Thanks to Owen Shepherd of the Public Domain C Library for helping design and formalize these interfaces.
81 lines
2.5 KiB
C++
81 lines
2.5 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2014.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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stdio/vasprintf.cpp
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Prints a string to a newly allocated buffer.
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*******************************************************************************/
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#include <stdarg.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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struct vasprintf_state
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{
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char* string;
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size_t string_length;
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size_t string_used;
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};
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static size_t vasprintf_callback(void* user, const char* string, size_t length)
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{
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struct vasprintf_state* state = (struct vasprintf_state*) user;
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if ( !state->string )
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return 0;
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size_t needed_length = state->string_used + length + 1;
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if ( state->string_length < needed_length )
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{
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size_t new_length = 2 * state->string_used;
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if ( new_length < needed_length )
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new_length = needed_length;
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size_t new_size = new_length * sizeof(char);
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char* new_string = (char*) realloc(state->string, new_size);
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if ( !new_string )
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{
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free(state->string);
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state->string = NULL;
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return 0;
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}
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state->string = new_string;
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state->string_length = new_length;
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}
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memcpy(state->string + state->string_used, string, sizeof(char) * length);
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state->string_used += length;
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return length;
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}
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extern "C"
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int vasprintf(char** restrict result_ptr,
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const char* restrict format,
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va_list list)
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{
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const size_t DEFAULT_SIZE = 32;
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struct vasprintf_state state;
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state.string_length = DEFAULT_SIZE;
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state.string_used = 0;
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if ( !(state.string = (char*) malloc(state.string_length * sizeof(char))) )
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return *result_ptr = NULL, -1;
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int result = vcbprintf(&state, vasprintf_callback, format, list);
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if ( !state.string )
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return *result_ptr = NULL, -1;
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state.string[state.string_used] = '\0';
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return *result_ptr = state.string, result;
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}
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