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Diffstat (limited to 'zwgc/new_string.c')
| -rw-r--r-- | zwgc/new_string.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/zwgc/new_string.c b/zwgc/new_string.c new file mode 100644 index 0000000..6c3896b --- /dev/null +++ b/zwgc/new_string.c @@ -0,0 +1,196 @@ +/* This file is part of the Project Athena Zephyr Notification System. + * It is one of the source files comprising zwgc, the Zephyr WindowGram + * client. + * + * Created by: Marc Horowitz <marc@athena.mit.edu> + * + * $Source$ + * $Author$ + * + * Copyright (c) 1989 by the Massachusetts Institute of Technology. + * For copying and distribution information, see the file + * "mit-copyright.h". + */ + +#include <sysdep.h> + +#if (!defined(lint) && !defined(SABER)) +static const char rcsid_new_string_c[] = "$Id$"; +#endif + +/* + * string - a module providing operations on C strings. (i.e., char *'s) + * + * Overview: + * + * A string is a standard C string. I.e., a char pointer to a + * null-terminated sequence of characters. 0 is NOT considered a valid + * string! Various operations are available. See the string_spec file + * for details. + * + * Note: This module assumes that malloc NEVER returns 0 for reasonable + * requests. It is the users responsibility to either ensure that + * this happens or supply a version of malloc with error + * handling. + * + * Some strings are mutable. + */ + +#ifdef DEBUG +#define assert(x) if (!(x)) abort() +#else +#define assert(x) +#endif + +#include "new_memory.h" + +#define string_Length(s) strlen(s) +typedef char *string; + +/* + * string string_CreateFromData(char *data, int length): + * Requires: data[0], data[1], ..., data[length-1] != 0 + * Effects: Takes the first length characters at data and + * creates a string containing them. The returned string + * is on the heap & must be freed eventually. + * I.e., if passed "foobar" and 3, it would return + * string_Copy("foo"). + */ + +string string__CreateFromData(data, length) + char *data; + int length; +{ + string result; + + assert(length>=0); + + result = (string)malloc(length+1); + assert(result); + + (void) memcpy(result, data, length); + result[length] = 0; + + return(result); +} + +/* + * string string_Copy(string s): + * Effects: Returns a copy of s on the heap. The copy must be + * freed eventually. + */ + +string string__Copy(s) + string s; +{ + int length; + string result; + + assert(s); + + length = string_Length(s)+1; + result = (string)malloc(length); + assert(result); + + (void) memcpy(result, s, length); + return(result); +} + +/* + * string string_Concat(string a, b): + * Effects: Returns a string equal to a concatenated to b. + * The returned string is on the heap and must be + * freed eventually. I.e., given "abc" and "def", + * returns string_Copy("abcdef"). + */ + +string string__Concat(a, b) + string a, b; +{ + string result; + int a_length, b_size, result_size; + + a_length = string_Length(a); + b_size = string_Length(b)+1; + result_size = a_length+b_size; + result = (string)malloc(result_size); + assert(result); + + (void) memcpy(result, a, a_length); + (void) memcpy(result+a_length, b, b_size); + + return(result); +} + +/* + * string string_Concat2(string a, b): + * Modifies: a + * Requires: a is on the heap, b does not point into a. + * Effects: Equivalent to: + * string temp; + * temp = string_Concat(a,b); + * free(a); + * return(temp); + * only faster. I.e., uses realloc instead of malloc+memcpy. + */ + +string string__Concat2(a, b) + string a, b; +{ + int a_length = string_Length(a); + int b_size = string_Length(b)+1; + +#ifdef DEBUG_MEMORY + assert(memory__on_heap_p(a)); +#endif + + a = (string)realloc(a, a_length+b_size); + assert(a); + (void) memcpy(a+a_length, b, b_size); + + return(a); +} + +/* + * string string_Downcase(string s): + * Modifies: s + * Effects: Modifies s by changing every uppercase character in s + * to the corresponding lowercase character. Nothing else + * is changed. I.e., "FoObAr19." is changed to "foobar19.". + * S is returned as a convenience. + */ + +string string_Downcase(s) + string s; +{ + char *ptr; + + for (ptr=s; *ptr; ptr++) { + if (isupper(*ptr)) + *ptr = tolower(*ptr); + } + + return(s); +} + +/* + * string string_Upcase(string s): + * Modifies: s + * Effects: Modifies s by changing every lowercase character in s + * to the corresponding uppercase character. Nothing else + * is changed. I.e., "FoObAr19." is changed to "FOOBAR19.". + * S is returned as a convenience. + */ + +string string_Upcase(s) + string s; +{ + char *ptr; + + for (ptr=s; *ptr; ptr++) { + if (islower(*ptr)) + *ptr = toupper(*ptr); + } + + return(s); +} |