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xo-indentlog: add general-purposee pretty-printing [WIP]

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This commit is contained in:
Roland Conybeare 2025-07-13 21:17:13 -05:00
commit 28172fc3d6
24 changed files with 1326 additions and 121 deletions
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129
include/xo/indentlog/log_streambuf.hpp
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@ -2,6 +2,7 @@
#pragma once
#include "print/quoted_char.hpp"
#include <iostream>
#include <vector>
#include <cstring> // e.g. for std::memcpy()
@ -9,13 +10,14 @@
#include <cassert>
namespace xo {
/* recycling buffer for logging.
* write to self-extending storage array;
*/
template <typename CharT, typename Traits>
/** recycling buffer for logging and pretty-printing
* - write to self-extending storage array
* - track position relative to start of line
**/
template <typename CharT, typename Traits = std::char_traits<CharT>>
class log_streambuf : public std::streambuf {
public:
log_streambuf(std::uint32_t buf_z) {
log_streambuf(std::uint32_t buf_z, bool debug_flag = false) : debug_flag_{debug_flag} {
this->buf_v_.resize(buf_z);
this->reset_stream();
} /*ctor*/
@ -25,40 +27,93 @@ namespace xo {
char const * hi() const { return this->lo() + this->capacity(); }
std::uint32_t pos() const { return this->pptr() - this->pbase(); }
/** number of characters since start of line (last \n or \r) **/
std::uint32_t lpos() const { return pos() - solpos_; }
bool debug_flag() const { return debug_flag_; }
void reset_stream() {
char * p_lo = &(this->buf_v_[0]);
char * p_hi = p_lo + this->capacity();
/* tells parent our buffer extent */
this->setp(p_lo, p_hi);
this->solpos_ = 0;
} /*reset_stream*/
void rewind_to(std::uint32_t p) {
/* .setp(): using for side effect: sets .pptr to .pbase */
this->setp(this->pbase(), this->epptr());
this->pbump(p);
}
protected:
/** expand buffer storage (by 2x), preserve current contents **/
void
expand_to(std::size_t new_z) {
char * old_pptr = pptr();
std::streamsize old_n = old_pptr - pbase();
assert(old_n <= static_cast<std::streamsize>(buf_v_.size()));
assert(new_z > buf_v_.capacity());
this->buf_v_.resize(new_z);
char * p_base = &(this->buf_v_[0]);
char * p_hi = p_base + this->buf_v_.capacity();
this->setp(p_base, p_hi);
this->pbump(old_n);
} /*expand*/
virtual std::streamsize
xsputn(char const * s, std::streamsize n) override {
/* s must be an address in [this->lo() .. this->lo() + capacity()] */
assert(this->hi() >= this->pptr());
assert(hi() >= pptr());
#ifdef NOT_USING_DEBUG
std::cout << "xsputn: pbase=" << (void *)(this->pbase())
<< ", pptr=" << (void*)(this->pptr())
<< "(+" << (this->pptr() - this->lo()) << ")"
<< ", n=" << n << " -> (+" << (this->pptr() + n - this->lo()) << ")"
<< ", buf_v.size=" << this->buf_v_.size()
<< std::endl;
#endif
//std::cout << "xsputn: s=" << quot(string_view(s, n)) << ", n=" << n << std::endl;
if (pptr() + n > hi()) {
this->expand_to(std::max(2 * this->buf_v_.capacity(), std::size_t(this->pos() + n + 1)));
}
if (debug_flag_) {
std::cout << "xsputn: pbase=" << (void *)(this->pbase())
<< ", pptr=" << (void*)(this->pptr())
<< "(+" << (this->pptr() - this->lo()) << ")"
<< ", n=" << n << " -> (+" << (this->pptr() + n - this->lo()) << ")"
<< ", buf_v.size=" << this->buf_v_.size()
<< std::endl;
}
std::streamsize ncopied = 0;
if (this->pptr() + n > this->hi()) {
n = this->hi() - this->pptr();
std::memcpy(this->pptr(), s, n);
ncopied = this->hi() - this->pptr();
} else {
std::memcpy(this->pptr(), s, n);
ncopied = n;
}
this->pbump(n);
return n;
if (debug_flag_) {
std::cout << "xsputn: copying ncopied=" << ncopied << " (/n=" << n << ") bytes into range [lo,hi)"
<< ", lo=" << (void*)this->pptr()
<< ", hi=" << (void*)(this->pptr() + n)
<< std::endl;
}
std::memcpy(this->pptr(), s, ncopied);
/* scan range [pptr, pptr+n] backwards, to account for newline (if any) */
for (char const * p_lo = this->pptr(), * p_hi = p_lo + n - 1, * p = p_hi; p >= p_lo; --p) {
if (*p == '\n' || *p == '\r') {
this->solpos_ = (p+1 - this->pbase());
break;
}
}
this->pbump(ncopied);
return ncopied;
} /*xsputn*/
virtual int_type
@ -69,25 +124,31 @@ namespace xo {
assert(old_n <= static_cast<std::streamsize>(this->buf_v_.size()));
std::size_t new_z = 2 * this->buf_v_.size();
if (debug_flag_) {
std::cout << "overflow: new_ch=" << quoted_char(new_ch) << std::endl;
}
this->expand_to(2 * buf_v_.size());
this->buf_v_.resize(new_z);
this->buf_v_[old_n] = new_ch;
this->pbump(1);
/* 'buffered range' will now be .buf_v[old_n .. new_z] */
char * p_base = &(this->buf_v_[0]);
//char * p_lo = &(this->buf_v_[old_n+1]);
char * p_hi = p_base + this->buf_v_.capacity();
if ((new_ch == static_cast<int_type>('\n')) || (new_ch == static_cast<int_type>('\r')))
this->solpos_ = this->pos();
this->setp(p_base, p_hi);
this->pbump(old_n + 1); /*see 'this->buf_v_[old_n] - new_ch' above*/
return new_ch;
if (new_ch == Traits::eof()) {
/* reminder: returning eof sets badbit on ostream */
return Traits::not_eof(new_ch);
} else {
return new_ch;
}
} /*overflow*/
/* off. offset, relative to starting point dir.
* dir.
* which. in|out|both
*
* Note that off=0,dir=cur,which=out reads offset
*/
virtual pos_type seekoff(off_type off,
std::ios_base::seekdir dir,
@ -114,8 +175,14 @@ namespace xo {
} /*seekoff*/
private:
/* buffered output stored here */
/** position (relative to pbase) one character after last \n or \r.
* Use to drive @ref lpos
**/
std::size_t solpos_ = 0;
/** buffered output stored here **/
std::vector<char> buf_v_;
/** true to debug log_streambuf itself **/
bool debug_flag_ = false;
}; /*log_streambuf*/
} /*namespace xo*/