From: Francois Fleuret Date: Sun, 5 Jul 2009 11:41:08 +0000 (+0200) Subject: Introduced a struct hash_table_t to clean the code a bit. X-Git-Url: https://fleuret.org/cgi-bin/gitweb/gitweb.cgi?a=commitdiff_plain;h=10592c71e9df8aa493b039873a7668b09e974a9c;p=selector.git Introduced a struct hash_table_t to clean the code a bit. --- diff --git a/selector.c b/selector.c index 6c0f7f5..41f29e0 100644 --- a/selector.c +++ b/selector.c @@ -126,62 +126,78 @@ void error_feedback() { } } -/********************************************************************* - A quick and dirty hash table +/* A quick and dirty hash table */ + +/* The table itself stores indexes of the strings taken in a char + **table. When a string is added, if it was already in the table, + **the new index replaces the previous one. */ + +typedef struct { + int size; + int *entries; +} hash_table_t; - The table itself stores indexes of the strings taken in a char - **table. When a string is added, if it was already in the table, the - new index replaces the previous one. */ +hash_table_t *new_hash_table(int size) { + int k; + hash_table_t *hash_table; + + hash_table = (hash_table_t *) malloc(sizeof(hash_table_t)); -int *new_hash_table(int hash_table_size) { - int *result, k; - result = (int *) malloc(hash_table_size * sizeof(int)); - for(k = 0; k < hash_table_size; k++) { - result[k] = -1; + hash_table->size = size; + hash_table->entries = (int *) malloc(hash_table->size * sizeof(int)); + + for(k = 0; k < hash_table->size; k++) { + hash_table->entries[k] = -1; } - return result; + + return hash_table; +} + +void free_hash_table(hash_table_t *hash_table) { + free(hash_table->entries); + free(hash_table); } /* Adds new_string in the table, associated to new_index. If this string was not already in the table, returns -1. Otherwise, returns the previous index it had. */ -int add_and_get_previous_index(const char *new_string, int new_index, - char **strings, - int *hash_table, int hash_table_size) { +int add_and_get_previous_index(hash_table_t *hash_table, + const char *new_string, int new_index, + char **strings) { unsigned int code = 0; int k; /* This is my recipe. I checked, it seems to work (as long as - hash_table_size is not a multiple of 387433 that should be + hash_table->size is not a multiple of 387433 that should be okay) */ for(k = 0; new_string[k]; k++) { code = code * 387433 + (unsigned int) (new_string[k]); } - code = code % hash_table_size; + code = code % hash_table->size; - while(hash_table[code] >= 0) { + while(hash_table->entries[code] >= 0) { /* There is a string with that code */ - if(strcmp(new_string, strings[hash_table[code]]) == 0) { + if(strcmp(new_string, strings[hash_table->entries[code]]) == 0) { /* It is the same string, we keep a copy of the stored index */ - int result = hash_table[code]; + int result = hash_table->entries[code]; /* Put the new one */ - hash_table[code] = new_index; + hash_table->entries[code] = new_index; /* And return the previous one */ return result; } /* This collision was not the same string, let's move to the next in the table */ - code = (code + 1) % hash_table_size; + code = (code + 1) % hash_table->size; } /* This string was not already in there, store the index in the table and return -1 */ - hash_table[code] = new_index; + hash_table->entries[code] = new_index; return -1; } @@ -574,9 +590,9 @@ void update_screen(int *current_focus_line, int *displayed_focus_line, /*********************************************************************/ -void store_line(const char *t, - int nb_lines_max, int *nb_lines, char **lines, - int hash_table_size, int *hash_table) { +void store_line(hash_table_t *hash_table, + const char *t, + int nb_lines_max, int *nb_lines, char **lines) { int dup; /* Remove the zsh history prefix */ @@ -598,7 +614,7 @@ void store_line(const char *t, the list if necessary */ if(hash_table) { - dup = add_and_get_previous_index(t, *nb_lines, lines, hash_table, hash_table_size); + dup = add_and_get_previous_index(hash_table, t, *nb_lines, lines); } else { dup = -1; } @@ -616,9 +632,9 @@ void store_line(const char *t, (*nb_lines)++; } -void read_file(const char *input_filename, - int nb_lines_max, int *nb_lines, char **lines, - int hash_table_size, int *hash_table) { +void read_file(hash_table_t *hash_table, + const char *input_filename, + int nb_lines_max, int *nb_lines, char **lines) { char raw_line[BUFFER_SIZE]; int start, end, k; @@ -659,9 +675,8 @@ void read_file(const char *input_filename, raw_line[eol] = '\0'; - store_line(raw_line + start, - nb_lines_max, nb_lines, lines, - hash_table_size, hash_table); + store_line(hash_table, raw_line + start, + nb_lines_max, nb_lines, lines); start = eol + 1; } @@ -686,7 +701,8 @@ int main(int argc, char **argv) { int color_fg_highlight, color_bg_highlight; char **lines, **labels; - int nb_lines, hash_table_size, *hash_table; + int nb_lines; + hash_table_t *hash_table; if(!ttyname(STDIN_FILENO)) { fprintf(stderr, "The standard input is not a tty.\n"); @@ -855,27 +871,29 @@ int main(int argc, char **argv) { lines = (char **) malloc(nb_lines_max * sizeof(char *)); nb_lines = 0; - hash_table_size = nb_lines_max * 10; - hash_table = 0; if(remove_duplicates) { - hash_table = new_hash_table(hash_table_size); + hash_table = new_hash_table(nb_lines_max * 10); + } else { + hash_table = 0; } if(input_filename[0]) { - read_file(input_filename, - nb_lines_max, &nb_lines, lines, - hash_table_size, hash_table); + read_file(hash_table, + input_filename, + nb_lines_max, &nb_lines, lines); } while(i < argc) { - read_file(argv[i], - nb_lines_max, &nb_lines, lines, - hash_table_size, hash_table); + read_file(hash_table, + argv[i], + nb_lines_max, &nb_lines, lines); i++; } - free(hash_table); + if(hash_table) { + free_hash_table(hash_table); + } /* Now remove the null strings */