feat(sv): add string view lib

CMakeLists.txt

@@ -5,11 +5,15 @@ project(
   DESCRIPTION "C Libraries for recreational Programming."
   LANGUAGES C)
 
-add_library(c-libs ${CMAKE_CURRENT_SOURCE_DIR}/src/dyn-arr.c)
+add_library(c-libs ${CMAKE_CURRENT_SOURCE_DIR}/src/dyn-arr.c
+                   ${CMAKE_CURRENT_SOURCE_DIR}/src/string-view.c)
 target_include_directories(
   c-libs PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
                 $<INSTALL_INTERFACE:include>)
 
+add_executable(strings ${CMAKE_CURRENT_SOURCE_DIR}/app/strings.c)
+target_link_libraries(strings PRIVATE c-libs)
+
 include(CTest)
 if(BUILD_TESTING)
   find_package(PkgConfig REQUIRED)

app/strings.c

@@ -0,0 +1,49 @@
+#include "c-libs/dyn-arr.h"
+#include "c-libs/string-view.h"
+#include <ctype.h>
+
+int main() {
+  StringView sv = sv_new("Hello World\n");
+
+  sv_puts(sv);
+  sv_puts(sv_drop(sv_shrink(sv, 3), 2));
+  sv_puts(sv_drop(sv_shrink(sv, 5), 9));
+
+  StringView sv2 = sv_new("AAA Test BBB");
+  sv_puts(sv2);
+  puts("");
+  sv2 = sv_seek(sv2, ' ');
+  sv_puts(sv2);
+  puts("");
+  sv2 = sv_seek_back(sv2, ' ');
+  sv_puts(sv2);
+  puts("");
+
+  StringView csv = sv_new("  100 ,  2000,   10  ,1,871");
+
+  StringView *values = NULL;
+  darr_init(values, 0);
+
+  while (sv_len(csv)) {
+    StringView item = sv_split_at(&csv, ',');
+    darr_push(values, sv_trim(item, isspace));
+  }
+
+  char *all = sv_concat_with_sep(values, darr_size(values), sv_new("::"));
+  puts(all);
+
+  darr_clear(values);
+
+  StringView ccsv = sv_new(all);
+  while (sv_len(ccsv)) {
+    StringView item = sv_split_at_sv(&ccsv, sv_new("::"));
+    darr_push(values, sv_trim(item, isspace));
+  }
+
+  char *all2 = sv_concat_with_sep(values, darr_size(values), sv_new("-+-"));
+  puts(all2);
+
+  free(all);
+  free(all2);
+  darr_free(values);
+}

include/c-libs/string-view.h

@@ -0,0 +1,350 @@
+#ifndef CLIBS_STRING_VIEW_H
+#define CLIBS_STRING_VIEW_H
+
+#include <malloc.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+
+/// A string view consisting of a start pointer _data_
+/// and an end pointer _end_. The end points behind the last character.
+typedef struct {
+  const char *data;
+  const char *end;
+} StringView;
+
+///
+///@brief Get the length of a string view
+///
+///@param StringView sv the string view
+///
+///@return size_t it's length (data - end)
+///
+size_t sv_len(StringView sv);
+
+///
+///@brief Construct a new string view with a data and length specification
+///
+///@param const char *str the string to view (can be non-null-terminated)
+///@param size_t len the length of the string
+///
+///@return StringView the new string view
+///
+StringView sv_new_sized(const char *str, size_t len);
+
+///
+///@brief Construct a new string view from a null-terminated string
+///
+///@param const char *str the null-terminated string
+///
+///@return StringView a new string view {.data = str, .end = str + strlen(str)}
+///
+StringView sv_new(const char *str);
+
+///
+///@brief Drop the first n chars of a string view (non-destructive)
+///
+///@param StringView sv the original sv
+///@param size_t n the number of chars to drop from the beginning
+///
+///@return StringView the resulting sv
+///
+StringView sv_drop(StringView sv, size_t n);
+
+///
+///@brief Get the first n chars of a string view (non-destructive)
+///
+///@param StringView sv the original sv
+///@param size_t n the number of chars to take
+///
+///@return StringView the resulting sv
+///
+StringView sv_take(StringView sv, size_t n);
+
+///
+///@brief Remove the n last chars of a sv (non-destructive)
+///
+///@param StringView sv the original sv
+///@param size_t n the number of chars to remove from the end
+///
+///@return StringView the resulting sv
+///
+StringView sv_shrink(StringView sv, size_t n);
+
+///
+///@brief call _putc_ for each char in the string view
+///
+///@param StringView sv the string view to print
+///
+void sv_puts(StringView sv);
+
+///
+///@brief Remove chars from the front until a specified char is encountered
+///(non-destructive)
+///
+///@param StringView sv the original sv
+///@param char c the char to find
+///
+///@return StringView the resulting string view (may be empty)
+///
+StringView sv_seek(StringView sv, char c);
+
+///
+///@brief Like sv_seek but seeking from end to begin
+///
+///@param StringView sv the original sv
+///@param char c the char to find
+///
+///@return StringView the resulting string view
+///
+StringView sv_seek_back(StringView sv, char c);
+
+///
+///@brief Remove chars from the front matching pred (non-destructive)
+///
+///@param StringView sv the original sv
+///@param int (*pred)(int) the predicate (returns non-zero if char shall be
+/// removed)
+///
+///@return StringView the resulting string view
+///
+StringView sv_trim_front(StringView sv, int (*pred)(int));
+
+///
+///@brief Like sv_trim_front but from end to begin
+///
+///@param StringView sv the original sv
+///@param int (*pred)(int) the predicate (returns non-zero if char shall be
+///
+///@return StringView the resulting string view
+///
+StringView sv_trim_back(StringView sv, int (*pred)(int));
+
+///
+///@brief Effectively sv_trim_front and sv_trim_back
+///
+///@param StringView sv the original sv
+///@param int (*pred)(int) the predicate (returns non-zero if char shall be
+///
+///@return StringView the resulting string view
+///
+StringView sv_trim(StringView sv, int (*pred)(int));
+
+///
+///@brief Split the string view at the first occurance of c. (destructive, sv
+/// will be the "second half" after the split)
+///
+///@param StringView *sv the string view to split at. Will be the part after the
+/// first _c_ if no c found this is empty.
+///@param char c the character to split at
+///
+///@return StringView the part before _c_, of no _c_ found this will be equal to
+/// sv
+///
+StringView sv_split_at(StringView *sv, char c);
+
+///
+///@brief Check of two string_views have equal contents
+///
+///@param StringView a
+///@param StringView b
+///
+///@return int non-zero if a is equal to b
+///
+int sv_eq(StringView a, StringView b);
+
+///
+///@brief Like sv_split_at but using sep as a separator (destructive)
+///
+///@param StringView *sv the string to split. Will contain the second half (can
+/// be empty if no sep found)
+///@param StringView sep
+///
+///@return StringView will be the first half (can be equal to sv, if no sep
+/// found)
+///
+StringView sv_split_at_sv(StringView *sv, StringView sep);
+
+///
+///@brief Create a null-terminated string from the sv, by copying the contents.
+/// Must be freed
+///
+///@return char the new c-string, must be freed
+///
+char *sv_clone(StringView sv);
+
+///
+///@brief Concatenate a list of string views with a separator. The result must
+///be freed
+///
+///@return char a null-terminated string containing all svs separated with sep.
+///Must be freed
+///
+char *sv_concat_with_sep(const StringView *svs, size_t n, StringView sep);
+
+#endif
+
+#ifdef CLIBS_STRING_VIEW_IMPL
+
+size_t sv_len(StringView sv) { return sv.end - sv.data; }
+
+StringView sv_new_sized(const char *str, size_t len) {
+  return (StringView){
+      .data = str,
+      .end = str + len,
+  };
+}
+
+StringView sv_new(const char *str) { return sv_new_sized(str, strlen(str)); }
+
+StringView sv_drop(StringView sv, size_t n) {
+  return (StringView){
+      .data = sv.data + n,
+      .end = sv.end,
+  };
+}
+
+StringView sv_take(StringView sv, size_t n) {
+  return (StringView){
+      .data = sv.data,
+      .end = sv.data + n < sv.end ? sv.data + n : sv.end,
+  };
+}
+
+StringView sv_shrink(StringView sv, size_t n) {
+  return (StringView){
+      .data = sv.data,
+      .end = sv.end - n,
+  };
+}
+
+void sv_puts(StringView sv) {
+  while (sv.data < sv.end) {
+    putc(*sv.data++, stdout);
+  }
+}
+
+StringView sv_seek(StringView sv, char c) {
+  while (sv.data < sv.end && *sv.data != c) {
+    sv.data++;
+  }
+
+  return sv;
+}
+
+StringView sv_seek_back(StringView sv, char c) {
+  while (sv.data < sv.end && *(sv.end - 1) != c) {
+    sv.end--;
+  }
+
+  return sv;
+}
+
+StringView sv_trim_front(StringView sv, int (*pred)(int)) {
+  while (sv.data < sv.end && pred(*sv.data)) {
+    sv.data++;
+  }
+
+  return sv;
+}
+
+StringView sv_trim_back(StringView sv, int (*pred)(int)) {
+  while (sv.data < sv.end && pred(*(sv.end - 1))) {
+    sv.end--;
+  }
+
+  return sv;
+}
+
+StringView sv_trim(StringView sv, int (*pred)(int)) {
+  return sv_trim_front(sv_trim_back(sv, pred), pred);
+}
+
+StringView sv_split_at(StringView *sv, char c) {
+  StringView current = *sv;
+
+  while (sv->data < sv->end && *sv->data != c) {
+    sv->data++;
+  }
+
+  // Remove sep, current is the first part, sv the second
+  if (sv->data < sv->end) {
+    current.end = sv->data++;
+  }
+
+  return current;
+}
+
+int sv_eq(StringView a, StringView b) {
+  if (sv_len(a) != sv_len(b)) {
+    return 0;
+  }
+
+  while (a.data < a.end) {
+    if (*a.data != *b.data) {
+      return 0;
+    }
+
+    a.data++;
+    b.data++;
+  }
+
+  return 1;
+}
+
+StringView sv_split_at_sv(StringView *sv, StringView sep) {
+  StringView current = *sv;
+  size_t sep_len = sv_len(sep);
+
+  while (sv->data < sv->end && !sv_eq(sv_take(*sv, sep_len), sep)) {
+    sv->data++;
+  }
+
+  // Remove sep, current is the first part, sv the second
+  if (sv_len(*sv) >= sep_len) {
+    current.end = sv->data;
+    sv->data += sep_len;
+  } else {
+    sv->data = sv->end;
+  }
+
+  return current;
+}
+
+char *sv_clone(StringView sv) {
+  size_t n = sv_len(sv) + 1;
+  char *data = malloc(n);
+
+  data[n - 1] = 0;
+  memcpy(data, sv.data, n - 1);
+
+  return data;
+}
+
+char *sv_concat_with_sep(const StringView *svs, size_t n, StringView sep) {
+  size_t len = 1; // Reserve nullterminator
+  size_t sep_len = sv_len(sep);
+
+  for (int i = 0; i < n; i++) {
+    len += sv_len(svs[i]);
+  }
+  len += sep_len * (n - 1);
+
+  char *data = malloc(len);
+  char *write_head = data;
+
+  for (int i = 0; i < n; i++) {
+    if (i > 0) {
+      memcpy(write_head, sep.data, sep_len);
+      write_head += sep_len;
+    }
+
+    size_t l = sv_len(svs[i]);
+    memcpy(wri
+    write_head += l;
+  }
+
+  return data;
+}
+
+#endif

src/string-view.c

@@ -0,0 +1,2 @@
+#define CLIBS_STRING_VIEW_IMPL
+#include "c-libs/string-view.h"