/* Generate assembler source containing symbol information * * Copyright 2002 by Kai Germaschewski * * This software may be used and distributed according to the terms * of the GNU General Public License, incorporated herein by reference. * * Usage: nm -n vmlinux | scripts/kallsyms [--all-symbols] > symbols.S * * ChangeLog: * * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com> * Changed the compression method from stem compression to "table lookup" * compression * * Table compression uses all the unused char codes on the symbols and * maps these to the most used substrings (tokens). For instance, it might * map char code 0xF7 to represent "write_" and then in every symbol where * "write_" appears it can be replaced by 0xF7, saving 5 bytes. * The used codes themselves are also placed in the table so that the * decompresion can work without "special cases". * Applied to kernel symbols, this usually produces a compression ratio * of about 50%. * */ #include <stdio.h>#include <stdlib.h>#include <string.h>#include <ctype.h> /* maximum token length used. It doesn't pay to increase it a lot, because * very long substrings probably don't repeat themselves too often. */#define MAX_TOK_SIZE 11#define KSYM_NAME_LEN 127 /* we use only a subset of the complete symbol table to gather the token count, * to speed up compression, at the expense of a little compression ratio */#define WORKING_SET 1024 /* first find the best token only on the list of tokens that would profit more * than GOOD_BAD_THRESHOLD. Only if this list is empty go to the "bad" list. * Increasing this value will put less tokens on the "good" list, so the search * is faster. However, if the good list runs out of tokens, we must painfully * search the bad list. */#define GOOD_BAD_THRESHOLD 10 /* token hash parameters */#define HASH_BITS 18#define HASH_TABLE_SIZE (1 << HASH_BITS)#define HASH_MASK (HASH_TABLE_SIZE - 1)#define HASH_BASE_OFFSET 2166136261U#define HASH_FOLD(a) ((a)&(HASH_MASK)) /* flags to mark symbols */#define SYM_FLAG_VALID 1#define SYM_FLAG_SAMPLED 2 struct sym_entry { unsigned long long addr; char type; unsigned char flags; unsigned char len; unsigned char *sym;}; static struct sym_entry *table;static int size, cnt;static unsigned long long _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext;static int all_symbols = 0;static char symbol_prefix_char = '\0'; struct token { unsigned char data[MAX_TOK_SIZE]; unsigned char len; /* profit: the number of bytes that could be saved by inserting this * token into the table */ int profit; struct token *next; /* next token on the hash list */ struct token *right; /* next token on the good/bad list */ struct token *left; /* previous token on the good/bad list */ struct token *smaller; /* token that is less one letter than this one */ }; struct token bad_head, good_head;struct token *hash_table[HASH_TABLE_SIZE]; /* the table that holds the result of the compression */unsigned char best_table[256][MAX_TOK_SIZE+1];unsigned char best_table_len[256]; static voidusage(void){ fprintf(stderr, "Usage: kallsyms [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n"); exit(1);} /* * This ignores the intensely annoying "mapping symbols" found * in ARM ELF files: $a, $t and $d. */static inline intis_arm_mapping_symbol(const char *str){ return str[0] == '$' && strchr("atd", str[1]) && (str[2] == '\0' || str[2] == '.');} static intread_symbol(FILE *in, struct sym_entry *s){ char str[500]; char *sym; int rc; rc = fscanf(in, "%llx %c %499s\n", &s->addr, &s->type, str); if (rc != 3) { if (rc != EOF) { /* skip line */ fgets(str, 500, in); } return -1; } sym = str; /* skip prefix char */ if (symbol_prefix_char && str[0] == symbol_prefix_char) sym++; /* Ignore most absolute/undefined (?) symbols. */ if (strcmp(sym, "_stext") == 0) _stext = s->addr; else if (strcmp(sym, "_etext") == 0) _etext = s->addr; else if (strcmp(sym, "_sinittext") == 0) _sinittext = s->addr; else if (strcmp(sym, "_einittext") == 0) _einittext = s->addr; else if (strcmp(sym, "_sextratext") == 0) _sextratext = s->addr; else if (strcmp(sym, "_eextratext") == 0) _eextratext = s->addr; else if (toupper(s->type) == 'A') { /* Keep these useful absolute symbols */ if (strcmp(sym, "__kernel_syscall_via_break") && strcmp(sym, "__kernel_syscall_via_epc") && strcmp(sym, "__kernel_sigtramp") && strcmp(sym, "__gp")) return -1; } else if (toupper(s->type) == 'U' || is_arm_mapping_symbol(sym)) return -1; /* include the type field in the symbol name, so that it gets * compressed together */ s->len = strlen(str) + 1; s->sym = (char *) malloc(s->len + 1); strcpy(s->sym + 1, str); s->sym[0] = s->type; return 0;} static intsymbol_valid(struct sym_entry *s){ /* Symbols which vary between passes. Passes 1 and 2 must have * identical symbol lists. The kallsyms_* symbols below are only added * after pass 1, they would be included in pass 2 when --all-symbols is * specified so exclude them to get a stable symbol list. */ static char *special_symbols[] = { "kallsyms_addresses", "kallsyms_num_syms", "kallsyms_names", "kallsyms_markers", "kallsyms_token_table", "kallsyms_token_index", /* Exclude linker generated symbols which vary between passes */ "_SDA_BASE_", /* ppc */ "_SDA2_BASE_", /* ppc */ NULL }; int i; int offset = 1; /* skip prefix char */ if (symbol_prefix_char && *(s->sym + 1) == symbol_prefix_char) offset++; /* if --all-symbols is not specified, then symbols outside the text * and inittext sections are discarded */ if (!all_symbols) { if ((s->addr < _stext || s->addr > _etext) && (s->addr < _sinittext || s->addr > _einittext) && (s->addr < _sextratext || s->addr > _eextratext)) return 0; /* Corner case. Discard any symbols with the same value as * _etext _einittext or _eextratext; they can move between pass * 1 and 2 when the kallsyms data are added. If these symbols * move then they may get dropped in pass 2, which breaks the * kallsyms rules. */ if ((s->addr == _etext && strcmp(s->sym + offset, "_etext")) || (s->addr == _einittext && strcmp(s->sym + offset, "_einittext")) || (s->addr == _eextratext && strcmp(s->sym + offset, "_eextratext"))) return 0; } /* Exclude symbols which vary between passes. */ if (strstr(s->sym + offset, "_compiled.")) return 0; for (i = 0; special_symbols[i]; i++) if( strcmp(s->sym + offset, special_symbols[i]) == 0 ) return 0; return 1;} static voidread_map(FILE *in){ while (!feof(in)) { if (cnt >= size) { size += 10000; table = realloc(table, sizeof(*table) * size); if (!table) { fprintf(stderr, "out of memory\n"); exit (1); } } if (read_symbol(in, &table[cnt]) == 0) cnt++; }} static void output_label(char *label){ if (symbol_prefix_char) printf(".globl %c%s\n", symbol_prefix_char, label); else printf(".globl %s\n", label); printf("\tALGN\n"); if (symbol_prefix_char) printf("%c%s:\n", symbol_prefix_char, label); else printf("%s:\n", label);} /* uncompress a compressed symbol. When this function is called, the best table * might still be compressed itself, so the function needs to be recursive */static int expand_symbol(unsigned char *data, int len, char *result){ int c, rlen, total=0; while (len) { c = *data; /* if the table holds a single char that is the same as the one * we are looking for, then end the search */ if (best_table[c][0]==c && best_table_len[c]==1) { *result++ = c; total++; } else { /* if not, recurse and expand */ rlen = expand_symbol(best_table[c], best_table_len[c], result); total += rlen; result += rlen; } data++; len--; } *result=0; return total;} static voidwrite_src(void){ int i, k, off, valid; unsigned int best_idx[256]; unsigned int *markers; char buf[KSYM_NAME_LEN+1]; printf("#include <asm/types.h>\n"); printf("#if BITS_PER_LONG == 64\n"); printf("#define PTR .quad\n"); printf("#define ALGN .align 8\n"); printf("#else\n"); printf("#define PTR .long\n"); printf("#define ALGN .align 4\n"); printf("#endif\n"); printf(".data\n"); output_label("kallsyms_addresses"); valid = 0; for (i = 0; i < cnt; i++) { if (table[i].flags & SYM_FLAG_VALID) { printf("\tPTR\t%#llx\n", table[i].addr); valid++; } } printf("\n"); output_label("kallsyms_num_syms"); printf("\tPTR\t%d\n", valid); printf("\n"); /* table of offset markers, that give the offset in the compressed stream * every 256 symbols */ markers = (unsigned int *) malloc(sizeof(unsigned int)*((valid + 255) / 256)); output_label("kallsyms_names"); valid = 0; off = 0; for (i = 0; i < cnt; i++) { if (!table[i].flags & SYM_FLAG_VALID) continue; if ((valid & 0xFF) == 0) markers[valid >> 8] = off; printf("\t.byte 0x%02x", table[i].len); for (k = 0; k < table[i].len; k++) printf(", 0x%02x", table[i].sym[k]); printf("\n"); off += table[i].len + 1; valid++; } printf("\n"); output_label("kallsyms_markers"); for (i = 0; i < ((valid + 255) >> 8); i++) printf("\tPTR\t%d\n", markers[i]); printf("\n"); free(markers); output_label("kallsyms_token_table"); off = 0; for (i = 0; i < 256; i++) { best_idx[i] = off; expand_symbol(best_table[i],best_table_len[i],buf); printf("\t.asciz\t\"%s\"\n", buf); off += strlen(buf) + 1; } printf("\n"); output_label("kallsyms_token_index"); for (i = 0; i < 256; i++) printf("\t.short\t%d\n", best_idx[i]); printf("\n");} /* table lookup compression functions */ static inline unsigned int rehash_token(unsigned int hash, unsigned char data){ return ((hash * 16777619) ^ data);} static unsigned int hash_token(unsigned char *data, int len){ unsigned int hash=HASH_BASE_OFFSET; int i; for (i = 0; i < len; i++) hash = rehash_token(hash, data[i]); return HASH_FOLD(hash);} /* find a token given its data and hash value */static struct token *find_token_hash(unsigned char *data, int len, unsigned int hash){ struct token *ptr; ptr = hash_table[hash]; while (ptr) { if ((ptr->len == len) && (memcmp(ptr->data, data, len) == 0)) return ptr; ptr=ptr->next; } return NULL;} static inline void insert_token_in_group(struct token *head, struct token *ptr){ ptr->right = head->right; ptr->right->left = ptr; head->right = ptr; ptr->left = head;} static inline void remove_token_from_group(struct token *ptr){ ptr->left->right = ptr->right; ptr->right->left = ptr->left;} /* build the counts for all the tokens that start with "data", and have lenghts * from 2 to "len" */static void learn_token(unsigned char *data, int len){ struct token *ptr,*last_ptr; int i, newprofit; unsigned int hash = HASH_BASE_OFFSET; unsigned int hashes[MAX_TOK_SIZE + 1]; if (len > MAX_TOK_SIZE) len = MAX_TOK_SIZE; /* calculate and store the hash values for all the sub-tokens */ hash = rehash_token(hash, data[0]); for (i = 2; i <= len; i++) { hash = rehash_token(hash, data[i-1]); hashes[i] = HASH_FOLD(hash); } last_ptr = NULL; ptr = NULL; for (i = len; i >= 2; i--) { hash = hashes[i]; if (!ptr) ptr = find_token_hash(data, i, hash); if (!ptr) { /* create a new token entry */ ptr = (struct token *) malloc(sizeof(*ptr)); memcpy(ptr->data, data, i); ptr->len = i; /* when we create an entry, it's profit is 0 because * we also take into account the size of the token on * the compressed table. We then subtract GOOD_BAD_THRESHOLD * so that the test to see if this token belongs to * the good or bad list, is a comparison to zero */ ptr->profit = -GOOD_BAD_THRESHOLD; ptr->next = hash_table[hash]; hash_table[hash] = ptr; insert_token_in_group(&bad_head, ptr); ptr->smaller = NULL; } else { newprofit = ptr->profit + (ptr->len - 1); /* check to see if this token needs to be moved to a * different list */ if((ptr->profit < 0) && (newprofit >= 0)) { remove_token_from_group(ptr); insert_token_in_group(&good_head,ptr); } ptr->profit = newprofit; } if (last_ptr) last_ptr->smaller = ptr; last_ptr = ptr; ptr = ptr->smaller; }} /* decrease the counts for all the tokens that start with "data", and have lenghts * from 2 to "len". This function is much simpler than learn_token because we have * more guarantees (tho tokens exist, the ->smaller pointer is set, etc.) * The two separate functions exist only because of compression performance */static void forget_token(unsigned char *data, int len){ struct token *ptr; int i, newprofit; unsigned int hash=0; if (len > MAX_TOK_SIZE) len = MAX_TOK_SIZE; hash = hash_token(data, len); ptr = find_token_hash(data, len, hash); for (i = len; i >= 2; i--) { newprofit = ptr->profit - (ptr->len - 1); if ((ptr->profit >= 0) && (newprofit < 0)) { remove_token_from_group(ptr); insert_token_in_group(&bad_head, ptr);Lines 1–500 of 728. Load more
/* Generate assembler source containing symbol information * * Copyright 2002 by Kai Germaschewski * * This software may be used and distributed according to the terms * of the GNU General Public License, incorporated herein by reference. * * Usage: nm -n vmlinux | scripts/kallsyms [--all-symbols] > symbols.S * * ChangeLog: * * (25/Aug/2004) Paulo Marques <pmarques@grupopie.com> * Changed the compression method from stem compression to "table lookup" * compression * * Table compression uses all the unused char codes on the symbols and * maps these to the most used substrings (tokens). For instance, it might * map char code 0xF7 to represent "write_" and then in every symbol where * "write_" appears it can be replaced by 0xF7, saving 5 bytes. * The used codes themselves are also placed in the table so that the * decompresion can work without "special cases". * Applied to kernel symbols, this usually produces a compression ratio * of about 50%. * */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <ctype.h> /* maximum token length used. It doesn't pay to increase it a lot, because * very long substrings probably don't repeat themselves too often. */ #define MAX_TOK_SIZE 11 #define KSYM_NAME_LEN 127 /* we use only a subset of the complete symbol table to gather the token count, * to speed up compression, at the expense of a little compression ratio */ #define WORKING_SET 1024 /* first find the best token only on the list of tokens that would profit more * than GOOD_BAD_THRESHOLD. Only if this list is empty go to the "bad" list. * Increasing this value will put less tokens on the "good" list, so the search * is faster. However, if the good list runs out of tokens, we must painfully * search the bad list. */ #define GOOD_BAD_THRESHOLD 10 /* token hash parameters */ #define HASH_BITS 18 #define HASH_TABLE_SIZE (1 << HASH_BITS) #define HASH_MASK (HASH_TABLE_SIZE - 1) #define HASH_BASE_OFFSET 2166136261U #define HASH_FOLD(a) ((a)&(HASH_MASK)) /* flags to mark symbols */ #define SYM_FLAG_VALID 1 #define SYM_FLAG_SAMPLED 2 struct sym_entry { unsigned long long addr; char type; unsigned char flags; unsigned char len; unsigned char *sym; }; static struct sym_entry *table; static int size, cnt; static unsigned long long _stext, _etext, _sinittext, _einittext, _sextratext, _eextratext; static int all_symbols = 0; static char symbol_prefix_char = '\0'; struct token { unsigned char data[MAX_TOK_SIZE]; unsigned char len; /* profit: the number of bytes that could be saved by inserting this * token into the table */ int profit; struct token *next; /* next token on the hash list */ struct token *right; /* next token on the good/bad list */ struct token *left; /* previous token on the good/bad list */ struct token *smaller; /* token that is less one letter than this one */ }; struct token bad_head, good_head; struct token *hash_table[HASH_TABLE_SIZE]; /* the table that holds the result of the compression */ unsigned char best_table[256][MAX_TOK_SIZE+1]; unsigned char best_table_len[256]; static void usage(void) { fprintf(stderr, "Usage: kallsyms [--all-symbols] [--symbol-prefix=<prefix char>] < in.map > out.S\n"); exit(1); } /* * This ignores the intensely annoying "mapping symbols" found * in ARM ELF files: $a, $t and $d. */ static inline int is_arm_mapping_symbol(const char *str) { return str[0] == '$' && strchr("atd", str[1]) && (str[2] == '\0' || str[2] == '.'); } static int read_symbol(FILE *in, struct sym_entry *s) { char str[500]; char *sym; int rc; rc = fscanf(in, "%llx %c %499s\n", &s->addr, &s->type, str); if (rc != 3) { if (rc != EOF) { /* skip line */ fgets(str, 500, in); } return -1; } sym = str; /* skip prefix char */ if (symbol_prefix_char && str[0] == symbol_prefix_char) sym++; /* Ignore most absolute/undefined (?) symbols. */ if (strcmp(sym, "_stext") == 0) _stext = s->addr; else if (strcmp(sym, "_etext") == 0) _etext = s->addr; else if (strcmp(sym, "_sinittext") == 0) _sinittext = s->addr; else if (strcmp(sym, "_einittext") == 0) _einittext = s->addr; else if (strcmp(sym, "_sextratext") == 0) _sextratext = s->addr; else if (strcmp(sym, "_eextratext") == 0) _eextratext = s->addr; else if (toupper(s->type) == 'A') { /* Keep these useful absolute symbols */ if (strcmp(sym, "__kernel_syscall_via_break") && strcmp(sym, "__kernel_syscall_via_epc") && strcmp(sym, "__kernel_sigtramp") && strcmp(sym, "__gp")) return -1; } else if (toupper(s->type) == 'U' || is_arm_mapping_symbol(sym)) return -1; /* include the type field in the symbol name, so that it gets * compressed together */ s->len = strlen(str) + 1; s->sym = (char *) malloc(s->len + 1); strcpy(s->sym + 1, str); s->sym[0] = s->type; return 0; } static int symbol_valid(struct sym_entry *s) { /* Symbols which vary between passes. Passes 1 and 2 must have * identical symbol lists. The kallsyms_* symbols below are only added * after pass 1, they would be included in pass 2 when --all-symbols is * specified so exclude them to get a stable symbol list. */ static char *special_symbols[] = { "kallsyms_addresses", "kallsyms_num_syms", "kallsyms_names", "kallsyms_markers", "kallsyms_token_table", "kallsyms_token_index", /* Exclude linker generated symbols which vary between passes */ "_SDA_BASE_", /* ppc */ "_SDA2_BASE_", /* ppc */ NULL }; int i; int offset = 1; /* skip prefix char */ if (symbol_prefix_char && *(s->sym + 1) == symbol_prefix_char) offset++; /* if --all-symbols is not specified, then symbols outside the text * and inittext sections are discarded */ if (!all_symbols) { if ((s->addr < _stext || s->addr > _etext) && (s->addr < _sinittext || s->addr > _einittext) && (s->addr < _sextratext || s->addr > _eextratext)) return 0; /* Corner case. Discard any symbols with the same value as * _etext _einittext or _eextratext; they can move between pass * 1 and 2 when the kallsyms data are added. If these symbols * move then they may get dropped in pass 2, which breaks the * kallsyms rules. */ if ((s->addr == _etext && strcmp(s->sym + offset, "_etext")) || (s->addr == _einittext && strcmp(s->sym + offset, "_einittext")) || (s->addr == _eextratext && strcmp(s->sym + offset, "_eextratext"))) return 0; } /* Exclude symbols which vary between passes. */ if (strstr(s->sym + offset, "_compiled.")) return 0; for (i = 0; special_symbols[i]; i++) if( strcmp(s->sym + offset, special_symbols[i]) == 0 ) return 0; return 1; } static void read_map(FILE *in) { while (!feof(in)) { if (cnt >= size) { size += 10000; table = realloc(table, sizeof(*table) * size); if (!table) { fprintf(stderr, "out of memory\n"); exit (1); } } if (read_symbol(in, &table[cnt]) == 0) cnt++; } } static void output_label(char *label) { if (symbol_prefix_char) printf(".globl %c%s\n", symbol_prefix_char, label); else printf(".globl %s\n", label); printf("\tALGN\n"); if (symbol_prefix_char) printf("%c%s:\n", symbol_prefix_char, label); else printf("%s:\n", label); } /* uncompress a compressed symbol. When this function is called, the best table * might still be compressed itself, so the function needs to be recursive */ static int expand_symbol(unsigned char *data, int len, char *result) { int c, rlen, total=0; while (len) { c = *data; /* if the table holds a single char that is the same as the one * we are looking for, then end the search */ if (best_table[c][0]==c && best_table_len[c]==1) { *result++ = c; total++; } else { /* if not, recurse and expand */ rlen = expand_symbol(best_table[c], best_table_len[c], result); total += rlen; result += rlen; } data++; len--; } *result=0; return total; } static void write_src(void) { int i, k, off, valid; unsigned int best_idx[256]; unsigned int *markers; char buf[KSYM_NAME_LEN+1]; printf("#include <asm/types.h>\n"); printf("#if BITS_PER_LONG == 64\n"); printf("#define PTR .quad\n"); printf("#define ALGN .align 8\n"); printf("#else\n"); printf("#define PTR .long\n"); printf("#define ALGN .align 4\n"); printf("#endif\n"); printf(".data\n"); output_label("kallsyms_addresses"); valid = 0; for (i = 0; i < cnt; i++) { if (table[i].flags & SYM_FLAG_VALID) { printf("\tPTR\t%#llx\n", table[i].addr); valid++; } } printf("\n"); output_label("kallsyms_num_syms"); printf("\tPTR\t%d\n", valid); printf("\n"); /* table of offset markers, that give the offset in the compressed stream * every 256 symbols */ markers = (unsigned int *) malloc(sizeof(unsigned int)*((valid + 255) / 256)); output_label("kallsyms_names"); valid = 0; off = 0; for (i = 0; i < cnt; i++) { if (!table[i].flags & SYM_FLAG_VALID) continue; if ((valid & 0xFF) == 0) markers[valid >> 8] = off; printf("\t.byte 0x%02x", table[i].len); for (k = 0; k < table[i].len; k++) printf(", 0x%02x", table[i].sym[k]); printf("\n"); off += table[i].len + 1; valid++; } printf("\n"); output_label("kallsyms_markers"); for (i = 0; i < ((valid + 255) >> 8); i++) printf("\tPTR\t%d\n", markers[i]); printf("\n"); free(markers); output_label("kallsyms_token_table"); off = 0; for (i = 0; i < 256; i++) { best_idx[i] = off; expand_symbol(best_table[i],best_table_len[i],buf); printf("\t.asciz\t\"%s\"\n", buf); off += strlen(buf) + 1; } printf("\n"); output_label("kallsyms_token_index"); for (i = 0; i < 256; i++) printf("\t.short\t%d\n", best_idx[i]); printf("\n"); } /* table lookup compression functions */ static inline unsigned int rehash_token(unsigned int hash, unsigned char data) { return ((hash * 16777619) ^ data); } static unsigned int hash_token(unsigned char *data, int len) { unsigned int hash=HASH_BASE_OFFSET; int i; for (i = 0; i < len; i++) hash = rehash_token(hash, data[i]); return HASH_FOLD(hash); } /* find a token given its data and hash value */ static struct token *find_token_hash(unsigned char *data, int len, unsigned int hash) { struct token *ptr; ptr = hash_table[hash]; while (ptr) { if ((ptr->len == len) && (memcmp(ptr->data, data, len) == 0)) return ptr; ptr=ptr->next; } return NULL; } static inline void insert_token_in_group(struct token *head, struct token *ptr) { ptr->right = head->right; ptr->right->left = ptr; head->right = ptr; ptr->left = head; } static inline void remove_token_from_group(struct token *ptr) { ptr->left->right = ptr->right; ptr->right->left = ptr->left; } /* build the counts for all the tokens that start with "data", and have lenghts * from 2 to "len" */ static void learn_token(unsigned char *data, int len) { struct token *ptr,*last_ptr; int i, newprofit; unsigned int hash = HASH_BASE_OFFSET; unsigned int hashes[MAX_TOK_SIZE + 1]; if (len > MAX_TOK_SIZE) len = MAX_TOK_SIZE; /* calculate and store the hash values for all the sub-tokens */ hash = rehash_token(hash, data[0]); for (i = 2; i <= len; i++) { hash = rehash_token(hash, data[i-1]); hashes[i] = HASH_FOLD(hash); } last_ptr = NULL; ptr = NULL; for (i = len; i >= 2; i--) { hash = hashes[i]; if (!ptr) ptr = find_token_hash(data, i, hash); if (!ptr) { /* create a new token entry */ ptr = (struct token *) malloc(sizeof(*ptr)); memcpy(ptr->data, data, i); ptr->len = i; /* when we create an entry, it's profit is 0 because * we also take into account the size of the token on * the compressed table. We then subtract GOOD_BAD_THRESHOLD * so that the test to see if this token belongs to * the good or bad list, is a comparison to zero */ ptr->profit = -GOOD_BAD_THRESHOLD; ptr->next = hash_table[hash]; hash_table[hash] = ptr; insert_token_in_group(&bad_head, ptr); ptr->smaller = NULL; } else { newprofit = ptr->profit + (ptr->len - 1); /* check to see if this token needs to be moved to a * different list */ if((ptr->profit < 0) && (newprofit >= 0)) { remove_token_from_group(ptr); insert_token_in_group(&good_head,ptr); } ptr->profit = newprofit; } if (last_ptr) last_ptr->smaller = ptr; last_ptr = ptr; ptr = ptr->smaller; } } /* decrease the counts for all the tokens that start with "data", and have lenghts * from 2 to "len". This function is much simpler than learn_token because we have * more guarantees (tho tokens exist, the ->smaller pointer is set, etc.) * The two separate functions exist only because of compression performance */ static void forget_token(unsigned char *data, int len) { struct token *ptr; int i, newprofit; unsigned int hash=0; if (len > MAX_TOK_SIZE) len = MAX_TOK_SIZE; hash = hash_token(data, len); ptr = find_token_hash(data, len, hash); for (i = len; i >= 2; i--) { newprofit = ptr->profit - (ptr->len - 1); if ((ptr->profit >= 0) && (newprofit < 0)) { remove_token_from_group(ptr); insert_token_in_group(&bad_head, ptr);