - - lim = buff + done; - - sz = 1; - for (p = buff; p < lim; p++) - if (*p == '\n') sz++; - - /* --- Build a table of line starts --- */ - - line = xmalloc(sz * sizeof(char *)); - i = 0; - line[i++] = buff; - for (p = buff; p < lim; p++) - if (*p == '\n') *p = 0, line[i++] = p + 1; - *lim = 0; - - /* --- Build a table of lines --- * - * - * This reverses the mapping which the symbol table performs, so that its - * accuracy can be tested. - */ - - flag = xmalloc(sz * sizeof(sym_word *)); - for (i = 0; i < sz; i++) - flag[i] = 0; - entries = 0; - - sym_createTable(&tbl); - - for (;;) { - i = (unsigned)rand() % sz; - - switch (rand() % 5) - { - case 0: { - sym_word *w; - - /* printf("find `%s'\n", line[i]); */ - if ((rand() & 1023) == 0) { - putchar('.'); fflush(stdout); - } - - w = sym_find(&tbl, line[i], -1, 0, 0); - if (w != flag[i]) - printf("*** error: find `%s' gave %p not %p\n", - line[i], (void *)w, (void *)flag[i]); - else if (w && w->i != i) - printf("*** error: find sym for `%s' gives index %i not %i\n", - line[i], w->i, i); - } break; - - case 1: { - unsigned f; - sym_word *w; - - /* printf("create `%s'\n", line[i]); */ - if ((rand() & 1023) == 0) { - putchar('+'); fflush(stdout); - } - - w = sym_find(&tbl, line[i], -1, sizeof(sym_word), &f); - if (f) - { - if (w != flag[i]) - printf("*** error: create `%s' gave %p not %p\n", - line[i], (void *)w, (void *)flag[i]); - else if (w && w->i != i) - printf("*** error: create sym for `%s' gives index %i not %i\n", - line[i], w->i, i); - } - else - { - if (flag[i]) - printf("*** error: create `%s' gave new block, should be %p\n", - line[i], (void *)flag[i]); - else { - flag[i] = w; - w->i = i; - entries++; - } - } - } break; - - case 2: { - sym_iter it; - sym_word *w, **ntbl; - int v = (rand() % entries) == 0; - if (!v) - break; - printf("\niterated %i entries\n", entries); - break; - - printf("iterate\n"); - - ntbl = xmalloc(sz * sizeof(sym_word *)); - memcpy(ntbl, flag, sz * sizeof(sym_word *)); - sym_createIter(&it, &tbl); - - while ((w = sym_next(&it)) != 0) { - if (ntbl[w->i] == 0) - printf("*** error: iterate returned duff item %i\n", w->i); - else - ntbl[w->i] = 0; - } - - for (i = 0; i < sz; i++) - if (ntbl[i]) printf("*** error: iterate didn't return item %i\n", - i); - free(ntbl); - } break; - - case 3: { - sym_base *b; - int v = rand() & 255 ? 0 : 1; - break; - - printf("dump\n"); - - for (i = 0; i <= tbl.mask; i++) { - if (!tbl.a[i]) continue; - if (v) printf(" %i: ", i); - b = tbl.a[i]; - while (b) { - if ((b->hash & tbl.mask) != i) - printf("*** error: bad hash value found"); - if (v) printf("`%s'(%08lx:%lu) ", - line[((sym_word *)b)->i], - b->hash, - b->hash & tbl.mask); - b = b->next; - } - if (v) putchar('\n'); - } - } break; - - case 4: { - if (flag[i]) { - /* printf("remove `%s'\n", flag[i]->base.name); */ - if ((rand() & 1023) == 0) { - putchar('-'); fflush(stdout); - } - sym_remove(&tbl, flag[i]); - flag[i] = 0; - entries--; - } - } break; - } - - } - - return (0); -} - -#endif - -/*----- That's all, folks -------------------------------------------------*/