| 1 | |
| 2 | /******************************************** |
| 3 | zmalloc.c |
| 4 | copyright 1991, Michael D. Brennan |
| 5 | |
| 6 | This is a source file for mawk, an implementation of |
| 7 | the AWK programming language. |
| 8 | |
| 9 | Mawk is distributed without warranty under the terms of |
| 10 | the GNU General Public License, version 2, 1991. |
| 11 | ********************************************/ |
| 12 | |
| 13 | /*$Log: zmalloc.c,v $ |
| 14 | * Revision 5.1 91/12/05 07:56:35 brennan |
| 15 | * 1.1 pre-release |
| 16 | * |
| 17 | */ |
| 18 | |
| 19 | /* zmalloc.c */ |
| 20 | #include "mawk.h" |
| 21 | #include "zmalloc.h" |
| 22 | |
| 23 | void PROTO( mawk_exit, (int) ) ; |
| 24 | |
| 25 | extern struct yacc_mem *yacc_memp ; |
| 26 | |
| 27 | /* |
| 28 | zmalloc() gets mem from malloc() in CHUNKS of 2048 bytes |
| 29 | and cuts these blocks into smaller pieces that are multiples |
| 30 | of eight bytes. When a piece is returned via zfree(), it goes |
| 31 | on a linked linear list indexed by its size. The lists are |
| 32 | an array, pool[]. |
| 33 | |
| 34 | E.g., if you ask for 22 bytes with p = zmalloc(22), you actually get |
| 35 | a piece of size 24. When you free it with zfree(p,22) , it is added |
| 36 | to the list at pool[2]. |
| 37 | */ |
| 38 | |
| 39 | #define POOLSZ 16 |
| 40 | |
| 41 | #define CHUNK 256 |
| 42 | /* number of blocks to get from malloc */ |
| 43 | |
| 44 | static PTR PROTO( emalloc, (unsigned) ) ; |
| 45 | void PROTO( errmsg, (int , char *, ...) ) ; |
| 46 | |
| 47 | static PTR emalloc(size) |
| 48 | unsigned size ; |
| 49 | { PTR p ; |
| 50 | static char out[] = "out of memory" ; |
| 51 | |
| 52 | if( !(p = (PTR) malloc(SIZE_T(size))) ) |
| 53 | if ( mawk_state == EXECUTION ) rt_error(out) ; |
| 54 | else /* I don't think this will ever happen */ |
| 55 | { compile_error(out) ; mawk_exit(1) ; } |
| 56 | return p ; |
| 57 | } |
| 58 | |
| 59 | |
| 60 | typedef union zblock { |
| 61 | char dummy[ZBLOCKSZ] ; |
| 62 | union zblock *link ; |
| 63 | } ZBLOCK ; |
| 64 | |
| 65 | /* ZBLOCKS of sizes 1, 2, ... 16 |
| 66 | which is bytes of sizes 8, 16, ... , 128 |
| 67 | are stored on the linked linear lists in |
| 68 | pool[0], pool[1], ... , pool[15] |
| 69 | */ |
| 70 | |
| 71 | static ZBLOCK *pool[POOLSZ] ; |
| 72 | |
| 73 | PTR bmalloc( blocks ) |
| 74 | register unsigned blocks ; |
| 75 | { |
| 76 | register ZBLOCK *p ; |
| 77 | static unsigned amt_avail ; |
| 78 | static ZBLOCK *avail ; |
| 79 | |
| 80 | if ( blocks > POOLSZ ) return emalloc(blocks<<ZSHIFT) ; |
| 81 | |
| 82 | if ( p = pool[blocks-1] ) |
| 83 | { pool[blocks-1] = p->link ; return (PTR) p ; } |
| 84 | |
| 85 | if ( blocks > amt_avail ) |
| 86 | { if ( amt_avail ) /* free avail */ |
| 87 | { avail->link = pool[--amt_avail] ; pool[amt_avail] = avail ; } |
| 88 | |
| 89 | /* use parser tables first */ |
| 90 | if ( yacc_memp->zblocks >= blocks ) |
| 91 | { avail = (ZBLOCK *) yacc_memp->mem ; |
| 92 | amt_avail = yacc_memp++ -> zblocks ; |
| 93 | /* make sure its -- aligned */ |
| 94 | if ( (int) avail & 7 ) |
| 95 | { avail = (ZBLOCK*)((char *)avail + 8 - ((int)avail&7)) ; |
| 96 | amt_avail-- ; |
| 97 | } |
| 98 | } |
| 99 | else |
| 100 | if ( !(avail = (ZBLOCK *) malloc(SIZE_T(CHUNK*ZBLOCKSZ))) ) |
| 101 | { /* if we get here, almost out of memory */ |
| 102 | amt_avail = 0 ; |
| 103 | return emalloc(blocks << ZSHIFT) ; |
| 104 | } |
| 105 | else amt_avail = CHUNK ; |
| 106 | } |
| 107 | |
| 108 | /* get p from the avail pile */ |
| 109 | p = avail ; avail += blocks ; amt_avail -= blocks ; |
| 110 | return (PTR) p ; |
| 111 | } |
| 112 | |
| 113 | void bfree( p, blocks) |
| 114 | register PTR p ; |
| 115 | register unsigned blocks ; |
| 116 | { |
| 117 | |
| 118 | if ( blocks > POOLSZ ) free(p) ; |
| 119 | else |
| 120 | { |
| 121 | ((ZBLOCK *)p)->link = pool[--blocks] ; |
| 122 | pool[blocks] = (ZBLOCK *) p ; |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | PTR zrealloc( p, old_size, new_size ) |
| 127 | register PTR p ; |
| 128 | unsigned old_size, new_size ; |
| 129 | { register PTR q ; |
| 130 | |
| 131 | (void) memcpy(q = zmalloc(new_size), p, |
| 132 | SIZE_T(old_size < new_size ? old_size : new_size)) ; |
| 133 | |
| 134 | zfree(p, old_size) ; |
| 135 | return q ; |
| 136 | } |
| 137 | |
| 138 | |