#include #include "char_buffer.h" #include "xmalloc.h" #define CHAR_BUFFER_ALIGN_SHIFT 2 #define CHAR_BUFFER_ALIGN (1 << CHAR_BUFFER_ALIGN_SHIFT) #define CHAR_BUFFER_ALIGN_MASK (CHAR_BUFFER_ALIGN - 1) static inline size_t roundup_size(size_t s) { return (s + CHAR_BUFFER_ALIGN_MASK) & ~CHAR_BUFFER_ALIGN_MASK; } /* copy data like memcpy but assume that data are aligned with CHAR_BUFFER_ALIGN and padded with zeros at the end of buffer. */ static inline void bufcopy(char* _dst, const char* _src, size_t _sz) { int* dst = (int *) _dst; const int* src = (const int*) _src; int const * const end_ptr = dst + (_sz>> CHAR_BUFFER_ALIGN_SHIFT); while (dst < end_ptr) { *(dst++) = *(src++); } } void char_buffer_init(struct char_buffer *b, size_t sz) { b->size = roundup_size(sz); b->data = xmalloc(b->size); b->data[0] = 0; b->length = 0; } void char_buffer_free(struct char_buffer *b) { free(b->data); } static void char_buffer_resize(struct char_buffer *b, size_t req_size) { req_size = round_two_power(req_size); char *new_data = xmalloc(req_size); bufcopy(new_data, b->data, b->length); free(b->data); b->data = new_data; b->size = req_size; } int char_buffer_append(struct char_buffer *b, const char *str) { const size_t len = strlen(str); const int string_offset = b->length; const size_t new_len = string_offset + roundup_size(len+1); if (new_len> b->size) char_buffer_resize(b, new_len); /* zero the final word of the destination buffer */ int* const end_ptr = ((int *) (b->data + new_len)) - 1; *end_ptr = 0; /* copy the string data into destination buffer. The final zero is not needed since the last word of dest buffer was padded with zeros. */ memcpy(b->data + string_offset, str, len); b->length = new_len; return string_offset; }